Paleo-health of Neolithic wet-rice farmers in the Yangtze River Delta: a comparison with early millet farmers in northern China

Abstract

Several cases that do not fit the agricultural adaptation model, in which people’s health deteriorated with the shift from hunting-gathering to farming, have been reported, such as the introduction of rice agriculture during the Yayoi Period in Japan and the Iron Age in Southeast Asia, where health was maintained or improved. However, the health of rice farmers in the homeland areas has rarely been reported. This study aims to clarify the frequency and degree of stress markers inscribed on Neolithic human bones in the Yangtze River Delta, one of the origins of rice agriculture, and to elucidate the state of adaptation when humans first engaged in rice agriculture. The materials of this study are the Early Neolithic site of Majiabang, and the Late Neolithic sites of Guangfulin and Jiangzhuang. Several millet farming groups in northern China were used as comparative materials. The results show that the Neolithic rice farming groups in the Yangtze River Delta generally had a higher frequency of stress markers than the millet farming groups in northern China. In particular, the Late Neolithic Guangfulin assemblage had higher frequencies, while the Early Neolithic Majiabang assemblage tended to have relatively low frequencies of porotic hyperostosis and cribra orbitalia. These results suggest that people’s health deteriorated in the Late Neolithic period, when the scale of paddy rice cultivation expanded, as a result of the new subsistence activities and rice-oriented diet.

Introduction

Archaeological data suggest that there were at least five regions in the world where the subsistence strategy independently changed from hunting and gathering to agriculture without outside influences (cf. Bellwood, 2005). In East Asia, the Yangtze River Delta, one of these regions of agricultural origins, is the best understood homeland zone of wet-rice domestication based on archaeological evidence from Early Neolithic sites such as Shangshan (上山), Kuahuqiao (跨湖橋), Hemudu (河姆渡), and Tianluoshan (田螺山) (Zong et al., 2007; Fuller et al., 2009). The following two events in the Yangtze Delta suggest that wet-rice agriculture had already produced increased population density and active population movements by the Middle Neolithic at the latest. First, urbanization developed in the Middle Neolithic at Yangtze sites such as the Liangzhu (良渚) site complex (Renfrew and Liu, 2018). Secondly, spinal tuberculosis is present in the Yangtze Delta during Middle Neolithic times, probably representing the earliest evidence of tuberculosis in East Asia (Okazaki et al., 2019). This finding supports the above-mentioned circumstances because Mycobacterium tuberculosis thrives in specific social environments, such as those with relatively high population density and active inter-group movements such as migration (Roberts, 2012). Morphometric analyses of the crania of Middle Neolithic wet-rice farmers also shows that wet-rice agricultural technologies had spread to surrounding regions in the context of substantial intercourse between the Yangtze Delta and northern China (Okazaki et al., 2021).

The results of many bioarchaeological studies show a general global decline in health accompanying the adoption of agriculture and associated trends such as sedentism and increased population density and migration (Cohen and Armelagos, 1984; Larsen, 1997; Cohen and Crane-Kramer, 2007). The frequencies of oral diseases (dental caries, antemortem tooth loss, dental abscess, and alveolar resorption) and physical stress markers (e.g. enamel hypoplasia, porotic hyperostosis, cribra orbitalia) increased with intensifying agriculture in most cases, in particular in North and South America (south-central United States (Georgia/Florida, North Carolina), Mexico, Peru, Chile). However, variation in the pattern of health changes is still significant between regions and time periods. The most exceptional cases have been reported from prehistoric wet-rice farmers in Thailand and Japan, where frequencies of physical stress markers remained unchanged or even decreased, and subadult growth remained satisfactory with the adoption of wet-rice agriculture, although oral diseases partly increased (Domett and Tayles, 2007; Douglas and Pietrusewsky, 2007; Temple, 2010; Okazaki, 2013). What factors contributed to the irregular pattern of health changes observed in these wet-rice farmers is debated, with relevant issues including the characteristics of rice and differences in the process of intensifying agriculture among regions and periods (Cohen and Crane-Kramer, 2007). The following possible factors have been suggested: (1) brown rice is not only originally rich in nutrition but also easily stored (Domett and Tayles, 2006); (2) sedentism was already advanced before the adoption of agriculture in Japan (Okazaki, 2013); and (3) the people in Thailand and Japan adopted a mature form of wet-rice technology since there was a time lag in the spread of rice farming between the core and surrounding areas in both regions (Temple, 2010). However, it is necessary to clarify the health conditions of prehistoric people in the core area of wet-rice agriculture in order to understand variations in human adaptations to farming and examine if the time lag explanation is possible. The aim of this study is to report the frequencies and degree of stress markers from Neolithic skeletal samples unearthed in the Yangtze Delta, China. The results of this study are expected to increase our understanding of the background of early human adaptation to wet-rice agriculture.

Materials and Methods

The skeletal samples mainly targeted in this study are composed of three assemblages of Neolithic wet-rice farmers from the Yangtze Delta (Table 1). Two of the three assemblages stem from Middle Neolithic sites: Guangfulin (広富林) (Songze and Liangzhu culture) in Shanghai City and Jiangzhuang (蒋庄) (Liangzhu culture) in Jiangsu province. The third is from the Majiabang (馬家浜) site (Majiabang culture, c. 5000–4000 BCE) of Zhejiang province dated to the Early Neolithic (Figure 1). Additionally, the following skeletal samples of early millet farmers in northern China are used for comparison: Middle Neolithic Jiangjialiang (姜家梁) group in Hebei province, Early Neolithic Beiqian (北阡) group in Shandong province, Eastern Zhou dynasty Xinghong (興弘) group in Henan province, Eastern Zhou dynasty Tuchengzi (土城子) group in Inner Mongolia, and Sixteen Kingdoms Lamadong (喇嘛洞) in Liaoning province (Table 1).

Table 1.

The human skeletal materials used in this study

Groups		Regions	Date	Periods	Cereal1	References2
Majiabang	馬家浜	Zhejiang	c. 4350–3980 cal BCE	Majiabang culture	Rice	Okazaki and Takamuku (2019), ZPICRA and JM (2019)
Guangfulin	広富林	Shanghai	c. 3338–2670 cal BCE	Songze - Liangzhu culture	Rice	Chen et al. (2007), Okazaki et al. (2019, 2021)
Jiangzhuang	蒋庄	Jiangsu	c. 2860–2480 cal BCE	Liangzhu culture	Rice	Nanjing Museum (2016), Zhu (2018)
Beiqian	北阡	Shandong	c. 4300–4000 BCE	Early Dawenkou culture	Millet	Nakahashi et al. (2013), Okazaki and Luan (2013)
Jiangjialiang	姜家梁	Hebei	c. 2207–2163 BCE	Longshan culture	Millet	Okazaki et al. (2013)
Xinghong	興弘	Henan	771–221 BCE	Eastern Zhou dynasty	Millet and wheat	Nakahashi (2014), Okazaki et al. (2016)
Tuchengzi	土城子	Inner Mongolia	771–206 BCE	Eastern Zhou and Qin dynasty	Millet	Okazaki et al. (2016)
Lamadong	喇嘛洞	Liaoning	289–370 ADE	Sixteen Kingdoms	Millet	Okazaki et al. (2013)

¹ Archaeologically and stable-isotopically estimated main cereals are indicated here for these assemblages.

² The sources for the related information on the site and human skeletal material.

Abbreviations: ZPICRA, Zhejiang Provincial Institute of Cultural Relics and Archaeology; JM, Jiaxing Museum.

Figure 1.

The location of the archaeological sites

Guangfulin site

The site is located on the flatlands of the Songjiang District of Shanghai City. The site is approximately 60 km east of one of the five major lakes in China, Lake Tai, and nearly 100 km east-northeast of the Liangzhu site complex (Figure 1). The excavations were carried out between 1999 and 2015, ultimately resulting in the recovery of more than 300 human skeletal individuals (Archaeological Department of Shanghai Museum, 2002, 2008). The skeletal materials considered in this study stem from the human skeletal remains excavated at the Guangfulin site in 2010. These skeletal remains date to the Songze (c. 3900–3200 BCE) and Liangzhu (c. 3200–2400 BCE) cultural periods, based on a combination of archaeological evidence, including stratigraphy and analysis of associated burial goods, as well as radiocarbon dating (5305 ± 130 and 4690 ± 150 cal BP) of carbonized material recovered from the Songze and Liangzhu layers, respectively (Chen et al., 2007; Okazaki et al., 2019, 2021).

Guangfulin is a cemetery site and associated residential or agricultural field remains have not yet been detected. However, given the location and date of the site, it is probable that the Guangfulin population was engaged in rice farming. The archaeological site report for Guangfulin is currently in preparation under the supervision of one of the present authors (J.C.). Soil flotation has confirmed the presence of carbonized rice, gourd, melon, prickly waterlily, water chestnut, peach, and Japanese plum, and evidence for hunting of deer, wild boar or pig, crocodile, crane, wild goose, and elephant is also present. Although detailed analyses have yet to be completed, these plants and animals may also have been used to provision the larger Liangzhu site complex (Nakamura, 2015; Liu et al., 2017), which may represent the beginnings of an early state. The Liangzhu site complex shows evidence of urbanization including: ramparts surrounding the area and waterways connecting to river networks; the construction of dams, evidenced by the presence of sandbags; apparent specialization of labor dedicated to the production of elaborate jade goods; and remains of a granary that could have contained up to 15 tons of rice grain.

Majiabang site

The site is located on the flatland of Jiaxing City in north Zhejiang, the midpoint on the road between the Guangfulin and Liangzhu sites mentioned above. The first excavation was conducted in 1959, the results of which determined the relative dating of sites in the circum-Lake Tai region: Majiabang, Songze, and Liangzhu in that order (cf. Zhejiang Provincial Institute of Cultural Relics and Archaeology (ZPICRA) and Jiaxing Museum (JM), 2019). The second excavation was done during 2009 and 2011, and a total of 80 hole-shaped graves were detected (ZPICRA and JM, 2019). Some of these had wooden plates laid on the bottom and were possibly originally wooden coffin tombs. These tombs were positioned closely together and most of them were partly destroyed by each other at the time of construction. Most of the burial postures were in the prone position with the legs extended (N = 54), a style which characterized the Majiabang culture, while the supine position with extended legs (N = 11) and lateral position with flexed legs (N = 4) also existed in a few cases (ZPICRA and JM, 2019). There are 132 burial goods unearthed from 54 tombs, comprising 66 pots, 60 bone instruments, 4 jades, and 2 stone tools, as well as 54 animal bones. The date of burial is confirmed as the Late Majiabang culture according to the types of burial goods and radiocarbon dating using carbonized plant and wooden funeral accessories (4350 (81.9%) 4220 cal BCE and 4240 (95.4%) 3980 cal BCE) (ZPICRA and JM, 2019).

The ratio of carbonized rice, prickly waterlily, and water chestnuts in that order is the highest among the plant remains found by soil flotation in and around the site (ZPICRA and JM, 2019). The results of phytolith analyses from coring surveys at 71 points at 20-m to 40-m intervals around the site suggest the existence of a paddy-field farming layer in the Majiabang cultural stage (ZPICRA and JM, 2019). The species identification and the minimum numbers of individuals for animal bones unearthed in and around the site show that the number of mammals (e.g. various large and small deer, buffalo, wild boar) is the largest, and fishes (e.g. carp and northern snakehead) is the second largest, as well as a certain number of Testudines (ZPICRA and JM, 2019). The results of carbon stable isotope analysis using tooth enamel show little input of C4 plants (ZPICRA and JM, 2019). Accordingly, wet-rice agriculture is thought to have become a main subsistence activity for the people in the site at least by the late Majiabang culture, while hunting, fishing, and gathering aquatic plants such as prickly waterlily and water chestnuts still held an important position in their life.

Jiangzhuang site

The site is located on a plain surrounded by canals at the border between the cities of Dongtai and Xinghua in Jiangsu province in the north Yangtze Delta region. In total, 284 graves, 8 house remains, and 100 pits were excavated (Nanjing Museum, 2016). The graves were placed closely together and some of them (N = 80) partly destroyed each other at the time of construction. The burial styles were varied and can be categorized into burying (possible first funeral) and reburying (second funeral). The first one was usually of a single individual in supine position with extended legs while the second one includes multiple individuals and sometimes the collection of bones after cremation. The burial goods that accompanied reburial usually included jade bi (璧) or jade cong (琮), thought to be symbols of divine power, while those with only primary burials contained little or no jade. These graves are interpreted as tombs of aristocrats and commoners, respectively, by local archaeologists. The jade products exhibit no differences with those unearthed in the Liangzhu site complex, demonstrating that the Liangzhu culture ranged across the Yangtze River to the north. In contrast, the ceramics, in particular their bases, display local characteristics (S. Nakamura, personal communication). Some of the tombs contain single wooden coffins (独木棺), which are classified into flat and curved bottom types. The date of the burials was estimated as the Liangzhu culture based on types of burial goods and supported by radiocarbon dating using bone collagen (four dates mostly converged into the range of 2860–2480 cal BCE; Itahashi et al., unpublished data).

A large quantity of seeds and animal bones was detected from the pits around the cemetery. Most of the seeds were carbonized rice, prickly waterlily, and water chestnuts, and the animal bones mainly included deer, boar, dog, water buffalo, as well as aquatic animals such as fish and turtles (Nanjing Museum, 2016). The ratio of the minimum number of individuals for these identified spieces is unknown because analysis is still in progress. The results of carbon and nitrogen stable isotope analysis using bone collagen show little or no contribution from the intake of C4 plants and marine resources (δ¹³ C_col value = –20.0 ± 0.5‰, δ¹⁵ N_col value = 10.1 ± 0.7‰ on average; Itahashi et al., unpublished data). Therefore, the main diet was C3 plants, probably rice, and terrestrial animals such as deer and boar.

Adult age at death and biological sex

The age at death and the sex of the Guangfulin individuals were estimated using standard morphological observations of the cranium and os coxae (Buikstra and Ubelaker, 1994; White and Folkens, 2005). Biological sex was assessed by direct examination of diagnostic features of the sexually dimorphic hip bone (Phenice, 1969; Bruzek, 2002; Walker, 2005; Takahashi, 2006). Age at death was estimated based on age-related changes in the pubic symphysis (Todd, 1920; Hanihara, 1952; Sakaue, 2006) and the auricular surface morphology (Lovejoy et al., 1985; Buckberry and Chamberlain, 2002; Igarashi et al., 2005). When the hip bone was unavailable, assessment of biological sex followed metric assessment of postcranial bones (Nakahashi and Nagai, 1986) and cranial features (Buikstra and Ubelaker, 1994). Estimation of age at death was based on evaluation of the degree of obliteration of cranial sutures if the hip bone was not preserved (Meindl and Lovejoy, 1985; Sakaue, 2015).

Subadult age at death

Subadult age at death was principally estimated using standards on tooth formation and eruption, but for individuals thought to be older than 13 years, priority was given to skeletal epiphysis closure (cf. Okazaki, 2010). Because the sexing of subadult skeletal remains is problematic, no attempt was made to divide the sample groups according to sex.

Linear enamel hypoplasia

Incremental growth lines, called perikyma, similar to annual rings of trees, can be observed on the surface of tooth enamel (a line forms in 6–12 days). Perikyma are usually very faint by macroscopic observation, but sometime becomes prominent as linear grooves or pits in a row due to temporary disturbance of their formation. These stress markers are defined as linear enamel hypoplasia (LEH). The frequencies and degrees of LEH in incisors and canines are examined in this study because previous studies have reported that LEH is easily observed on the surface of these teeth (Goodman and Rose, 1990).

LEH defects are thought to be generally caused by body-wide physiological insults sufficient to disrupt ameloblastic activity (e.g. malnutrition, chronic diarrhea, infectious diseases, metabolic disorder) and local ones such as trauma in very rare cases. In Mexico, people with adequate nutritional supplementation during tooth formation had lower LEH frequency compared with those without it (Goodman et al., 1991). In China, people who had spent their childhoods during the 1959–1961 famine had a higher LEH frequency than those of other generations (Zhou and Corruccini, 1998). If LEH is utilized as a proxy for physiological insult, antimeric calculation is better because systemic factors theoretically produce LEH on bilateral teeth (Temple, 2010). Therefore, LEH on unilateral teeth is not counted as affected except in cases where the opposite tooth is lost. This manner of calculation is reasonable for increasing sample size because the ratio of postmortem tooth loss is relatively high for incisors in parts of the samples in this study.

For macroscopic observation, we shone a light on the tooth crown vertically to the occlusal surface using a desk or portable light to accentuate the roughness of the labial surface as necessary. When it was difficult to differentiate LEH and normal growth lines because the line was so faint, K.O. examined the existence of furrows by feeling with a dental pick and compared the line to the adjacent one by use of a magnifying glass (10×). Teeth were excluded from the study when wear reduced more than half of the crown height. The LEH prevalence in this manner could represent a minimum estimate (cf. Temple, 2010).

Porotic hyperostosis and cribra orbitalia

Porotic hyperostosis (PH) and cribra orbitalia (CO) are two stress markers, forming pitting and porosity on the external surface of the cranium vault and orbital roofs, respectively. These lesions could result in a sieve-like formation due to the expansion and exposure of the internal spongy bone in response to marrow hypertrophy when this is severe. These lesions are relatively common in ancient human crania and are traditionally thought to be associated with iron deficiency or hereditary anemia (e.g. thalassemia and sicklemia) (cf. Walker et al., 2009).

Recent studies suggest that megaloblastic and hemolytic anemia are more appropriate factors for these lesions, which are caused by vitamin B12 or folic acid deficiency although iron-deficiency anemia is also a possible factor (Walker et al., 2009; Oxenham and Cavill, 2010). Vitamin B12 is absorbed and incorporated into body tissue mainly by intaking animal protein. Vitamin B12-deficiency anemia such as megaloblastic anemia therefore often becomes an issue among people who mostly do not consume animal protein (e.g. vegans and vegetarians) if they do not use nutritional supplements (cf. Walker et al., 2009). The impact on mothers and infants during suckling might become significant if they both share the nutrients of vitamin B12 by breast-feeding. It could be also dangerous for the infants during weaning since they are sensitive to diarrhea from insanitary conditions, which can accelerate the loss of vitamin B12 or folic acid from the body.

Except for marrow hypertrophy induced by vitamin B12-deficiency anemia, subperiosteal bleeding associated with nutritional deficiency such as scurvy and rickets, induced by vitamin C deficiency and vitamin D deficiency, respectively, are also factors contributing to these lesions (Ortner, 2003; Walker et al., 2009). However, the latter could be excluded here because there is sufficient sunshine to prevent vitamin D deficiency in the Yangtze River Delta. Trachoma, an infectious disease in the eye caused by Chlamydia trachomatis, is also a possible factor contributing to these lesions (Webb, 1990).

For macroscopic observation, the existence of the lesions was confirmed and was classified into three degrees according to the standard criteria of Buikstra and Ubelaker (1994): mild, pitting is sparse (Buikstra and Ubelaker degree score 1); moderate, pitting is dense or for CO pitting is distributed loosely throughout half of the orbital roof (Buikstra and Ubelaker degree score 2–3); severe, pitting is followed by increased spongy bone (Buikstra and Ubelaker degree score 4). It should be noted that factors contributing to the severe lesions are some form of anemia, while the factors of the mild or moderate lesions are indistinguishable from other non-specific disorders such as scurvy and rickets (Ortner, 2003; Pechenkina et al., 2007). The samples observed for PH in this study were defined as preserved on one side of parietal bones at least because PH usually appears adjacent to the cranial sutures of the lambdoid, sagittal, and coronal. The samples observed for CO in this study were defined as preserved on one side of orbital roofs with over one-third of the area, including lacrimal fossa. Both frequencies were calculated as follows: the number of affected individuals was divided by the total number of observed individuals.

These frequency data were calculated for age, biological sex, and group using Excel (Microsoft), and were statistically examined by Pearson’s chi-squared test using the computer program package SPSS 24 (IBM).

Results

Frequencies of stress markers are generally higher in subadults, especially infants, compared with adults. Numbers of subadults are small and the ratio of each age cohort varies among the three assemblages in this study. The frequencies here were therefore calculated using individuals aged over 12 years, which were classified into two age groups of young adults (12–35 years) and old adults (over 35 years).

Linear enamel hypoplasia

Table 2 shows the LEH frequencies in the segments of maxillary first incisor (MxFI), maxillary canine (MxC), and mandibular canine (MnC). For age, the trend of the pattern of difference between both age cohorts is varied among the Neolithic and Dynastic assemblages, but the frequency of MxC was significantly higher in young adults than old adults in Lamadong (17.0% versus 5.6%, P = 0.045). For biological sex, the trend of the pattern of difference between males and females is also not constant among the assemblages, but the frequency of MxC was higher in males than females in Jiangzhuang (54.5% versus 12.5%, P = 0.008). Figure 2 shows that wet-rice farmers generally had higher frequencies of LEH than millet farmers. The frequencies of all three tooth segments were significantly higher in Guangfulin than Jiangjialiang (MxFI, 50.0% versus 14.7%, P = 0.003; MxC, 60.0% versus 28.6%, P = 0.004; MnC, 74.2% versus 50.0%, P = 0.027, Table 2). Majiabang (MxFI, 57.1% versus 14.7%, P = 0.014; MnC, 88.9% versus 50.0%, P = 0.029) and Jiangzhuang (MxFI, 47.4% versus 14.7%, P = 0.010) also had significantly higher frequencies of MxFI and MnC compared with Jiangjialiang, respectively (Table 2). Furthermore, the ratio of teeth with multiple defect lines to those with single defect lines was generally larger in wet-rice farming groups, especially in Guangfulin, compared with millet farming groups (Table 3, Figure 3).

Table 2.

The frequencies of linear enamel hypoplasia by age, biological sex, and assemblage

	Guangfulin				Majiabang				Jiangzhuang				Beiqian					Jiangjialiang					Xinghong					Tuchengzi					Lamadong
	LEH	Observed	%		LEH	Observed	%		LEH	Observed	%		LEH	Observed	%			LEH	Observed	%			LEH	Observed	%			LEH	Observed	%			LEH	Observed	%
Young
MxC	12	22	54.5		4	9	44.4		13	29	44.8		0	3	0.0			7	32	21.9			10	32	31.3			13	39	33.3			16	94	17.0
MxFI	11	20	55.0		2	4	50.0		7	13	53.8		0	4	0.0			2	23	8.7			4	21	19.0			3	22	13.6			7	57	12.3
MnC	14	18	77.8		5	6	83.3		17	28	60.7		3	10	30.0			13	29	44.8			17	28	60.7			15	35	42.9			25	107	23.4
Old
MxC	4	6	66.7		2	4	50.0		4	12	33.3		0	4	0.0			9	24	37.5			10	27	37.0			9	41	22.0			3	54	5.6
MxFI	2	7	28.6		1	2	50.0		2	6	33.3		0	3	0.0			3	11	27.3			4	18	22.2			1	26	3.8			0	26	0.0
MnC	7	10	70.0		2	2	100.0		4	11	36.4		2	11	18.2			17	31	54.8			13	27	48.1			21	50	42.0			11	65	16.9
Male
MxC	6	10	60.0		4	8	50.0		12	22	54.5		1	5	20.0			12	32	37.5			9	22	40.9			10	38	26.3			7	57	12.3
MxFI	6	13	46.2		2	3	66.7		5	12	41.7		1	6	16.7			4	21	19.0			3	13	23.1			1	21	4.8			1	32	3.1
MnC	8	12	66.7		4	4	100.0		15	23	65.2		6	17	35.3			15	31	48.4			12	23	52.2			19	41	46.3			13	68	19.1
Female
MxC	10	16	62.5		1	3	33.3		2	16	12.5		0	2	0.0			4	23	17.4			9	32	28.1			12	40	30.0			9	73	12.3
MxFI	8	13	61.5		2	4	50.0		3	6	50.0		0	1	0.0			1	12	8.3			4	22	18.2			3	26	11.5			5	40	12.5
MnC	14	17	82.4		2	3	66.7		6	15	40.0		0	8	0.0			15	28	53.6			14	28	50.0			16	41	39.0			18	86	20.9
Total
MxC	18	30	60.0		7	14	50.0		17	42	40.5		1	8	12.5	*		16	56	28.6	**		21	60	35.0	*		22	80	27.5	**		25	167	15.0	**
MxFI	14	28	50.0		4	7	57.1		9	19	47.4		1	8	12.5			5	34	14.7	**		8	40	20.0	**		4	48	8.3	**		8	90	8.9	**
MnC	23	31	74.2		8	9	88.9		23	41	56.1		6	26	23.1	**		30	60	50.0	*		32	57	56.1			36	86	41.9	**		42	189	22.2	**

The names of the groups (sites) are in bold face for wet-rice farmers.

Significance is set at P < 0.05. Significant probabilities between young and old or male and female are in bold face.

Significant probabilities between Guangfulin and each other assemblage are indicated by asterisks (*P < 0.05, **P < 0.01).

Figure 2.

Comparison of the prevalence of linear enamel hypoplasia between early wet-rice and millet farmers. The names of the groups (sites) are highlighted by asterisks for wet-rice farmers.

Table 3.

The proportion of stress markers among different severity levels

	Group	Guangfulin				Majiabang				Jiangzhuang				Beiqian				Jiangjialiang
	Grade	Single	Multiple			Single	Multiple			Single	Multiple			Single	Multiple			Single	Multiple
Linear enamel hypoplasia	N	35	38			15	11			55	30			—	—			55	15
	%	47.9	52.1			57.7	42.3			64.7	35.3			—	—			78.6	21.4
	Grade	Small	Moderate	Large		Small	Moderate	Large		Small	Moderate	Large		Small	Moderate	Large		Small	Moderate	Large
Cribra orbitalia	N	10	3	1		1	0	0		6	2	0		4	1	0		15	1	0
	%	71.4	21.4	7.1		100.0	0.0	0.0		75.0	25.0	0.0		80.0	20.0	0.0		93.8	6.3	0.0
Porotic hyperostosis	N	10	1	0		2	0	0		6	1	0		2	0	0		8	2	0
	%	90.9	9.1	0.0		100.0	0.0	0.0		85.7	14.3	0.0		100.0	0.0	0.0		80.0	20.0	0.0
	Group	Xinghong				Tuchengzi				Lamadong
	Grade	Single	Multiple			Single	Multiple			Single	Multiple
Linear enamel hypoplasia	N	65	13			64	13			92	11
	%	83.3	16.7			83.1	16.9			89.3	10.7
	Grade	Small	Moderate	Large		Small	Moderate	Large		Small	Moderate	Large
Cribra orbitalia	N	8	2	0		12	1	0		44	8	0
	%	80.0	20.0	0.0		92.3	7.7	0.0		84.6	15.4	0.0
Porotic hyperostosis	N	4	0	0		2	0	0		16	0	0
	%	100.0	0.0	0.0		100.0	0.0	0.0		100.0	0.0	0.0

The names of the groups (sites) are in bold face for wet-rice farmers.

Figure 3.

Instances of multiple defects caused by linear enamel hypoplasia: (A) individual M254; (B) individual M289.

Porotic hyperostosis and cribra orbitalia

Table 4 shows the frequencies of PH. For age, the frequencies were generally higher in young adults than old adults although these differences did not reach significance in all assemblages. The difference almost attained significance in Lamadong (9.9% versus 3.1%, P = 0.053). For biological sex, the frequencies of PH were mostly higher in males than females in all assemblages except for Beiqian and Tuchengzi. The difference between both sexes reached significance in Jiangjialiang and Xinghong (23.5% versus 6.1%, P = 0.045; 18.5% versus 0.0%, P = 0.006, respectively). For groups, Figure 4 shows that the frequency of PH is the highest in Guangfulin, followed by Jiangzhuang and Jiangjialiang, and the lowest in Tuchengzi among the assemblages. Differences of the frequency between Guangfulin (24.5%) and others attained significance in Beiqian (4.7%, P = 0.008), Xinghong (8.7%, P = 0.017), Tuchengzi (1.6%, P < 0.001), and Lamadong (6.6%, P < 0.001). For severity, most of the PH observed in this study was categorized as mild. Moderate PH was confirmed only in Guangfulin (9%), Jiangzhuang (14.3%), and Jiangjialiang (20%), while severe PH was seen only in subadults under the age of 12 years, who are not included in the calculations (Table 3, Figure 5).

Table 4.

The frequencies of porotic hyperostosis by age, biological sex, and assemblage

	Guangfulin				Majiabang				Jiangzhuang				Beiqian					Jiangjialiang				Xinghong					Tuchengzi					Lamadong
	PH	Observed	%		PH	Observed	%		PH	Observed	%		PH	Observed	%			PH	Observed	%		PH	Observed	%			PH	Observed	%			PH	Observed	%
Young male	4	8	50.0		1	5	20.0		4	16	25.0		1	9	11.1			6	19	31.6		3	9	33.3			0	15	0.0			4	34	11.8
Young female	3	15	20.0		0	3	0.0		3	15	20.0		1	8	12.5			1	14	7.1		0	10	0.0			1	33	3.0			7	77	9.1
Old male	2	10	20.0		1	9	11.1		1	8	12.5		0	14	0.0			2	15	13.3		2	18	11.1			0	38	0.0			3	63	4.8
Old female	1	8	12.5		0	1	0.0		0	7	0.0		0	8	0.0			1	19	5.3		0	28	0.0			1	29	3.4			0	33	0.0
Young	8	28	28.6		1	9	11.1		7	32	21.9		2	17	11.8			7	33	21.2		3	19	15.8			1	48	2.1			11	111	9.9
Old	3	18	16.7		1	10	10.0		1	15	6.7		0	22	0.0			3	34	8.8		2	46	4.3			1	67	1.5			3	96	3.1
Male	6	18	33.3		2	14	14.3		5	24	20.8		1	23	4.3			8	34	23.5		5	27	18.5			0	53	0.0			7	97	7.2
Female	4	23	17.4		0	4	0.0		3	22	13.6		1	16	6.3			2	33	6.1		0	38	0.0			2	62	3.2			7	110	6.4
Total	13	53	24.5		2	20	10.0		8	49	16.3		2	43	4.7	**		10	68	14.7		6	69	8.7	*		2	122	1.6	**		16	243	6.6	**

The names of the groups (sites) are in bold face for wet-rice farmers.

Significance is set at P < 0.05. Significant probabilities between young and old or male and female are in bold face.

Significant probabilities between Guangfulin and each other assemblage are indicated by asterisks (*P < 0.05, **P < 0.01).

Figure 4.

Comparison of the prevalence of porotic hyperostosis between early wet-rice and millet farmers. The names of the groups (sites) are highlighted by asterisks for wet-rice farmers.

Figure 5.

Instance of a severe condition caused by porotic hyperostosis. The parietal bone of individual M176.

Table 5 shows the frequencies of CO. For age, the trend of the pattern of difference between both age cohorts varied among the assemblages, but the frequencies were significantly higher in young adults than old adults in Guangfulin (52.6% versus 15.4%, P = 0.033) and Lamadong (23.0% versus 10.1%, P = 0.013). For biological sex, the trend of the pattern of difference between males and females was also not constant, and no significant difference was seen. For groups, Figure 6 shows that the frequency of CO is by far the highest in Guangfulin, followed by Jiangjialian, Jiangzhuang, Lamadong, and the lowest in Majiabang among the assemblages. There were differences of the frequencies between each pair of Guangfulin (38.9%) and the following groups: Majiabang (6.7%, P = 0.021), Beiqian (17.6%, P = 0.049), Xinghong (13.8%, P = 0.002), Tuchengzi (12.4%, P < 0.001), and Lamadong (20.4%, P = 0.013). Furthermore, for severity, the ratio of moderate or severe CO was the highest in Guangfulin (28.6%) among the assemblages (Table 3, Figure 7).

Table 5.

The frequencies of cribra orbitalia by age, biological sex, and assemblage

	Guangfulin				Majiabang					Jiangzhuang				Beiqian					Jiangjialiang				Xinghong					Tuchengzi					Lamadong
	CO	Observed	%		CO	Observed	%			CO	Observed	%		CO	Observed	%			CO	Observed	%		CO	Observed	%			CO	Observed	%			CO	Observed	%
Young male	3	6	50.0		0	5	0.0			2	12	16.7		0	5	0.0			5	21	23.8		3	11	27.3			0	12	0.0			10	34	29.4
Young female	7	11	63.6		0	4	0.0			2	12	16.7		2	6	33.3			3	13	23.1		2	15	13.3			6	31	19.4			16	79	20.3
Old male	2	7	28.6		1	3	33.3			3	8	37.5		3	13	23.1			5	13	38.5		1	20	5.0			3	33	9.1			5	66	7.6
Old female	0	6	0.0		0	1	0.0			1	6	16.7		1	6	16.7			2	17	11.8		2	28	7.1			4	23	17.4			5	33	15.2
Young	10	19	52.6		0	9	0.0			5	25	20.0		2	11	18.2			8	34	23.5		5	26	19.2			6	43	14.0			26	113	23.0
Old	2	13	15.4		1	4	25.0			4	14	28.6		4	19	21.1			7	30	23.3		3	48	6.3			7	56	12.5			10	99	10.1
Male	5	13	38.5		1	8	12.5			5	20	25.0		3	18	16.7			10	34	29.4		4	31	12.9			3	45	6.7			15	100	15.0
Female	7	17	41.2		0	5	0.0			3	18	16.7		3	12	25.0			5	30	16.7		4	43	9.3			10	54	18.5			21	112	18.8
Total	14	36	38.9		1	15	6.7	*		9	41	22.0		6	34	17.6	*		16	65	24.6		11	80	13.8	**		13	105	12.4	**		52	255	20.4	*

The names of the groups (sites) are in bold face for wet-rice farmers.

Significance is set at P < 0.05. Significant probabilities between young and old or male and female are in bold face.

Significant probabilities between Guangfulin and each other assemblage are indicated by asterisks (*P < 0.05, **P < 0.01).

Figure 6.

Comparison of the prevalence of cribra orbitalia between early wet-rice and millet farmers. The names of the groups (sites) are highlighted by asterisks for wet-rice farmers.

Figure 7.

Instances of moderate and severe conditions caused by cribra orbitalia: (A) individual M64; (B) individual M157; (C) individual M316; (D) individual M320.

Discussion

Linear enamel hypoplasia

It has been discussed whether the life expectancy of individuals affected with LEH is shorter on average than that of individuals not affected, related to the developmental origins of health and disease (the so-called Barker hypothesis) (e.g. Armelagos et al., 2009; Merrett et al., 2016). We therefore examined if there was any difference in the LEH frequencies between young adults and old adults in this study. As a result, significant difference was limited to Lamadong, where the LEH prevalence of MxC was statistically higher in young adults than in old adults (Table 2). At Lamadong, individuals who had not suffered from metabolic stress during infancy could enjoy a longer life than those who had suffered from the condition.

Regarding the difference between males and females, significant difference was seen only in Jiangzhuang, where the LEH prevalence of MxC was statistically higher in males than in females (Table 2). It is difficult here to clarify what factors caused the difference between both sexes. If anything, it might be related to the fact that some of the tombs were archaeologically thought to be for nobles, with several individuals lacking almost all parts of the body except for the crania which were deposited in a manner seemingly following the master of the tomb. This possibility should be examined when the formal report on the excavation is published.

The results of this study show that the LEH frequencies were statistically higher in the Neolithic wet-rice farmers, in particular at Guangfulin, compared to the Neolithic and early Dynastic millet farmers (Table 2, Figure 2). Furthermore, the ratios of teeth with multiple defects were also higher in the Neolithic wet-rice farmers, in particular Guangfulin although it was difficult to rule out possible bias from the differences in degree of dental wear among the groups (Table 3). These results suggest that the Neolithic wet-rice farmers repeatedly suffered from significant metabolic stress during infancy. The LEH defect is inscribed during the time that the lateral enamel of the tooth is developing, between the age of one and five years in the anterior teeth (i.e. permanent incisors and canines). The following could be suggested as probable factors contributing to metabolic stress at that age: malnourishment, diarrhea, and infectious diseases (Goodman et al., 1991). It is widely known that the timing of weaning and the quality of weaning foods could have a substantial impact on the factors contributing to LEH formation (Goodman et al., 1987, 1991). Infants are generally protected from external pathogens by the maternal immune system, which is incorporated into the infants through breast milk (Jackson and Nazar, 2006). Infants are, however, moved off the maternal immune system as weaning is introduced, and the difference in nutrients of weaning foods could significantly influence their health. This possibility should be archaeologically and ethnographically examined to see if there are some differences in the nutrients of weaning foods between wet-rice and millet societies. Infectious disease should also be counted as a factor contributing to LEH formation in the societies of wet-rice farmers since tuberculosis could have been prevalent at Guangfulin as mentioned above (Okazaki et al., 2019). Before the modern era, most tuberculosis patients were subadults or young adults, and the simultaneous appearance of infectious diseases including bone tuberculosis and LEH is reported (Ortner, 2003).

Porotic hyperostosis and cribra orbitalia

In PH, the prevalence was generally higher in young adults than in old adults although the differences did not attain a statistically significant level in this study (Table 4). In CO, the trend of the pattern of prevalence was not constant among the groups, but the prevalence was statistically significantly higher in young adults than in old adults among Guangfulin and Lamadong (Table 5). These results could be explained by remodeling of the cortical bone after healing rather than by the Barker hypothesis, which covered up the bone changes due to PH and CO. The differences of both frequencies of PH and CO between males and females were not constant. Statistically significant differences were only confirmed in the PH prevalences of Jiangjialiang and Xinghong, which were higher in males than in females (Table 4, Table 5). Most PH in both assemblages was graded as mild (80%, 100%, respectively, Table 3), and possibly included some mere periostitis reactions caused by trauma. This might lead to a higher PH prevalence in males in both assemblages because of behavior associated with higher trauma (e.g. fighting, hunting, and fishing).

The results of this study show that the prevalence of both PH and CO in Guangfulin was remarkably higher than in other groups (Figure 4, Figure 6). This could be explained if the age distribution of Guangfulin inclined to younger ages, contributing to the result. However, in the case that the data were limited to young adults, excluding old adults, the prevalence at Guangfulin was still similarly higher than other groups (Table 4, Table 5). Furthermore, 28.5% of the CO was graded as moderate or severe in Guangfulin, which was the highest among the groups, and no severe CO was seen in other groups (Table 3). The people could have therefore suffered from anemia due to some nutritional deficiencies (e.g. iron, vitamin B12, folic acid, vitamin C) as well as infectious diseases of the eyes at Guangfulin. It is known that these nutritional deficiencies during infancy are often associated with parasite exposure and diarrhea. The matter of parasite load relevant to their activity on water should be considered because rice is grown under water. For example, a water environment increases the risk of infectious diseases spread by mosquitos such as malaria or Japanese encephalitis (e.g. Ikeshoji, 1986; Masuoka et al., 2010). Furthermore, it also increases the risk of schistosomiasis, which could penetrate the human body under water (e.g. Kazura et al., 1985).

Health of early wet-rice farmers

The results of this study generally show that the early wet-rice farmers of the Yangtze Delta, especially at Guangfulin, suffered from a much higher prevalence of stress markers compared to the early millet farmers of northern China. This means that health and nutritional status were worse during the subadult age stage, in particular during infancy, in the early wet-rice farmers.

Previous studies have demonstrated that the prevalence of stress markers remains stable or even decreases when wet-rice farming was later introduced to surrounding areas (i.e. Thailand and Japan). The disagreement between the results of this and previous studies might be due to the development of wet-rice agriculture during the period of over 3000 years when it was spreading from the core zone to surrounding zones, as well as the availability and variability of local resources. The prevalence of stress markers for the early Neolithic assemblages at the Tianluoshan and Hemudu sites located in the Yangtze River Delta have also been reported, even though the sample numbers were insufficient. At these latter sites, the prevalence of LEH and CO were not so high and were roughly comparable to those of hunting-gathering groups in southern China during the same period (Sawada et al., 2023). This result is partly consistent with the trends of the Early Neolithic assemblage in the present material. The Majiabang assemblage had the lowest prevalence of CO among the groups examined here, although the prevalence of LEH was relatively high.

A strontium isotope analysis using dental crown enamel suggested a certain number of immigrants at the Guangfulin site (T. Gakuhari et al., unpublished data). The deterioration of health status associated with immigration is well known worldwide today and could be related to the prevalence of tuberculosis at Guangfulin (Okazaki et al., 2019). Additionally, it is well known that the gene variants ADH1B*2 and ALDH2*2, encoding alcohol and acetaldehyde dehydrogenases, respectively, are very rare in other regions of the world, but are highly prevalent in East Asian populations. The ‘aldehyde hypothesis’ has been proposed as a possible reason for this phenomenon, suggesting that they were produced plastically during adaptation to infectious diseases in the Neolithic period and later (Darwin and Stanley, 2022; Deiana et al., 2024). Not only tuberculosis but other possible infectious diseases associated with activity in and around water (malaria, Japanese encephalitis, schistosomiasis) might lead to the difference in health status between the Neolithic wet-rice and millet farmers.

The results of this study imply an increase of the prevalence of stress markers during the transition between the Early and Late Neolithic when rice farming developed. It is possible that the Late Neolithic wet-rice farmers of the Songze and Liangzhu cultures had not yet become fully accustomed to the new subsistence system and suffered from serious physical stress.

Acknowledgments

We thank Dr S. Yonemoto, Dr K. Ohno, Ms Y. Muramatsu, Mr H. Tomita, Mr M. Matsuura, and Mr B. Zhen for their assistance in cleaning and arranging the skeletal remains, the fellow researchers of the JSPS KAKENHI grant project (Rice Farming and Chinese Civilization) for their advice regarding Chinese archaeology. This work was supported by JSPS KAKENHI grant numbers JP26440259, JP15H05969, JP18K06443, JP20H05821, and JP23H00695.

References

• Archaeological Department of Shanghai Museum (2002) Brief report on the excavation of the Guangfulin site, Shanghai in 1999 through 2000. Kaogu (Archaeology), 2002-10: 895–912 (in Chinese with English summary).
• Archaeological Department of Shanghai Museum (2008) Brief report on the excavation of the Guangfulin site, Shanghai in 2001 through 2005. Kaogu (Archaeology), 2008-8: 675–693 (in Chinese with English summary).
•  Armelagos  G.J.,  Goodman  A.H.,  Harper  K.N., and  Blakey  M.L. (2009) Enamel hypoplasia and early mortality: bioarchaeological support for the Barker hypothesis. Evolutionary Anthropology, 18: 261–271.
•  Bellwood  P. (2005) First Farmers: The Origins of Agricultural Societies. Blackwell, Oxford.
•  Bruzek  J. (2002) A method for visual determination of sex, using the human hip bone. American Journal of Physical Anthropology, 117: 157–168.
•  Buckberry  J.L. and  Chamberlain  A.T. (2002) Age estimation from the auricular surface of the ilium: a revised method. American Journal of Physical Anthropology, 119: 231–239.
•  Buikstra  J.E. and  Ubelaker  D.H. (1994) Standards for data collection from human skeletal remains. Proceedings of a seminar at the Field Museum of Natural History. Arkansas Archeological Survey Research Series No. 44, Arkansas Archeological Survey, Arkansas.
•  Chen  J.,  Chen  Z.Y., and  Li  C.H. (2007) Analysis of the environments of the Guangfulin site in Songjiang county, Shanghai. Kaogu (Archaeology), 2007: 647–655 (in Chinese with English summary).
•  Cohen  M.N. and  Armelagos  G.J. (1984) Paleopathology at the Origins of Agriculture. Academic Press, Orlando, FL.
•  Cohen  M.N. and  Crane-Kramer  G.M.M. (2007) Ancient Health: Skeletal Indicators of Agricultural and Economic Intensification. University Press of Florida, Gainesville, FL.
•  Darwin  K.H. and  Stanley  S.A. (2022) The aldehyde hypothesis: metabolic intermediates as antimicrobial effectors. Open Biology, 12: 220010. doi: 10.1098/rsob.220010
•  Deiana  G.,  Sun  R.,  Huang  J.,  Napolioni  V., and  Ciccocioppo  R. (2024) Contribution of infectious diseases to the selection of ADH1B and ALDH2 gene variants in Asian populations. Alcoholism Clinical & Experimental Research 1–12. doi: 10.1111/acer.15288
•  Domett  K. and  Tayles  N. (2006) Human biology from the Bronze Age to the Iron Age in the Mun River valley of northeastern Thailand. In: Oxenham M. and Tayles N. (eds.), Bioarchaeology of Southeast Asia. Cambridge University Press, Cambridge, pp. 220–240.
•  Domett  K. and  Tayles  N. (2007) Population health from the Bronze to the Iron Age in the Mun River Valley, Northeastern Thailand. In: Cohen M.M. and Crane-Kramer G.M.M. (eds.), Ancient Health: Skeletal Indicators of Agricultural and Economic Intensification. University Press of Florida, Gainesville, FL, pp. 286–299.
•  Douglas  M.T. and  Pietrusewsky  M. (2007) Biological consequences of sedentism: agricultural intensification in Northeast Thailand. In: Cohen M.M. and Crane-Kramer G.M.M. (eds.), Ancient Health: Skeletal Indicators of Agricultural and Economic Intensification. University Press of Florida, Gainesville, FL, pp. 300–319.
•  Fuller  D.Q.,  Qin  L.,  Zheng  Y.F.,  Zhao  Z.J.,  Chen  X.G.,  Hosoya  L.A., and  Sun  G.P. (2009) The domestication process and domestication rate in rice: spikelet bases from the lower Yangtze. Science, 323: 1607–1610.
•  Goodman  A.H. and  Rose  J.C. (1990) Assessment of systemic physiological perturbations from dental enamel hypoplasias and associated histological structures. Yearbook of Physical Anthropology, 33: 59–110.
•  Goodman  A.H.,  Allen  L.H.,  Hernandez  G.P.,  Amador  A.,  Arriola  L.V.,  Chavez  A., and  Pelto  G.H. (1987) Prevalence and age at development of enamel hypoplasias in Mexican children. American Journal of Physical Anthropology, 72: 7–19.
•  Goodman  A.H.,  Martinez  C., and  Chavez  A. (1991) Nutritional supplementation and the development of linear enamel hypoplasias in children from Tezonteopan, Mexico. American Journal of Clinical Nutrition, 53: 773–781.
•  Hanihara  K. (1952) Age changes in the male Japanese pubic bone. Journal of the Anthropological Society of Nippon, 62: 245–260 (in Japanese with English summary).
•  Igarashi  Y.,  Uesu  K.,  Wakebe  T., and  Kanazawa  E. (2005) New method for estimation of adult skeletal age at death from the morphology of the auricular surface of the ilium. American Journal of Physical Anthropology, 128: 324–339.
•  Ikeshoji  T. (1986) Distribution of the mosquitoes, Culex tritaeniorhynchus, in relation to disposition of sound traps in a paddy field. Japan Society of Medical Entomology and Zoology, 37: 153–159.
•  Jackson  K.M. and  Nazar  A.M. (2006) Breastfeeding, the immune response, and long-term health. Journal of Osteopathic Medicine, 106: 203–207.
•  Kazura  J.W.,  Neill  M.,  Peters  P.A.S., and  Dennis  E. (1985) Swamp rice farming: possible effects on endemicity of schistosomiasis mansoni and haematobia in a population in Liberia. American Journal of Tropical Medicine and Hygiene, 34: 107–111.
•  Larsen  C.S. (1997) Bioarchaeology: Interpreting Behavior from the Human Skeleton. Cambridge University Press, Cambridge.
•  Liu  B.,  Wang  N.Y.,  Chen  M.H.,  Wu  X.H.,  Mo  D.W., et al (2017) Earliest hydraulic enterprise in China, 5100 years ago. Proceedings of the National Academy of Sciences of the United States of America, 114: 13637–13642.
•  Lovejoy  C.O.,  Meindl  R.S.,  Pryzbeck  T.R., and  Mensforth  R.P. (1985) Chronological metamorphosis of the auricular surface of the ilium: a new method for the determination of adult skeletal age at death. American Journal of Physical Anthropology, 68: 15–28.
•  Masuoka  P.,  Klein  T.A.,  Kim  H.C.,  Claborn  D.M.,  Achee  N., et al (2010) Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea. Geospatial Health, 5: 45–57.
•  Meindl  R.S. and  Lovejoy  C.O. (1985) Ectocranial suture closure: a revised method for the determination of skeletal age at death based on the lateral-anterior sutures. American Journal of Physical Anthropology, 68: 57–66.
•  Merrett  D.C.,  Zhang  H.,  Xiao  X.,  Zhang  Q.,  Wei  D.,  Wang  L.,  Zhu  H., and  Yang  D.Y. (2016) Enamel hypoplasia in northeast China: evidence from Houtaomuga. Quaternary International, 405: 11–21.
•  Nakahashi  T. (2014) Human cranial morphology during the spring and autumn and Warring States periods in Zhongyuan region, China. In: Nakahashi T. and Fan W.Q. (eds.), Ancient People in Central China. Kyushu University Press, Fukuoka, pp. 87–105.
•  Nakahashi  T. and  Nagai  M. (1986) Sex assessment of fragmentary skeletal remains. Journal of the Anthropological Society of Nippon, 94: 289–305.
•  Nakahashi  T.,  Takamuku  H., and  Luan  F. (2013) The human skeletons of the Dawenkou period in Beiqian site, Shangdong province. Eastern Archaeology, 10: 13–51 (in Chinese with English abstract).
•  Nakamura  S. (2015) The Study on the Liangzhu Ruins: The Report of the JSPS KAKENHI Grant-in-Aid for Scientific Research (A) in 2010 through 2014. Kanazawa University, Kanazawa (in Japanese).
• Nanjing Museum (2016) Liangzhu culture of the Jiangzhuang site in the Xinghua and Dongtai cities, Jiangzu. Kaogu (Archaeology), 2016: 739–751 (in Chinese with English summary).
•  Okazaki  K. (2010) Developmental perspectives on neurocranial proportions in Japan. HOMO, 61: 314–336.
•  Okazaki  K. (2013) Change in the linear growth of long bones with the adaptation of wet-rice agriculture in Japan. In: Pechenkina E. and Oxenham M. (eds.), Bioarchaeology of East Asia: Movement, Contact, Health. University Press of Florida, Gainesville, FL, pp. 368–398.
•  Okazaki  K. and  Luan  F. (2013) Oral diseases of the human skeletal remains of the Dawenkou cultural period unearthed from Beiqian site in Jimo city, Shangdong province. Eastern Archaeology, 10: 65–79 (in Chinese with English abstract).
•  Okazaki  K. and  Takamuku  H. (2019) Study on the unearthed human skeletal remains. In: Zhejiang Provincial Institute of Cultural Relics and Archaeology (ZPICRA) and Jiaxing Museum (JM) (eds.), Majiabang. Cultural Relics Publishing House, Beijing, pp. 232–242 (in Chinese).
•  Okazaki  K.,  Wei  D., and  Zhu  H. (2013) Variations in oral health of millet agriculturalists in the northern ‘Great Wall’ region of China from the Middle Neolithic to the Sixteen Kingdoms period. Anthropological Science, 121: 187–201.
•  Okazaki  K.,  Fan  W.,  Wei  D., and  Zhu  H. (2016) Difference in public oral health at the spring/autumn and Warring States period between the Central Plains and the northern Great Wall region in China. Quaternary International, 405: 34–43.
•  Okazaki  K.,  Takamuku  H.,  Yonemoto  S.,  Itahashi  Y.,  Gakuhari  T.,  Yoneda  M., and  Chen  J. (2019) Paleopathological approach to early human adaptation for wet-rice agriculture: first case of Neolithic spinal tuberculosis at the Yangtze River Delta of China. International Journal of Paleopathology, 24: 236–244.
•  Okazaki  K.,  Takamuku  H.,  Kawakubo  Y.,  Hudson  M., and  Chen  J. (2021) Cranial morphometric analysis of early wet-rice farmers in the Yangtze River Delta of China. Anthropological Science, 129: 203–222.
•  Ortner  D.J. (2003) Identification of Paleopathological Conditions in Human Skeletal Remains. Academic Press, Amsterdam.
•  Oxenham  M.F. and  Cavill  I. (2010) Porotic hyperostosis and cribra orbitalia: the erythropoietic response to iron-deficiency anaemia. Anthropological Science, 118: 199–200.
•  Pechenkina  E.A.,  Benfer  R.A., and  Ma  X. (2007) Diet and health in the Neolithic of the Wei and middle Yellow River Basins, northern China. In: Cohen M.N. and Crane-Kramer G.M.M (eds.), Ancient Health. University Press of Florida, Gainesville, FL, pp. 255–272.
•  Phenice  J.W. (1969) A newly developed method of sexing the pelvis. American Journal of Physical Anthropology, 30: 297–301.
•  Renfrew  C. and  Liu  B. (2018) The emergence of complex society in China: the case of Liangzhu. Antiquity, 92: 975–990.
•  Roberts  C. (2012) Re-emerging infections: developments in bioarchaeological contributions to understanding tuberculosis today. In: Grauer A.L. (ed.), A Companion to Paleopathology. Blackwell, Oxford, pp. 434–457.
•  Sakaue  K. (2006) Application of the Suchey–Brooks system of pubic age estimation to recent Japanese skeletal material. Anthropological Science, 114: 59–64.
•  Sakaue  K. (2015) A Bayesian approach to age estimation from cranial suture closure in Japanese people. Bulletin of the National Museum of Nature and Science, Series D, Anthropology, 41: 1–11.
•  Sawada  J.,  Sun  G.,  Huang  W.,  Kubota  S.,  Saeki  F.,  Okazaki  K.,  Yoneda  M., and  Nakamura  S. (2023) Paleopathological characteristics of Neolithic early rice farmers in the lower reaches of the Yangtze river. Frontiers in Earth Science, 11: 1225928.
•  Takahashi  H. (2006) Curvature of the greater sciatic notch in sexing the human pelvis. Anthropological Science, 114: 187–191.
•  Temple  D.H. (2010) Patterns of systemic stress during the agricultural transition in prehistoric Japan. American Journal of Physical Anthropology, 142: 112–124.
•  Todd  T.W. (1920) Age changes in the pubic bone: 1. The male white pubis. American Journal of Physical Anthropology, 3: 285–334.
•  Walker  P.L. (2005) Greater sciatic notch morphology: sex, age and population differences. American Journal of Physical Anthropology, 127: 385–391.
•  Walker  P.L.,  Bathurst  R.R.,  Richman  R.,  Gjerdrum  T., and  Andrushko  V.A. (2009) The causes of porotic hyperostosis and cribra orbitalia: a reappraisal of the iron-deficiency-anemia hypothesis. American Journal of Physical Anthropology, 139: 109–125.
•  Webb  S.G. (1990) Prehistoric eye disease (trachoma?) in Australian Aborigines. American Journal of Physical Anthropology, 81: 91–100.
•  White  T.D. and  Folkens  P.A. (2005) The Human Bone Manual. Academic Press, Cambridge.
• Zhejiang Provincial Institute of Cultural Relics and Archaeology (ZPICRA) and Jiaxing Museum (JM) (2019) Majiabang. Cultural Relics Publishing House, Beijing (in Chinese).
•  Zhou  L. and  Corruccini  R.S. (1998) Enamel hypoplasias related to famine stress in living Chinese. American Journal of Human Biology, 10: 723–733.
•  Zhu  X. (2018) The research on the human skeletons from the Liangzhu culture’s tombs excavated in Jiangzhuang, Xinghua, Jiangsu. Ph.D. dissertation, Jilin University, Changchun (in Chinese with English abstract).
•  Zong  Y.,  Chen  Z.,  Innes  J.B.,  Chen  C.,  Wang  Z., and  Wang  H. (2007) Fire and flood management of coastal swamp enabled first rice paddy cultivation in east China. Nature, 449: 459–463.