2025 年 32 巻 10 号 p. 1203-1210
Pediatric lifestyle disease screening in Japan plays a crucial role in the early detection of obesity, dyslipidemia, hypertension, and type 2 diabetes. However, it is not mandated by national law, instead being conducted independently by local governments, which results in significant regional disparities. While many programs focus only on obese children, this approach risks missing high-risk individuals with normal weight, such as those with familial hypercholesterolemia (FH) or non-obese type 2 diabetes. Regional initiatives in cities such as Fukuoka, Niigata, Kumamoto, and Kitakyushu have demonstrated various effective models, including the use of growth and obesity curves, expanded screening parameters, and school–healthcare collaborations. National surveys show that fewer than 30% of municipalities conduct such screenings, often with limited standardization. Kagawa Prefecture presents a notable example of integrating FH screening with lifestyle checkups to achieve high participation and follow-up rates. To expand and improve its effectiveness, universal screening based on standardized criteria is essential. Efforts should also focus on public education, early intervention, and coordinated systems involving school nurses and teachers, pediatricians and family doctors, local medical associations, educational boards, and municipal health authorities. Universal screening, combined with individualized follow-up and strong community collaboration, can help healthcare providers, educators, and local governments in Japan respond more effectively to the growing prevalence of pediatric obesity and metabolic disorders. This approach also promotes equitable access to preventive care for children.
In Japan, pediatric lifestyle disease screening aims to detect early risk factors, such as obesity, dyslipidemia, hypertension, and type 2 diabetes, while also serving as a valuable opportunity for health education and lifestyle modification among children. Despite its significance, this screening is not mandated under the School Health and Safety Act and is implemented independently by local governments. Consequently, there is no nationwide standard, and substantial regional disparities persist in implementation.
This type of screening was first introduced in 1987 in 28 prefectures under the name Shoni Seijinbyo Kenshin (literally, “pediatric screening for adult-onset diseases”), reflecting a public health initiative to detect and address early metabolic risk factors in childhood1). Although its importance has gained increasing recognition over time, a nationally unified program has not yet been established. A national survey conducted in 2019 revealed that such screening programs are currently implemented in less than 25% of municipalities, primarily led by local boards of education or municipal governments2, 3).
In many areas, screening targets only children with obesity, which may lead to failure in identifying children with type 2 diabetes or familial hypercholesterolemia (FH) who are not overweight but still require early intervention. Thus, the universal screening of all children at specific ages has been proposed as a more effective approach. In addition, the longitudinal use of growth and obesity curves during school health checkups is essential for detecting deviations in physical development and facilitating timely interventions.
This article reviews the current status of pediatric lifestyle disease screening in Japan and, based on regional initiatives and national survey findings, discusses the key challenges and necessary steps for its broader implementation and systematization.
Since 2016, Fukuoka City has implemented screening for all 4th-grade elementary students as part of a school-based cardiac examination led by the local medical association4). Using height and weight data, obesity categories were determined, and children with moderate or severe obesity were referred for a secondary evaluation. Based on the 2017–2018 data, over 70% of children showed improvement in their obesity index before the follow-up consultation, and 60% of the remaining students improved after it, suggesting that screening and subsequent medical referrals effectively contributed to positive changes in lifestyle.
Niigata CityStarting as a pilot in 2000, Niigata City’s program involves 4th-grade elementary and 1st-year junior high school students who voluntarily participated. Screening included the obesity index, blood pressure, and blood tests. Screening results were categorized, and health professionals provided mini-lectures based on these results to educate students. The program reflects a strong collaboration between schools and healthcare providers5).
Mitsuke CityMitsuke City has conducted screenings since 1999 for 4th-grade elementary and 1st-year junior high students6). After screening, individual counseling was conducted during school visits. From 2016 to 2019, approximately 90% of eligible students participated in the screening, and more than 60% received individual counseling. These high rates indicate strong involvement and support from the local community including schools, families, and healthcare providers.
Tokyo (Suginami Ward): A New Comprehensive ApproachIn 2019, Suginami Ward, a district of Tokyo, launched a comprehensive pediatric screening system to address broader lifestyle-related risks beyond traditional obesity-focused methods6). This model program was based on a new screening system developed and evaluated in Tokyo, which emphasized the early identification of non-obese at-risk children and strengthened school–medical collaboration7). The program incorporated new parameters, such as waist circumference, waist-to-height ratio, non-high-density lipoprotein-cholesterol (HDL-C), HbA1c, and alanine aminotransferase (ALT)], allowing the assessment of visceral fat, lipid metabolism, glucose tolerance, and liver function. Visceral fat is more strongly associated with metabolic risk than is subcutaneous fat in obese Japanese children8, 9). A waist-to-height ratio (WHtR) ≥ 0.5 has been shown to be a valid and age-independent cutoff value for detecting excessive visceral fat accumulation in Japanese children10). These enhancements aimed to better detect conditions, such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD).
The results of screenings conducted among 4th-grade elementary students showed notable prevalence rates: 12% for abdominal obesity, 8.2% for dyslipidemia, 6.7% for obesity, 2.8% for liver dysfunction, 2.1% for elevated HbA1c, and 1.6% for hypertension. Based on a 3-tier evaluation system, 9.7% of the students required medical consultation, 16.6% required health guidance, and 73.7% were considered within the normal range. This model demonstrated the feasibility and effectiveness of broader early screening strategies.
Kumamoto City: Early Detection and Follow-upKumamoto City has conducted lifestyle disease screening for 4th-grade elementary students since 2011 11). The program consists of anthropometric measurements and blood tests. Children with abnormal results are referred for a further evaluation. Between 2011 and 2020, over 68,000 students were screened, and 6,521 were identified as obese. Secondary evaluations showed that even moderately overweight children were at risk for dyslipidemia, particularly a high low-density lipoprotein-cholesterol (LDL-C) level, often accompanied by a family history. Notably, some non-obese students also required follow-up, highlighting the importance of waist circumference measurements and taking the family history in identifying high-risk individuals.
Oita City: Long-term Trends and Local ChallengesOita City has conducted screening for 5th-grade elementary students, providing data over a 27-year period12). The results showed that the prevalence of obesity, particularly severe obesity, has remained above the national average. From 1994 to 2018, obesity rates fluctuated around 10%–11%, with no significant long-term reduction. Factors such as limited access to healthcare services, reduced health education resources, and regional lifestyle patterns in rural areas may contribute to the continued high rates of obesity.
In addition, longitudinal data revealed a decrease in HDL-C levels and slight increases in Total cholesterol (TC), triglycerides (TG) and non-HDL-C levels, especially among obese children. These changes suggest worsening of lipid profiles over time and a growing need for early intervention. These results underscore the importance of regular health checkups and targeted support strategies in regions where childhood obesity remains prevalent.
Nationwide Status of Pediatric Lifestyle Disease Screening in JapanA nationwide survey conducted in 2019 investigated the implementation of pediatric lifestyle disease screening in Japan2). Of the 814 district medical associations contacted, 492 responded (response rate: 60.4%). Among these, only 25.8% (127 associations) reported that such screenings were conducted in their municipalities. Most of these programs (85.4%) were organized by local governments and often led by the Boards of Education.
The implementation of pediatric lifestyle disease screening programs has demonstrated considerable variation in the target populations, screening methods, and settings. With regard to target grades, 62.6% of the programs encompassed both elementary and junior high school students, most commonly targeting 4th-grade elementary and 1st-year junior high school students. In terms of screening modality, 50.4% employed universal screening, covering ≥ 70% of the eligible population, whereas 17.1% utilized partial, voluntary screening, with participation rates below 70%. In addition, 22.8% of the programs adopted obesity-based screening, limited to children classified as obese. The sites of implementation also differed: universal screenings were predominantly conducted within school settings and frequently included blood testing, whereas obesity-based screenings were more often carried out in public health centers or medical facilities.
Pediatric lifestyle disease screening in Japan remains limited, with only approximately 20% of municipalities implementing programs and wide variations in methods and criteria. Several key challenges have emerged from regional efforts and national survey findings. Standardized nationwide screening criteria are urgently required. Parental understanding and follow-up rates remain low, especially in children with moderate or severe obesity. Collaboration with primary care physicians is insufficient, and access to specialist care is limited.
Universal screening provides important opportunities for health education and early detection of lifestyle-related diseases. Early life conditions, including fetal and infant nutrition, have been linked to later risk of metabolic disorders13). However, this requires more resources, staff, and coordination, which can be burdensome for schools and local governments. On the other hand, while limiting screening to only obese children may reduce the workload, it risks overlooking children with serious health issues despite having a normal weight, such as those with FH or non-obese type 2 diabetes.
To support early intervention and provide equitable healthcare for all children, it is essential to adopt a standardized nationwide screening system. Recent findings support this need by proposing age-specific cutoff values for metabolic syndrome components, which may help standardize pediatric screening criteria in Japan14). This should be accompanied by increased public awareness, improved referral pathways to medical care, and the establishment of legal and financial frameworks to ensure consistent implementation across all municipalities.
Kagawa Prefecture: A Model of Integrated Screening for Nationwide ApplicationKagawa Prefecture has developed a leading example of integrated pediatric screening, combining lifestyle disease prevention and universal screening for FH15). Motivated by the region’s high prevalence of lifestyle-related diseases, the prefecture launched a pediatric lifestyle disease-screening program in 2012, followed by full-scale FH screening in 2018. These efforts have led to a standardized, prefecture-wide protocol and centralized data management under the “All Kagawa” initiative.
Lifestyle disease screening targets all 4th-grade elementary students (9–10 years old), with approximately 8,000 children examined annually and a high participation rate of 90%–95%. Screening included anthropometric measurements, blood tests (LDL-C, HDL-C, TG, glucose, aspartate aminotransferase (AST)/alanine aminotransferase (ALT)), and lifestyle questionnaires. The program is managed jointly by the prefectural government, local medical associations, schools, and university hospitals. Children with abnormal results are advised by school nurses to seek medical care, supported by pediatric guidelines developed by the Kagawa Pediatric Society, and implemented in coordination with family physicians.
FH screening employs a three-step protocol: (1) initial screening based on an LDL-C level ≥ 140 mg/dL, (2) a secondary evaluation by family physicians, and (3) confirmatory genetic testing at core hospitals. Between 2018 and 2019, among 15,665 children who underwent screening, approximately 580 had elevated LDL-C levels (≥ 140 mg/dL). Of these, 67 underwent genetic testing, and 41 (61%) were confirmed to carry mutations associated with FH. These included 36 mutations in the low-density lipoprotein receptor gene (LDLR), 4 in the proprotein convertase subtilisin/kexin type 9 gene (PCSK9), and 1 in the apolipoprotein B gene (APOB). The median LDL-C level was significantly higher in the mutation-positive children than in those without mutations (184 mg/dL vs. 152 mg/dL, p = 0.005). Notably, all children with LDL-C levels ≥ 250 mg/dL tested positive for FH mutations.
Kagawa also introduced reverse cascade screening to identify affected family members by leveraging the autosomal dominant inheritance pattern of FH. As a result, the adult FH diagnosis rate reached approximately 10%, nearly 10 times the national average. The prefecture developed a system in which both children and their parents could receive care at the same medical facility, ensuring a smooth follow-up and long-term disease management.
Kagawa’s integrated screening program serves as a model for a nationwide implementation. It provides robust evidence for the effectiveness of FH screening in school-aged populations and demonstrates the value of starting cardiovascular disease prevention in childhood. Ongoing efforts to increase follow-up rates and accumulate data will be the key to expanding this approach across Japan.
Kitakyushu City: Early Identification Through Growth Curve MonitoringIn response to the 2016 revision of Japan’s School Health and Safety Act enforcement regulations, Kitakyushu City introduced a citywide initiative to utilize growth and obesity curves as part of its annual school health checkups16). Since fiscal year 2016, students identified with either severe obesity (obesity index ≥ 50%) or rapid obesity progression (≥ 20% increase from their lowest recorded value) have been referred to designated medical institutions capable of providing detailed examinations (Table 1).
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By using the “Child Health Management Program” to generate individual growth and obesity curves, students are categorized into the following nine groups. “Groups 2, 4, 5, 7, and 9 are considered potentially pathological and require medical evaluation. |
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|---|---|
| No. | Classification Criteria |
| 1 | Current height is at or above the 97th percentile |
| 2 | Current height is ≥ 1 SD above the child’s lowest recorded height Z-score |
| 3 | Current height is at or below the 3rd percentile |
| 4 | Current height is ≥1 SD below the child’s highest recorded height Z-score |
| 5 | Current t height is ≤ −2.5 Z-score |
| 6 | Current obesity index is ≥ 20% (Kitakyushu City uses ≥ 50%) |
| 7 | Current obesity index is ≥ 20% higher than the child’s lowest previous obesity index |
| 8 | Current besity index is ≤ −20% (Kitakyushu City uses ≤ −25%) |
| 9 | Current obesity index is ≥ 20% lower than the child’s highest previous obesity index |
From 2016 to 2018, among the students identified through school health screening as requiring detailed medical evaluation, 206 visited the Department of Pediatrics at the University of Occupational and Environmental Health Hospital, the author’s affiliated institution. Among these, 191 students with mild to severe obesity (7.1–15.9 years old; obesity index range 10.9%–126.0%) were assessed for metabolic abnormalities. As shown in Fig.1, the number of referrals varied by school-grade level. While cases of severe obesity were observed across all grades, referrals due to rapid increases in obesity were most frequent among students in elementary grades 3–5. These findings suggest that rapid progression of obesity tends to occur between the 3rd and 5th grades in elementary school, indicating that early screening and interventionbefore this critical periodmay be essential for effective prevention. In this context, the use of growth curves in school health checkups to recommend medical evaluations is particularly valuable, as it enables timely intervention not only in specific grades but across all grade levels.
Number of Children Referred in Each Grade by Obesity Severity and Progression Identified Through School Health Screening
The presence of clinical findings increased with obesity severity, with elevated ALT and TG levels being particularly common, seen in about 50% of boys and 30% of girls, even in moderate obesity cases (Fig.2).
Prevalence of Abnormal Findings Among Diagnostic Criteria for Pediatric Obesity
A follow-up study conducted 1 year later on 206 students found that approximately two-thirds of those who continued medical care showed improvement in their obesity index (Fig.3). Younger children (under 10 years old) had higher improvement rates and fewer dropouts (Fig.4). Those who improved showed an average 10% decrease in the obesity index and improvements in clinical markers (Fig.5). These results suggest that school-based screening can effectively prompt families to reevaluate lifestyle habits and engage in sustained behavioral changes. However, approximately 35% of the students in our study discontinued follow-up (Fig.3). A lack of understanding among students and their families regarding the importance of lifestyle modification and the need to address obesity makes it difficult to maintain motivation and ensure continued participation in medical care. To address this issue, Kitakyushu City has actively involved schools, particularly homeroom teachers and school nurses, in promoting follow-up visits. These staff members support students by recognizing their progress and sharing outcomes with relevant personnel. In addition, personalized feedback was provided, and close coordination was maintained among schools, school nurses, and physicians to ensure continued support for each child.
One-year Follow-up After Intervention, Stratified by Obesity Severity (Moderate vs. Severe Obesity)
Follow-up Outcomes One Year After Intervention, Stratified by Age
Changes in the Prevalence of Abnormal Findings from Initial Visit to Final Evaluation
This comprehensive effort illustrates how growth curve-based monitoring during school health checkups can serve as a powerful screening and intervention tool for pediatric obesity and metabolic syndrome. It also emphasizes the importance of early and individualized intervention, as well as consistent school-community collaboration, to reduce dropout and sustain long-term health improvements.
Pediatric lifestyle disease screening plays a vital role in preventing future health problems; however, its implementation across Japan remains limited due to its non-mandatory status. The absence of a legal framework has led to significant regional disparities, and national expansion has not yet been realized. Furthermore, programs that target only obese children risk missing non-obese cases of type 2 diabetes and FH, both of which can develop without obvious weight-related symptoms.
To address these issues, it is essential to promote standardized universal screening for all children in specific grades. Screening results should be utilized not only for early detection but also for enhancing health education and raising awareness among children and families. Strengthened cooperation among schools, families, and healthcare providers will further support effective interventions and follow-up.
An illustrative example is Kagawa Prefecture, where lifestyle diseases and FH screenings have been integrated into a unified prefecture-wide program. This model demonstrates the feasibility of combining metabolic and genetic risk detection and offers insights for broader national applications.
In particular, the prevention, education, and early screening of pediatric obesity should not be limited to specific grade levels but should be implemented across all grades, including younger children, before the onset or progression of obesity becomes apparent. Longitudinal cohort data from Japan indicate that weight gain trajectories leading to obesity often begin in early school years, reinforcing the importance of age-appropriate and continuous screening efforts17). Monitoring tools such as growth and obesity curves, which track height and weight trends over time during school health checkups, are useful for the early detection of both obesity and undernutrition.
Efforts must also include stronger collaboration among the Boards of Education, schools, local medical associations, and healthcare institutions. These partnerships ensured consistent follow-up and continuous support for children and families across different regions.
In conclusion, while pediatric lifestyle disease screening has meaningfully contributed to child health management in Japan, further challenges remain. The development of national screening criteria for pediatric lifestyle-related conditions, such as obesity, dyslipidemia, type 2 diabetes, and FH, is a critical next step along with improved parental awareness, enhanced collaboration with primary care providers, and expanded access to specialist care. A coordinated, community-based approach is essential to promote healthy growth and the long-term well-being of children throughout the country.
