Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Volume 20, Issue 1
Displaying 1-11 of 11 articles from this issue
Review Article
  • Hiroharu Kamioka, Kiichiro Tsutani, Hiroyasu Okuizumi, Yoshiteru Mutoh ...
    2010 Volume 20 Issue 1 Pages 2-12
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: October 31, 2009
    Background: The objective of this review was to summarize findings on aquatic exercise and balneotherapy and to assess the quality of systematic reviews based on randomized controlled trials.
    Methods: Studies were eligible if they were systematic reviews based on randomized clinical trials (with or without a meta-analysis) that included at least 1 treatment group that received aquatic exercise or balneotherapy. We searched the following databases: Cochrane Database Systematic Review, MEDLINE, CINAHL, Web of Science, JDream II, and Ichushi-Web for articles published from the year 1990 to August 17, 2008.
    Results: We found evidence that aquatic exercise had small but statistically significant effects on pain relief and related outcome measures of locomotor diseases (eg, arthritis, rheumatoid diseases, and low back pain). However, long-term effectiveness was unclear. Because evidence was lacking due to the poor methodological quality of balneotherapy studies, we were unable to make any conclusions on the effects of intervention. There were frequent flaws regarding the description of excluded RCTs and the assessment of publication bias in several trials. Two of the present authors independently assessed the quality of articles using the AMSTAR checklist.
    Conclusions: Aquatic exercise had a small but statistically significant short-term effect on locomotor diseases. However, the effectiveness of balneotherapy in curing disease or improving health remains unclear.
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Original Article
  • Sam-ang Seubsman, Lynette L-Y. Lim, Cathy Banwell, Nintita Sripaiboonk ...
    2010 Volume 20 Issue 1 Pages 13-20
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: November 21, 2009
    Background: As obesity increases, middle-income countries are undergoing a health-risk transition. We examine the association between socioeconomic status (SES) and emerging obesity in Thailand, and ascertain if an inverse relationship between SES and obesity has appeared.
    Methods: The data derived from 87 134 individuals (54% female; median age, 29 years) in a national cohort of distance-learning Open University students aged 15–87 years and living throughout Thailand. We calculated adjusted odds ratios for associations of SES with obesity (body mass index, ≥25) across 3 age groups by sex, after controlling for marital status, age, and urbanization.
    Results: Obesity increased with age and was more prevalent among males than females (22.7% vs 9.9%); more females were underweight (21.8% vs 6.2%). Annual income was 2000 to 3000 US dollars for most participants. High SES, defined by education, income, household assets, and housing type, associated strongly with obesity—positively for males and inversely for females—especially for participants younger than 40 years. The OR for obesity associated with income was as high as 1.54 for males and as low as 0.68 for females (P for trend <0.001).
    Conclusions: Our national Thai cohort has passed a tipping point and assumed a pattern seen in developed countries, ie, an inverse association between SES and obesity in females. We expect the overall population of Thailand to follow this pattern, as education spreads and incomes rise. A public health problem of underweight females could emerge. Recognition of these patterns is important for programs combating obesity. Many middle income countries are undergoing similar transitions.
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  • Naoto Taguchi, Yasuki Higaki, Shinichi Inoue, Hiromi Kimura, Keitaro T ...
    2010 Volume 20 Issue 1 Pages 21-29
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: November 07, 2009
    Background: Although studies suggest that exercise training improves physical performance and health-related quality of life (HRQOL) among elderly people, most of these studies have investigated relatively healthy persons. The objective of the present study was to determine the effects of a 12-month multicomponent exercise program on physical performance, daily physical activity, and HRQOL among very elderly people with minor disabilities.
    Methods: The subjects consisted of 65 elders (median age: 84 years) who were certified to receive long-term care in the form of support only or Level 1 care (the lowest level of care required); 31 were allocated to the intervention group and 34 to the control group. The intervention group participated in supervised exercises once a week for 12 months and in home-based exercises. The exercise program consisted of various exercises related to flexibility, muscle strength, balance, and aerobic performance.
    Results: After 12 months of exercise training, the intervention group had significant improvements in lower-limb strength and on the sit-and-reach test; these effects were not observed in the control group. The control group had significant decreases in grip strength, 6-minute walking distance, walking speed, and stride length; these decreases were not observed in the intervention group. No clear differences in HRQOL measurements or changes in physical activity were detected between groups.
    Conclusions: The 12-month multicomponent exercise program may effectively improve and maintain the physical performance of very elderly individuals with minor disabilities.
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  • Masaki Ohsawa, Karen Kato, Kazuyoshi Itai, Kozo Tanno, Yosuke Fujishim ...
    2010 Volume 20 Issue 1 Pages 30-39
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: October 31, 2009
    Background: Many studies have estimated the prevalence of anti-hepatitis C virus (HCV) antibody among hemodialysis (HD) patients; however, the prevalence of HCV core antigen—which indicates the presence of chronic HCV infection—is not known.
    Methods: Standardized prevalence ratios (SPRs) for anti-HCV antibody and HCV core antigen among HD patients (n = 1214) were calculated on the basis of data from the general population (n = 22 472) living in the same area.
    Results: The prevalences of anti-HCV antibody and HCV core antigen were 12.5% and 7.8%, respectively, in male hemodialysis patients, and 8.5% and 4.1% in female hemodialysis patients. The SPRs (95% confidence interval) for anti-HCV antibody and HCV core antigen were 8.39 (6.72–10.1) and 12.9 (9.66–16.1), respectively, in males, and 5.42 (3.67–7.17) and 8.77 (4.72–12.8) in females.
    Conclusions: The prevalences of chronic HCV infection among male and female HD patients were 13-fold and 9-fold, respectively, those of the population-based controls. Further studies should therefore be conducted to determine the extent of chronic HCV infection among HD patients in other populations and to determine whether chronic HCV infection contributes to increased mortality in HD patients.
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  • Megumi Hara, Yasuki Higaki, Takeshi Imaizumi, Naoto Taguchi, Kazuyo Na ...
    2010 Volume 20 Issue 1 Pages 40-45
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: November 07, 2009
    Background: Although many studies have examined factors that influence the response to postal questionnaires, few have addressed baseline recruitment for cohort studies involving genetic analyses. The aim of this study was to describe the method used for a baseline survey, the Japan Multi-institutional Collaborative Cohort Study (J-MICC Study), in Saga Prefecture, and to examine the factors that might influence the recruitment of participants in such studies.
    Methods: The Saga J-MICC Study is an ongoing population-based prospective cohort study of the genetic and environmental interactions associated with lifestyle-related disease. From 2005 through 2007, a total of 61 447 residents between the ages of 40 and 69 were invited by mail to participate in this study. The survey date and time were arranged by telephone.
    Results: Among that population, 31 002 (50.5%) responded and 12 078 (19.7%) agreed to participate. A completed questionnaire and blood pressure and anthropometric data were collected from all participants; blood, DNA specimens, and accelerometer measures were obtained from the great majority of them. Female sex and older age were associated with a higher participation rate. In addition, the convenience of the survey location and the sending of a reminder significantly improved the participation rate (odds ratio, 1.3).
    Conclusions: Our findings suggest that making the survey location as convenient as possible and sending a reminder can both substantially improve participation rate in population-based studies.
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  • Masayuki Okuda, Shinichi Sugiyama, Ichiro Kunitsugu, Yuji Hinoda, Yumi ...
    2010 Volume 20 Issue 1 Pages 46-53
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: October 24, 2009
    Background: Cutoffs based on percentage overweight (POW) are used for screening students in Japan; however, body mass index (BMI) is more common in the rest of the world. To screen for risk factors related to obesity among Japanese primary and secondary school students, we compared fasting and postprandial values, and the receiver operating characteristic (ROC) curves for the POW and BMI criteria.
    Methods: The subjects were students aged 10 and 13 years living in Shunan City, Japan between 2006 and 2008 (n = 6566). POW and International Obesity Taskforce (IOTF) BMI criteria were used to screen for obesity-related risk factors. The lower (20%, 18-year-old equivalent: 25 kg/m2) and higher (50%, 18-year-old equivalent: 30 kg/m2) cutoffs were examined, and ROC curves were drawn.
    Results: Fasting cholesterol levels were higher than postprandial levels. The prevalences of overweight/obesity were 6.6% to 10.0% using the lower cutoff and 0.6% to 5.0% using the higher cutoff. Among overweight subjects under fasting conditions, dyslipidemia was present in 12% to 52%, hypertriglyceridemia in 29% to 54%, hyperglycemia in 11% to 21%, and hypertension in 15% to 40%. Although the use of the lower and higher POW cutoffs resulted in lower sensitivity and the higher specificity, the POW and BMI ROC curves largely overlapped. However, for girls aged 10 years, the POW curve for ≥3 risks factors was lower than that of the latter (P = 0.013).
    Conclusions: For Japanese aged 10 and 13 years, both BMI and POW are useful for risk factor screening. However, subjects may be misclassified with dyscholesterolemia if postprandial blood samples are used.
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  • Tomohiro Saito, Hiroshi Nitta, Osami Kubo, Seiichiro Yamamoto, Naohito ...
    2010 Volume 20 Issue 1 Pages 54-61
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: November 14, 2009
    Background: The strength of the association between brain tumors in children and residential power-frequency magnetic fields (MF) has varied in previous studies, which may be due in part to possible misclassification of MF exposure. This study aimed to examine this association in Japan by improving measurement techniques, and by extending measurement to a whole week.
    Methods: This population-based case-control study encompassed 54% of Japanese children under 15 years of age. After excluding ineligible targeted children, 55 newly diagnosed brain tumor cases and 99 sex-, age-, and residential area-matched controls were included in the analyses. The MF exposures of each set of matching cases and controls were measured in close temporal proximity to control for seasonal variation; the average difference was 12.4 days. The mean interval between diagnosis and MF measurements was 1.1 years. The weekly mean MF level was defined as the exposure. The association was evaluated using conditional logistic regression analysis that controlled for possible confounding factors.
    Results: The odds ratios (95% CI) for exposure categories of 0.1 to 0.2, 0.2 to 0.4, and above 0.4 µT, against a reference category of <0.1 µT, were 0.74 (0.17–3.18), 1.58 (0.25–9.83), and 10.9 (1.05–113), respectively, after adjusting for maternal education. This dose-response pattern was stable when other variables were included in the model as possible confounding factors.
    Conclusions: A positive association was found between high-level exposure—above 0.4 µT—and the risk of brain tumors. This association could not be explained solely by confounding factors or selection bias.
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  • Yasunori Niwa, Shizukiyo Ishikawa, Tadao Gotoh, Kazunori Kayaba, Yosik ...
    2010 Volume 20 Issue 1 Pages 62-69
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: December 05, 2009
    Background: Metabolic syndrome increases the morbidity and mortality of cardiovascular diseases. However, few studies have examined the association between the incidence of stroke and metabolic syndrome, as defined by Japanese criteria. The aim of this study was to identify the association between stroke and metabolic syndrome, as defined by criteria used in Japan.
    Methods: A total of 2205 subjects (920 men and 1285 women) were examined between 1992 and 1995 as part of the Jichi Medical School Cohort Study. Metabolic syndrome was defined using the Japanese criteria. Medical records, computed tomography, and magnetic resonance imaging were used to diagnose stroke. The Cox proportional-hazards model was used to analyze the association between metabolic syndrome and incident stroke.
    Results: The prevalence of metabolic syndrome at baseline was 9.0% in men and 1.7% in women. There were 96 incident strokes during an 11.2-year follow-up period, 14 of which occurred in subjects with metabolic syndrome. Among subjects with metabolic syndrome, the age-adjusted hazard ratio (95% confidence interval) for stroke was 1.93 (0.94–3.96) in men and 6.85 (2.68–17.47) in women. After adjusting for age, smoking status, and alcohol drinking status, the hazard ratio was 1.89 (0.88–4.08) in men and 7.24 (2.82–18.58) in women. Age-adjusted hazard ratios associated with having 2 or more components of metabolic syndrome, with and without central obesity, were 2.93 (1.21–7.08) and 3.20 (1.23–8.31) in men and 1.75 (0.69–4.44) and 8.64 (2.82–28.03) in women, respectively.
    Conclusions: The presence of metabolic syndrome, as defined by Japanese criteria, increases the risk of stroke; this effect was highly significant among women.
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  • Lon Say Heng, Hiroshi Yatsuya, Satoshi Morita, Junichi Sakamoto
    2010 Volume 20 Issue 1 Pages 70-76
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: December 12, 2009
    Background: We determined the prevalence of vaginal douching (cleansing of the vagina with liquid) in a sample of Cambodian women, and examined the associations of douching with genitourinary symptoms and infections, after controlling for potential confounding factors, including genitourinary symptoms and sociodemographic factors.
    Methods: A total of 451 adolescent and adult females aged 15 to 49 years who attended 17 maternal and child health (MCH) clinics in 7 provinces of Cambodia in 2001 were consecutively enrolled as a part of the Sexually Transmitted Infection Sentinel Survey. Sociodemographic factors, genitourinary symptoms, and frequency of douching were assessed by face-to-face interviews using a structured questionnaire. Vaginal infections were examined by using standard diagnostic procedures specific to each pathogen.
    Results: The proportion of participants who douched at least once a week was 76.7% (n = 346). Douching was significantly more prevalent in urban than in rural women (85.7%, n = 198 vs 67.3%, n = 148; P < 0.001). Frequency of douching was significantly associated with genitourinary symptoms, which were most prevalent in participants who douched from several times a week to once a day; genitourinary symptoms were less prevalent in those who douched more than once a day. Douching was significantly associated with vaginal candidiasis, but not with trichomoniasis or bacterial vaginosis, and this association persisted even after controlling for sociodemographic factors and genitourinary symptoms.
    Conclusions: Vaginal douching was very common among Cambodian women visiting MCH clinics. Further investigations are warranted to elucidate the reasons for douching. In addition, women should be informed that douching may endanger their reproductive health.
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  • Tomoyuki Hanaoka, Katsumi Mita, Azuma Hiramoto, Yasuyuki Suzuki, Shizu ...
    2010 Volume 20 Issue 1 Pages 77-81
    Published: January 05, 2010
    Released on J-STAGE: January 05, 2010
    Advance online publication: November 28, 2009
    Background: Although the prognosis for survival in people with severe functional disabilities is a serious concern for their families and health care practitioners, there have been few reports on survival rates for this population. Every year, the Japanese Association of Welfare for Persons with Severe Motor and Intellectual Disability collects anonymous records of individual registrations and deaths from all private and public institutions, excepting national institutions. We used these data to estimate the prognosis for survival.
    Methods: We reviewed the records of 3221 people with severe motor and intellectual disabilities (SMID); all subjects had lived in one of 119 public or private institutions in Japan between 1961 and 2003. Kaplan–Meier survival estimates were calculated according to disability type and birth year range.
    Results: Of the 3221 persons, 2645 were alive and 576 had died. The survival rate at the age of 20 for all subjects was 79% (95% confidence interval, 78%–81%). Among people who were unable to sit, those with lower intelligence quotients had lower survival rates.
    Conclusions: The survival rate among people with SMID housed in public and private institutions in Japan was much worse than that of the general population, and has not improved since the 1960s.
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