Environmental Health and Preventive Medicine

To investigate the association of serum lipids and high-sensitivity C-reactive protein (hs-CRP) with obesity in school children and to explore whether hs-CRP levels could be used to predict the presence or absence of obesity 12 months later. The subjects were school children (6–11 years old) in Japan. Blood sampling and physical measurements were performed in school (2001); low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, and hs-CRP levels were measured. Data from children who could be followed 12 months later were analyzed. Subjects weighing 20 % or more over his/her standard weight were regarded as obese, and the association of obesity with serum parameters was analyzed. Data from 612 subjects were analyzed (follow-up rate, 75.4 %). The mean of each serum parameter was significantly higher (inverse for HDL-C; lower) in obese than that in non-obese children. Logistic regression analysis for obesity at baseline showed that the odds ratio (OR) of hs-CRP was the highest [OR, 2.15; 95 % confidence interval (CI), 1.65–2.78 for an interquartile rage (IQR) increase]; the association with triglycerides and LDL-C/HDL-C was significant. At the 12-month follow-up, the OR of high hs-CRP remained the highest of all serum parameters (2.09; 95 % CI, 1.63–2.69 for an IQR increase). High levels of triglycerides, LDL-C/HDL-C, and hs-CRP increased the risk of obesity in school children. Hs-CRP is considered to be a better predictor of obesity 12 months later than is LDL-C/HDL-C.

To evaluate the impacts of health examinations (HE) and smoking on disease mortality risk in Japan. By using the large cohort database of a Japanese life insurance company, 720,611 subjects aged 20 to 80 years, who had contracted for life insurance between April 1, 1995 and March 31, 1998, were followed up until September 30, 1999. Cox’s proportional hazard model was used to estimate age-adjusted relative risk (RR) for disease death. After adjusting for age, disease mortality in smokers was significantly higher than that in non-smokers (men, RR 1.51, 95% CI: 1.25–1.81; women, RR 1.54, 95% CI: 1.12–2.11). Meanwhile, disease mortality in HEees (those who had got HE within the past 2 years) was significantly lower than that in non-HEees (men, RR 0.70, 95% CI: 0.56–0.88; women, RR 0.71, 95% CI: 0.54–0.92). The magnitude of the impact of HE on disease mortality risk varied according to smoking status. Non-smokers showed a significantly lower risk associated with HE, whereas smokers did not. HE may allow an appreciable reduction in disease mortality, however, the reduction effect may be limited to non-smokers. Smoking cessation may be essential to improve the preventive effects of HE.

The present study investigated the relationship between coping skills and job satisfaction among Japanese full-time occupational physicians (OPs). In 2000 we mailed self-administered questionnaires to 716 full-time OPs who were members of “Sanyu-kai”, the only Japanese association of full-time OPs. The questionnaires included age, gender, marital status, main type of company’s work, the number of full-time OPs, the number of employees, working years as an OP, tenure in the present company, job stress, and coping skills question. The coping skills questions consisted of 11 items which were decided after discussion among several experienced full-time OPs. In total, 351 (49%) of the OPs returned suitable questionnaires for analyses. Considering age, gender, marital status, and coping skills, multiple regression analysis (stepwise method) found that age, simplification of work, obvious roles for staff, consultations, and communication in the community and company were factors which contributed significantly to job satisfaction. Structural equation modeling showed that age and coping skills such as work system improvements, consultations, and communication in the community and company influenced job satisfaction. Our results indicated that the age and coping skills influenced job satisfaction among full-time OPs. Our results are also considered to support the training of OPs in the future.

Most studies have investigated the association between parental socioeconomic factors and dental caries in children based on educational and income levels; studies focusing on parental occupation, however, have been relatively limited. This cross-sectional study examined the associations between parental occupations and levels of education and household income and the prevalence of dental caries in Japanese children aged 3 years. Study subjects were 6315 children. Oral examination results were obtained from the parents or guardians, who transcribed the information recorded by medical staff at a public health center from their maternal and child health handbooks to our self-administered questionnaire. Children were classified as having dental caries if one or more primary teeth had decayed or had been filled. Adjustment was made for sex, age, region of residence, breastfeeding duration, between-meal snack frequency, toothbrushing frequency, use of fluoride, regular dental check-ups, maternal smoking during pregnancy, and living with at least one household smoker. The prevalence of dental caries was 14.7%. Compared with having an unemployed father, having a father employed in professional and engineering, clerical, sales, security, or manufacturing process was significantly associated with a lower prevalence of dental caries. Compared with having an unemployed mother, having a mother employed in professional and engineering or service was significantly inversely associated with the prevalence of dental caries. Significant inverse associations were observed between parental levels of education and household income and the prevalence of dental caries. The findings of our study suggest that parental occupation affects the prevalence of dental caries in children. We confirm that higher levels of parental education and household income decreased the prevalence of dental caries.

To examine changes in psychological distress prevalence among pregnant women in Miyagi Prefecture, which was directly affected by the Great East Japan Earthquake and tsunami, and compare it with the other, less damaged areas of Japan. This study was conducted in conjunction with the Japan Environment and Children`s Study. We examined 76,152 pregnant women including 8270 in Miyagi Regional Center and 67,882 in 13 other regional centers from the all-birth fixed data of the Japan Environment and Children’s Study. We then compared the prevalence and risk of distress in women in Miyagi Regional Center and women in the 13 regional centers for 3 years after the disaster. Women in the Miyagi Regional Center suffered more psychological distress than those in the 13 regional centers: OR 1.38 (95% CI, 1.03–1.87) to 1.92 (95% CI, 1.42–2.60). Additionally, women in the inland area had a consistently higher prevalence of psychological distress compared to those from the 13 regional centers: OR 1.67 (95% CI, 1.18–2.38) to 2.19 (95% CI, 1.60–2.99). The lack of pre-disaster data in the Japan Environment and Children’s Study made it impossible to compare the incidence of psychological distress before and after the March 2011 Great East Japan Earthquake. However, 3 years after the Great East Japan Earthquake, the prevalence of pregnant women with psychological distress did not improve in Miyagi Regional Center. Further, the prevalence of mental illness in inland areas was consistently higher than that in the 13 regional centers after the disaster.

Scale development of health-related quality of life (HRQOL) measures, including physical and mental health measures, among public datasets from Japan is needed for comparative studies on health conditions among different age, gender, and socio-economic subgroups. Multi-attributable scales of continuous/discrete variables on HRQOL could be more flexible for different kinds of epidemiologic and socio-econometric studies rather than single-item measures. The objectives of this study were to create multi-dimensional scales for physical, mental, and summary health measures and to describe the age-related trends of these scales in Japan. We utilized data from the 2007 Comprehensive Survey of the Living Conditions of People on Health and Welfare (LCPHW: Kokumin Seikatsu Kiso Chosa) (n = 383,745) to measure physical health (0 = worst score, 16 = best score) by summarizing four items: general health status, bedridden status/mobility, self-care/usual activities, and pain (0 = worst score, 4 = best score for each item). Mental health was measured using a Japanese version of K6 (0 = worst score, 4 = best score, modified from original version in which 24 = worst score and 0 = best score). We then created a summary health scale using the simple sum of physical and mental health (0 = worst score, 20 = best score). The reliability and validity of the scales were evaluated and their age-related trends described. The internal consistency reliability of the physical and summary health scales was not sufficiently high (Cronbach’s α = 0.64 and 0.67, respectively) and the age-related trend was smooth and monotonous. The internal consistency reliability of the mental health scale (K6) was high (Cronbach’s α = 0.90), while the age-related trend peaked at age 65–74 years. While K6 was a measure with high reliability for describing mental health, use of the physical and summary health scale in the Japanese population requires further discussion. Additional validation tests of the summary scales also need to be performed, in which our methodology is applied to other data sets that include strict diagnostic results based on a structural interview.

Moyamoya disease—an idiopathic vascular disorder of intracranial arteries—is often accompanied by hypertension. RNF213 has been identified as a susceptibility gene for moyamoya disease. In the present study, the association of p.R4810K (G>A) with blood pressure (BP) was investigated in a Japanese population. Three independent study populations, the Nyukawa (n = 984), Noshiro (n = 2,443) and Field (n = 881) studies, joined this study. BP, body weight and height were measured. Past and present symptoms and disease and medication histories were assessed by interview. Associations of p.R4810K (rs112735431, ss179362673) of RNF213 with BP were investigated. Two linkage disequilibrium blocks were constructed for moyamoya patients with p.R4810K (n = 140) and the general population (n = 384) using 39 single nucleotide polymorphisms (SNPs) spanning 390 kb around RNF213. A total of 60 carriers (3 for AA genotype and 57 for GA genotype) were found in these samples, and the minor allele frequencies were 1.4 % in the Nyukawa and Field studies and 0.2 % in the Noshiro study. Regression analyses adjusted for age, sex and body mass index based on an additive model demonstrated significant associations with systolic BP (mmHg/allele): β (standard error) was 8.2 (2.9) in the Nyukawa study (P = 4.7 × 10−3), 18.7 (5.4) in the Noshiro study (P = 4.6 × 10−4) and 8.9 (2.0) (P = 1.0 × 10−5) in the three populations. In contrast, diastolic BP showed significant associations only in the Noshiro study. Linkage disequilibrium blocks contained none of the BP-associated proxy SNPs reported by previous studies. Our study suggests that p.R4810K of RNF213 is associated strongly with systolic BP.

The effects of prenatal exposure to toxic elements on birth outcomes and child development have been an area of concern. This study aimed to assess the profile of prenatal exposure to toxic elements, arsenic (As), bismuth (Bi), cadmium (Cd), mercury (total mercury (THg), methylmercury (MHg), inorganic mercury (IHg)), lead (Pb), antimony (Sb) and tin (Sn), and essential trace elements, copper (Cu), selenium (Se) and zinc (Zn), using the maternal blood, cord blood and placenta in the Tohoku Study of Child Development of Japan (N = 594–650). Inductively coupled plasma mass spectrometry was used to determine the concentrations of these elements (except mercury). Levels of THg and MeHg were measured using cold vapour atomic absorption spectrophotometry and a gas chromatograph-electron capture detector, respectively. Median concentrations (25th–75th) of As, Cd, Pb, Sb, Sn and THg in the maternal blood were 4.06 (2.68–6.81), 1.18 (0.74–1.79), 10.8 (8.65–13.5), 0.2 (0.06–0.40) and 0.2 (0.1–0.38) ng mL−1 and 5.42 (3.89–7.59) ng g−1, respectively. Median concentrations (25th–75th) of As, Cd, Pb, Sb, Sn and THg in the cord blood were 3.68 (2.58–5.25), 0.53 (0.10–1.25), 9.89 (8.02–12.5), 0.39 (0.06–0.92) and 0.2 (0.2–0.38) ng mL−1 and 9.96 (7.05–13.8) ng g−1, respectively. THg and Sb levels in the cord blood were twofold higher than those in the maternal blood. Cord blood to maternal blood ratios for As, Cd and Sb widely varied between individuals. To understand the effects of prenatal exposure, further research regarding the variations of placental transfer of elements is necessary.

Communicating health messages is an important way to influence people’s behaviors towards health issues. Providers need to incorporate audience’s perspective to design more persuasive messages. This study aimed to develop rating scales for measuring audience’s perception of effectiveness of health messages in Japanese people. The comprehensibility scale including five items and the persuasiveness scale including seven items were designed based on literature review. A cross-sectional web-based survey was conducted among Japanese adults aged 35–45 years to assess the reliability and validity of the scales. Participants were asked to rate a text message that encouraged help-seeking intention for insomnia. All scale items were scored on a 1-to-5 point Likert scale, and they were averaged to produce an overall score for each scale. Explanatory factor analysis revealed a two-factor solution that agreed with the comprehensibility and persuasiveness scales, respectively. Correlation coefficients between each set of items ranged between 0.63–0.87 for the comprehensibility scale and 0.37–0.76 for the persuasiveness scale. Cronbach alpha (0.88) indicated satisfactory internal consistency of the set of items. The mean (SD) of the comprehensibility and persuasiveness scores were 3.70 (0.82) and 3.15 (0.61), respectively, without ceiling or floor effects. These scores were significantly associated with intended future use of the message. The proportion of participants who reported a positive help-seeking intention for insomnia was significantly higher in the higher score groups for both scales. Multiple logistic regression analysis showed that the comprehensibility and persuasiveness scores were significantly associated with the help-seeking intention for insomnia. The proposed rating scales exhibited adequate reliability and validity for measuring the comprehensibility and persuasiveness of insomnia health-seeking message in middle-aged Japanese people. Further studies are needed to confirm the generalizability of the results, but these scales may be useful for pretesting a health message with audience members to make it more acceptable and persuasive to the intended audience. Not applicable; this is not a report of intervention trial.