Journal of Epidemiology Vol. 27(2017) No. 6

Iodine deficiency remains a considerable challenge worldwide, even after decades of efforts to address the problem. The aim of this review is to present the current situation in historically iodine-deficient Pakistan regarding iodine nutritional status and place it in a global perspective. We collected relevant articles from online bibliographic databases and websites of concerned organizations that addressed prevalence of goiter/iodine deficiency and barriers to sustainable control. We divided the studies into pre- and post-1994, a landmark year when Pakistan formally adopted the universal salt iodization (USI) programme. Overall, 56 studies reported goiter/iodine deficiency prevalence in Pakistan. Before 1994, six studies (30%) reported a goiter prevalence ≥70%, while nine studies (45%) reported a goiter prevalence between 30% and 70%. Only five studies (25%) found a goiter prevalence less than 30%, of which only two studies reported prevalence <10%. From 1994 onwards, 15 studies (41.7%) reported a goiter/iodine deficiency (ID) prevalence ≥50%, of which seven studies reported prevalence ≥70%, while three studies (8.3%) found a goiter prevalence of 30%–49%, nine studies (25%) found a goiter prevalence of 10%–29%, and five studies (13.9%) reported prevalence of <10%. Four studies (11.1%) reported lower goiter prevalence but higher prevalence of iodine deficiency. The efforts in the past two decades resulted in up to a 50% decline in iodine deficiency disorders (IDD). Variable remaining factors and the recent results, however, indicate that this decline may be non-uniform and even over-estimated. Coordinated and regionally adopted efforts for eradication of IDD from all stakeholders should be pursued. Policy makers should take steps to protect future generations and alert concerned organizations about the importance of careful assessments and estimates of iodine nutritional status.

Background: The relation of income and socioeconomic status with suicide rates remains unclear. Most previous studies have focused on the relationship between suicide rates and macroeconomic factors (e.g., economic growth rate). Therefore, we aimed to identify the relationship between individuals' socioeconomic position and suicide risk.

Methods: We analyzed suicide mortality rates across socioeconomic positions to identify potential trends using observational data on suicide mortality collected between January 2003 and December 2013 from 1,025,340 national health insurance enrollees. We followed the subjects for 123.5 months on average. Socioeconomic position was estimated using insurance premium levels. To examine the hazard ratios of suicide mortality in various socioeconomic positions, we used Cox proportional hazard models.

Results: We found that the hazard ratios of suicide showed an increasing trend as socioeconomic position decreased. After adjusting for gender, age, geographic location, and disability level, Medicaid recipients had the highest suicide hazard ratio (2.28; 95% CI, 1.87–2.77). Among the Medicaid recipients, men had higher hazard ratios than women (2.79; 95% CI, 2.17–3.59 vs. 1.71; 95% CI, 1.25–2.34). Hazard ratios also varied across age groups. The highest hazard ratio was found in the 40–59-year-old group (3.19; 95% CI, 2.31–4.43), whereas the lowest ratio was found in those 60 years and older (1.44; 95% CI, 1.09–1.87).

Conclusions: Our results illuminate the relationship between socioeconomic position and suicide rates and can be used to design and implement future policies on suicide prevention.

Background: The growth of youth with Down syndrome (DS) differs from that of youth without DS, and growth charts specific to DS have been developed. However, little is known about the growth of Brazilian youth with DS. The objective of this study was to construct growth charts for Brazilian youth with DS and compare the growth data with the Child Growth Standards of the World Health Organization (WHO) and charts for children with DS from other studies.

Methods: Mixed longitudinal and cross-sectional data were collected at University of Campinas, 48 specialized centers for people with intellectual disabilities, and two foundations for people with DS between 2012 and 2015. A total of 10,516 growth measurements from birth to 20 years of age were available from 938 youth with DS (53.7% boys) born between 1980 and 2013. The Lambda Mu Sigma method was applied to construct the curves using generalized additive models for location, scale, and shape.

Results: Length/height-for-age, weight-for-age, and head circumference-for-age percentile curves were generated for Brazilian boys and girls from birth to 20 years of age. Differences in growth of Brazilian youth ranged from −0.8 to −3.2 z-scores compared to WHO standards, and −1.9 to +1.3 compared to children with DS in other studies.

Conclusions: These specific growth charts may guide clinicians and families in monitoring the growth of Brazilian children and adolescents with DS.

Background: In China, waterborne outbreaks of infectious diarrheal disease mainly occur in schools, and contaminated well water is a common source of pathogens. The objective of this review was to present the attack rates, durations of outbreak, pathogens of infectious diarrheal disease, and sanitary conditions of wells in primary and secondary schools in China, and to analyze risk factors and susceptibility of school children.

Methods: Relevant articles and reports were identified by searching PubMed, Web of Science, China National Knowledge Infrastructure, China Information System for Disease Control and Prevention, and the Chinese Field Epidemiology Training Program. Essential information, including urban/rural areas, school types, attack rates, pathogens, durations of outbreak, report intervals, and interventions were extracted from the eligible articles. Wilcoxon signed-rank test, Kruskal–Wallis H test, and Spearman correlation test were conducted in statistical analyses. Sex- and age-specific attack rate ratios were calculated as pooled effect sizes.

Results: We screened 2188 articles and retrieved data of 85 outbreaks from 1987 to 2014. Attack rates of outbreaks in rural areas (median, 12.63 cases/100 persons) and in primary schools (median, 14.54 cases/100 persons) were higher than those in urban areas (median, 5.62 cases/100 persons) and in secondary schools (median, 8.74 cases/100 persons) (P = 0.004 and P = 0.013, respectively). Shigella, pathogenic Escherichia coli, and norovirus were the most common pathogens. Boys tended toward higher attack rates than girls (sex-specific attack rate ratio, 1.13; 95% CI, 1.00–1.29, P = 0.05). Unsanitary conditions of water wells were reported frequently, and unhealthy behavior habits were common in students.

Conclusion: School children were susceptible to waterborne disease in China. Chinese government should make efforts to improve access to safe water in schools. Health education promotion and conscientiousness of school leaders and teachers should be enhanced.

Background: The prevalence of abdominal obesity is increasing dramatically worldwide. This study aimed to estimate the current prevalence of abdominal obesity from the 2011 China Health and Nutrition Survey (CHNS) and compare the data with other countries.

Methods: Waist circumference (WC) of 12,326 Chinese adults (aged 20 years or older) from the 2011 CHNS were analyzed by age group and region. Abdominal obesity was defined as a WC ≥90 cm for men and WC ≥80 cm for women based on World Health Organization (WHO) recommendations for Asians.

Results: In 2011, the age-adjusted mean WC was 85.9 cm (95% confidence interval [CI], 85.6–86.2 cm) for men and 80.7 cm (95% CI, 80.4–80.9 cm) for women. Based on the WHO recommendations, the ageadjusted prevalence of abdominal obesity was 44.0% (95% CI, 43.1%–44.8%) overall, 35.3% (95% CI, 34.1%–36.6%) in men, and 51.7% (95% CI, 50.5%–52.9%) in women. Moreover, the age-adjusted prevalence was 44.0% (95% CI, 42.7%–45.2%) in rural populations, 42.5% (95% CI, 40.7%–44.2%) in urban populations, and 45.2% (95% CI, 43.5%–46.9%) in megacity populations. The prevalence in China (35.3% for men and 51.7% for women) was lower than in Japan (50.8% for men) and the United States (43.5% for men and 64.7% for women). Similar results were observed when applying the criteria suggested by the Working Group on Obesity in China.

Conclusions: In 2011, the age-adjusted prevalence of abdominal obesity in China was 35.3% in men and 51.7% in women.

Background: Living status (e.g., living with family or alone) may affect dietary habits. We compared nutritional adequacy according to living status and the frequency of eating out-of-home foods in young Japanese women.

Methods: Female dietetic students (aged 18–20 years; n = 4,017) participated in a cross-sectional multicenter study, which was conducted in 85 dietetic schools in 35 of 47 prefectures in Japan. Habitual dietary intake was assessed with a validated diet history questionnaire. Nutritional adequacy was determined based on the Dietary Reference Intakes for Japanese, 2015, for two goals: preventing non-communicable chronic disease (a tentative dietary goal for preventing lifestyle-related diseases [DG] that tracks five nutrients) and avoiding insufficient intake of mainly vitamins and minerals (estimated average requirement [EAR] that tracks 14 nutrients).

Results: Women living with their family were less likely to meet DG nutrient levels, but more likely to meet EAR nutrient levels compared with those living alone. In contrast, women living alone had more inadequate nutrients with EAR and fewer nutrients with not-meeting DG than those living with families. A higher frequency of eating out-of-home was significantly associated with a higher prevalence of notmeeting DG nutrient levels only in the women living with their family.

Conclusions: The prevalence of nutritional adequacy varied based on living status. In addition, women living with their family and those with a high frequency of eating out-of-home foods had the highest prevalence of not-meeting DG. Effective ways of improving dietary quality among young Japanese women differ by living status.

Background: To date, the amount of heterogeneity among studies of the body mass index-mortality association attributable to differences in the age distribution and length of follow-up has not been quantified. Therefore, we wanted to quantify the amount of heterogeneity attributable to age and follow-up in results of studies on the body mass index-mortality relation.

Methods: We used optima of the body mass index mortality association reported for 30 populations and performed meta-regression to estimate the amount of heterogeneity attributable to sex, ethnicity, mean age at baseline, percentage smokers, and length of follow-up.

Results: Ethnicity as single factor accounted for 36% (95% CI, 11–56%) of heterogeneity. Mean age and length of follow-up had an interactive effect and together accounted for 56% (95% CI, 24–74%) of the remaining heterogeneity. Sex did not significantly contribute to the heterogeneity, after controlling for ethnicity, age, and length of follow-up.

Conclusions: A considerable amount of heterogeneity in studies of the body mass index-mortality association is attributable to ethnicity, age, and length of follow-up.