Background: The association between body size, weight change and depression has not been systematically summarised, especially for individuals who are underweight.Aims: To conduct a systematic review and a meta-analysis to examine the association between indices of body size, weight change and depression.Method: A total of 183 studies were selected. Fully adjusted hazard ratios (HRs) or odds ratios (ORs) were extracted. A total of 76 studies contributed to data synthesis with a random-effect model, and subgroup analyses were conducted to evaluate the effect of potential moderators.Results: In cohort studies, underweight at baseline increased the risk of subsequent depression (OR = 1.16, 95% CI 1.08–1.24). Overweight (BMI 25–29.9 kg/m²) showed no statistically significant relationship with depression overall; however, the subgroup analyses found different results according to gender (men: OR = 0.84, 95% CI 0.72–0.97, women: OR = 1.16, 95% CI 1.07–1.25). In cross-sectional designs, obesity with BMI >40kg/m²showed a greater pooled odds ratio than obesity with BMI >30kg/m².Conclusions: Both underweight and obesity increase the risk of depression. The association between overweight and depression differs by gender.

Background: Smoking is by far the most important cause of cancer that can be modified at the individual level. Cancer incidence and mortality rates in Korea are the highest among all Asian countries, and smoking prevalence in Korean men is one of the highest in developed countries. The purpose of the current study was to perform a systematic review and provide an evidence-based assessment of the burden of tobacco smoking-related cancers in the Korean population. Methods: Sex- and cancer-specific population-attributable fractions (PAF) were estimated using the prevalence of ever-smoking and second-hand smoking in 1989 among Korean adults, respectively, and the relative risks were estimated from the meta-analysis of studies performed in the Korean population for ever-smoking and in the Asian population for passive smoking. National cancer incidence data from the Korea Central Cancer Registry and national cancer mortality data from Statistics Korea for the year 2009 were used to estimate the cancer cases and deaths attributable to tobacco smoking. Results: Tobacco smoking was responsible for 20,239 (20.9%) cancer incident cases and 14,377 (32.9%) cancer deaths among adult men and 1,930 (2.1%) cancer incident cases and 1,351 (5.2%) cancer deaths among adult women in 2009 in Korea. In men, 71% of lung cancer deaths, 55%–72% of upper aerodigestive tract (oral cavity, pharynx, esophagus and larynx) cancer deaths, 23% of liver, 32% of stomach, 27% of pancreas, 7% of kidney and 45% of bladder cancer deaths were attributable to tobacco smoking. In women the proportion of ever-smoking-attributable lung cancer was 8.1%, while that attributable to second-hand smoking among non-smoking women was 20.5%. Conclusions: Approximately one in three cancer deaths would be potentially preventable through appropriate control of tobacco smoking in Korean men at the population level and individual level. For Korean women, more lung cancer cases and deaths were attributable to second-hand than ever-smoking. Effective control programs against tobacco smoking should be further developed and implemented in Korea to reduce the smoking-related cancer burden.

Both short and long sleep duration have been consistently studied as a risk factor for obesity, hyperglycemia and hypertension. In this cross-sectional study, we provide an updated analysis of the Health Examinees (HEXA) study on the association between sleep duration and metabolic syndrome (MetS) occurrence among Koreans age 40–69 year olds. A total of 133,608 subjects (44,930 men, 88,678 women) were enrolled in the HEXA study 2004–2013. Sleep duration was categorized into 4 sleep categories (< 6 h, 6 to < 8 h, 8 to < 10 h, ≥10 h). MetS criterion was based on the National Cholesterol Education Program, Adult Treatment Panel III. Logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Compared with individuals sleeping 6 to < 8 h per day, less than 6 h of sleep was associated with MetS (multivariable adjusted OR: 1.12, 95% CI: 1.05–1.19) and elevated waist circumference (1.15, 1.08–1.23) among men; with elevated waist circumference (1.09, 1.04–1.14) among women. Greater than 10 h of sleep was associated with MetS (1.28, 1.08–1.50) and elevated triglycerides (1.33, 1.14–1.56) among men; with MetS (1.40, 1.24–1.58), elevated waist circumference (1.14, 1.02–1.27), elevated triglycerides (1.41, 1.25–1.58), reduced high-density lipoprotein cholesterol (HDL-C) (1.24, 1.12–1.38), and elevated fasting glucose (1.39, 1.23–1.57) among women. Less than 6 h of sleep is associated with elevated waist circumference among both men and women and with MetS among men only. Greater than 10 h of sleep is associated with MetS and elevated triglycerides among both men and women and with elevated waist circumference, reduced HDL-C, and elevated fasting glucose among women only.

Atopic dermatitis (AD) is a chronic skin disease which has been known to negatively influence the mental health of patients. However, only a few studies have explored the prevalence of psychiatric problems among AD patients, particularly among adolescents. In this study, we aimed to assess the association of AD with depressive symptoms and suicidal behaviors among adolescents by analyzing data from the 2013 Korean Youth Risk Behavior Survey, a nationwide web-based survey. Data from 72,435 adolescent middle and high school students in Korea were analyzed. Students self-reported AD diagnosed by a doctor and yes-or-no answers to questions about depressive symptoms and suicide ideation, suicide planning, and suicide attempts were analyzed. Relationships between AD and depressive symptoms or suicidal behaviors were tested by logistic regression models after controlling for potential confounding factors. The proportion of adolescents who had AD was 6.8%. The proportion of adolescents reporting depressive feelings was 31.0%, suicide ideation was 16.3%, suicide planning was 5.8%, and suicide attempts was 4.2%. Compared to adolescents without AD, adolescents with AD were significantly more likely to experience depressive feelings (odds ratio [OR]: 1.27, 95% confidence interval [Cl]: 1.19-1.36), suicide ideation (OR: 1.34, 95% Cl: 1.24-1.45), suicide planning (OR: 1.46, 95% Cl: 1.32-1.65), and suicide attempts (OR: 1.51, 95% Cl: 1.33-1.72). In the multivariate model, the relationships between AD and suicide ideation (OR: 1.26, 95% Cl:1.16-1.36), suicide planning (OR: 1.28, 95% Cl:1.14-1.44), and suicide attempt (OR: 1.29, 95% Cl:1.13-1.49) were statistically significant. Adolescents who have AD are associated with a higher prevalence of depression symptoms and suicidal behaviors. Adolescent AD patients may need interventions from clinicians and caregivers that use a holistic approach to prevent psychological comorbidities, although further research is needed to clarify this relationship.

Background: Although previous meta-analyses have suggested a dose–response relationship between body mass index (BMI) and thyroid cancer risk, limited evidence has been presented about Asian populations. To assess this association among Asian populations, where underweight is more prevalent than in other regions, a pooled analysis from the Asia Cohort Consortium was conducted. Methods: Baseline height and weight were measured in five cohorts and self-reported in eight cohorts. Thyroid cancer incidence was ascertained by linkage to local cancer registries. Cohorts were treated as a stratum in the Cox proportional hazard model to estimate the pooled hazard ratios (HRs) and corresponding confidence intervals (CIs) from the estimates for each cohort. All analyses were stratified by sex. Results: A total of 538,857 men and women from 13 cohorts from mainland China, Korea, Japan, and Singapore were included in the analysis. During a mean of 15.1 years of follow-up, 1132 thyroid cancer cases were ascertained. Using a BMI of 18.5–22.9 kg/m ² as a reference, an elevated risk of thyroid cancer was observed for groups with a BMI between 25 and 29.9 kg/m ² (HR: 1.31, [CI: 0.95–1.80]) and a BMI of 30 kg/m ² and greater (HR: 1.84, [CI: 0.89–3.81]) in men. Thyroid cancer risk was elevated in women with a BMI of 23–24.9 kg/m ² (HR: 1.26, [CI: 1.07–1.48]). The HRs for 5-U increment of BMI showed a linear association among men (HR: 1.25, [CI 1.10–1.55]) but not among women (HR: 1.07, [CI: 0.97–1.18]). Although the overall thyroid cancer risk was lower among underweight men and women, the papillary cancer risk may be elevated among underweight men (HR: 2.24, [CI: 0.75–6.66]). Conclusion: While higher BMI is associated with an elevated risk of thyroid cancer in both men and women, the association of underweight BMI may differ by sex and histological subtype.