The association between serum selenium levels and type 2 diabetes mellitus (T2DM) is controversial. We performed a systematic review and non-linear dose–response meta-analysis of observational studies to investigate the association in the present study. A comprehensive literature search was conducted using MEDLINE and EMBASE databases. A pooled odds ratio (OR) and related 95 % confidence interval (95 % CI) for T2DM between the highest and lowest serum selenium categories, and a non-linear dose–response relationship between selenium and T2DM were estimated. A total of five studies (of 13,460 participants) were identified as meeting the inclusion criteria. The pooled OR indicated that there was a significantly higher prevalence of T2DM in the highest category of blood selenium compared with the lowest (OR = 1.63, 95 % CI: 1.04–2.56, P = 0.033). Moreover, a significant non-linear dose–response relationship was observed between serum selenium levels and T2DM (P < 0.001). Serum selenium levels were positively associated with T2DM in populations with relatively low serum selenium levels (132.5 μg/l). The positive association between serum selenium levels and T2DM existed in populations with relatively low levels and high levels of serum selenium, indicating a likely U-shaped non-linear dose–response relationship between serum selenium and T2DM.

The objective of this study was to evaluate the association between dietary antioxidant intake (carotenoid, vitamin C, E and selenium) intake and metabolic syndrome (MS). This cross-sectional study included 2069 subjects undergoing a regular health checkup. Biochemical test results and data on dietary intakes were collected for analysis. Adjustment for energy intake and multi-variable logistic regression were performed to determine adjusted odds ratios (ORs) and corresponding 95% confidence intervals (95%CI) for the relationship between dietary antioxidants intake and MS. The lowest quartile of antioxidant intake was regarded as the reference category. Dietary vitamin C intake (P values for trend were 0.02 in energy adjusted analysis and 0.08 in multivariable adjusted analysis) had a negative association with MS, as did selenium intake in the second quartile (energy adjusted OR: 0.60, 95%CI: 0.43 to 0.85; multivariable adjusted OR: 0.60, 95%CI: 0.43 to 0.86). However, there was no significant relationship between dietary carotenoid and vitamin E intake and MS. Subjects with low intake of vitamin C might be predisposed to development of MS, while dietary selenium intake had a moderate negative association with MS. Dietary carotenoid and vitamin E intake was not associated with MS.

Suicide is a leading cause of death among men who have sex with men (MSM) and suicidal ideation may put individuals at higher risk of suicide. A great disparity of lifetime prevalence of suicidal ideation among MSM was observed across studies, indicating the importance of a reliable estimation of the pooled lifetime prevalence. However, the only one published meta-analysis estimating the pooled lifetime prevalence of suicidal ideation among MSM was conducted in 2008 with only 2 eligible studies. Subsequently, there was a rapid increase of publications about lifetime suicidal ideation among MSM, suggesting that an update on the pooled lifetime prevalence of suicidal ideation among MSM was necessary. Therefore, this study aimed to update the estimation of the pooled lifetime prevalence of suicidal ideation among MSM. Electronic databases of PubMed, CINAHL, Scopus (social science), Embase and PsycInfo were searched until September 2017 to identify relevant studies. Cross-sectional studies exploring the lifetime prevalence of suicidal ideation among MSM were enrolled. Heterogeneity was evaluated using the Cochran Q test and quantified using the I 2 statistic. The possibility of publication bias was assessed using both Begg’s rank test and Egger’s linear test, and an Egger’s funnel plot for asymmetry was presented. Subgroup analyses were performed according to the geographic area, sample source and HIV status. Nineteen studies with a total of 26,667 MSM were included, of which 9374 were identified with suicidal ideation. A high degree of heterogeneity (P ≤ 0.001, I 2 =99.2%) was observed among the eligible studies, with the reported prevalence ranging from 13.18 to 55.80%. The pooled lifetime prevalence of suicidal ideation among MSM by a random effects model was 34.97% (95% confidence interval: 28.35%–41.90%). Both the Begg’s rank test and Egger’s linear test indicated low possibility of publication bias. Subgroup analyses showed that the lifetime prevalence of suicidal ideation among MSM differed significantly by geographic area, sample source and HIV status (P < 0.05). The high pooled lifetime prevalence of suicidal ideation among MSM found in this meta-analysis significantly underscores the importance of early assessment of suicidal ideation among MSM, as well as the need for strengthening the psychological interventions.

Victims exposed to serious traumatic experiences may develop post-traumatic stress disorder (PTSD) and suffer this mental health problem for a long time. Different types of trauma displayed a chronicity rate of PTSD within the range of 6.3-68.9 %. As one of the most common and severe natural disasters, the natural progression of flood related PTSD has not been revealed. The aim of this study was to estimate the chronicity rate and identify the prognostic factors of PTSD in flood victims. Flood victims, who were over the age of 16 and diagnosed with PTSD in 2000 in Huarong, Ziyang, and Anxiang counties of Hunan province, China, were enrolled in this survey. Current probable PTSD was analyzed using the PTSD Checklist-Civilian version. Data were collected in face-to-face interviews and analyzed using univariate analysis and multiple logistic regression models. The rate of current probable PTSD was 15.4 %. The current occurrences of re-experiencing, avoidance/numbing, and hyper-arousal symptom groups were 69.3 %, 17.2 %, and 50.2 %, respectively. Significant prognostic factors for current probable PTSD were flood-related stressors (e.g., life-threatening experiences, extreme physical adversity, and extreme psychological adversity) and frequency of general collective action. The relationships still existed when taking the fluctuation of frequency of general collective action into consideration. Gender and education level showed no influence on the recovery from PTSD. The impact of age in this study was inconsistent; in the 2000 model, around 2006 model, around 2013 model, and all FGCA model, older age was positive prognosis factor for PTSD; in the univariate analysis and fluctuation model, age showed no influence on the recovery from PTSD. Our findings indicated that PTSD can persist 13 years after a flood. Demographic characteristics (e.g., age, gender, and education level) seem to have no influence on the recovery from PTSD. Trauma-related stressors and social participation are important predictors for remission from chronic PTSD.