Depressive Symptoms as a Mediator between Excessive Daytime Sleepiness and Suicidal Ideation among Chinese College Students.

The purpose of this study was to verify the mediating role of depressive symptoms between excessive daytime sleepiness and suicidal ideation in college students. Of the 6944 participants, 2609 (37.6%) were male and 4335 (62.4%) were female. College students with excessive daytime sleepiness (p < 0.001) and those with depressive symptoms (p < 0.001) were more likely to have suicidal ideation. Moreover, both excessive daytime sleepiness (ß = 0.14, 95% CI: 1.01−1.32) and depressive symptoms (ß = 1.47, 95% CI: 3.80−5.00) were associated with suicidal ideation. The effect size of the mediating role of depressive symptoms in excessive daytime sleepiness to suicidal ideation was 50.41% for the entire sample, 58.33% for males, and 42.98% for females. Depressive symptoms partially mediated the relationship between excessive daytime sleepiness and suicidal ideation. The timely assessment of depressive symptoms in college students with excessive daytime sleepiness, and intervention, may reduce their risk of suicidal ideation.

Suicide and non-suicide mortality and associated risk factors among suicide attempters: A 10-year follow-up of a large cohort in rural China.

Previous suicide attempt is a strong risk factor for subsequent suicide and other causes of mortality, but evidence from China is sparse. In this study, follow up face-to-face interviews were conducted with suicide attempters or a key informant, and any subsequent deaths were examined through local cause-of-death censoring databases to ascertain details surrounding the death. Competitive risk models and Cox proportional hazard regression models were used to ascertain significant risk factors of suicide, non-suicide and overall deaths following suicide attempt. Predictive nomograms were also constructed to predict the probability of suicide, non-suicide, and overall deaths. A total of 1103 suicide attempters were successfully interviewed with an average follow-up time of 7.48 (7.38-7.57) years. The cumulative rates of suicide at 1, 2, 3, 5 and 10 years were 0.27%, 0.63%, 0.91%, 1.56%, and 1.83%, respectively. Factors significantly associated with subsequent suicide were advancing age, history of suicide attempt, and mental disorders. Significant risk factors for non-suicide death included males, advancing age, and physical illness. Overall deaths during the follow-up period were associated with males, advancing age, physical illness, and mental disorders. Predictive models showed good ability with satisfactory C-indexes (between 0.77 and 0.86) and excellent calibration performance in predicting the varying causes of subsequent death among suicide attempters in rural China.

Prediction of recurrent suicidal behavior among suicide attempters with Cox regression and machine learning: a 10-year prospective cohort study.

BACKGROUND: Research on predictors and risk of recurrence after suicide attempt from China is lacking. This study aims to identify risk factors and develop prediction models for recurrent suicidal behavior among suicide attempters using Cox proportional hazard (CPH) and machine learning methods. METHODS: The prospective cohort study included 1103 suicide attempters with a maximum follow-up of 10 years from rural China. Baseline characteristics, collected by face-to-face interviews at least 1 month later after index suicide attempt, were used to predict recurrent suicidal behavior. CPH and 3 machine learning algorithms, namely, the least absolute shrinkage and selection operator, random survival forest, and gradient boosting decision tree, were used to construct prediction models. Model performance was accessed by concordance index (C-index) and the time-dependent area under the receiver operating characteristic curve (AUC) value for discrimination, and time-dependent calibration curve along with Brier score for calibration. RESULTS: The median follow-up time was 7.79 years, and 49 suicide attempters had recurrent suicidal behavior during the study period. Four models achieved comparably good discrimination and calibration performance, with all C-indexes larger than 0.70, AUC values larger than 0.65, and Brier scores smaller than 0.06. Mental disorder emerged as the most important predictor across all four models. Suicide attempters with mental disorders had a 3 times higher risk of recurrence than those without. History of suicide attempt (HR = 2.84, 95% CI: 1.34-6.02), unstable marital status (HR = 2.81, 95% CI: 1.38-5.71), and older age (HR = 1.51, 95% CI: 1.14-2.01) were also identified as independent predictors of recurrent suicidal behavior by CPH model. CONCLUSIONS: We developed four models to predict recurrent suicidal behavior with comparable good prediction performance. Our findings potentially provided benefits in screening vulnerable individuals on a more precise scale.

Effects of vitamin D-related gene polymorphisms on attempted suicide.

OBJECTIVE: Emerging evidence suggests that vitamin D might protect from attempted suicide. The study aimed to investigate the associations between single-nucleotide polymorphisms (SNPs) related to vitamin D levels identified in a large genome-wide association study and attempted suicide in rural China. METHODS: This 1:1 matched case-control study included altogether 510 suicide attempters and 510 community controls. Genotypes of four target SNPs (DHCR7-rs12785878, CYP2R1-rs10741657, GC-rs2282679, and CYP24A1-rs6013897) were determined, and a genetic risk score (GRS) was constructed to evaluate the combined effect of them. Demographic and psychological information was acquired through face-to-face interviews. RESULTS: The A allele of CYP24A1-rs6013897 was significantly associated with attempted suicide (OR = 1.27, 95% CI, 1.03-1.58, P = 0.029), even after adjusting for demographic and psychological confounders (adjusted OR = 1.53, 95% CI, 1.01-2.30, P = 0.043). The GRS analyses revealed a significantly higher risk of attempted suicide with a greater number of low vitamin D alleles (adjusted OR = 1.33, 95% CI, 1.13-1.58, P < 0.001). Subgroup analyses stratified by sex indicated that the genetic associations were only significant among males with adjusted ORs of 3.77 (95% CI, 1.56-9.10) for the A allele of rs6013897 and 2.04 (95% CI, 1.32-3.17) for GRS. CONCLUSIONS: Our findings identity CYP24A1-rs6013897 as a potential biomarker for attempted suicide and indicate that a genetic predisposition to lower vitamin D levels may contribute to attempted suicide. It suggests the possibility that vitamin D may have the preventive potential for attempted suicide.

Psychometric properties of the psychological strain scales (PSS) in suicide attempters and community controls of rural China.

BACKGROUND: Psychological Strain Scales (PSS) were developed to measure four types of strain comprising value strain, deprivation strain, aspiration strain, and coping strain. This study aimed to evaluate the psychometric properties of the Chinese version of 40-item PSS in suicide attempters and community controls of rural China. METHODS: Data of this study came from the investigation of 132 suicide attempters and their paired community controls matched with the same sex, age (±3 years) and residence in five counties in rural Shandong, China. The Chinese version of PSS, the Center for Epidemiologic Studies Depression Scale (CES-D), the Trait Anxiety Inventory (TAI) and the Self-esteem Scale (SES) were administered and reliability test and validity test of the PSS were conducted. RESULTS: Cronbach's α and Guttman Spilt-Half coefficient of PSS was 0.942 and 0.842 for suicide attempters, and 0.950 and 0.874 for community controls. For both suicide attempters and community controls, the Exploratory Factor Analysis indicated a one-factor structure of each strain scale, which accorded with the original factor structure proposed by the authors. The scores of the total PSS and four subscales were positively correlated with the scores of CES-D and TAI; and negatively correlated with the score of SES, which indicated a good performance in convergent validity. LIMITATIONS: This study was limited to its generalizability to the Chinese urban population. CONCLUSIONS: The Chinese version of the 40-item PSS has satisfactory psychometric properties in terms of reliability and validity in Chinese rural suicide attempters and community controls.

Family Functioning and Suicide Among the Elderly in Rural China: A Case-Control Psychological Autopsy Study.

This study aimed to examine the association between family functioning and suicide among the elderly in rural China. This 1:1 paired case-control psychological autopsy study included 242 suicides at age 60 or more and an equal number of controls matched on age (±3 years), gender, and residency. Family functioning was assessed by the Family Adaptation Partnership Growth Affection Resolve Index. Family dysfunction was reported more frequently in suicides than in paired controls. Severe family dysfunction denoted a significant risk factor for suicide only in women after adjusting for potential confounding factors. Suicides with family dysfunction were prone to have unstable marital status, physical illness, mental disorders, family suicide history, and more stressful life events than those with good family functioning. The findings suggest that the intervention enhancing family functioning may be effective in decreasing suicide among the elderly in rural China.

Depressive symptoms are associated with short and long sleep duration: A longitudinal study of Chinese adolescents.

AIMS: Sleep loss and irregular sleep patterns in adolescents are major public health concerns in the modern society. This study aimed to explore the associations between short and long sleep duration and depressive symptoms among Chinese adolescents. METHODS: A total of 7311 adolescents who participated in the baseline survey and were followed up 1 year or 2 years later were included in the analyses. Participants completed a self-administered questionnaire at baseline and follow-up surveys. The Center for Epidemiologic Studies Depression (CES-D) scale was used to assess depressive symptoms. Generalized estimating equation (GEE) and restrictive cubic spline models were used to estimate the association between sleep duration and depressive symptoms. RESULTS: After adjusting for adolescent and family covariates, sleep duration <8 h and >=9 h on weekdays and sleep duration <8 h and >=12 h on weekends were significantly associated with depressive symptoms compared with sleep 8 h. Weekend-weekday sleep difference >=3 h or <-1 h (ie. sleeping >1 h on weekdays than weekends) was also associated with depressive symptoms. There were U-shaped relationships between sleep duration on weekdays, weekends, or weekday-weekend sleep difference and depressive symptoms. LIMITATIONS: Sleep duration and depression were measured by self-report. CONCLUSIONS: Our findings highlight the risk of short and long sleep duration, and weekday-weekend sleep imbalance for depression in adolescents.

Study of concentration of amniotic fluid alpha-fetal protein in thalassemia fetus.

OBJECTIVES: To test the hypothesis that concentration of amniotic fluid alpha-fetal protein (AFAFP) is increased in thalassemia fetus. METHODS: A total of 135 cases of amniocentesis admitted from July 2013 to December 2014 were included in this study. Among them 98 cases of normal fetuses were assigned into control group and 37 cases of thalassemia fetus were included as thalassemia fetus group. Alpha-fetoprotein levels detected by enzyme linked immunosorbent assay and the alpha-fetoprotein concentration were compared between the two groups. There is no significant difference in gestational age between the two groups. RESULTS: 1. AFP concentration in thalassemia fetus group was significantly higher than that of normal control group [(1541.65 ± 734.78) µg/mL vs. (2728.84 ± 1539.97) µg/mL], and amniotic fluid AFP concentration was related to fetal thalassemia. 2. AFAFP concentration in pure α-thalassemia fetus was higher than that of ß-thalassemia fetus or mixed α- and ß-thalassemia fetus, but the difference was not significant. CONCLUSIONS: Concentration of amniotic fluid alpha-fetal protein is increased in thalassemia fetus. AFP concentration in α-thalassemia fetus was higher than that of ß-thalassemia or mixed α- and ß-thalassemia fetus but difference was not significance. Further studies are needed to explore the possible correlation between Down syndrome and biochemical markers of thalassemia.