Zhi-Hua Zhang

The role of preexisting diabetes mellitus on incidence and mortality of endometrial cancer: a meta-analysis of prospective cohort studies.

Objective The results of cohort studies are controversial regarding the association between preexisting diabetes mellitus (DM) and the risk of endometrial cancer (EC) incidence and mortality. The aim of this meta-analysis was to assess whether an association exists between them in prospective studies. Methods The PubMed and EMBASE database were searched for prospective cohort studies of preexisting DM on EC occurrence, mortality outcomes, updated up to June 2012. Data were independently extracted by 2 investigators using a standardized protocol. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were estimated by the use of fixed-effect or random-effect models. Between-study heterogeneity was investigated using &khgr;2-based Cochran Q statistic test and I2 statistics. Results A total of 21 cohort studies (20 articles) involving 12,195 incident cases and 575 deaths caused by EC were included in the analysis. Among these, 15 studies reported the risk of EC incidence, and 6 studies reported risk of EC mortality. The meta-analysis showed that DM was associated with an increased incidence of EC (SRR, 1.81; 95% CI, 1.38–2.37; test for heterogeneity: Q = 280.96, P < 0.001, I2 = 95.4%), compared with individuals without diabetes or the general population. Subgroup analyses were conducted by geographical region, study design, year of publication, diabetes ascertainment, type of DM, and adjustments for some variables, and the positive association between DM and risk of EC was consistently observed in each subgroup. Sensitivity analyses also showed that no single study significantly influenced the pooled relative risk. No significant publication bias (P = 0.173) was found. Diabetes mellitus was not positively associated with EC mortality (SRR, 1.23; 95% CI, 0.80–1.90; test for heterogeneity: Q = 11.95, P = 0.035, I2 = 58.2%). Conclusions This meta-analysis of cohort studies suggests that there is a significant association between DM and increased risk of EC incidence but no increased risk of EC mortality.

Internet addiction, adolescent depression, and the mediating role of life events: Finding from a sample of Chinese adolescents

The aim of this study is to examine the mediating role of life events in the relation between Internet addiction and depression using an adolescent sample in China. A total of 3507 urban adolescent students were asked to complete the questionnaires including Youngs Internet Addiction Scale, Adolescent Self-Rating Life Events Checklist, and Center for Epidemiologic Studies Depression Scale, Parent-Child Conflict Tactics Scales, and demographic characteristics. Path analyses demonstrated that life events fully mediated the relationship between Internet addiction and adolescent depression. Specificity for the mediating role of life events was demonstrated in comparison to alternative competing mediation models. The findings support our hypothesis that the effect of Internet addiction on adolescent depression is mediated by the life events. Further research is required to test the temporal relationship between Internet addiction and adolescent depression and explore mechanisms underlying the pathways leading to adolescent depression.

Current Evidence on the Relationship Between Two Polymorphisms in the NBS1 Gene and Breast Cancer Risk: a Meta-analysis

INTRODUCTION Published studies on the association between Nijmegen breakage syndrome 1(NBS1) gene polymorphisms and breast cancer risk have been inconclusive, and a meta-analysis was therefore performed for clarification. METHODS Eligible articles were identified by a search of MEDLINE and EMBASE bibliographic databases for the period up to March 2012. The presence of between-study heterogeneity was investigated using the chi-square-based Cochrans Q statistic test. When there was statistical heterogeneity, the random effects model was chosen; otherwise, fixed effects estimates were reported as an alternative approach. RESULTS A total of 11 eligible articles (14 case-control studies) were identified, nine case-control studies were for the 657del5 mutation (7,534 breast cancer cases, 14,034 controls) and five case-control studies were for the I171V mutation (3,273 breast cancer cases, 4,004 controls). Our analysis results indicated that the 657del5 mutation was associated with breast cancer risk (carriers vs. non- carriers: pooled OR=2.63, 95% CI: 1.76-3.93), whereas the I171V mutation was not (carriers vs. non-carriers: pooled OR=1.52, 95% CI: 0.70-3.28). CONCLUSION The present meta-analysis suggests that the 657del5 gene mutation in the NBS1 gene plays a role in breast cancer risk, while the I171V mutation does not exert a significant influence.

Prevalence of Suicide Attempts among College Students in China: A Meta-Analysis

Background Suicide is the leading cause of death among 15–34 year olds in China, but no national data are available on the suicide and suicide attempts rates of college students, a sub-group of youth with 23 million. Several studies have reported the prevalence of suicide attempts among college students, however, no meta-analysis pooling the prevalence of suicide attempts is found. Objective and Methods This study aims to estimate the pooled prevalence of suicide attempts among college students in China. The relevant studies up to August 2014 were systematically searched via electronic databases (PubMed-Medline, Embase, Chinese Wanfang database, Chinese National Knowledge Infrastructure and Chinese VIP database). We only selected original articles that either reported the prevalence of suicide attempts or sufficient data for calculating the prevalence. Results A total of 29 eligible studies, with 88,225 college students, were finally included. The maximum and minimum reported prevalences of suicide attempts among college students in China were 0.4% and 10.5%, respectively. The pooled prevalence of suicide attempts was 2.8% (95%CI: 2.3%–3.3%). Subgroup analyses showed that the pooled estimate of prevalence of life time suicide attempts was 2.7% (95%CI: 2.1%–3.3%), and 12-month suicide attempts was 2.9% (95%CI: 2.0%–3.8%). The prevalence for males was 2.4% (95%CI: 1.8%–3.0%), and for females was 2.7% (95%CI: 1.9%–3.7%). The prevalences among college students in grade 1 through 4 were 2.8% (95%CI: 1.7%–3.8%), 1.8% (95%CI: 1.2%–2.3%), 2.0% (95%CI: 0.8%–3.1%), and 2.9% (95%CI: 0.1%–6.7%), respectively. The prevalences among college students from rural and urban areas were 5.1% (95%CI: 2.8%–7.5%) and 3.7% (95%CI: 1.4%–5.9%), respectively. Conclusions 2.8% prevalence of suicide attempts and more than 600,000 suicide attempters among college students indicate that suicide attempt among college students is an important public health problem in China. More attention should be paid to the current situation.

Associated factors for HIV and syphilis infection among men who have sex with men only and men who have sex with both men and women in cities of China

Summary The aims of this paper were to find out the status of HIV and syphilis infection and to examine the sexual behaviours between men who have sex with men only (MSM/M) and men who have sex with both men and women (MSM/W), as well as to determine the correlates for HIV and syphilis infection among MSM/M and MSM/W, respectively. Among 1693 MSM who participated in the study, the proportions of MSM/M and MSM/W were 82.1% and 17.9%, respectively. The prevalences of HIV infection were 7.0% in MSM/M and 6.6% in MSM/W and the prevalences of syphilis infection were 11.9% and 13.2%, respectively. Among the MSM/M subset, the correlates both for HIV and syphilis infection included having more sexual partners, and being receptive or both insertive and receptive for anal sex. Among the MSM/W subset, living in Chengdu was associated with HIV infection and using condoms inconsistently during anal sex was associated with syphilis infection. The findings of this survey call for interventions tailored according to the needs of different subsets of MSM.

The Association Between Milk Consumption and Bladder Cancer Risk: Appraisal of a Recent Meta-Analysis

To the Editor: We have read with great interest the meta-analysis by Mao et al. (1), which examined the association between milk consumption and bladder cancer risk. Nevertheless, we have several concerns related to the article. First, using the same search strategy and end-of-search date as those of Mao et al. (1), we have located a cohort study and 2 case-control studies in Pubmed, which were reported by Ursin et al. (2), Balbi et al. (3) and La Vecchia et al. (4) respectively. Ursin et al. (2) investigated 15,914 individuals after 11.5 years of follow-up in Norway. No association was established with bladder cancer incidence and milk consumption [>2 glasses per day in contrast to <1 glass per day: relative risk (RR) = 0.8, 95% confidence interval (CI) = 0.4–1.5], in analyses adjusted for age, residential, and smoking characteristics. Balbi et al. (3) conducted a case-control study on 144 cases of bladder carcinoma and 576 hospitalized controls in Uruguay. Whole milk was not associated with bladder cancer risk [tertiles of intake Q3 vs. Q1: odds ratio (OR) = 1.57, 95% CI = 0.98–2.52). The study by La Vecchia et al. (4), including 163 cases and 181 controls, was conducted in northern Italy, and risk of bladder cancer was not related to milk consumption (tertiles of intake Q3 vs. Q1: OR = 1.10, 95% CI = 0.67–1.79). The 3 studies have not been included in the meta-analysis, even though it satisfied the search criteria. Second, in the section of statistical analysis, the authors stated that P value <0.05 for the Q-test indicated heterogeneity among the studies. Actually, P value <0.10 rather than <0.05 for the Q-test indicated heterogeneity among studies (5).