Impact of menarche age on the near-term and long-term obesity of adult females / 中华流行病学杂志

Objective: To study the relationship between the age of menarche and the near-term/long-term obesity in adult women. Methods: We analyzed the baseline data of 30 895 women with complete data on menarche and body measurement that was from the China Kadoorie Biobank (CKB) study from 2004 to 2008. The age of menarche was divided into three groups: ≤12, 13-16 and ≥17 years old. Prematurity was set at age ≤12 years. Multivariate logistic regression was used to analyze the effects of menarche age on the near/long-term obesity in female adults. Results: The average menarche age of respondent appeared as (15.64±1.92) years old, with prematurity number as 1 421, accounting for 4.6% of the total numbers. Regarding the postponing of dates of birth, the age of menarche in women showed an advancing tendency. Among all the adult women under study, 803 developed near-term obesity, with the prevalence as 2.6%, while the number of long-term obesity was 3 738, accounting for 12.1%. Refining factors of age, lifestyle, menopausal status, hypertension and diabetes showed that the menarche age was related to the risks of both short-term and long-term obesity in women and the ORs (95%CI) were 2.45 (1.74-3.45) and 1.99 (1.69-2.34), respectively. There was no multiplicative interaction shown between the menarche age and menopausal status on long-term obesity (P=0.324). Conclusion: Premature menarche appeared a risk factor for near-term/long-term obesity in adult females.

Progress in research of family-based cohort study on common chronic non-communicable diseases in rural population in northern China / 中华流行病学杂志

Family-based cohort study is a special type of study design, in which biological samples and environmental exposure information of the member in a family are collected and related follow up is conducted. Family-based cohort study can be applied to explore the effect of genetic factors, environmental factors, gene-gene interaction, and gene-environment interaction in the etiology of complex diseases. This paper summarizes the objectives, methods and results, as well as the opportunities and challenges of the family-based cohort study on common chronic non-communicable diseases in rural population in northern China.

Prevalence of diabetes in Chinese adults: a Meta-analysis / 中华流行病学杂志

Objective: To evaluate the prevalence and trend of diabetes mellitus among Chinese adults during the past thirty years. Methods: Papers, published before October 1, 2017 and related to the prevalence of diabetes mellitus among Chinese adults, were searched through PubMed, China Knowledge Resource Integrated Database, Wanfang Digital Database and VIP Citation Databases. Stata 13.0 software was used to estimate the prevalence of diabetes mellitus, with pooled prevalence calculated based on random effects. Subgroup analysis was conducted based on time, sex, areas and body mass index groups of investigation. Continuous fractional polynomial regression model on the midpoint of each survey period, weighted by the number of participants in each study, was used to estimate and illustrate the trends of prevalence of diabetes over the years. Results: In total, 15 studies were included and two of them were excluded in the primary analysis with the age limitation of participants as ≥40 years old, for recruitment. The average prevalence of diabetes among Chinese adults was 6.3% (95%CI: 4.6%-8.0%), during the past thirty years. The pooled prevalence appeared higher in urban than in rural areas and higher in men than in women. Between 1980 and 2013, the increase of Chinese diabetes prevalence did not follow the linear trend. Before 2000, the average prevalence showed as 3.5% (95%CI: 2.0%-4.9%), with an annual increase rate as 0.17%. Since 2000, the average annual prevalence of diabetes mellitus had appeared around 8.0% (95%CI: 6.0%-10.1%), with an annual growth rate of 0.72% (95%CI: 0.34%-1.10%). Conclusion: The prevalence of diabetes in Chinese adults had been rapidly increasing since the year 2000, indicating that efforts should be strengthened for diabetes prevention, in China.

A Meta-analysis on the relations between short-term exposure to PM(2.5) and both mortality and related emergency visits in China / 中华流行病学杂志

Objective: To carry out a quantitative estimate that related to the effects of short-term exposure to PM(2.5) on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis. Methods: We selected all the studies published before March 2018 from China National Knowledge Infrastructure, Wanfang database, PubMed and EMBASE and data on relative risk (RR), excess risk (ER) and their 95%CIs: appeared in these papers were extracted. According to the differences in the size or direction (heterogeneity) of the results, we computed summary estimates of the effect values using a random-effect or fixed effect model. We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias. Results: A total of 33 original studies, indexed in databases, were identified. Among those studies, 39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 μg/m(3), for 10 μg/m(3) increases in PM(2.5) concentrations, it would increase the daily numbers of deaths by 0.49% (95%CI: 0.39%-0.59%) and 0.30% (95%CI: 0.10%-0.51%) for all-cause deaths and all-cause emergency-room visits, respectively. For subgroup analysis, the combined effect of PM(2.5) in causing short-term all-cause deaths in the northern areas (ER=0.42%, 95%CI: 0.30%-0.54%) seemed lower than that in the southern areas (ER=0.63%, 95%CI: 0.44%-0.82%). The combined effect of PM(2.5) concentration below 75 μg/m(3) (ER=0.50%, 95%CI: 0.37%-0.62%) was higher than that of PM(2.5) concentration ≥75 μg/m(3) (ER=0.39%, 95%CI: 0.26%-0.52%). Conclusion: Within the concentration range from 47.7 to 176.7 μg/m(3), short-term exposure to current level of PM(2.5) might increase both the all-cause daily mortality and daily emergency visits in China.