The mean age of menarche among Chinese schoolgirls declined by 6 months from 2005 to 2014.

AIM: This study assessed the trends in the age at menarche in Chinese schoolgirls from the majority Han group and 21 ethnic minorities from 2005 to 2014. We also compared the group differences during the study period. METHODS: A total of 344 230 girls aged 9-18 years were extracted from the 2005, 2010 and 2014 Chinese National Survey on Students' Constitution and Health. The age at menarche for each subgroup was estimated by probit analysis. The chi-square test and Z-test were used to compare the differences between the groups. RESULTS: The overall average age at menarche in Chinese schoolgirls decreased from 12.8 years in 2005 to 12.3 years in 2014. The Han girls and girls from 17 ethnic minorities showed decreasing trends in the age at menarche, while four ethnic minorities demonstrated fluctuating increasing trends over time. The gaps in age at menarche between the Han group and 14 of the ethnic minorities became smaller over the study period and were similar by 2014. CONCLUSION: The overall findings were a decrease in the age at menarche in China and smaller gaps between the majority Han group and ethnic minority groups. Ethnic-specific public health policies are urgently needed on issues such as contraception.

National trends in stunting, thinness and overweight among Chinese school-aged children, 1985-2014.

OBJECTIVE: We sought to examine changes in regional and sex disparities in stunting, thinness, and overweight among Chinese school-aged children from 1985 to 2014. METHODS: We analyzed data on 1,489,953 children aged 7-18 years in the Chinese National Survey on Students' Constitution and Health. Stunting, thinness, and overweight were defined according to WHO anthropomorphic definitions. After adjustment for age, socioeconomic status, and school, logistic regression was used to estimate the prevalence of stunting, thinness, and overweight by region and sex over 30 years' time. RESULTS: From 1985 to 2014, the prevalence of stunting progressively decreased from 16.4% in 1985 to 2.3% in 2014, thinness prevalence also declined overtime, from 8.4 to 4.0% and overweight prevalence continually increased from 1.1% in 1985 to 20.4% in 2014 in Chinese school-aged children. Stunting and thinness were more common in rural areas, although urban/rural differences declined over time. Overweight was a greater problem in urban than rural areas, and this difference increased over time. Some provinces showed high levels of stunting, thinness, and overweight. The stunting prevalence of boys was higher than girls from 1985 and 1995, but lower than girls for the past 15 years. Thinness was consistently more common in boys than girls across regions and time. Overweight continuously increased for boys and girls; however, the increase was more rapid in boys. CONCLUSIONS: Over the past 30 years, Chinese children have shifted in anthropomorphic measures indicating a shift from problems of under-nutrition to measures consistent with over-nutrition, particularly in urban areas and among boys. Some regions are burdened by problems of both under- and over-nutrition. Regional and sex-specific guidelines and public health policies for childhood nutrition are needed in China.

Gender differences in suicidal ideation and health-risk behaviors among high school students in Beijing, China.

BACKGROUND: Suicide is still the leading cause of death in the 15 to 34-year age group, especially for girls aging 15 to 19-year old. In China particularly, the suicide rate of female is 60% higher than male. The gender difference on suicidal ideation and its patterns with academic, family, social and health-risk factors is unknown among adolescents in Beijing, China. METHODS: A total of 33 635 students in grades 7-12 in Beijing participated in the 2014 Chinese Youth Risk Behavior Surveillance. Data were stratified by gender and associations with suicidal ideation were analyzed using χ2 test and multivariate regression analyses. The interaction effects on suicidal ideation between gender and the related behaviors were also analyzed. RESULTS: The prevalence of suicidal ideation was significantly higher for girls (13.3%) than boys (10.7%). The multivariate regression analyses indicated that high academic pressure, running away from home, feeling lonely or sad/hopeless, being bullied, fighting, and binge drinking were significantly associated with suicidal ideation in boys and girls. Factors more strongly associated with suicidal ideation in girls than boys were being in junior vs senior high school (girl vs boys: 1.24 vs NA), high academic pressure (2.42 vs 1.55), ever smoking (1.52 vs NA), binge drinking (1.30 vs 1.17), fighting once (1.63 vs 1.06) and being sad/hopeless (2.39 vs 2.04) and their interaction with gender were all statistically significant (P < 0.05). A lower likelihood of suicidal ideation was found among boys, but not girls, who had PE class two or more days per week. CONCLUSIONS: Girls showed more vulnerability to suicidal ideation than boys particularly among girls in junior school, reporting high academic pressure, smoking, binge drinking and fighting. The combinations of risk factors and differential patterns for boys and girls point to high-risk groups and potential targets for gender-specific suicide prevention.