BackgroundDue to its high prevalence and associated sight-threatening pathologies, myopia has emerged as a major health issue in East Asia. The purpose was to test the impact on myopia development of a school-based intervention program aimed at increasing the time student spent outdoors.MethodsA total of 3051 students of two primary (grades 1-5, aged 6-11) and two junior high schools (grades 7-8, aged 12-14) in both urban and rural Northeast China were enrolled. The intervention group (n = 1735) unlike the control group (n = 1316) was allowed two additional 20-min recess programs outside the classroom. A detailed questionnaire was administered to parents and children. Uncorrected visual acuity (UCVA) was measured using an E Standard Logarithm Vision Acuity Chart (GB11533-2011) at baseline, 6-month and 1-year intervals. A random subsample (n = 391) participated in the clinic visits and underwent cycloplegia at the beginning and after 1 year.ResultsThe mean UCVA for the entire intervention group was significantly better than the entire control group after 1 year (P < 0.001). In the subgroup study, new onset of myopia and changes in refractive error towards myopia were direction during the study period was significantly lower in the intervention group than in the control group (3.70 % vs. 8.50 %, P = 0.048; -0.10 ± 0.65 D/year vs. -0.27 ± 0.52 D/year, P = 0.005). Changes in axial length and IOP were also significantly lower following the intervention group (0.16 ± 0.30 mm/year vs. 0.21 ± 0.21 mm/year, P = 0.034; -0.05 ± 2.78 mmHg/year vs. 0.67 ± 2.21 mmHg/year, P = 0.006).ConclusionsIncreasing outdoor activities prevented myopia onset and development, as well as axial growth and elevated IOP in children.Trial registrationCurrent controlled trials NCT02271373.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-015-0052-9) contains supplementary material, which is available to authorized users.

Elevated light levels in classrooms have a significant effect on myopia onset, decreases in refraction, and axial growth; if the findings of lighting intervention are reproduced in future studies, the ambient light levels in schools should be improved.

BackgroundMyopia has become a significant global public health concern, and is highly prevalent worldwide especially in Asian countries. It is associated with genetic factors as well as socioeconomic status; however, the underlying cause for school myopia has not been established. This study evaluates the impact of living environment on school myopia in Chinese school-aged children.MethodsA large cross-sectional sample of area- and ethnicity-matched school children; a total of 43, 771 children from 12 cities participated in this study. The presence of myopia was self-reported and potential risk factors were determined by questionnaires.ResultsThe self-reported prevalence of myopia in Chinese children was 31.8 % (n = 13, 928). In multiple logistic regression analysis, higer risk of myopia among school-aged children was significantly positively associated with both parental myopia (OR = 3.57; 95 % CI: 3.26–3.90), living in 1–3 floor (OR = 1.28; 95 % CI: 2.57–3.15), 4–6 floor (OR = 1.84; 95 % CI: 1.73–1.95) and 7 floor or more (OR = 2.02; 95 % CI: 1.88–2.16). Particularly, housing type was independently associated with myopia after stratified by parental myopia. An increasing prevalence of myopia was found with increasing floor of housing type in each outdoor time group.ConclusionsHousing type was independently associated with myopia, after stratified by parental myopia. Flat room, lower living floor and more outdoor time may be protective factors for myopia among school-aged children in mainland China.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-016-0324-z) contains supplementary material, which is available to authorized users.

The aim of this study was to estimate the risk factors of bacterial vaginosis (BV) among rural married women of childbearing age in Anhui Province of China. A cross-sectional study was conducted and the method of stratified cluster sampling was used to identify a sample of 53,652 married women aged 18-49 years. All women were asked to complete an interviewer-administered standardized questionnaire, covering sociodemographic characteristics, history of menstruation, marriage and procreation, sexual life, personal hygienic behaviors, and reproductive tract infections (RTIs) knowledge, followed by the gynecological examination and laboratory inspection. A total of 53,286 married women aged 18-49 years were included in this analysis. The prevalence of BV was 11.99 % (6,391/53,286). Risk factors for BV included the minority nationality, women's lower education levels, husband's elder age, over 35 days of menstrual cycle, less than 3 days of menstruation, dysmenorrhea, usage of an intrauterine device (IUD), lack of RTIs knowledge, higher frequency of washing genitals before having sex with husband and changing underwear, lower frequency of sexual intercourse per month, and suffering from other RTIs. The results suggest that BV can be affected by many factors among rural married women of reproductive age, so comprehensive, scheduled programs at healthcare educations should be provided for women in order to prevent BV.

The study shows that the prevalence of induced abortion is still very high among married women in rural China, and highly effective methods of contraception (sterilization, intrauterine device) decrease women's recourse to induced abortion.