OBJECTIVESTo explore the association between elevated light levels in classrooms and change in vision acuity among elementary and secondary students.

METHODSA total of 4 elementary (grade 1-5) and secondary (grade 7-8) schools in urban and rural areas in Sujiatun, Shenyang, China were selected by cluster sampling as experimental schools, and lighting systems have been rebuilt to improve the ambient light levels in 56 classrooms in November 2012. The control schools were chosen for the comparable academic burden and adjacent location to experimental schools, 4 schools in all. Cluster sampling of all students in the selected schools as the subjects was carried out. A total of 2 092 students were chosen as experimental group and 1 595 students were in the control group. The luxmeter was used to measure illuminance of classrooms in two groups at baseline, and intervention for 1 month, respectively.Students in both groups were underwent 3 times for vision acuity examination by standard logarithmic visual acuity chart at baseline, intervention for 6 month and intervention for 1 year, respectively. The light levels of desk and blackboard in two groups were compared by Wilcoxon test. Multivariate analysis of covariance with repeated measures was performed to assess three vision acuity results between groups.

RESULTSAfter intervention, the average illuminance of desk (117.5 vs 532.5 lx, Z = -5.38, P < 0.001) and blackboard (75.6 vs 423.5 lx, Z = -5.38, P < 0.001) and uniformity of desk (Z = -4.28, P < 0.001) with new lighting were improved significantly than that with old lighting, however the uniformity of blackboard was lower than baseline significantly (0.64 vs 0.70, Z = -2.34, P = 0.019). The average scores of vision acuity in students at baseline, intervention for 6 month and intervention for 1 year were 4.87 ± 0.23, 4.84 ± 0.25 and 4.85 ± 0.23 in experimental group, and 4.88 ± 0.22, 4.84 ± 0.25 and 4.81 ± 0.27 in control group, respectively. The significant differences between groups were found and F values were 1.41, 0.13, 19.99, P values were 0.235,0.724, <0.001. At last the average vision acuity in experimental group were significantly better than that in control group either among elementary (4.90 ± 0.20) vs (4.87 ± 0.21) score, F = 13.61, P < 0.001 or secondary students (4.73 ± 0.28) vs (4.68 ± 0.32) score, F = 14.25, P < 0.001.

CONCLUSIONSVisual acuity loss could be decreased in students with elevated light levels which may slow the response to myopiagenic stimuli for eyes, therefore the ambient light levels of blackboard and desk in classroom should be improved.

Adolescent ; Child ; China ; Humans ; Lighting ; Schools ; Students ; Visual Acuity

OBJECTIVETo describe the epidemiological characteristics on the supplement of folic acid in progestation and early pregnancy, and to probe the protective effects of supplement of folic acid in early pregnancy against pregnant depression, in Ma'anshan city, Anhui province.

METHODSIn this cohort study, 5 150 subjects who had their first antenatal examination at Ma'anshan Maternal and Child Care Centers were recruited under informed consent, from October 2008 to October 2010. All the information were collected through questionnaires in the first, second and third trimesters respectively. A "Center for Epidemiological Studies Depression Scale (CES-D)" was used to assess the mood of depression in the second questionnaire. Single factor analysis and the unconditional multivariate logistic regression were applied to analyze the association of supplement folic acid in peri-conceptional period and pregnancy depression.

RESULTSIn the study, the prevalence of those who had never taken the supplement folic acid but only the supplement folic acid in progestation and supplement in the first-trimester, or supplement in the peri-conceptional period were 27.3%,0.5%, 27.4% and 17.9%, respectively. The incidence of pregnancy depression was 4.8% (247/5 150). Data from logistic regression analysis showed that, supplement of folic acid only in the first-trimester or in the peri-conceptional period were negatively associated with pregnancy depression even after adjustment for potential confounders. The adjusted odds ratio were 0.63 (95%CI:0.44-0.90) and 0.61 (95%CI:0.39-0.95) respectively.

CONCLUSIONSupplement of folic acid in peri-conceptional period could be a preventive factor for pregnancy depression.

Adult ; Cohort Studies ; Depression ; prevention & control ; Female ; Folic Acid ; administration & dosage ; therapeutic use ; Humans ; Pregnancy ; Prenatal Care ; Prospective Studies ; Surveys and Questionnaires

OBJECTIVETo evaluate the associations between pregestational body mass index (BMI), weight gain during first half of pregnancy and the risk for gestational diabetes mellitus (GDM).

METHODSA prospective cohort study was conducted among 1,914 local pregnant women, receiving the first prenatal examination during the first 14 weeks of gestation, in Ma'anshan of Anhui province from May 2013 to September 2014. The body weight and height were measured for these pregnant women and questionnaire surveys were conducted among them at enrollment, middle gestation and late gestation, respectively. During 24-28 week of gestation, 75 g oral glucose tolerance test was conducted for them. The independent and joint associations between pregestational BMI/weight gain and the risk of GDM were examined by using logistic regression model.

RESULTSThe prevalence of GDM was 14.73%. There was significant negative correlation between pregestational BMI and weight gain during the first half of pregnancy (r=-0.085, P<0.01), meanwhile the weight gain of GDM women was significantly higher than that of women without GDM. The women with pregestational overweight or obesity had increased risks of GDM. The results from the logistic regression analysis showed that the risk factors included age≥35 years (OR=3.06, 95% CI: 1.68-5.58), fasting plasma glucose level during early pregnancy (OR=2.17, 95% CI: 1.57-3.00), pregestational overweight (OR=2.08, 95% CI: 1.38-3.13), pregestational obesity (OR=3.73, 95% CI: 1.84-7.56).

CONCLUSIONPregestational overweight or obesity and body weight gain during pregnancy were associated with increased risk of GDM.

Body Mass Index ; Diabetes, Gestational ; epidemiology ; Female ; Glucose Tolerance Test ; Humans ; Obesity ; epidemiology ; Overweight ; epidemiology ; Pregnancy ; Prospective Studies ; Risk Factors ; Weight Gain