Association between maternal body height and risk of preterm birth / 中华流行病学杂志

Objective: To investigate the association between maternal body height and risk of preterm birth. Methods: A total of 11 311 pregnant women who gave birth of live singletons were recruited from the Healthy Baby Cohort Study in Hubei province, China from September 2012 to October 2014. Finally 11 070 pregnant women were selected as study subjects. Data were collected by using questionnaires, their prenatal care records and medical records. The women were divided into 4 groups according to the quartiles distribution (<158 cm, 158- cm, 160- cm, and >164 cm). Gestational age was estimated according to maternal last menstrual time. Preterm birth was defined as delivering a live singleton infant at 28-37 weeks' gestational age. Logistic regression was used to calculate the odds ratios (OR) and 95% confidence intervals (CI) for the association between body height and preterm birth. Results: Among the 11 070 pregnant women, the incidence of preterm birth was 5.9%. Logistic regression analysis indicated that women in group with body height <158 cm had 46% (OR=1.46, 95%CI: 1.16-1.83) higher risk of giving preterm birth than those in group with body height >164 cm after adjustment for potential confounders. Every 1- cm increase in body height was associated with 3% lower risk of preterm birth (OR=0.97, 95%CI: 0.95-0.99). Conclusion: Shorter body height was a risk factor for preterm birth. It is necessary to strengthen the monitoring in pregnant women with short body height to reduce the risk of preterm birth.

Prevalence and trends of overweight and obesity in children and adolescents from 2013 to 2017 in Shenzhen / 中华流行病学杂志

Objective: To examine the status and trends of overweight and obesity in children and adolescents aged 6-17 in Shenzhen between 2013 and 2017. Methods: Six primary schools, three junior high schools and three high schools were selected in Shenzhen from 2013 to 2017, through stratified cluster sampling method. Height and weight of the selected students were measured. Results: In total, 94 868 students were monitored from 2013 to 2017. The average prevalence rates of overweight and obesity were 13.31% and 9.60%, respectively. The prevalence rates of overweight and obesity appeared higher in boys (17.60% and 12.43%) than those in girls (10.27% and 5.93%). The prevalence of overweight was higher than obesity. Both prevalence rates of overweight and obesity were declining over the past five years. The maximal prevalence rates of overweight of boys and girls were from 10 to 12 and 13 to 15 years of age, while the obesity was from 6 to 9 years old, respectively. Conclusion: The prevalence rates of overweight and obesity were on the decline from 2013 to 2017, however, attention should be paid to the obesity problem in students.

Spatial-temporal analysis on pulmonary tuberculosis in Beijing during 2005-2015 / 中华流行病学杂志

Objective: To analyze the spatial distribution and identify the high risk areas of pulmonary tuberculosis at the township level in Beijing during 2005-2015. Methods: Data on pulmonary tuberculosis cases was collected from the tuberculosis information management system. Global autocorrelation analysis, local indicators of spatial association and Kulldorff's Scan Statistics were applied to map the spatial distribution and detect the space-time clusters of the pulmonary tuberculosis cases during 2005-2015. Results: Spatial analysis on the incidence of pulmonary tuberculosis at the township level demonstrated that the spatial autocorrelation was positive during the study period. The values of Moran's I ranged from 0.224 3 to 0.291 8 with all the P values less than 0.05. Hotspots were primarily distributed in 8 towns/streets as follows: Junzhuang, Wangping, Yongding and Tanzhesi in Mentougou district, Yancun in Fangshan district, Wangzuo town in Fengtai district, Tianqiao street in Xicheng district and Tianzhu town in Shunyi district. Spatiotemporal clusters across the entire study period were identified by using Kulldorff's spatiotemporal scan statistic. The primary cluster was located in Chaoyang and Shunyi districts, including 17 towns/streets, as follows: Cuigezhuang, Maizidian, Dongfeng, Taiyanggong, Zuojiazhuang, Hepingjie, Xiaoguan, Xiangheyuan, Dongba, Jiangtai, Wangjing, Jinzhan, Jiuxianqiao, Laiguangying, Sunhe towns/streets in Chaoyang district, Houshayu and Tianzhu town in Shunyi district, during January to December 2005. Conclusion: Incidence rates of pulmonary tuberculosis displayed spatial and temporal clusterings at the township level in Beijing during 2005-2015, with high risk areas relatively concentrated in the central and southern parts of Beijing.

Analysis on reproductive health service, demographics and characteristics of internal migrant population in three municipalities of China / 中华流行病学杂志

Objective: To investigate the utilization of reproductive health services and relating factors among internal migrant population in Beijing, Shanghai and Chongqing. Methods: A multi-stage cluster sampling method was adopted in this cross-sectional study, conducted in Beijing, Shanghai and Chongqing from August 2014 to August 2015. Standard methods on statistics and nonlinear canonical correlation were applied. Results: Out of the 6 545 internal migrant persons, 41.76% ever used the reproductive health services in the past year. Results from the nonlinear canonical correlation analysis revealed that the utilization of reproductive health services was correlated with the demographic features (=0.28, P<0.000 1) and characteristics of the population mobility (=0.21, P<0.000 1), respectively. For the above said demographic features, canonical variable L(1) which represented the demographic features was mainly determined by area, occupation and education attainment. Canonical variable M(1) that reflected the utilization of reproductive health services, was mainly determined by factors as free contraceptives, education on contraception/reproductive health, and pregnancy diagnosis/antenatal care. As for the characteristics of the population mobility, canonical variable U(1), which represented population mobility characteristics, was mainly determined by factors as purpose of migration, current pattern of residence and the length of annual stay in the area. Again, the canonical variable V(1), reflecting the use of reproductive health services was mainly determined by factors as free contraceptives, check-up on reproductive tract infection, education on contraception/reproductive health, and pregnancy diagnosis/antenatal care. Conclusions: The utilization of reproductive health services was low among the internal migrant population under study. Responsible departments for health and family planning in those cities should make internal migrants attach importance to reproductive health.

Specific indoor environmental quality parameters in College computer classrooms

The indoor environmental quality parameters, including temperature, relative humidity, air velocity, particulate matter concentration, illumination level, sound level, carbon dioxide concentration and ventilation rate in two computer classrooms and one general classroom were evaluated. Analytical results reveal average carbon dioxide concentration in the three classrooms during daytime classes was 785"1681 ppm. These values exceeded the exposure limits for indoor air quality suggested by the Environmental Protection Administration of the Republic of China, Taiwan [ROCEPA]. The particulate matter concentration in the general classroom was 0.087 mg/m[3], which exceeded the indoor air quality exposure limit for Type-1 venues recommended by the ROCEPA. Illumination level in the two computer classrooms was 386 and 176 Lux; these values are far lower than the illumination level for school classrooms suggested by Ministry of Education, Taiwan. Indoor sound levels in the three classrooms during non-class [51.4"61.9 dB[A] and class times [61.0"73.6 dBA exceeded the limit recommended by the Ministry of Education, Japan. The ventilation rates for the three classrooms were 0.41"0.65 h[-1]; such low ventilation rates were likely responsible for the very high indoor carbon dioxide concentrations in the three classroom during class periods. These analytical results indicate schools should examine the efficacy of air-conditioning equipment in classrooms, particularly computer classrooms. Schools should also pay attention to ventilation rates and sound levels. Due to the poor ventilation rates in computer classrooms, this study suggests that problems arisen from the accumulation of specific toxicants dispersed by computer equipment, such as polybrominated diphenyl ethers, need further investigations