Analysis on the current situation of insufficient sleep and its association with physical exercise among Chinese Han students aged 9-18 years, in 2014 / 中华流行病学杂志

Objective: To describe the situation of insufficient sleep and the association between insufficient sleep and physical exercise, among Chinese Han students aged 9-18 years. Methods: We selected 172 197 Chinese Han students aged 9-18 years from the project 2014 Chinese National Survey on Students Constitution and Health. The average sleep duration per day of less than 9 h for children aged 9-12 years and of less than 8 h for adolescents aged 13-18 years, were defined as insufficient sleep. We described the distribution of sleep duration and the prevalence rates of insufficient sleep for each subgroup. Logistic regression models were established to assess the association between insufficient sleep and physical exercise. Results: In 2014, 6.6%, 30.8%, 26.3%, 20.8%, 13.8% and 1.8% of the Chinese Han students self-reported sleep duration were <6, 6-, 7-, 8- and ≥10 h, respectively. The overall prevalence rate of insufficient sleep was 77.2%, with 75.8% for boys and 78.6% for girls. No gender disparity was found at each 9-11 age groups. However, in the 12-18 age groups, the prevalence rates for girls were significantly higher than that for boys. The prevalence rates of insufficient sleep for primary school, middle school and high school students were66.6%, 74.1% and 93.8%, respectively. Rates were increasing with age for children aged 9-12 years and adolescents aged 13-18 years respectively. The three provinces with the lowest prevalence rates of insufficient sleep were Zhejiang (68.8%), Jiangsu (66.7%) and Shaanxi (65.2%). Data from the logistic regression models revealed that, when comparing to those students with only exercise of <0.5 h per day, the exercise hours of 0.5-1 h (OR=0.72, 95%CI: 0.69-0.74) or ≥1 h (OR=0.46, 95%CI: 0.44-0.47) per day seemed as protective factors for insufficient sleep. When compared with physical exercise frequency <2 times per week, the 2 times (OR=0.82, 95%CI: 0.78-0.86) or >2 times (OR=0.65, 95%CI: 0.62-0.68) frequencies also appeared as protective. Conclusions: The prevalence rate of insufficient sleep prevailing among students aged 9-18 years was high, in China. Our data called for setting up effective measures to deal with this situation.

Relationship between white spot syndrome virus [WSSV] loads and characterizations of water quality in Litopenaeus vannamei culture ponds during the tropical storm

An in-situ experiment was conducted to investigate the effect of tropical storm on the white spot syndrome virus [WSSV] loads in Litopenaeus vannamei rearing ponds. White spot syndrome virus loads, heterotrophic bacteria, Vibrio and water quality [including temperature, dissolved oxygen [DO], salinity, pH, NH4-N, and NO2-N] were continually monitored through one tropical storm. The WSSV loads decreased when tropical storm made landfall, and substantially increased when typhoon passed. The variation of WSSV loads was correlated with DO, temperature, heterotrophic bacteria count, and ammonia-N concentrations. These results suggested that maintaining high level DO and promoting heterotrophic bacteria growth in the shrimp ponds might prevent the diseases' outbreak after the landfall of tropical storm