OBJECTIVETo explore the impact of the socio-economic factors on the temperature-mortality association in different cities in southern China.

METHODSDaily mortality registration data, meteorological data and air pollution data of the cities as Changsha and Kunming during 2006-2009, and cities as Guangzhou and Zhuhai during 2006-2010, were collected to explore modifying effects, stratified by age, gender, education and place of death, of socio-economic factors on the association between temperature and mortality, by distributed lag non-linear model. The accumulative effect of temperature-mortality were separately analyzed in each city, under the high temperature (0-3 days) and low temperature (0-20 days) situation. The association between temperature and mortality was evaluated by general linear threshold model. The above process was firstly adopted to analyze the impact in single city and then Meta analysis was applied to analyze the impact in several cities by effect-combine.

RESULTSThe relationship between temperature and mortality in the four cities showed nonlinearity. The minimum mortality risk was separately 23.5 °C, 20.5 °C, 25.0 °C and 26.0 °C in Changsha, Kunming, Guangzhou and Zhuhai. The results of effect-combine showed that low-temperature (RR = 1.67, 95%CI:1.54-1.80) has a higher gross effect than high-temperature (RR = 1.11, 95%CI:1.01-1.18) on population. With the age increasing, risk of death increased both under high and low temperature situation, and the effect of low temperature was greater (RR = 1.83, 95%CI:1.65-2.04) for the elderly than it of high temperature (RR = 1.17, 95%CI:1.03-1.33). The mortality risk among females (cold and hot effects(95%CI) were 1.75(1.57-1.97) and 1.11(0.99-1.25), respectively)was higher than it among males (cold and hot effects(95%CI) were 1.59(1.45-1.77) and 1.11(1.03-1.19), respectively). Whereas the mortality risk on higher education population was significantly higher (cold and hot effects (95%CI) were 1.89(1.48-2.45)and 1.34(1.19-1.48), respectively) than it on other educated people.

CONCLUSIONAge, gender, educational level and place of death showed modifying effects on the association between temperature and mortality. The elderly, women and highly educated people were vulnerable to the temperature influence on mortality.

Aged ; Air Pollution ; China ; Cold Temperature ; adverse effects ; Female ; Hot Temperature ; adverse effects ; Humans ; Male ; Mortality ; Nonlinear Dynamics ; Risk ; Socioeconomic Factors

ObjectiveTo understand the epidemiological characteristics of recovered COVID-19 cases with re-positive nucleic acid in Pudong New Area of Shanghai, and to provide a reference for the prevention and control of COVID-19. MethodsA three-month health follow-up and nucleic acid testing were conducted on 339 COVID-19 cases cured and discharged between May 20 and June 20, 2022, in Pudong New Area, Shanghai, to analyze their epidemiological characteristics. ResultsAmong the 339 follow-up cases, 75 cases experienced re-positive nucleic acid results, with a recurrence rate of 22.12%. Factors such as gender, age group, occupation, presence of heart disease, hypertension, and full vaccination status had no effect on the re-positive results. Being diagnosed as a confirmed case during the first presence of infection, having diabetes, and a hospitalization period of ≤7 days were related factors for recurrence. The median interval between discharge and re-positive nucleic acid results was 26 days. The close contacts of the re-positive cases did not contract COVID-19 after the isolation and observation period. ConclusionThere is a possibility of re-positive nucleic acid results after COVID-19 recovery and discharge. Cases initially diagnosed as confirmed cases and those with a hospitalization period of no more than 7 days have a high rate of re-positivity. No secondary transmission is observed from the re-positive cases.