The joint effects of mixture exposure to multiple meteorological factors on step count: A panel study in China.

The public health burden of increasing extreme weather events has been well documented. However, the influence of meteorological factors on physical activity remains limited. Existing mixture effect methods cannot handle cumulative lag effects. Therefore, we developed quantile g-computation Distributed lag non-linear model (QG-DLNM) by embedding a DLNM into quantile g-computation to allow for the concurrent consideration of both cumulated lag effects and mixture effects. We gathered repeated measurement data from Henan Province in China to investigate both the individual impact of meteorological factor on step counts using a DLNM, and the joint effect using the QG-DLNM. We projected future step counts linked to changes in temperature and relative humidity driven by climate change under three scenarios from the sixth phase of the Coupled Model Intercomparison Project. Our findings indicate there are inversed U-shaped associations for temperature, wind speed, and mixture exposure with step counts, peaking at 11.6 °C in temperature, 2.7 m/s in wind speed, and 30th percentile in mixture exposure. However, there are negative associations between relative humidity and rainfall with step counts. Additionally, relative humidity possesses the highest weights in the joint effect (49% contribution). Compared to 2022s, future step counts are projected to decrease due to temperature changes, while increase due to relative humidity changes. However, when considering both future temperature and humidity changes driven by climate change, the projections indicate a decrease in step counts. Our findings may suggest Chinese physical activity will be negatively influenced by global warming.

Change in global burden of unintentional drowning from 1990 to 2019 and its association with social determinants of health: findings from the Global Burden of Disease Study 2019.

OBJECTIVE: To systematically analyse global, regional and national burden change of unintentional drowning from 1990 to 2019, and to further quantify the contribution of social determinants of health (SDH) on the change. DESIGN: Data from the Global Burden of Disease Study 2019 were used in this study. SETTING AND PARTICIPANTS: Individuals of all ages and genders from 204 countries and territories. MAIN OUTCOME MEASURES: The main outcomes were the age-standardised rates (ASRs) of mortality and disability-adjusted life-years (DALYs) of unintentional drowning. The percentage change in the ASRs were used to estimate the joint effect of SDH on trends in global burden of drowning. RESULTS: We observed that the global burden of unintentional drowning declined markedly from 1990 to 2019, with age-standardised mortality rate and DALYs rate decreasing by 61.5% and 68.2%, respectively. Women, children, middle Socio-Demographic Index (SDI) countries, South-East Asia and Western Pacific region had higher reduction. At national level, greater reductions were observed in Armenia and Republic of Korea, but significant increases in Cabo Verde and Vanuatu. We found that every one percentile increase in six SDHs (Gross Domestic Product (GDP) per person, SDI, educational attainment, health spending, health workers and urbanisation) was associated with a decrease of 0.15% and 0.16% in drowning age-standardised mortality rate and DALYs rate globally, respectively. Health spending and GDP per capita were the main contributors to the reduction of drowning globally. CONCLUSIONS: The global burden of unintentional drowning significantly declined in the past three decades, and the improvement of SDHs such as GDP per capita and health spending mainly contributed to the decrease. Our findings indicate that improvement of SDHs is critical for drowning prevention and control.

The Combined Effects of Short-Term Exposure to Multiple Meteorological Factors on Unintentional Drowning Mortality: Large Case-Crossover Study.

BACKGROUND: Drowning is a serious public health problem worldwide. Previous epidemiological studies on the association between meteorological factors and drowning mainly focused on individual weather factors, and the combined effect of mixed exposure to multiple meteorological factors on drowning is unclear. OBJECTIVE: We aimed to investigate the combined effects of multiple meteorological factors on unintentional drowning mortality in China and to identify the important meteorological factors contributing to drowning mortality. METHODS: Unintentional drowning death data (based on International Classification of Diseases, 10th Edition, codes W65-74) from January 1, 2013, to December 31, 2018, were collected from the Disease Surveillance Points System for Guangdong, Hunan, Zhejiang, Yunnan, and Jilin Provinces, China. Daily meteorological data, including daily mean temperature, relative humidity, sunlight duration, and rainfall in the same period were obtained from the Chinese Academy of Meteorological Science Data Center. We constructed a time-stratified case-crossover design and applied a generalized additive model to examine the effect of individual weather factors on drowning mortality, and then used quantile g-computation to estimate the joint effect of the mixed exposure to meteorological factors. RESULTS: A total of 46,179 drowning deaths were reported in the 5 provinces in China from 2013 to 2018. In an effect analysis of individual exposure, we observed a positive effect for sunlight duration, a negative effect for relative humidity, and U-shaped associations for temperature and rainfall with drowning mortality. In a joint effect analysis of the above 4 meteorological factors, a 2.99% (95% CI 0.26%-5.80%) increase in drowning mortality was observed per quartile rise in exposure mixture. For the total population, sunlight duration was the most important weather factor for drowning mortality, with a 93.1% positive contribution to the overall effects, while rainfall was mainly a negative factor for drowning deaths (90.5%) and temperature and relative humidity contributed 6.9% and -9.5% to the overall effects, respectively. CONCLUSIONS: This study found that mixed exposure to temperature, relative humidity, sunlight duration, and rainfall was positively associated with drowning mortality and that sunlight duration, rather than temperature, may be the most important meteorological factor for drowning mortality. These findings imply that it is necessary to incorporate sunshine hours and temperature into early warning systems for drowning prevention in the future.

Chronic methamphetamine exposure alters immune function in normal and retrovirus-infected mice.

Methamphetamine (MA) abuse represents a growing problem in the USA with an increase of sudden death. To evaluate the immune function alterations due to chronic methamphetamine use, we examined C57BL/C mice with LP-BM5 retrovirus infection plus methamphetamine exposure. Mice were randomly assigned to the following groups: placebo, placebo retrovirus-infected, uninfected MA treated and retrovirus-infected MA treated. Placebo, MA-treated groups were intraperitoneally injected with saline, MA, respectively, with a gradually increasing dose from 15 to 40 mg/kg for 12 weeks (5 days/week). Con A- and LPS-induced mitogenesis of splenocytes, cytokine production by splenocytes culture and lipid peroxides in the liver were measured. Heart tissue histopathology was analyzed in all the groups with murine cytomegalovirus (CMV) superinfection. Our data showed that MA treatment significantly decreased production of IL-2 and interferon gamma (IFN-gamma) in uninfected mice but did not further suppress the reduced Th1 cytokines in retrovirus-infected mice. There were no significant effects on cytokines IL-4 and IL-6. However, tumor necrosis factor (TNF-alpha) was significantly increased in both uninfected and infected mice due to MA treatment. Lipid peroxides in liver were significantly increased both in uninfected and retrovirus-infected mice due to MA exposure. Vitamin E levels in liver were significantly decreased in uninfected mice due to MA treatment. CMV superinfection greatly increased the cardiac lesions in retrovirus-infected mice while no significant histopathology changes were detected due to MA treatment. Our data suggest that MA has immunomodulation activity, suppressing Th1 cytokine production and enhancing some Th2 cytokine secretion, as well as increasing lipid peroxides in uninfected mice. The interaction between LP-BM5 and MA remains unclear.