Hao Wang, Miaomiao Wei, Taikun Lu, Chao Wang, Xiaoshuang Xia, Lin Wang, Xin Li
After adjusting available covariates, preconception NLR, PLR, and SII exhibited outcome-specific threshold associations with adverse fetal and neonatal outcomes, yet unmeasured confounders (preconception infection, maternal nutrition, etc.) may overestimate these correlations. Owing to the large sample, many significant results carry modest effect sizes with limited individual clinical utility; these markers merely offer population-based epidemiological references instead of standalone screening indicators for rural preconception risk stratification. Our results require validation in modern urban and multicenter cohorts due to the historical rural-only study population.
BACKGROUND: Although long-term exposure to ambient fine particulate matter (PM2.5) is an established risk factor for stroke, evidence on the detrimental effects of its specific constituents remains limited. This study aimed to investigate the associations between long-term exposure to PM2.5 constituents and incident stroke, and to identify the key contributor.
METHODS: We conducted a nationwide prospective cohort study using data from the China Health and Retirement Longitudinal Study (CHARLS) between 2013 and 2018. Incident stroke cases were identified from CHARLS self-reported physician diagnoses during follow-up interviews. PM2.5 constituent concentration data were derived from the Tracking Air Pollution in China (TAP) dataset, while temperature and relative humidity data were obtained from the European Center for Medium-Range Weather Forecasts Reanalysis v5 (ERA5). Individual records were matched with environmental exposure data to quantify the associations between specific PM2.5 constituents (sulfate, nitrate, ammonium, organic matter, and black carbon) and the incident stroke. Multivariate Cox models and quantile-based g-computation were applied to assess the associations of PM2.5 constituents with incident stroke and to identify the key contributor.
RESULTS: Over a median follow-up of 5.0 years, 610 incident stroke cases occurred among 8,724 participants. All five constituents were significantly associated with stroke onset, the adjusted hazard ratios (95% confidence interval [CI]) for each interquartile range increase were 1.55 (95% CI: 1.35-1.79) for PM2.5, 1.55 (95% CI: 1.34-1.79) for sulfate, 1.37 (95% CI: 1.18-1.59) for nitrate, 1.42 (95% CI: 1.24-1.63) for ammonium, 1.59 (95% CI: 1.40-1.80) for organic matter, and 1.77 (95% CI: 1.54-2.03) for black carbon, respectively. In the joint effect analysis, black carbon (28.6%) exhibited the largest weight within the mixture. Stratified analyses revealed that individuals aged over 65 years and residents of southern China were more susceptible.
CONCLUSION: Long-term exposure to PM2.5 constituents is associated with an elevated risk of incident stroke, with black carbon showing the strongest association among the five constituents. Older adults and residents of southern China were found to exhibit heightened susceptibility. These findings highlight the importance of mitigating the growing stroke burden through tailored clinical approaches and targeted regulation of carbonaceous emissions, accounting for demographic and regional vulnerabilities.