Cold and fine particulate pollution jointly associated with higher cardiovascular mortality

Researchers examined how short-term fine particulate matter (PM2.5) exposure and temperature modified each other’s associations with cardiovascular mortality in Anhui Province, China. The time-stratified case-crossover study included 111,567 cardiovascular deaths during 2019–2023. Conditional logistic regression and distributed lag nonlinear models assessed associations across temperature and pollution strata, using minimum-mortality temperature as the reference for extreme-temperature comparisons.

Higher PM2.5 exposure amplified the association between extreme cold and cardiovascular mortality: the reported odds ratio increased from 1.03 (95% CI 0.92–1.14) to 1.90 (1.41–2.58). Low temperatures also strengthened the PM2.5-associated mortality estimate, from 1.02 (0.98–1.07) to 1.19 (1.18–1.21). The supplied text does not specify the PM2.5 increment underlying these estimates. PM2.5 amplified the association with extreme heat, but there was no evidence that heat reciprocally modified the pollution association.

Mutual amplification was most pronounced for acute cardiovascular subtypes, rather than chronic subtypes. Adults aged 65 years or older and married people were identified as more susceptible groups. The findings support considering cold and air pollution together in environmental cardiovascular risk prevention, but the observational design cannot establish causality or demonstrate benefits from a specific intervention. The study received National Natural Science Foundation of China funding; the authors declared no competing interests.