Independent and Joint Associations of Long-Term Ambient Meteorological Exposures and Socioeconomic Deprivation with Major Adverse Cardiovascular Events: A Prospective Cohort Study.

Although acute meteorological events are recognized cardiovascular hazards, the combined cardiovascular impacts of long-term meteorological exposures and socioeconomic deprivation remain poorly characterized. Among 469,347 UK Biobank participants, we evaluated independent and interactive associations of 1-year average ambient temperature, relative humidity, and the Townsend deprivation index (TDI) with incident major adverse cardiovascular events (MACE), stroke, myocardial infarction (MI), and cardiovascular death. Over median 13.7-year follow-up, 31,626 MACE, 12,565 strokes, 17,062 MIs, and 7,161 cardiovascular deaths occurred. In Cox models, the highest versus lowest temperature category was associated with lower MACE risk (HR, 0.87; 95% CI, 0.84-0.91), whereas high humidity (HR, 1.10; 95% CI, 1.05-1.14) and high deprivation (HR, 1.39; 95% CI, 1.34-1.44) were independently associated with elevated risk. Under a counterfactual assigning the least deprived category's risk to both more deprived categories, 11.75% (95% CI, 9.68-13.77%) of incident MACE and 17.15% (12.68-21.39%) of cardiovascular deaths over 10 years would be attributable to deprivation (total-effect specification, omitting smoking, body mass index, hypertension and diabetes; fully adjusted, 6.67% and 11.09%). Temperature and humidity showed multiplicative interactions with TDI: versus the joint low-risk reference, low temperature with high deprivation had HR 1.55 (95% CI, 1.40-1.71) for MACE and high humidity with high deprivation HR 1.51 (1.34-1.71); additive interactions were significant only at intermediate temperature or intermediate humidity (RERI, 0.20 and 0.16). The deprivation gradient was stable in every sensitivity analysis; the temperature association did not persist within assessment centres, nor the humidity association under a time-varying specification, although both persisted across exposure windows and air-pollution adjustment. These findings indicate that long-term lower temperatures and higher humidity, together with socioeconomic deprivation, are independently and jointly associated with elevated cardiovascular risk, underscoring the need for integrated climate and social welfare policies to mitigate health disparities in vulnerable populations.