Interactions between cigarette smoking and ambient PM_2.5 for cardiovascular mortality

Area of Science:

• Environmental Health
• Epidemiology
• Cardiovascular Disease Research

Background:

• Long-term exposure to fine particulate matter (PM2.5) is linked to increased all-cause and cardiovascular mortality.
• The interaction between PM2.5 exposure and cigarette smoking on mortality risk, particularly cardiovascular, is not well understood.

Purpose of the Study:

• To investigate the interaction between long-term PM2.5 exposure and cigarette smoking on all-cause and cardiovascular mortality.
• To quantify the public health burden attributed to the combined effects of PM2.5 and smoking.

Main Methods:

• Analysis of data from 429,406 participants in the American Cancer Society Cancer Prevention Study-II.
• Utilized Cox proportional and additive hazards models to assess mortality associations and interactions.
• Employed modeled PM2.5 concentrations to estimate exposure levels.

Main Results:

• PM2.5 exposure was associated with increased cardiovascular mortality in never smokers (HR: 1.09).
• Cigarette smoking significantly increased mortality risk (HR: 1.89) in low PM2.5 areas.
• A small, significant additive interaction (Excess Relative Risk: 0.10) was observed between high PM2.5 and smoking for cardiovascular mortality.

Conclusions:

• PM2.5 is associated with all-cause and cardiovascular mortality in both smokers and never smokers.
• Evidence suggests a small additive interaction between PM2.5 and cigarette smoking on cardiovascular mortality.
• Reducing cigarette smoking offers the greatest potential to decrease mortality, but PM2.5 reduction also contributes to preventing smoking-attributed deaths.