Styrene exposure and ischemic heart disease: a case-cohort study

Area of Science:

• Occupational Health
• Environmental Epidemiology
• Cardiovascular Disease Research

Background:

• Particulate matter in ambient air is associated with increased mortality and hospital admissions for ischemic heart disease.
• Styrene, present in low doses in air, adheres to particulates and may exert cardiovascular effects.
• Previous industrial studies indicate a higher incidence of cardiovascular disease among styrene-exposed workers.

Purpose of the Study:

• To investigate a potential dose-response relationship between occupational styrene exposure and ischemic heart disease.
• To assess the association between recent styrene exposure and acute ischemic heart disease death in a cohort of male workers.

Main Methods:

• A case-cohort study design was employed, including 498 ischemic heart disease deaths and a random sample of 997 workers.
• The study population comprised male workers from two U.S. styrene-butadiene rubber-manufacturing plants (1943-1984).
• Proportional hazards models were utilized to analyze the association between styrene exposure and mortality.

Main Results:

• Recent styrene exposure demonstrated a significant association with acute ischemic heart disease death among active workers.
• Workers with 2 or more years of employment exposed to 0.2-<0.3 ppm styrene in the last 2 years had a relative hazard of 2.95.
• Exposure to >=0.3 ppm styrene in the most recent 2 years for similarly employed workers showed a relative hazard of 4.30 for acute ischemic heart disease death.

Conclusions:

• Occupational exposure to styrene is significantly associated with an increased risk of fatal ischemic heart disease.
• A dose-response relationship appears to exist, with higher styrene concentrations correlating with greater mortality risk.
• Findings underscore the importance of managing styrene exposure in occupational settings to mitigate cardiovascular risks.