Exposure to secondhand smoke is associated with increased left ventricular mass

Area of Science:

• Cardiovascular Health
• Environmental Health
• Public Health

Background:

• Chronic hypertension is a known risk factor for left ventricular hypertrophy.
• Emerging evidence links secondhand smoke (SHS) exposure to chronic hypertension.
• The study investigates the impact of SHS on electrocardiographic left ventricular (LV) mass in non-smokers.

Purpose of the Study:

• To examine the association between SHS exposure and LV mass in non-smokers.
• To determine if there is a dose-response relationship between SHS exposure levels and LV mass.
• To identify potential effect modification by demographic and clinical factors.

Main Methods:

• Analysis of 4982 non-smoker participants from NHANES-III.
• Definition of non-smoking (serum cotinine ≤10 ng/mL) and SHS exposure (serum cotinine ≥1 ng/mL).
• Estimation of LV mass using an electrocardiographic model and multivariable linear regression.

Main Results:

• Approximately 9.8% of participants reported SHS exposure.
• SHS exposure was associated with a 2.9 g/m² increase in LV mass index.
• A dose-response relationship was observed between cotinine levels and LV mass index, with significant effect modification in obese individuals (4.8 g/m² increase).

Conclusions:

• SHS exposure is associated with increased LV mass in a diverse non-smoking population.
• The association demonstrates a dose-response relationship and is amplified in obese individuals.
• Findings emphasize the cardiovascular harm of passive smoking and advocate for stricter smoking restrictions.