Alcohol and coronary heart disease risk - Is there an unknown confounder?

Aims: To evaluate whether confounding by several known or suspected coronary heart disease risk factors are likely to explain the lower coronary heart disease risk among light alcohol drinkers compared with never-drinkers. Design: A population-based cross-sectional study. Methods: Hypertension, body mass index (BMI), diabetes, depression, sleep disturbances, smoking, physical activity, life satisfaction, psychological distress, trait anxiety, independent and dependent life events, length of working hours, job control, job strain and effort-reward imbalance were compared between never-drinkers and light drinkers (<70 g of alcohol per week). Data on 41 099 participants (6222 men, 34 877 women) were derived from two ongoing cohort studies, the '10-Town Study' and 'Finnish Hospital Personnel Study', in Finland in 2000-02. Results: Of the 16 comparisons under study, seven showed significant differences between never-drinkers and light drinkers. Five of the differences favoured never-drinkers and two showed a disadvantage. The latter were low BMI and low leisure-time physical activity, both more common among never-drinkers than among light drinkers. In contrast, smoking, sleep disturbances, trait anxiety, effort-reward imbalance and dependent life events were less common among never-drinkers than among light drinkers. Conclusions: None of the risk factors studied was a likely candidate for an unknown confounder.