Objective
Evaluate whether smoking exposure and depressive symptoms accumulated over 25 years are synergistically associated with subclinical heart disease, measured by coronary artery calcification (CAC).
Methods
Participants (baseline: 54.5% female; 51.5% Black; age range=18–30 years) were followed prospectively from 1985 to 2010 in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Smoking status was queried yearly from Year 0 to Year 25 to compute packyears of smoking exposure. Depressive symptoms were measured on the Center for Epidemiologic Studies Depression (CES-D) scale every five years to compute cumulative scores from Year 5 to Year 25. A three-level multinomial logistic regression was used to evaluate the association between cumulative smoking, cumulative depressive symptoms, and their interaction with moderate-risk CAC (score 1-99) and higher-risk CAC (score ≥100) compared to no CAC (score =0) at Year 25. Models were adjusted for sociodemographic, clinical, and behavioral covariates.
Results
Among 3,189 adults, the cumulative smoking x depressive symptoms interaction was not significant for moderate-risk CAC (p=.057), but was significant for higher-risk CAC (p=.001). For adults with a 30-packyear smoking history, average CES-D scores 2, 10, and 16 were respectively associated with odds ratios (95% confidence intervals) 3.40 (2.36–4.90), 4.82 (3.03–7.66), and 6.25 (3.31–11.83) for higher-risk CAC (all ps<.05).
Conclusion
Cumulative smoking exposure and cumulative depressive symptoms have a synergistic association with subclinical heart disease, where higher lifetime smoking exposure and depressive symptoms are associated with greater odds of CAC.