The joint effects of clinically relevant depressive symptoms and cardiovascular risk factors on incident cardiovascular disease among older adults in the community

Objective: To determine if there is a synergistic effect between clinically relevant depressive symptoms and cardiovascular risk factors that disproportionately increases the risk of cardiovascular disease (CVD) among older adults with depressive symptoms. Methods: Data were obtained from the Longitudinal Aging Study Amsterdam, a longitudinal cohort study. N = 3091 respondents with up to seven years of follow-up were included. Incident CVD was based on self-report, medication use, general practitioners' diagnoses and causes of death. A score of ≥16 points on the Center for Epidemiological Studies Depression Scale indicated clinically relevant depressive symptoms. Risk factors included were sex, education, obesity, smoking, alcohol use, physical inactivity and diabetes mellitus. Data were analysed with Cox regression models. Measures of multiplicative and additive interaction were calculated to determine if the presence of both depressive symptoms and a risk factor amplified the risk of CVD. Results: Of all participants, 12.6% had clinically relevant depressive symptoms and, after a median follow-up of six years, 15.7% developed CVD. Only the additive interaction between physical inactivity and depressive symptoms was statistically significant and explained 40.6% of the CVD risk among inactive persons with depressive symptoms. Conclusion: In the general population, we did not detect synergistic effects for most risk factors. However, older adults with clinically relevant depressive symptoms and a physically inactive lifestyle appeared to be at a particularly high risk to develop CVD and may represent an important target for cardiovascular prevention.