Chronic episodes of depression may be "causally linked" to an increased risk for coronary heart disease (CHD). Recent findings from the ongoing Whitehall II study, which began in 1985, showed that patients who had depressive symptoms during 1 or 2 assessments did not have an added risk for CHD.
There was, however, a significant increase in risk if they reported symptoms during 3 or more assessments. The aim of the Whitehall II study was to track cardiovascular disease over time and included n=10,308 civil servants (mean age 44.4 years; 67% men; 90% white) from London, UK. This analysis examined multiple measurements over four 5-year observation cycles and three 10-year cycles, for a total follow-up of 24 years.
Results over the 5-year observation cycles showed a cumulative effect of depressive symptoms on the risk of CHD consistent with an increasing dose response and additionally further analyses showed no "reverse causation." So, the patients with prevalent major CHD were not found to be more likely to have depressive symptoms. The researchers note that this lends credence to their claim of a causal association from depression to CHD. It is also worth mentioning that the researchers found no significant link between long-term depressive symptoms and an increased risk for stroke.
Essentially, this study showed that depression is a risk factor for vascular disease. Whether or not the association is causal, supporting individuals to recover from chronic or repeated episodes of depression has merit, particularly if the individual is then better able to reduce any vascular risk, for example, by quitting smoking. The study was published in the European Journal of Preventive Cardiology on the 3rd February, 2014.
NB: Cumulative GHQ-30 caseness was significantly associated with incident CHD in a dose-response manner. The age- and sex-adjusted hazard ratio (HR) for CHD when depressive symptoms were recorded on 1 or 2 questionnaires was 1.12 (95% confidence interval [CI], 0.7 - 1.7). However, the adjusted HR for 3 or 4 questionnaires was 2.06 (95% CI, 1.2 - 3.7). CES-D caseness also predicted increased risk for CHD (adjusted HR, 1.81; 95% CI, 1.1 - 3.1; P = .03).