Sleep disorders afflict tens of thousands of people with depression, and a new study published in the Journal of Sleep Research furthers concerns about the sleep status of depressed patients. The study suggests that poor sleep may go some way to explaining the relationship between depressive symptoms and cardiovascular disease-related deaths. The study showed that after accounting for sociodemographic variables, depressive symptoms still increased the risk of cardiovascular death by 67%, a statistically significant difference; however, this significance disappeared when sleep status was taken into account. In fact, the strength of this association decreased by 21% when sleep variables were taken into account. A total of 5813 subjects from the Whitehall II research project in the United Kingdom, aged 50-74 years (between 2003-2004 at study baseline), were recruited for the study. Of these subjects, 14.6% had depressive symptoms with a score of ≥16 on the Flow Center Depression Scale, 8.0% had sleep deprivation with an average of less than 5 hours of sleep per night, and 31% had sleep disturbance, i.e., had sleep disorders or had taken sleep aids for at least 15 nights in the previous month. During the average follow-up period of 8.8 years, 338 subjects died, including 98 from cardiovascular disease. The study showed that sleep deprivation and sleep disorders were significantly associated with depressive symptoms, but had a weak or no association with cardiovascular mortality and no association with all-cause mortality; however, these sleep abnormalities did increase cardiovascular mortality in depressed patients. The researchers also noted that because depressive symptoms and sleep variables were considered together, they had difficulty determining the likelihood that sleep factors were confounders rather than “moderators” of the association between depressive symptoms and mortality risk. “For example, sleep problems can independently influence the onset of depressive symptoms and increase the risk of death, making them confounding factors.” However, “the findings make perfect biological sense, as previous studies have demonstrated that sleep problems are associated with some of the major risk factors for cardiovascular disease, such as obesity, hypertension, diabetes and inflammation,” the researchers noted. The researchers noted. ”Suggesting to us that sleep problems in depressed patients are of concern given the protective effect of high sleep quality.”