Rest/activity rhythms and cardiovascular disease in older men.

Prior studies have suggested an increased risk of cardiovascular disease (CVD)-related mortality in older adults with disturbed circadian rest/activity rhythms (RARs). The objective goal of this study was to examine the association between disrupted RARs and risk of CVD events in older men. A total of 2968 men aged 67 yrs and older wore wrist actigraphs for 115 ± 18 consecutive hours. RAR parameters were computed from wrist actigraphy data and expressed as quartiles (Q). CVD events consisted of a composite outcome of coronary heart disease (CHD), stroke, and peripheral vascular disease (PVD) events. Secondary analyses examined associations between RARs and individual components of the composite outcome (CHD, stroke, and PVD). There were 490 CVD events over an average of 4.0 ± 1.2 yrs. Overall, reduced amplitude (HR = 1.31, 95% confidence interval [CI] 1.01-1.71 for Q2 vs. Q4) and greater minimum (HR = 1.33, 95% CI 1.01-1.73 for Q4 vs. Q1) were associated with an increased risk of CVD events in multivariable-adjusted models. In secondary analyses, there was an independent association between reduced amplitude (HR = 1.36, 95% CI 1.00-1.86) and greater minimum activity counts (HR = 1.39, 95% CI 1.02-1.91) with increased risk of CHD events. Reduced F value (HR = 2.88, 95% CI 1.41-5.87 for Q1 vs. Q4 and HR = 2.71, 95% CI 1.34-5.48 for Q2 vs. Q4) and later occurring acrophase of the RAR (HR = 1.65, 95% CI 1.04-2.63 for Q4 vs. Q2-3) were associated with an increased risk of PVD events. Results were similar in men without a history of CVD events. The findings revealed that among older men, measures of decreased circadian activity rhythm robustness (reduced amplitude and greater minimum activity) were associated with an increased risk of CVD events, primarily through increased risk of CHD or stroke events, whereas measures of reduced circadian activity rhythmicity were not associated with risk of CVD events overall, but were associated with an increased risk of PVD events. These results should be confirmed in other populations.