Depressive symptoms, physical inactivity and risk of cardiovascular mortality in older adults: the Cardiovascular Health Study
- Sithu Win1,
- Kapil Parakh1,
- Chete M Eze-Nliam2,
- John S Gottdiener3,
- Willem J Kop3,
- Roy C Ziegelstein1
- 1Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- 2Department of Psychiatry and Behavioural Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- 3Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Correspondence to Roy C Ziegelstein, Johns Hopkins University School of Medicine, Department of Medicine, B-1-North, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224-2780, USA;
Contributors All authors had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
- Accepted 23 December 2010
Background Depressed older individuals have a higher mortality than older persons without depression. Depression is associated with physical inactivity, and low levels of physical activity have been shown in some cohorts to be a partial mediator of the relationship between depression and cardiovascular events and mortality.
Methods A cohort of 5888 individuals (mean 72.8±5.6 years, 58% female, 16% African-American) from four US communities was followed for an average of 10.3 years. Self-reported depressive symptoms (10-item Center for Epidemiological Studies Depression Scale) were assessed annually and self-reported physical activity was assessed at baseline and at 3 and 7 years. To estimate how much of the increased risk of cardiovascular mortality associated with depressive symptoms was due to physical inactivity, Cox regression with time-varying covariates was used to determine the percentage change in the log HR of depressive symptoms for cardiovascular mortality after adding physical activity variables.
Results At baseline, 20% of participants scored above the cut-off for depressive symptoms. There were 2915 deaths (49.8%), of which 1176 (20.1%) were from cardiovascular causes. Depressive symptoms and physical inactivity each independently increased the risk of cardiovascular mortality and were strongly associated with each other (all p<0.001). Individuals with both depressive symptoms and physical inactivity had greater cardiovascular mortality than those with either individually (p<0.001, log rank test). Physical inactivity reduced the log HR of depressive symptoms for cardiovascular mortality by 26% after adjustment. This was similar for persons with (25%) and without (23%) established coronary heart disease.
Conclusions Physical inactivity accounted for a significant proportion of the risk of cardiovascular mortality due to depressive symptoms in older adults, regardless of coronary heart disease status.
Funding The research reported in this article was supported by contract numbers N01-HC-85239, N01-HC-85079 through N01-HC-85086, N01-HC-35129, N01 HC-15103, N01 HC-55222, N01-HC-75150, N01-HC-45133, grant number U01 HL080295 from the National Heart, Lung, and Blood Institute, with additional contribution from the National Institute of Neurological Disorders and Stroke. A full list of principal CHS investigators and institutions can be found at http://www.chs-nhlbi.org/pi.htm. RCZ was supported by grant R24AT004641 from the National Center for Complementary and Alternative Medicine and by the Miller Family Scholar Program of the Johns Hopkins Center for Innovative Medicine.
Competing interests None.
Ethics approval The institutional review board at each centre approved the study and participants gave informed consent.
Provenance and peer review Not commissioned; externally peer reviewed.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.