The Effect of Depression and Cognitive Impairment on 7-year Cardiorespiratory Fitness in Chinese Aged 65 and Older

Objective: To examine the influence of depression and cognitive impairment at baseline on the subsequent levels of cardiorespiratory fitness at 7 years and to compare maximal oxygen uptake (VO2max), the distance walked in the 6-minute walk test (6MWD) and self-reported physical activity in relation to depression and cognitive impairment. Methods: A total of 1,179 Chinese older adults aged 65 and above who participated in the MrOs (Hong Kong) and MsOs (Hong Kong) study during 2001-2003 were re-assessed after 7 years of follow-up. Baseline information on depression, cognitive function and a number of health-related variables were obtained through interview. The outcome variables were cardiorespiratory fitness as measured by VO2max, 6MWD, and physical activity as measured with the Physical Activity Scale of the Elderly (PASE) at 7 years. Results: Subjects with depression at baseline were associated with lower VO2max during a follow-up period of approximately 7 years and this relationship remained significant after adjustment for physical activity, gait speed, and other potential confounders for men only (P<0.05) but not for women. Cognitive impairment at baseline was also associated with shorter 6MWD during the follow-up (P<0.05); however, the association was eliminated in sexstratified analyses. There was no relationship between baseline depression and cognitive impairment with the subsequent levels of physical activity. Conclusions: Among older men, baseline depression was associated with lower VO2max but not 6MWD or PASE score over 7 years. Our findings reinforce that VO2max is better than 6MWD or self-reported physical activity as a measurement of cardiorespiratory fitness in relation to depression in elderly population.