Healthy Lifestyle May Improve Longevity Even Into Old Age
September 4, 2012 — A healthy lifestyle may improve longevity even into old age, according to a population-based cohort study published online August 30 in the British Medical Journal.
"Lifestyle, social networks, and leisure activities have been studied individually in relation to longevity in several studies and others have examined the possible association of these factors with longevity while taking into account their coexistence and interactions," Debora Rizzuto, a PhD student from the Aging Research Center, Department of Neurobiology, Health Care Sciences and Society at Karolinska Institutet and Stockholm University in Sweden, and colleagues write. "Only a few studies, however, have examined the relation between the combinations of various modifiable factors and longevity. Among the previous studies that have included the oldest old population (≥85 years), only four had an observational period longer than 10 years."
The purpose of this study was to examine modifiable characteristics associated with longevity among adults at least 75 years of age, using a prospective cohort of 1810 such adults enrolled in the Kungsholmen Project in Stockholm. During the 18-year follow-up, the investigators studied median age at death, based on vital status records from 1987 through 2005.
Most of the participants (1661; 91.8%) died during follow-up. Life span exceeded 90 years in half of the participants. Age at death was 1.0 year younger in the current smokers than in nonsmokers (95% confidence interval [CI], 0.0 - 1.9 years). However, survival in former smokers was similar to that of never-smokers, suggesting that smoking cessation in middle age could lessen the effect of smoking on mortality.
Physical activity, such as regular swimming, walking, or gymnastics, was the leisure activity most strongly linked to longevity. Those participants who regularly engaged in these activities had a median age at death 2.0 years older (95% CI, 0.7 - 3.3 years) than participants who did not.
The investigators defined a low-risk profile as healthy lifestyle behaviors, taking part in 1 or more leisure activity, and having a rich or moderate social network. They defined a high-risk profile as unhealthy lifestyle behaviors, no leisure activities, and a limited or poor social network. Compared with participants who had a high-risk profile, those who had a low-risk profile had an increase in median survival of 5.4 years.
A subgroup analysis of the oldest old (aged at least 85 years) and of participants with chronic conditions showed that those with a low-risk profile had a median age at death that was 4 years greater than those with a high-risk profile.
Other factors associated with increased survival were female sex and higher educational level.
"Even after age 75 lifestyle behaviours such as not smoking and physical activity are associated with longer survival," the study authors write. "A low risk profile can add five years to women's lives and six years to men's. These associations, although attenuated, were also present among the oldest old (≥85 years) and in people with chronic conditions."
Limitations of this study include survival selection, information bias regarding alcohol intake, assessment of exposures only at baseline, and failure to examine dietary quality or overall quality of life.
"Our results suggest that encouraging favourable lifestyle behaviours even at advanced ages may enhance life expectancy, probably by reducing morbidity," the authors conclude.
The Swedish Council for Working Life and Social Research, Swedish Research Council for Medicine, Swedish Brain Power, Karolinska Institutet's Faculty funding for postgraduate students, and Stiftelsen Ragnhild och Einar Lundstr¨ms Minne funded this study. The study authors have disclosed no relevant financial relationships.
BMJ. Published online August 30, 2012. Full text
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