NATURAL-HISTORY OF LEISURE-TIME PHYSICAL-ACTIVITY AND ITS CORRELATES - ASSOCIATIONS WITH MORTALITY FROM ALL CAUSES AND CARDIOVASCULAR-DISEASE OVER 28 YEARS

The association between leisure-time physical activity and 28-year (19 65-1993) risk of death from all causes and cardiovascular disease was studied in 6,131 adults who participated in the Alameda County Study i n Northern California, Because study participants were interviewed on a number of occasions, it was possible to include in the analyses info rmation on changes over time in levels of leisure-time physical activi ty as well as changes in a wide variety of other risk factors. There w ere 47,616 person-years of observation for males (639 deaths from all causes and 321 from cardiovascular disease) and 57,666 person-years of observation for females (587 deaths from all causes and 388 from card iovascular disease), In analyses in which only the baseline values of all covariates were included, a four-point increase on the leisure-tim e physical activity scale, the interquartile range, was associated wit h reduced risk of death from all causes (relative risk (RR) = 0.90, 95 % confidence interval (CI) 0.83-0.99) and cardiovascular disease (RR = 0.85, 95% CI 0.75-0.97), When time-varying information on leisure-tim e physical activity and all other covariates was included, there was s till a protective effect for all-cause and cardiovascular disease mort ality (RR = 0.84, 95% CI 0.77-0.92 and RR = 0.81, 95% CI 0.71-0.93, re spectively). The association between leisure-time physical activity an d risk of death was not altered when information on variations over ti me in leisure-time physical activity and many determinants and consequ ences of physical activity were explicitly included in survival models .