Total mortality after changes in leisure time physical activity in 50 year old men: 35 year follow-up of population based cohort

Abstract

Objective: To examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation.

Design: Population based cohort study with follow-up over 35 years.

Setting: Municipality of Uppsala, Sweden.

Participants: 2205 men aged 50 in 1970-3 who were re-examined at ages 60, 70, 77, and 82 years.

Main outcome measure: Total (all cause) mortality.

Results: The absolute mortality rate was 27.1, 23.6, and 18.4 per 1000 person years in the groups with low, medium, and high physical activity, respectively. The relative rate reduction attributable to high physical activity was 32% for low and 22% for medium physical activity. Men who increased their physical activity level between the ages of 50 and 60 continued to have a higher mortality rate during the first five years of follow-up (adjusted hazard ratio 2.64, 95% confidence interval 1.32 to 5.27, compared with unchanged high physical activity). After 10 years of follow-up their increased physical activity was associated with reduced mortality to the level of men with unchanged high physical activity (1.10, 0.87 to 1.38). The reduction in mortality associated with increased physical activity (0.51, 0.26 to 0.97, compared with unchanged low physical activity) was similar to that associated with smoking cessation (0.64, 0.53 to 0.78, compared with continued smoking).

Conclusions: Increased physical activity in middle age is eventually followed by a reduction in mortality to the same level as seen among men with constantly high physical activity. This reduction is comparable with that associated with smoking cessation.

Fig 1 Cohort study base and numbers included in present study. Deaths presented as cumulative mortality from start of survey 1. Numbers not available represent those who were not living in the Uppsala region at time of invitation. They did not contribute information on physical activity at that survey but they could return at later survey if they had moved back to Uppsala. Numbers included represent those who were included in analysis. All men were traced in population register for mortality data, including those “not available”

Fig 2 Cumulative mortality from age 50 (Cox regression) according to leisure time physical activity level and total mortality. At end of follow-up, estimated proportions of deaths were 81.4 (95% confidence interval 80.8 to 82.0) for low physical activity, 72.0 (71.5 to 72.5) for medium, and 61.8 (61.4 to 62.2) for high

Fig 3 Cumulative mortality from age 60 (Kaplan-Meier) according to changes in leisure time physical activity level and total mortality. Slopes of curves correspond to mortality rates. Parallel curves indicate equal rates of death. At the end of follow-up, rates were 74.0 (95% confidence interval 67.0 to 80.6) for unchanged low-medium, 70.5 (64.8 to 76.0) for decreased from high to low-medium, 64.7 (57.4 to 71.9) for increased from low-medium to high, and 58.5 (50.8 to 66.3) for unchanged high