June 12, 2000
Lars Bo Andersen, PhD, DMSc; Peter Schnohr, MD; Marianne Schroll, PhD, DMSc; Hans Ole Hein, MD
Arch Intern Med. 2000;160(11):1621-1628. doi:10.1001/archinte.160.11.1621
Abstract
Background Physical activity is associated with low mortality in men, but little is known about the association in women, different age groups, and everyday activity.
Objective To evaluate the relationship between levels of physical activity during work, leisure time, cycling to work, and sports participation and all-cause mortality.
Design Prospective study to assess different types of physical activity associated with risk of mortality during follow-up after the subsequent examination. Mean follow-up from examination was 14.5 years.
Setting Copenhagen University Hospital, Copenhagen, Denmark.
Participants Participants were 13,375 women and 17,265 men, 20 to 93 years of age, who were randomly selected. Physical activity was assessed by self-report, and health status, including blood pressure, total cholesterol level, triglyceride levels, body mass index, smoking, and educational level, was evaluated.
Main Outcome Measure All-cause mortality.
Results A total of 2881 women and 5668 men died. Compared with the sedentary, age- and sex-adjusted mortality rates in leisure time physical activity groups 2 to 4 were 0.68 (95% confidence interval, 0.64-0.71), 0.61 (95% confidence interval, 0.57-0.66), and 0.53 (95% confidence interval, 0.41-0.68), respectively, with no difference between sexes and age groups. Within the moderately and highly active persons, sports participants experienced only half the mortality of nonparticipants. Bicycling to work decreased risk of mortality in approximately 40% after multivariate adjustment, including leisure time physical activity.
Conclusions Leisure time physical activity was inversely associated with all-cause mortality in both men and women in all age groups. Benefit was found from moderate leisure time physical activity, with further benefit from sports activity and bicycling as transportation.
A NUMBER of prospective studies have shown lower mortality rates in physically active men compared with sedentary men. Most studies of men have focused on the amount of leisure time physical activity. Also, physical activity at work, and the intensity of physical activity have been shown to be associated with a lower risk of disease and death. Less evidence exists for women. Lissner et al examined the relation between all-cause mortality and physical activity in women. They reported that mortality was twice as high in the group with the lowest activity level compared with the more active groups. In contrast, Blair et al found no difference in mortality between physical activity groups in women. They suggested that the physical activity assessment technique they used was less accurate in women than in men, since focus was on self-reported traditional sport and leisure time physical activities, omitting other activities pertinent to this group, such as housework and child care. Studies associating physical activity in daily living, such as cycling to work, to mortality are few.
The aim of this study was to analyze whether the risk from being physically inactive was consistent across age and sex groups. We examined the association of leisure time physical activity, physical activity at work, bicycling to work, and sports activities to mortality after adjustment for blood pressure, blood lipid levels, smoking, body mass index, and educational level.
Subjects and methods
Study population
This study is based on pooled data from 3 epidemiological surveys from the region of Copenhagen: The Copenhagen City Heart Study, The Glostrup Population Studies, and The Copenhagen Male Study.
A total of 13,455 women and 17,441 men have been examined. Information on chronic disease that could influence physical activity level and risk of death was obtained at the examination and, after 1977, additionally from hospital records. In 2960 women and 3959 men, a chronic disease had been diagnosed before baseline. Chronic diseases diagnosed according to International Classification of Diseases, Eighth Revision included cancers (diagnoses 140-172, 174-209, 230-239), cardiovascular diseases (diagnoses 400-448), lung diseases (diagnoses 490-493), and musculoskeletal diseases (diagnoses 710-738).
Bicycling to work
Information on bicycling as transportation to work was available for 783 women and 6171 men. Among these 6954 subjects, 2291 died during follow-up. The same tendencies were found in men and women when mortality rates were compared between those who cycled to work and those who did not, but the estimates were not significant in women. The average time spent cycling in those who did cycle to work was 3 hours per week. The analyses are presented for the whole group, with adjustment for sex. Bicycling to work was inversely related to years of education. Among the less educated subjects (<8 years of school), 27.8% used the bicycle to work, in the middle group (8-12 years of school) 24.5% cycled, and in the most educated group (≥12 years of school) 20.3% cycled. After adjustment for age, sex, and educational level, the relative risk in those who cycled was 0.70 (95% CI, 0.55-0.89). After additional adjustment for leisure time physical activity, body mass index, blood lipid levels, smoking, and blood pressure, the relative risk was 0.72 (95% CI, 0.57-0.91).
Comment
Relative risk of leisure time physical inactivity in different age groups
The present study showed a tendency toward increased benefit of physical activity associated with higher age. In women, the mortality rate in the most active group in the oldest age group was less than half the mortality rate in the sedentary group, whereas the relative risk between physical activity groups in the youngest group was 0.66. In men, no trend was observed. The relative risk between physical activity groups in the elderly was greater than seen in other studies. It has been proposed that physical activity prevents premature death but does not extend the life span. In the Harvard Alumni Study, the estimated number of added years gained by having an active lifestyle decreased with increasing age at entry. Other studies have found lower mortality rate with higher physical activity level in the elderly. Lindsted et al studied older men up to the age of 90 years, and Kaplan et al22 studied men and women older than 70 years. Both studies found lower mortality among the physically active. Simonsick et al found a 23% to 55% lower mortality rate in highly active men and women older than 65 years, and in the Framingham studies a relative risk of 0.24 was found in physically active women older than 75 years, but no difference was found in men.
It seems that most studies with a large number of older subjects find that a physically active lifestyle is beneficial in old age. To what extent mortality rates differ between activity groups among the elderly is still uncertain. The present study suggests that physical activity is as important in old age as it is in younger age in both sexes and may be even more important in older women.
Physical inactivity at work and bicycling to work
In women, the group with the highest physical activity level at work experienced a protective effect after adjustment for other risk factors and educational level. No benefit with increasing physical activity at work was found in men. Physical activity at work may have changed during the last decades with the introduction of labor-saving devices in the workplace. Powell et al stated that the study of San Francisco longshoremen would not now be possible because the proportion of men in the highest energy category at work has fallen from 40% to 5%. In some studies,5 where both physical activity at work and during leisure time have been assessed, researchers have failed to show a benefit of job-related activity in men; most other Scandinavian studies, support the present findings in women.
To our knowledge, no other study has analyzed the independent benefit of bicycling to work, probably because it is rare in most countries. Morris presented data on cycling and myocardial infarction from the study of civil servants at a 1-day conference in 1990. Seven percent reported cycling, and of those who cycled, most experienced only half the myocardial infarctions of those who reported no cycling. In Denmark, 46% of the 25-year-old men and women use the bicycle to travel to work every day throughout the year and about 70% in the summer.27 Even after adjustment for other risk factors, including leisure time physical activity, those who did not cycle to work experienced a 39% higher mortality rate than those who did.
Source – https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/485349
