Rn. Lemaitre et al., LEISURE-TIME PHYSICAL-ACTIVITY AND THE RISK OF NONFATAL MYOCARDIAL-INFARCTION IN POSTMENOPAUSAL WOMEN, Archives of internal medicine, 155(21), 1995, pp. 2302-2308
Background: Few studies have examined the association of physical acti
vity with coronary heart disease among women. Objective: To examine wh
ether participation in physical activity during leisure time decreases
the risk of myocardial infarction in postmenopausal women. Method: A
population-based, case-control study among enrollees of the Group Heal
th Cooperative of Puget Sound, a health maintenance organization based
in Seattle, Wash. Cases were postmenopausal women who sustained an in
cident nonfatal myocardial infarction during the period 1986 through 1
991. Controls were a random sample of Group Health Cooperative enrolle
es who were frequency matched to the cases by age and calendar year. P
articipation in physical activity during leisure time was assessed fro
m a telephone interview. A total of 268 cases and 925 controls were in
terviewed. Results: After adjustment for potential confounding factors
, the odds ratios for nonfatal myocardial infarction for women in the
second, third, and fourth quartile of total energy expenditure, relati
ve to women in the first quartile, were 0.52 (95% confidence interval,
0.34 to 0.80), 0.40 (95% confidence interval, 0.26 to 0.63), and 0.40
(95% confidence interval, 0.25 to 0.63), respectively. Similar odds r
atios were associated with the energy expended in nonstrenuous leisure
-time physical activity, and with walking for exercise. Conclusion: Th
is case-control study suggests that the risk of myocardial infarction
among postmenopausal women is decreased by 50% with modest leisure-tim
e energy expenditures, equivalent to 30 to 45 minutes of walking for e
xercise three times a week.