Walking good for older women |
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Study
There were 73,700 women in a womens' health observational study involving women aged 50 to 79 years at entry. Of these about 62,000 were white, 5,600 black, 2,800 hispanic, 2,300 asian, and 1,300 American indian or other racial background. They were enrolled between 1994 and 1998, with observation up to mid-2000. Women were free of cardiovascular disease and cancer at baseline.
There was a clinic visit at enrolment, during which self-administered questionnaires were completed about personal and family medical history, smoking, diet, physical activity and other lifestyle factors. Height, weight, hip and waist circumference, and blood pressure, were measured. The questionnaire on recreational physical activity was detailed, and used to calculate a weekly energy expenditure score in metabolic equivalents (MET-score). A sample of 1,092 women entered a reliability study to demonstrate the reproducibility of the assessment questionnaires.
The primary endpoints were newly diagnosed coronary heart disease (nonfatal myocardial infarction and death with a coronary cause) and total cardiovascular events (myocardial infarction, death from coronary cause, coronary or carotid revascularisation, angina, congestive heart failure, stroke). All endpoints were confirmed from medical records by blinded observers.
Results
There was an average of 3.2 years of follow up, giving 233,000 person-years of observation. There were 345 newly-diagnosed cases of coronary disease, 309 strokes, and 1,551 first cardiovascular events. The range of total weekly energy expenditure was from 0 to >33 MET-hours/week.
The age- and multivariate-adjusted risk of both coronary heart disease and total cardiovascular disease fell as the amount of exercise rose (Figure 1). The mean number of MET-hours per week in each quintile was 0, 4.2, 10, 18 and 33 respectively for quintiles 1-5. Similar reductions were seen for walking (0->17 MET-hours per week) and for vigorous exercise (0->210 minutes strenuous exercise a week).
Figure 1: Effect of increasing weekly MET-hours
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Trends for reduced risk with increased total physical activity and for walking was seen for white and black women, for all ages, and for different ranges of body mass index. For walking, pace was important. The multivariate relative risk and age and walking time adjusted relative risks both showed a significantly lower risk of cardiovascular disease when women walked at more than a casual pace (Figure 2). The faster they walked, the lower the risk. Women who walked more and who had some vigorous exercise as well during the week had a particularly lowered risk of cardiovascular disease. Figure 2: Effect of walking pace (mph) on relative risk for cardiovascular disease |
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CommentCardiovascular disease is not insignificant in older women. There were 1,551 first cardiovascular events (including 345 fatal and nonfatal heart attacks and 309 strokes) over 3.2 years among 73,743 women aged 50-79 years. That's one event in 50 women over three years on average. Cardiovascular disease in women who exercised and walked the most occurred at about half the rate of that in those who did not exercise or walk at all. This was true irrespective of race, age or body mass index. The strengths of this study were its size, being prospective, the racial and ethnic diversity of the women included, the detailed assessment of physical activity at baseline, and the uniform criteria for the end points. It makes a powerful case to find ways to make it easier for women to walk, because walking is beneficial in other ways too. It reinforces similar evidence for men. Joined up government could do no better than to establish ways to ensure that more of us walk longer, and faster, and more often. It would be more beneficial than most tablets. Reference:
Link
ImpAct 3
reported how a GP in England "prescribed" walking
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