From The Desk Of Clarence Bass
“Programmes (sic) for the promotion and maintenance of physical activity deserve
to be a much higher public health priority for women than they are now, across
the adult lifespan.”
Couch Potatoes More at Risk than Smokers
Physical Inactivity: The "Cinderella Risk Factor"
Australian researchers have given us another powerful reason to stay physically active at every stage of life.
They ranked high body mass, smoking, high blood pressure, and physical inactivity as risk factors for heart disease in Australian women. Many would have predicted that smoking was the most dangerous. And they would’ve been right, up to about age 30. After that, however, inactivity was the number one risk factor for heart disease.
The study, led by Wendy J. Brown, PhD, was published online May 8, 2014, in the British Journal of Sports Medicine.
The details are interesting, instructive, and a bit complicated. We’ll bypass the multi-step calculations and focus on the main findings.
The investigation used data from two earlier studies of disease risk, one global and the other limited to Australia.
The first, a study of risk factors for all diseases worldwide put high blood pressure at the top, smoking second, household air pollution third—and physical inactivity tenth. The Australian study, however, put overweight, smoking, high blood pressure, and inactivity at the top in that order. The pronounced differences in the two studies highlight the need to focus on individual countries. For example, Australia is a developed country with relatively high incomes and minimal air pollution. Physical activity levels also tend to be lower in developed countries. Australia and the United States, of course, have much in common.
Dr. Brown and colleagues narrowed their study to the top four risk factors in Australia and one disease—heart disease—a major problem in developed countries. Importantly, they tracked women’s health in 15 age groups from 22-27 to 85-90. No other study has looked at data from women over such a large age range.
They hypothesized that risk factors might change with a woman’s age. As you’ll see, they were correct.
A principal aim of the study was to determine the proportion of heart disease that would disappear if exposure to specific risk factors were to be eliminated. Again, they succeeded.
Low exposure for the four risk factors were determined using the following thresholds: no smoking, more than 150 minutes per week of moderate intensity activity, body mass index 23 or less, and systolic BP 115 or less. Beyond these minimum cut off points a risk factor was determined to be present. For example, any smoking or walking less than 30 minutes 5 days a week constituted risk factors.
The point of the study was to inform public priorities across the adult lifespan of Australian women. Here are the most telling findings.
Let’s start with the prevalence of smoking. They found that smoking was highest among women aged 22 to 27 years, at 28%, and lowest in those aged 73 to 78 years, at 5%.
Inactivity and high blood pressure, on the other hand, increased steadily across the lifespan from age 22 to 90 years, rising from 48% to 81% for inactivity and from less than 5% to 47% for hypertension.
High body mass (BMI over 23) was lowest, at 46%, in the youngest women (aged 22 to 27 years); peaked in middle age, at 79.2% in women aged 59 to 64 years; and then declined again to 62.4% in women aged 85 to 90 years.
Combining prevalence and relative risk data, smoking was the most important contributor to heart disease up to age 30, accounting for 59%; but its contribution to heart disease declined to 5.3% in women aged 73 to 78 years.
“Low” to “no” physical activity accounted for 47.2% of heart disease in women aged 22 to 27 years, rising to 50.9% in women aged 31 to 36 years and then gradually declined to 23.5% in women aged 85 to 90 years. Interestingly, as the women reached retirement age, 59 to 64, activity level increased. They apparently had more time for exercise in retirement—and it paid off.
In contrast, the largest proportion of heart disease risk attributed to high body mass was 32.7% in women aged 31 to 36 years, and to hypertension 10.7% in women aged 56 to 64 years.
Finally, they projected that the lives of more than 2000 middle-aged and older women could be saved each year--if Australian women between the ages of 30 to 90 were able to meet the recommended exercise quota.
“Our data suggest that national programmes (sic) for the promotion and maintenance of physical activity, across the adult lifespan, but especially in young adulthood, deserve to be a much higher public health priority for women than they are now,” the researchers concluded.
Brown and her colleagues crowned physical inactivity the “Cinderella risk factor.”
Exercise, long the servant girl, may be coming into its own, at least in Australia.
friendly hiker took this photo of Clarence congratulating Carol on her interval
workout in the foothills above their home.
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