(RxWiki News) Heart disease is the leading cause of death in women in high-income countries. It seems that the biggest risk factor for the condition may be a lifestyle habit that can be changed.
A recent study found that physical inactivity was the biggest risk factor for heart disease among women 30 years old and older.
The researchers believe that there should be more of an emphasis on the benefits of regular physical activity in public health programs and policies.
"Get active to protect the health of your heart."
The lead author of this study was Wendy J. Brown, PhD, from the Centre for Research on Exercise, Physical Activity and Health in the School of Human Movement Studies at the University of Queensland in Queensland, Australia.
The study included 32,154 participants who were taking part in an ongoing study tracking long-term health called the Australian Longitudinal Study on Women’s Health starting in 1996.
The study by Dr. Brown and team included 15 different age groups of women born from 1921 to 1926, 1946 to 1951 and 1973 to 1978. Participants completed health surveys every three years from 1996 through 2011.
The researchers calculated population attributable risk associated with the four biggest risk factors associated with heart disease in women across a lifespan:
- Smoking tobacco
- Physical inactivity
- Being overweight
- High blood pressure
Population attributable risk measures the amount of cases of a certain condition that would be eliminated in a population if risk factors associated with the condition were eliminated.
The findings showed that the prevalence of smoking tobacco decreased from 28 percent among the women aged 22 to 27 years old to 5 percent among the women aged 73 to 78 years old.
Physical inactivity and high blood pressure increased steadily across the women’s lifespans from age 22 to 90 years old.
The prevalence of overweight participants increased between the ages of 22 and 64 years, but then decreased from age 65 and older.
The researchers determined that 59 percent of the heart disease cases among women younger than 30 could be avoided if the women did not smoke tobacco — making smoking tobacco the biggest contributor to heart disease among women younger than 30 years old.
Across all age groups from 30 years old through late 80s, low physical activity or no physical activity accounted for more population attributable risk than any of the other heart disease risk factors.
The findings suggested that more than 2,000 women in Australia between 30 and 90 years old could have been saved each year from heart disease if every woman in that age range got at least 150 minutes of moderate intensity exercise per week (the recommended weekly exercise quota in Australia).
The researchers emphasized that these 2,000 saved women would come out of Australia alone, suggesting that the combined amount of potential saved lives due to eliminating physical inactivity in high-income countries combined would be very significant.
The population attributable risk of being overweight increased from age 22 to 39 years (the younger group) from 28 percent to 32 percent, then decreased from age 47 to 64 years old (the mid-age group) from 27 percent to 25 percent, and then from 16 percent to 11 percent between the ages of 73 and 90 years old (the older group).
Among the younger group, 2 to 3 percent of heart disease cases could have been eliminated if no one had high blood pressure, the researchers calculated. Among the mid-age and older groups, between 7 and 11 percent of the heart disease cases could have been eliminated if high blood pressure was eliminated.
The findings revealed that the odds of having each risk factor for heart disease changed across the women’s lifespans.
The researchers believe that public anti-smoking efforts for women under 30 years old are needed. However, they also believe that public health efforts aimed at overweight and obesity have overshadowed the effect of physical inactivity — the risk factor that accounted for the biggest population attributable risk among women aged 30 years old and older. Therefore, the researchers argued that more public emphasis should be placed on the necessity of physical activity.
"Our data suggest that national programs 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," Dr. Brown and team concluded.
One limitation of this research was that the women in the study may be over-representative of healthy women; therefore, the findings may underestimate the proportion of women at risk for heart disease. Second, the study did not take into account the interactions between multiple risk factors that may be present in a single person.
In addition, the population attributable risks were calculated using risk ratios based on population data from a previous study. Lastly, the researchers did not measure blood pressure, so they had to rely on self-reported cases of high blood pressure.
This study was published on May 8 in the British Journal of Sports Medicine.
The Australian Government Department of Health and Ageing provided funding.