A new study found that waist size was a predictor of heart failure among middle-aged and older men and women, and was found to be a risk factor even when BMI (body mass index) was in the normal range.
The study was the work of first author Dr Emily Levitan, a Research Fellow in the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess Medical Center (BIDMC), and colleagues, and is published online in the April 7 Rapid Access Report of the journal Circulation.
Heart failure (also called congestive heart failure) is the main reason that people over 65 end up in hospital. The main symptoms are fatigue, weakness, difficulty walking, a fast or irregular heart beat, and persistent wheezing or coughing.
It occurs when the heart can no longer pump enough blood for what the body needs. It is usually caused by existing problems such as high blood pressure and coronary artery disease.
The study adds more weight to the growing evidence that waist cricumference is an important factor in heart health.
Levitan said in a press statement that as it is now known that two thirds of adult Americans are overweight and obese, and that the prevalence of heart failure went up in the ten years between 1989 and 1999, she and her colleagues wanted to “understand if and how this increase in obesity was contributing to these rising figures”.
Levitan and colleagues used data from two Swedish population-based studies: one comprising nearly 37,000 women aged 48 to 83 who were part of the Swedish Mammography Cohort, and the other comprising over 43,000 men aged 45 to 79 who were part of the Cohort of Swedish Men.
All participants had filled in questionnaires about their height, weight, waist circumference, and other vital statistics, and they were followed over 7 years from 1998 to 2004 for incidence of first time heart failure.
The results showed that among the women there were 382 first time heart failure events (357 hospitalizations and 25 deaths) and among the men there were 718 first time heart failure events (679 hospitalizations and 39 deaths).
From the questionnaire responses, Levitan and colleagues determined that 34 per cent of the women were overweight, while 11 per cent were obese, and 46 per cent of the men were overweight while 10 per cent were obese.
On first analysis, they found that either BMI, waist circumference, waist to hip ratio, or waist to height ratio was linked to higher rates of heart failure.
When they looked at the figures more closely, they also found that among women with a BMI of 25 (within the normal range), a waist circumference increase of 10 cm was linked to a 15 per cent higher risk of heart failure. This increased to an 18 per cent higher risk among women with a BMI of 30.
Among men with a BMI of 25, a 10 cm increase in waist circumference was linked to a 16 per cent higher risk of heart failure, and this also went up to 18 per cent increased risk for men whose BMI was 30.
They also found that for the men, as BMI went up by one point, this was linked to a 4 per cent increase in heart failure risk, regardless of their waist size. For women though, rising BMI was only linked with higher heart failure risk among those with the largest waists.
And the final result they discovered was that the link between BMI and heart failure risk became less sensitive with age, suggesting that higher BMI has a stronger impact on heart failure risk in younger people.
Levitan said their findings emphasized the importance of maintaining a healthy weight.
“Previous research has looked at various types of heart disease and related health issues, and no matter the particulars of the study, they’ve all been pretty consistent in determining that excess body weight increases a person’s risk of heart disease,” she stressed.
The study was funded by the National Institutes of Health, the Swedish Research Council and the Swedish Foundation for International Cooperation in Research and Higher Education.
Levitan’s co-authors include BIDMC investigators Murray A Mittleman (senior author), Amy Z Yang, and Alicja Wok.
Written by: Catharine Paddock, PhD