Low-Carb Diet Research and News

NEW YORK (Reuters Health) - Fewer women are diagnosed with heart disease today than 20 years ago, thanks to a decline in smoking, improvements in diet and greater use of hormone replacement therapy during menopause, researchers report.

However, the growing prevalence of obesity appears to be slowing this trend, warn Dr. Frank B. Hu from Harvard School of Public Health in Boston, Massachusetts, and colleagues.

The investigators compiled detailed data on diet, exercise, smoking, use of hormones during menopause, and other lifestyle factors from nearly 86,000 women aged 34 to 59 with no history of heart disease or cancer in 1980. Women were re-questioned every 2 years until 1994.

According to results published in the August 24th issue of The New England Journal of Medicine, the incidence of heart disease declined by 31% from 1980-1982 to 1992-1994.

The rate of smoking decreased by 41%, diet improved substantially, and the percentage of postmenopausal women using hormone replacement therapy increased by 175%. Hormone replacement therapy contains estrogen, a hormone that protects against heart disease, the team notes.

Individually, the reduction in smoking accounted for 13% of the decline in heart disease incidence overall. Hormone use explained 9% of the reduction and dietary improvements were responsible for 16%, the authors report.

The investigators found that between 1980-1990, intake of trans fat fell by 31%, consumption of fiber rose by 90%, and daily intake of folate increased by 12%. The average intake of red meat and high-fat dairy products declined and consumption of poultry, fish and low-fat dairy products increased during this period.

But the rate of obesity, as defined by body mass index (BMI), rose by 38%. BMI is a measure of a person's weight in relation to height. A BMI greater than 24 indicates that a person is overweight.

The researchers suggest that consumption of refined carbohydrates might account for rising rates of obesity.

``The incidence of coronary disease would probably have declined even more if body mass index had not increased over time,'' they speculate.

Hu and his team conclude that their findings ``underscore the importance of diet and lifestyle in the primary prevention of coronary disease.''

SOURCE: The New England Journal of Medicine 2000;343:530-537.