Obesity Greatly Increases Risk of Getting Asthma, Study Finds

Harvard researchers say a study of thousands of nurses has provided the first strong evidence that obesity greatly increases the risk of developing asthma.

Even a little bit of fat increases the risk, and obese people--those who are roughly 35% overweight--are at least three times more likely to develop the respiratory ailment that afflicts millions of Americans, the researchers say.

For years, doctors have noted a connection between obesity and asthma. But the assumption was that asthma comes first, that patients were prone to putting on weight because breathing problems limited exercise.

The new study was designed to test that assumption, and the results “guarantee that obesity preceded the diagnosis of asthma,” said the research leader, Dr. Carlos A. Camargo Jr. of the Harvard Medical School in Boston.

One outside expert, however, said more study is needed.

The results will be presented this week at the international conference of the American Thoracic Society and the American Lung Assn.

Obesity and asthma are on the rise in developed nations. From 1982 to 1994, the rate of asthma rose 61% in this country, where health officials say one in three people is obese. An estimated 15 million Americans have asthma, which kills about 5,000 people a year.

Camargo’s study used data from women in the Nurses Health Study II. Of the 89,061 nurses tracked in the asthma study, 1,652 developed the ailment from 1991 to 1995.

Their weight and height were recorded at the start of the survey, which was controlled for such factors as age, race, smoking and physical activity.