NEW YORK (Reuters Health) - The occurrence of asthma increases by roughly 50 percent in overweight and obese men and women, compared with normal weight men and women, according to a report published Monday in the American Journal of Respiratory and Critical Care Medicine.

Nearly two thirds of U.S. adults are overweight or obese, and asthma affects roughly 7 percent of the adult population, Drs. E. Rand Sutherland and David A. Beuther from National Jewish Medical and Research Center, Denver, point out in their report.

If significant weight loss could be achieved in the population of overweight and obese individuals, they estimate that the number of new cases of asthma in U.S. adults "might fall by as much as 250,000 per year."

Significant weight loss in overweight and obese children promises significant decreases in asthma cases in children as well, they add.

The Denver team quantified the relationship between categories of body mass index (BMI) and the occurrence of asthma by pooling data from seven studies involving 333,102 adults.

A BMI of up to 25 is considered normal weight, up to 30 is classified as overweight and 30 or higher indicates obesity.

Compared with normal-weight adults, overweight and obese adults were 51 percent more likely to be diagnosed with asthma, the researchers found.

Sex did not seem to modify the strength of the association between excess weight and asthma incidence. For overweight and obese men, the odds of developing asthma were 46 percent greater and for overweight and obese women, it was 68 percent higher, compared with their normal-weight counterparts.

Moreover, there was a clear "dose-response effect" of elevated BMI -- the higher the BMI, the greater the odds of asthma. Overweight adults had 38-percent greater odds of asthma and obese adults had 92-percent greater odds of asthma, relative to normal-weight adults.

Obesity is a well-established risk factor for diabetes, sleep-disordered breathing, stroke, heart and blood vessel disease, arthritis and other common ailments, note Sutherland and Beuther. They say their findings support adding asthma to this list.