Researchers have found that women with a large waistline are at increased risk of developing asthma - even if they are not necessarily overweight.
Women with a excessive abdominal fat, specifically a waist wider than 88cm, are more likely to develop the condition, which affects more than five million Britons, the study revealed.
Experts also confirmed the link between obesity and developing asthma in adulthood.
A team from the Northern California Cancer Center in Berkeley studied data from the California Teachers Study, which started in 1995.
Of the 88,304 female teachers and school administrators who participated in the asthma research, 11,500 (13%) were obese with a body mass index (BMI) of over 30, including 1,334 who were rated extremely obese.
Overweight women with a BMI between 25 and 30 accounted for 21,657 people in the survey.
The study, published in the journal Thorax, revealed that those who were overweight were 40% more likely to develop asthma than women of normal weight, (BMI 18 to 25).
The risk for obese women developing asthma more than doubled, while that for extremely obese women more than tripled.
Even women with normal weight but measuring more than 88cm at the waist saw a modest rise in their risk.