A large study has indicated that a large waist size (even at a normal weight) may increase a woman's chance of having asthma.

Being overweight or obese was also shown to make asthma more likely - and to worsen the symptoms.

The study, carried out by Julie Von Behren and colleagues from the Northern California Cancer Center in Berkeley, looked at data from 88,304 women who had been involved in the California Teachers Study (which tracked women from age 18). They found that:

  • Women of a healthy weight were much less likely to have asthma than those who were overweight or obese
  • But women who were a healthy weight with a waist size over 34 inches were also more likely to have asthma

The research results were published in Thorax, a journal focused on respiratory medicine, as Obesity, Waist Size, and Prevalence of Current Asthma in the California Teachers Study Cohort.

The researchers said that their results confirmed a link between asthma and being overweight or obese, and cautioned that:

Obese and overweight women were at greater risk of severe asthma episodes, measured by urgent medical visits and hospitalizations.

They also emphasised how this study was the first to show a link between asthma and abdominal fat (extra inches around the waist), even in women of a normal weight.