While the exact causes of asthma remain elusive, a new study suggests the condition may be more common in women with irregular periods.
The finding adds to the evidence suggesting that female hormones play a role in the development of asthma and allergies, according to the report in the June issue of the journal Thorax.
"We noticed that women with asthma more often have irregular menstruation," said lead researcher Dr. Cecilie Svanes, a pulmonologist in the Department of Thoracic Medicine at Haukeland Hospital, in Bergen, Norway.
The researchers found that younger women with irregular periods were 58 percent more likely to develop asthma compared to women with regular periods.
Svanes speculated that this phenomenon may be related to polycystic ovarian syndrome, which leads to irregular periods and insulin resistance.
"Treatment of the insulin resistance will make some of these women fertile," she noted.
So, asthma may have common risk factors with polycystic ovarian syndrome, Svanes said.
"There is a lot of discussion when it comes to heart disease, but there has been very little discussion of this when it comes to lung disease.
This finding suggests that asthma could be associated with insulin resistance and metabolic syndrome, like all of the other Western Society diseases [heart disease, diabetes and obesity]."
In another, as yet unpublished study, Svanes's team found that hormonal imbalance in women is related to poorer lung function.
"This is very unusual," said Dr. Clifford Bassett, a clinical instructor at New York University School of Medicine and a spokesman for the American Academy of Allergy, Asthma and Immunology.
"The study is interesting and intriguing, but I am not sure how the clinician can utilize the information in terms of a day-to-day practical approach."