Women who use hormonal contraception for a long time are at an increased risk of developing asthma in middle age if they are overweight or obese, new Australian research shows.
The study involving 2,764 perimenopausal women from the Tasmanian Longitudinal Health Study found that body mass index significantly modified the relationship between hormonal contraception (HC) use and asthma.
The results, published in ERJ Open Research, showed that increasing years of pill use was associated with a significantly increased risk of asthma in middle-aged women who are overweight or obese.
But for women with a normal weight, the effect was reversed with longer-term HC use being protective against asthma.
Lead researcher Dr Melanie Matheson from the Centre for Epidemiology and Biostatistics at the University of Melbourne says the findings suggest women with a history of long-term HC use who are obese may need regular monitoring for asthma symptoms.
“If a GP knows a woman has been on the pill for a long period of time, and at that point in time when they’re assessing her she is overweight, it would be worthwhile assessing her asthma status as well,” she told the limbic.
It’s not clear why longer-term HC use and obesity increases the risk of asthma, but Dr Matheson suggests it may be related to the fact that people who are obese are in a state of chronic, low grade inflammation and thus already at an increased risk of having inflammatory-related diseases.
“It may be that the combination of the pill and being overweight perhaps pushes people over a certain threshold for systemic inflammation and that’s why they have an increased risk of asthma symptoms,” she explained.
Dr Matheson stresses that it’s too soon to recommend prescribing an alternative to HC for women who are overweight or obese, noting that more long-term studies are needed to investigate the interaction between HC and obesity to disentangle exactly what’s going on.
She believes her group is first to demonstrate the role of duration of HC use in this association.
“There have been other studies that have linked use of the pill to asthma but as far as we know this is the first study to actually look at duration.”