Oral Contraceptives May Curb Severe Asthma Attacks in Young Women

By Linda Carroll

November 25, 2020

(Reuters Health) - Premenopausal women with asthma who use oral contraception that contains estrogen may be less likely to experience severe exacerbations, a new study suggests.

An analysis of data from more than 80,000 women with asthma found a small but significant reduction in severe asthma attacks in those who had been on the pill for three or more years, researchers reported in Thorax.

Severe exacerbations were defined as asthma-related hospitalization, emergency department visits due to asthma, or prescription for oral corticosteroids.

"There's an intriguing relationship between sex and asthma," study leader Bright Nwaru at the University of Gothenburg noted in a statement. "And over the past 40 years many studies have been published trying to understand why boys have a higher incidence of asthma than girls. But starting from around the time of puberty this changes, and asthma becomes more common in women than in men."

Nwaru did not respond to a request for comment.

To explore the possibility that exogenous hormones might impact the likelihood of severe asthma attacks in women, Nwaru and colleagues turned to the UK's large population-based, longitudinal primary care Optimum Patient Care Research Database. They focused on reproductive age women (aged 16-45) with asthma.

Women were excluded from the analysis any year they were pregnant and included in years they were not pregnant. In total, the study cohort comprised 83,084 women with a total of 456,803 person-years follow-up over a 17 year period that ran from January 2000 to December 2016.

At baseline, 34% of the women were using some form of hormonal contraception, with 25% using an estrogen and progesterone combination and 9% using a contraceptive that depended on progesterone alone.

The researchers accounted for potential confounders, including gravidity, BMI, smoking, Charlson Comorbidity Index, gynecological conditions (such as endometriosis, polycystic ovary syndrome, fibroids and menstrual bleeding complaints) and an Index of Multiple Deprivation.

In adjusted models, previous and current use of combination hormonal contraceptives were associated with a reduced risk of severe asthma exacerbations, when compared with non-use. When the researchers focused on years of use, they found a reduced risk only in women who used contraceptives containing both estrogen and progesterone for three or more years: the Incidence Ratio Rate (IRR) in women who used the combined contraceptive for three to four years was 0.94 and among women who used the combined contraceptive for five or more years the IRR was 0.91. There was no reduction associated with contraceptives containing only progesterone.

The new research adds another piece to the puzzle of how sex hormones are connected to asthma and airway health, said Dr. Sonali Bose, an assistant professor of pulmonary, critical care and sleep medicine at the Icahn School of Medicine at Mount Sinai.

"The effect size is small, but rightly as they suggested, it is consistent with a mechanistic understanding of how these hormones can influence asthma," Dr. Bose said. "Work like this takes us one step closer to understanding the connection. It paves the way for future work."

Even if the findings are replicated, that doesn't mean women should necessarily be turning to contraceptives to ward off severe asthma attacks because these medications come with their own risks, Dr. Bose said.

SOURCE: https://bit.ly/3fsCiZy Thorax, online November 23, 2020.