Lifestyle Factors Outweigh Air Pollution in Determining Female ACOS

Teresa To, PhD

Individual risk factors appear to outweigh air pollution and other environmental factors when it comes to the risk of women with asthma developing chronic obstructive pulmonary disease (COPD).

Asthma and COPD overlap syndrome (ACOS) is a relatively common condition, with asthmatic women at a particularly high risk of developing COPD (and thus ACOS) as they age. A team of Canadian researchers wanted to better understand exactly why some women with asthma go on to develop ACOS, while others do not.

The team looked back at data from Ontario women who participated in the Canadian National Breast Screening Study between 1980 and 1985, isolating the patients in the study with asthma at the time. They then used an administrative health database to track those same women from 1992-2015.

A total of 4,051 women were included in the study. Of those, 42% (or 1,701 individuals) of the women with asthma in the 1980s developed COPD by the year 2015.

Corresponding author Teresa To, PhD, of the Hospital for Sick Children, in Toronto, said when researchers analyzed the data to identify risk factors, they found that things like low education levels, body mass index, heavy smoking, and rurality made the biggest difference.

But air pollution—defined in this study as exposure to fine particulate matter with a diameter of less than 2.5 micrometers (PM2.5)—did not increase the risk of ACOS to a statistically significant level.The investigator To said those findings differ from an earlier study of younger patients, which found air pollution did play a significant role in determining which patients with asthma also had COPD.

“One may speculate that this older cohort of women with asthma compared to younger women and men may be more likely to spend more time indoors than outdoors, therefore the direct exposure to outdoor air pollution may not have as strong an effect,” she told MD Magazine®.

Clinicians should use data like this to reinforce to patients the message that lifestyle factors can be an important determining factor in whether a patient’s asthma progresses to COPD, To added.

“Keeping good control of asthma, taking asthma medications, quitting smoking if you are a smoker, exercising and staying physically active are all key steps in maintaining good lung health,” she said.

That said, physicians need to work to fully understand patients’ individual situations, since some of the risk factors, such as low education and living in a rural area, are related to socioeconomic status (SES), which in itself has been tied to poorer outcomes in such patients.

“Research has shown that patients from a low SES family may receive less than optimal care (due to poor access or lack of a drug plan, therefore poor compliance to medications),” she said. “SES is also highly correlated with lifestyle factors. In sum, it is important for clinicians to support patients on acquiring good understanding of risks, symptoms, triggers, and disease control/management and to help them reduce the risk of exacerbations, improving health and quality of life.”

The study, “Asthma and COPD Overlap in Women: Incidence and Risk Factors,” was published last month in The Annals of the American Thoracic Society.