(Reuters Health) - Over 40 percent of women with asthma go on to develop more severe lung disease, a Canadian study suggests.

Most of the risk factors for developing chronic obstructive pulmonary disease, or COPD, can be reduced with lifestyle changes, however, the authors say.

Patients with asthma typically have bouts of trouble breathing due to inflammation and narrowing of the airways. Patients with COPD usually have conditions that cause constricted breathing all of the time, such as emphysema or chronic bronchitis.

Asthma and COPD overlap syndrome, or ACOS, describes people who have both diseases.

“Research and studies in recent years have found an alarming rise in ACOS, particularly in women,” lead study author Teresa To told Reuters Health in an email.

“Patients with ACOS suffer more exacerbations, are hospitalized more often and have a lower quality of life compared to those who have asthma or COPD alone,” said To, a researcher at the University of Toronto Dalla Lana School of Public Health.

Identifying and understanding risk factors for ACOS may help reduce the risk, improving health and quality of life, To said.

“Not everyone who has asthma will progress to develop COPD, but those who do are more likely to have lifestyle factors such as smoking, obesity, and low socioeconomic status,” she said.

Low socioeconomic status may be related to suboptimal access to care, under-treatment of asthma and poor compliance with medications, she added. “These, in turn, may lead to more frequent asthma attacks and therefore airway remodeling that increases the chances of developing ACOS.”

Other key risk factors associated with ACOS are “modifiable,” such as smoking and obesity, she said.

Keeping good control of asthma, taking asthma medications, quitting smoking, and staying physically active are key to maintaining good lung health, To said.

The researchers examined data for 4,051 Ontario women with asthma who participated in a larger, long-term study that began in 1980.

Participants provided information about their health histories and lifestyle and the researchers also followed their medical histories through databases during the period between 1992 and 2015. The average age at the end of the study was 79, according to the report in the Annals of the American Thoracic Society.

To’s team also estimated the women’s average exposure to particle pollution between 1998 and 2006 using their residence postal codes and satellite data.

Overall, 1,701 women, or 42 percent, developed COPD. Lower education, high body mass index, living in a rural area and smoking all increased the risk of developing COPD.

Exposure to fine-particle air pollution was not, however, linked with the risk.

The study was limited by a lack of information about when the participants had first developed asthma, as well as a lack of data on their exposure to second-hand smoke, the researchers note.

Since the study included only women, the researchers caution, the results may not apply to men. Other studies have shown that among nonsmokers, women have higher rates of COPD than men, suggesting they could be more vulnerable to other COPD risk factors, the study team writes.

A total of 1,041 women died during the study period, including 34 percent of the women who developed ACOS and 19 percent of women who did not.

“In general, those with ACOS have both a higher morbidity and mortality rate compared to those with just asthma or just COPD, men or women,” To said.

SOURCE: bit.ly/2BjdB1f Annals of the American Thoracic Society, online July 17, 2018.