Using corticosteroids for a long period of time to treat asthma is known to increase the risk of osteoporosis, but a new study suggests asthma could itself raise the risk of bone loss.
Researchers looked at data from 7,034 people in South Korea, 433 of whom had either airway hyperresponsiveness (AHR) or asthma; researchers purposely excluded patients who had a history of systemic corticosteroid use. (Airway hyperresponsiveness is a feature of asthma, though a person can also experience it without having a full diagnosis of asthma. It refers to the narrowing of the airways after being exposed to a constrictor agonist.)
The risk of low bone mineral density in the lumbar spine and femur was lower among those with airway hyperresponsiveness, compared with people without the condition, researchers found.
After taking into account factors such as body mass index, age, sex and smoking status, researchers found that the odds of having osteopenia or osteoporosis was 1.72 times higher among those who had airway hyperresponsiveness, compared with people without the condition. And the odds of having osteopenia or osteoporosis was 1.53 times higher among people who have ever had asthma, compared with people who had never had asthma.
"These findings suggest that the BMD [bone mineral density] and AHR [airway hyperresponsiveness] or asthma are closely related, although the exact causal relationship cannot be explained," the researchers wrote in the Annals of Allergy, Asthma & Immunology study.
While the study only shows an association, researchers speculated that people with asthma may face a higher osteoporosis risk because of vitamin D deficiency.