BACKGROUND Recent studies suggest an association between allergic diseases, including asthma, and lower vitamin D level, a well-known risk factor of osteoporosis. However, it is not yet clearly known whether patients with asthma are prone to bone loss.

OBJECTIVE To evaluate whether the occurrence of airway hyperresponsiveness (AHR) or asthma is related to significant changes in bone mineral density (BMD).

METHODS We retrospectively enrolled 7,034 patients who had undergone a health checkup program, including BMD tests and methacholine bronchial challenge tests, at the Seoul National University Hospital, Healthcare System Gangnam Center, from November 1, 2004 to April 30, 2011. Asthma was ascertained by self-reported medical diagnosis by a physician. Patients with a history of systemic corticosteroid medication use were excluded from the study.

RESULTS Among a total of 7,034 patients, 216 (3.1%) had a positive AHR test result, and 217 (3.1%) had a history of asthma. Lumbar spine and femur BMD of patients with AHR were significantly lower than those without AHR (-0.53 ± 1.50 vs -0.03 ± 1.49, -0.47 ± 0.97 vs -0.22 ± 0.99, respectively; P < .001 for both). After being adjusted for age, sex, body mass index, smoking status, postmenopausal state, and previous history of hormone replacement therapy, the proportion of patients with osteopenia or osteoporosis was much higher in the AHR-positive group than in the AHR-negative group (odds ratio, 1.715; 95% confidence interval, 1.252-2.349) and in the ever-asthma group than in the never-asthma group (odds ratio, 1.526; 95% confidence interval, 1.120-2.079).

CONCLUSION In the current study, AHR and asthma were related to clinically meaningful BMD decrease, although the causal relationship is unclear.