Association between airflow limitation severity and reduced bone mineral density in Japanese men

Abstract

Introduction

This study aimed to assess the association between airflow limitation (AL) severity and reduced bone mineral density (BMD) in Japanese men.

Subjects and methods

This cross-sectional study included 290 subjects aged over 40 years (mean age 72.0, SD 11.6), who underwent a comprehensive health examination, including spirometry and measurement of BMD at the left femoral neck using dual-energy X-ray absorptiometry (DXA), between 2016 and 2017 at Japanese Red Cross Kumamoto Health Care Center. AL was defined as forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) of <0.7. Reversibility tests were not performed in this study. The criteria used for the AL staging were developed according to the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) guidelines. The subjects were divided into the following three groups: a control group (normal pulmonary function), GOLD Stage I group (mild AL), and GOLD Stage II-IV group (moderate-to-very severe AL). BMD was classified based on the young adult mean (YAM) as normal (88.6% ≦ YAM [−1 SD ≦]), osteopenia (70% <YAM <88.6% [<- 1 SD and > −2.5 SD]), or osteoporosis (YAM ≦ 70% [≦ −2.5 SD]). Reduced BMD was defined as osteopenia, osteoporosis, or medication used for osteoporosis. Logistic regression analysis was used to assess the association between AL severity and the reduced BMD.

Results

The prevalence of reduced BMD in subjects with moderate-to-severe AL (76.2%) was significantly higher than in those without AL (47.9%) (p=0.030). In logistic regression models adjusted for age, body mass index, pack-years, physical activity, and alcohol drinking, the risk of reduced BMD (odds ratio: 3.87; 95% confidence interval: 1.20–12.49; p=0.024) was significantly higher in subjects with moderate-to-severe AL than in those with normal pulmonary function.

Conclusion

Present results suggest that reduced BMD is associated with AL severity in Japanese men.

Keywords:

• chronic obstructive pulmonary disease
• comorbidity
• bone mineral density
• osteoporosis
• airflow limitation
• pulmonary function

Acknowledgments

We thank the technicians at the Japanese Red Cross Kumamoto Health Care Center for their excellent technical assistance. We would like to thank Editage for English language editing.

Author contributions

Watanabe K, Onoue A, Kubota K, Higashi N, Hayashi T, Tsuda T and Omori H designed this research. Watanabe K, Onoue A, Kubota K and Omori H contributed to the data collection. All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspect of the work.

Disclosure

The authors report no conflicts of interest in this work.