The relationships between smoking amount, pulmonary function, and bone mineral density in middle-aged Korean men: KNHANES 2008-2011

Abstract

Introduction: Smoking induces bone loss

however, data on the relationship between smoking amount and bone mineral density (BMD) are lacking. Age and pulmonary function can affect BMD. We investigated the relationships between pack-years (PY) of smoking, pulmonary function, and BMD in middle-aged Korean men (50-64 years). Methods: This cross-sectional study used data from the Korean National Health and Nutrition Examination Survey, 2008-2011. All subjects underwent BMD measurements using dual energy X-ray absorptiometry and pulmonary function tests using standardized spirometry. Results: Herein, 388 never-smokers and 1088 ever-smokers were analyzed. PY of smoking negatively correlated with total hip BMD (r=-0.083

p=0.006) after adjusting for age and body mass index (BMI). Ever-smokers were classified into 3 groups according to PY of smoking

the highest tertile (n=482) showed a significantly lower total hip bone mass than the lowest tertile (n=214) after adjusting for confounding factors (age, BMI, FEV1, alcohol consumption, physical activity, and vitamin D) that could affect bone metabolism (<15 PY, 1.137±0.010

15-30 PY, 1.123±0.007

≥ 30 PY, 1.104±0.006 g/cm2

p=0.007). Forced expiratory volume in 1 second (FEV1) and Forced vital capacity (FVC) positively correlated with femur neck BMD (r=0.069, p=0.024

r=0.113, p=0.027, respectively). No significant relationship was observed between FEV1 and FVC tertiles and BMD at all other sites after adjusting for age and BMI. Conclusions: Smoking for >30 PY was significantly associated with low hip BMD after adjusting for pulmonary function in middle-aged Korean men. Long-term smoking may be a risk factor for bone loss in middle-aged men, independent of age, BMI, and pulmonary function.