Smoking predicts incident fractures in elderly men: Mr OS Sweden

Abstract

The aim of this study was to investigate the association between smoking and bone mineral density (BMD) and radiographically verified prevalent vertebral fractures and incident fractures in elderly men. At baseline 3003 men aged 69 to 80 years of age from the Swedish Mr Os Study completed a standard questionnaire concerning smoking habits and had BMD of the hip and spine measured using dual-energy X-ray absorptiometry (DXA); 1412 men had an X-ray of the thoracic- and lumbar spine. Radiologic registers were used to confirm reported new fractures after the baseline visit. At baseline, 8.4% were current smokers. Current smokers had a 6.2% lower BMD at the total hip and a 5.4% lower BMD at the lumbar spine (p < .001). Current smoking remained independently inversely associated with BMD at the hip and lumbar spine after adjusting for age, height, weight, calcium intake, physical activity, and centers as covariates. Prevalent vertebral fractures among current smokers were increased in unadjusted analyses [odds ratio (OR) = 1.90, 95% confidence interval (CI) 1.26-2.87] and after adjustment for lumbar BMD (OR = 1.67, 95% CI 1.09-2.55). Smokers had a high risk for two or more prevalent vertebral fractures (OR = 3.18, 95% CI 1.88-5.36). During the average follow-up of 3.3 years, 209 men sustained an X-ray-verified fracture. Incident fracture risk among smokers was calculated with Cox proportional hazard models. Current smokers had an increased risk of all new fractures [hazard ratio (HR) = 1.76, 95% CI 1.19-2.61]; nonvertebral osteoporotic fractures, defined as humerus, radius, pelvis, and hip fractures (HR = 2.14, 95% CI 1.18-3.88); clinical and X-ray-verified vertebral fractures (HR = 2.53, 95% CI 1.37-4.65); and hip fractures (HR = 3.16, 95% CI 1.44-6.95). After adjustment for BMD, including other covariates, no significant association between smoking and incident fractures was found. Current tobacco smoking in elderly men is associated with low BMD, prevalent vertebral fractures, and incident fractures, especially vertebral and hip fractures.