Cigarette smoking is known to be negatively associated with fragility fractures, but the reversibility of this effect remains unclear. This study aimed to investigate both the cumulative and reversible effects of cigarette smoking on fracture risk.
We analyzed prospective data of 5,992 elderly men with an average age of 74 years from the Osteoporotic Fractures in Men Study (MrOS). Smoking status (current, past, or never) was recorded at study recruitment, and fragility fractures were confirmed via medical records. The multivariable-adjusted Cox proportional hazards regression was used to estimate the adjusted hazard ratio (aHR) of fractures associated with smoking status, controlling for known confounding effects. Using the aHR and prevalence of smoking categories, we calculated the population-attributable fraction (PAF)[1] to quantify the potential reduction in fractures by eliminating smoking.
Over a median follow-up of 7.8 years (IQR: 4.1-12.0), 1084 men sustained a fragility fracture, including 237 hip fractures. Approximately 3.4% and 59.0% of men were current and past smokers, respectively. Compared to nonsmokers, current smokers had a significantly higher risk of any fracture [aHR= 1.85 (95% CI: 1.37-2.56)] and hip fracture [2.70 (1.47-4.95)], whereas past smokers did not show an increased risk [1.09 (0.96-1.23) and 1.04 (0.79-1.35) for any and hip fractures, respectively]. The association between current smoking and fracture risk was independent of confounding effects of age, bone mineral density, history of falls and prior fracture. Importantly, avoiding current smoking could reduce future fractures by 4% (Figure). Had no individuals ever smoked, as many as 27% of any fractures and 22% of hip fractures would have been prevented.
These findings indicate that the negative impact of cigarette smoking on bone fragility is reversible, suggesting that quitting smoking could substantially lower the risk of fractures. This underscores the importance of smoking cessation interventions for preventing fragility fractures in the community.