[Association of Cigarette Smoking with Muscle Mass Reduction and Low Muscle Strength in Community-Dwelling Elderly Men].

OBJECTIVES: Recently, attention has been paid to the impact of cigarette smoking on skeletal muscles, as its underlying pathophysiological mechanism has been gradually elucidated. In this study, we aimed to examine whether cigarette smoking is associated with muscle mass reduction and low muscle strength in elderly men. METHODS: The study participants comprised 417 community-dwelling elderly men (aged 73±6 years) without severe glucose intolerance, chronic kidney disease, or liver disease. Bioelectrical impedance analysis was performed to estimate appendicular skeletal muscle mass (ASM), which was normalized for height (ASM index, kg/m2). Handgrip strength (HGS) was measured using a Smedley grip dynamometer. Cumulative smoking exposure level during a lifetime was expressed in pack-years, which is a product of the average number of packs of cigarettes smoked per day and smoking duration in years. RESULTS: When the participants were stratified on the basis of cumulative smoking exposure (<10 pack-years, 10-39 pack-years, ≥40 pack-years), the ASM index and HGS progressively decreased with increasing exposure level (P for trend <0.01). In multiple regression analysis, heavy smoking (defined as ≥40 pack-years) was found to be a significant determinant of the ASM index and HGS, independent of potential confounding factors. Among former smokers, the subgroup that quit smoking for ≥20 years had a significantly higher ASM index and HGS than the subgroup that quit smoking for <10 years. The duration of smoking cessation was significantly associated with the ASM index and HGS, even after adjusting for cumulative smoking exposure. CONCLUSIONS: These findings suggest that cigarette smoking contributes to the loss of muscle mass and function in elderly men and that smoking cessation could reverse the impact of cigarette smoking on skeletal muscles.