The role of smoking and other modifiable lifestyle risk factors in maintaining and restoring lower body mobility in middle-aged and older Americans: results from the HRS and AHEAD. Health and Retirement Study. Asset and Health Dynamics Among the Oldest Old.

OBJECTIVES: To analyze the effect of smoking, smoking cessation, and other modifiable risk factors on mobility in middle-aged and older Americans.
DESIGN: Panel study; secondary data analysis.
SETTING: United States (national sample). PARTICIPANTS: The Health and Retirement Study (HRS) includes data on 12,652 Americans aged 50 to 61 in four waves (1992-1998). The Asset and Health Dynamics Among the Oldest Old (AHEAD) survey followed 8,124 community-dwelling people aged 70 years and older in three waves (1993-1998). MEASUREMENTS: The relationships between the primary outcome measure, lower body mobility (ability to walk several blocks and walk up one flight of stairs without difficulty), and smoking, exercise (HRS only), body mass index (BMI), and alcohol use were estimated in bivariate and multivariate analyses.
RESULTS: Not smoking was strongly positively related to mobility, and the relative effects were similar in both panels. Among those with impaired mobility at baseline, not smoking was also strongly related to recovery. In the middle aged, there were consistent dose-response relationships between amount smoked and impaired mobility. Fifteen years after quitting, the risk of impaired mobility returned to that of never smokers. There was also a strong dose-response relationship between level of exercise and mobility. Inverted U-shaped relationships with mobility were observed for BMI and alcohol consumption.
CONCLUSIONS: The relationships between not smoking and lower body mobility in middle-aged and older Americans are strong and consistent. Interventions aimed at reducing smoking have the potential to preserve mobility and thereby prolong health and independence in later life.