Introduction: Few studies have reported the relationship between smoking in middle age and long-term risk of impaired activities of daily living (ADL).
Methods: We analyzed 2,276 men and women aged 47-59 years at the baseline survey of NIPPON DATA80 in 1980. At the follow-up survey in 1999, ADL was surveyed among 1890 survivors. Multivariate-adjusted odds ratio (AOR) and 95% CI of impaired ADL or of composite outcome of either death or impaired ADL according to baseline smoking status were calculated by multiple logistic regression analyses.
Results: In 1999, 386 participants were dead, and 75 participants had impaired ADL. Compared with nonsmokers, AOR (95% CI) of impaired ADL was significantly higher in current smokers at baseline (odds ratio [OR] 2.11 [1.09-4.06]). Compared with nonsmokers, AOR of impaired ADL was higher as the number of cigarettes increased (OR 2.04 [1.02-4.06] for <20 cigarettes/day and OR 2.35 [0.94-5.88] for >20 cigarettes/day; p for trend = .04). AOR of composite outcome for current smoking was 1.83 (1.37-2.41).
Discussion: Smoking in middle age would increase future risks of impaired ADL. Smoking cessation may be important to prevent future impairment of ADL as well as death.