LAUSR

BACKGROUND This study aimed to assess the impacts of smoking cessation and resumption over 4 years on the risk of back pain at the 6-year follow-up among older adults in England. METHODS We analysed 6467 men and women aged ≥50 years in the English Longitudinal Study of Aging. Self-reported smoking status, assessed in waves 4 (2008-2009) and 6 (2012-2013), was used as exposure for the study, whereas self-reported back pain of moderate or severe intensity, assessed in wave 7 (2014-2015), was used as the outcome. A targeted minimum loss-based estimator was used with longitudinal modified treatment policies to adjust for baseline and time-varying covariates. RESULTS Regarding the estimation of the effects of changes in smoking status on the risk of back pain, during the follow-up, individuals who resumed smoking within 4 years had a higher risk of back pain than those who avoided smoking for over 4 years, and the relative risk (RR) (95% confidence interval [CI]) was 1.536 (1.214-1.942). Regarding the estimation of effects of smoking cessation on the risk of back pain, smoking cessation over 4 years was associated with a significantly lower risk of back pain, as indicated by the originally observed data, and the RR (95% CI) was 0.955 (0.912-0.999). CONCLUSIONS Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain. SIGNIFICANCE Older adults who avoided smoking for over 4 years had a lower risk of back pain. However, those who resumed smoking within 4 years had a higher risk of back pain. Our study data suggest the importance of maintaining smoking cessation to reduce the risk of back pain in the older population.