Nighttime sleep duration trajectories and incident incontinence in middle-aged and older adults: a prospective cohort study

Incontinence is a major public health concern among middle-aged and older adults, with substantial implications for functional independence, quality of life, and healthy ageing. Changes in sleep patterns may be involved in the development of incontinence. However, previous studies have largely relied on single-time-point sleep assessments, limiting their ability to capture long-term changes in nighttime sleep duration and interindividual heterogeneity. The prospective association between nighttime sleep duration trajectories and incident incontinence therefore remains unclear. This prospective cohort study used data from the China Health and Retirement Longitudinal Study collected in 2011, 2013, 2015, 2018, and 2020, and included 6,507 middle-aged and older adults without incontinence during 2011–2015. Latent class mixed models were used to identify nighttime sleep duration trajectories from 2011 to 2015. Multivariable Cox proportional hazards models were then used to evaluate associations between sleep trajectories and incident incontinence from 2018 to 2020. Two nighttime sleep duration trajectories were identified: a normal-stable trajectory (approximately 7 h/night) and a persistent short-duration trajectory (approximately 5 h/night). Compared with the normal-stable trajectory, the persistent short-duration trajectory was associated with a higher risk of incident incontinence after full adjustment (HR = 1.42, 95% CI: 1.18–1.72). Sensitivity analyses yielded consistent results, supporting the stability of the findings. A long-term short sleep trajectory was associated with an elevated risk of incident incontinence among middle-aged and older adults. Although the observed association was modest, sleep-duration assessment may provide complementary information regarding incontinence risk.