Insomnia symptom trajectories and incident cardiovascular disease in older adults: a longitudinal cohort study

Background Insomnia symptoms are prevalent in older adults and linked to cardiovascular disease (CVD), but the role of long-term symptom trajectories remains unclear. We investigated associations between insomnia symptoms, their trajectories over time and incident CVD in a population-based cohort. Methods This longitudinal study included 12 102 participants aged ≥50 years without baseline CVD from the US Health and Retirement Study (2002–2018). Insomnia symptoms (non-restorative sleep, difficulty initiating/maintaining sleep, early awakening) were assessed at baseline; trajectories were modelled over 4 years (2002–2006) using latent class analysis. Cox models estimated HRs for incident CVD (heart disease or stroke), adjusted for sociodemographics, lifestyle and comorbidities. Results During a median of 10.2-year follow-up, 3962 incident CVD events occurred. Compared with no symptoms, participants with one, two, or three to four symptoms had higher CVD risk (HR 1.16, 95% CI 1.05 to 1.27; HR 1.16, 95% CI 1.05 to 1.28; HR 1.26, 95% CI 1.15 to 1.38, respectively). Four trajectories were identified: persistent low (56.3%), decreasing (27.1%), increasing (7.2%) and persistent high (9.5%). Compared with persistent low, increasing (HR 1.28, 95% CI 1.10 to 1.50) and persistent high (HR 1.32, 95% CI 1.15 to 1.50) trajectories were associated with elevated CVD risk. Conclusions Greater burden of insomnia symptoms at baseline and trajectories over time were associated with higher CVD incidence in older adults.