Abstract
STUDY OBJECTIVES: To assess whether the association between insomnia and subclinical myocardial injury, as measured by cardiac troponin T (cTnT), differs across insomnia phenotypes. METHODS: We measured cTnT in 2188 participants in the Multi-Ethnic Study of Atherosclerosis study who had completed sleep questionnaires and undergone unattended polysomnography (PSG) and 7-day actigraphy. Insomnia symptoms were defined as reporting at least one of the following ≥5 nights/week over the past 4 weeks: trouble falling asleep, waking up several times a night, having trouble getting back to sleep after waking up too early, or taking sleeping pills to help falling asleep. Obstructive sleep apnea (OSA) was defined as an apnea-hypopnea index (AHI >15 events/h). Participants were classified into insomnia phenotypes, including comorbid insomnia and OSA (COMISA) and insomnia associated with actigraphy-estimated short sleep (<6 h) or sleep fragmentation. RESULTS: The mean age was 68.8 (SD 9.2) years, 53.6% were male. In total, 47.8% met threshold levels for insomnia symptoms, and 43.1% had an AHI >15. In adjusted linear regression models COMISA (β 0.08 [standard error (SE) 0.03], p < .01) and insomnia with short sleep duration (β 0.07 [SE 0.03], p < .05) were each associated with higher cTnT compared to a reference group with no insomnia. Insomnia with fragmented sleep (β 0.03 [SE 0.02]) was not associated with higher cTnT (p > .05) in adjusted analyses. OSA was associated with higher cTnT (β 0.09 [SE 0.03], p < .01) in adjusted models. CONCLUSIONS: COMISA and insomnia with short sleep duration, but not insomnia symptoms alone or fragmented sleep, were associated with increased circulating cTnT in older adults.