Multidimensional sleep behaviours and incident obesity in postmenopausal women: a prospective cohort study.

OBJECTIVE: Postmenopausal women are at high risk of both sleep disorders and obesity, yet prospective evidence linking multidimensional sleep behaviors to obesity risk in this population remains limited. This study aimed to examine the prospective associations between multidimensional sleep behaviours and incident obesity in postmenopausal women, and to explore whether blood biomarkers and plasma metabolites provide exploratory biological evidence. METHODS: This prospective cohort study included 68, 419 non-obese postmenopausal women from the UK Biobank. Sleep behaviors (duration, insomnia, chronotype, snoring, daytime sleepiness) were collected via questionnaires. Obesity events were identified using ICD-10 codes. Cox proportional hazards models were used to assess associations, and exploratory indirect-association analyses were performed to evaluate the potential involvement of blood biomarkers and plasma metabolites. RESULTS: During a median follow-up of 13.33 years, 1, 146 incident obesity cases were documented. Sleep duration showed an approximately U-shaped association with obesity risk: short sleep (≤6 hours, HR = 1.214) and long sleep (≥10 hours, HR = 1.654) were both associated with increased risk. Frequent insomnia (HR = 1.320), evening chronotype (HR = 1.224), and snoring (HR = 1.234) were also independent risk factors. Exploratory indirect-association analyses suggested small signals involving inflammation- and lipid-related biomarkers, but these findings should be interpreted as hypothesis-generating. CONCLUSION: Abnormal sleep duration, frequent insomnia, evening chronotype, and snoring were associated with a higher rate of incident obesity in postmenopausal women. Exploratory biomarker and metabolomic analyses provided only hypothesis-generating biological evidence. Incorporating sleep health management into obesity prevention strategies for this population is warranted.