Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 48 2 2026 06 15 Familial aggregation pattern of insufficient sleep: a cross-sectional study in Tabriz, Iran 166 175 10.34172/mj.026.35318 EN Elham Davtalab Esmaeili https://orcid.org/0000-0002-6811-6881 Erfan Golshan Sophia Mansouripour Leila R. Kalankesh https://orcid.org/0000-0002-4832-3170 Alireza Ghaffari https://orcid.org/0000-0003-0784-9974 Ali Hossein Zeinalzadeh https://orcid.org/0000-0003-2527-6276 Saeed Dastgiri https://orcid.org/0000-0002-8129-9125 Journal Article 10.34172/mj.026.35318 2025 12 24 2026 04 04 Background. This study was conducted to investigate the familial aggregation (FA) of insufficient sleep (IS) among individuals in northwestern Iran. Methods. This study was conducted in Tabriz, Iran, in 2024 and included 860 participants. Household heads (probands) were selected from a client list. Probands’ first-degree relatives, including spouses and children, were invited to participate. Insufficient sleep was assessed using a standardized questionnaire. Familial aggregation was evaluated using generalized estimating equations (GEEs) to estimate odds ratios (ORs) for father–offspring, mother–offspring, sibling, and spousal pairs. Results. Based on the results, the prevalence of insufficient sleep was 8.6% among fathers, 10.4% among mothers, and 7.2% among children. No evidence of spousal aggregation was observed (OR = 0.02, 95% CI: 0.004–0.053). Familial aggregation was identified between fathers and offspring (OR = 1.65, 95% CI: 1.06–2.45) and among siblings. For each sibling with insufficient sleep, the likelihood of insufficient sleep in another sibling increased by 2.4-fold (OR = 2.38, 95% CI: 1.95–5.38). Females were 2.24 times more likely to experience insufficient sleep than males (P = 0.002). In addition, single individuals showed higher odds of insufficient sleep compared with non-single participants. Conclusion. The findings indicate that insufficient sleep clusters within families and those family members play significant roles in shaping sleep behaviors. Women and single individuals were identified as high-risk groups for targeted screening. Practical Implications. Family-based screening and sleep health interventions, focusing on father–offspring and sibling relationships, may enhance detection and prevention. Integrating targeted screening for women and single individuals into primary healthcare services could strengthen public health strategies for sleep.