Chronotype, insomnia and clock gene expression in 751 Mexican older adults
In this abstract of a cohort of 751 community-dwelling Mexican older adults, an extreme morning chronotype was associated with lower odds of insomnia than an intermediate chronotype. Frailty was associated with differences in peripheral clock gene expression measured at a morning time point. [1]
Automatic summary · not editorially reviewed
The key findings
An extreme morning chronotype was associated with lower odds of insomnia than an intermediate chronotype. [1]
No significant associations between chronotype and metabolic parameters remained after adjustment and correction for multiple comparisons. [1]
Lower CLOCK expression remained associated with pre-frailty after adjustment for chronotype, insomnia, age, sex and body mass index. [1]
The source at a glance
- Study type / format
- Cohort study (abstract only)
- Population / context
- 751 community-dwelling older adults in Mexico; clock gene expression analyzed in a subsample of 82.
- Summary based on
- Study abstract
- Original publication
- October 14, 2026
Chronotype, insomnia and metabolic measures in older adults
The study asked how chronotype, insomnia, metabolic parameters and peripheral clock gene expression relate in older adults. Chronotype was assessed with the Morningness-Eveningness Questionnaire. Most participants had a morning chronotype. People with an extreme morning chronotype had lower odds of insomnia than those with an intermediate chronotype (adjusted odds ratio 0.393, 95% confidence interval 0.169–0.827, p = 0.020). After adjustment for covariates and correction for multiple comparisons, no significant associations between chronotype and metabolic parameters remained. These are associations, not evidence of cause.
Supporting source [1]
Clock genes in blood cells of pre-frail and frail participants
Clock gene expression was analyzed in peripheral blood mononuclear cells from a subsample of 82 participants. A principal component analysis found a coordinated pattern of clock gene expression: pre-frail and frail participants had lower scores on the first component than robust individuals. Gene-specific analyses showed lower expression of several clock genes in pre-frail and frail participants. Lower CLOCK expression remained significantly associated with pre-frailty after adjustment for chronotype, insomnia, age, sex and body mass index. The measurements were taken at a morning time point, so they describe one time of day only.
Supporting source [1]
Cohort design and open questions on frailty and circadian timing
This was a cohort of 751 community-dwelling older adults in Mexico, with regression models for insomnia and metabolic parameters and a smaller blood-cell subsample for gene expression. The authors conclude that morning chronotype was associated with lower odds of insomnia and that frailty was associated with differences in peripheral clock gene expression. They state that the relationship between circadian biology and frailty remains incompletely understood and call for longitudinal studies and circadian assessments at multiple time points. Such studies would be needed before any direction of effect could be inferred.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. The design is described as a cohort, but the abstract does not report follow-up duration or whether the analyses were cross-sectional. Clock gene expression was measured at a single morning time point in a subsample of 82. Associations do not establish causation.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Ortiz-Vázquez CE, Garcia-delaTorre P, Sánchez-García S, Aguilar-Arnal L, Mendoza-Viveros L. · europepmc.org · October 14, 2026