Compared Heritability of Chronotype Instruments in a Single Population Sample.
Level 4 - case-series / case-control
Cross-sectional family-based heritability analysis in a single cohort (level by design analogy)
PubMed 34313481 · doi:10.1177/07487304211030420
What was done
Heritability was calculated for three chronotype instruments: the Morningness-Eveningness Questionnaire (MEQ), the Munich Chronotype Questionnaire (MCTQ), and a single-question measure (MEQ Question 19), as well as two MEQ-derived subfactors, using a family-based cohort of 597 participants from the Brazilian Baependi Heart Study.
What was found
Best-fitted heritability values were 0.37 for MEQ, 0.32 for MCTQ, and 0.28 for the single-question chronotype measure. Heritability was 0.32 for the MEQ factor Dissipation of sleep pressure and 0.28 for Build-up of sleep pressure.
Why it matters
This provides the first direct heritability estimate for the MCTQ and indicates that single-item chronotype questions used in large GWAS cohorts capture substantial genetic variation comparable to full questionnaires.
Limits
The sample is restricted to a single population cohort in Brazil with 597 participants. The abstract does not report confidence intervals or standard errors for the estimates, nor does it provide cross-instrument genetic correlations.
Cited by
- supports Chronotypes, including morningness versus eveningness (night owls), are genetically determined.