Table 1.
Heritability (h2) estimates for circadian preference in twin and family studies.
| Study | Method of Assessing Heritability | Chronotype Measure | h2 (SE, 95% CI) |
|---|---|---|---|
| Twin studies | |||
| Toomey et al. (2015) | Additive genetic influences: maximum likelihood–based structural equation modeling package OpenMx, using the Cholesky analysis. | MEQ score | 0.42 (0.34, 0.50) |
| Barclay et al. (2014) | Additive genetic influences: structural equation modeling using the Mx package. | rMEQ (reduced 5-item MEQ) | 0.52 (0.46, 0.57) |
| Watson et al. (2012) | Additive genetic influences: structural equation modeling using the Cholesky analysis. | rMEQ (reduced 5-item MEQ) | 0.40 (0.27, 0.47) |
| Barclay et al. (2010) | Additive genetic influences: maximum likelihood–based structural equation modeling using the Mx package. | MEQ score | 0.52 (0.20, 0.61) |
| Koskenvuo et al. (2007) | Additive genetic influences: maximum likelihood–based structural equation modeling using the Mx package. | Single question according to the diurnal type scale: “Will you try to estimate to what extent your being a morning or an evening people?” [sic] | 0.49 (0.46, 0.52) |
| Hur (2007) | Additive genetic influences: maximum likelihood–based structural equation modeling using the Mx package. | CS: adapted 13-item MEQ | 0.45 (0.39, 0.50) |
| Vink et al. (2001 | Additive genetic influences: structural equation modeling using the Mx package. | Final ME question: “Are you a morning-active person or an evening-active person?” | 0.44 for adolescents and 0.47 for older individuals in their mid-40s |
| Hur et al. (1998) | Additive genetic influences: maximum likelihood–based modeling using the Mx package. | Abbreviated 13-item MEQ | 0.54 (0.45, 0.62) |
| Family studies | |||
| von Schantz et al. (2015) | Additive genetic influences: polygenic heritability estimates kinship2 package. | MEQ | 0.48 ± 0.08* |
| Evans et al. (2011) | Additive genetic influences: linear multivariate regression with variance component analysis using software SOLAR. | MEQ | 0.21 ± 0.09* |
| Klei et al. (2005) | Additive genetic influences: package Solar2 | CS: adapted 13-item MEQ | 0.237 ± 0.09* |
| GWAS studies | |||
| Jones et al. (2019) | SNP-based heritability assessed by BOLT-REM (Loh et al., 2015): additive genetic influences of chronotype calculated in the UK Biobank alone. | Single question (MEQ Question 19) | 0.137 (0.13, 0.14) |
| Jones et al. (2016) | SNP-based heritability assessed by LD score regression (Bulik-Sullivan et al., 2015): additive genetic influences of chronotype calculated in the UK Biobank alone. | Single question: (MEQ Question 19) | 0.12 (NA) |
| Lane et al. (2016) | SNP-based heritability assessed by LD score regression (Bulik-Sullivan et al., 2015): additive genetic influences of chronotype. | Single question: “Do you consider yourself to be?” with possible answer “Morning/evening person (chronotype)” | 0.194 (NA) |
| Hu et al. (2016) | SNP-based heritability assessed by genome-wide complex trait analysis (Yang et al., 2011): additive genetic influences of chronotype. | Combination of 2 questions: “Q1: Are you naturally a night person or a morning person? (Night owl, Early bird, Neither)” and MEQ Question 19 | 0.21 (0.13, 0.29) |
Abbreviations: CI = confidence interval; SE = standard error; MEQ = morningness-eveningness questionnaire; SOLAR = Sequential Oligogenic Linkage Analysis Routines; GWAS = genome-wide association studies; SNP = single-nucleotide polymorphism.
Note: *p < 0.05