Distribution and heritability of diurnal preference (chronotype) in a rural Brazilian family-based cohort, the Baependi study

Abstract

Diurnal preference (chronotype) is a useful instrument for studying circadian biology in humans. It harbours trait-like dimensions relating to circadian period and sleep homeostasis, but also has ontogenetic components (morningness increases with age). We used the Morningness-Eveningness questionnaire (MEQ) in the Baependi study, a family-based cohort study based in a small town in Minas Gerais, Brazil. The population is highly admixed and has a cohesive and conservative lifestyle. 825 individuals (497 female) aged 18–89 years (average ± SD = 46.4 ± 16.3) and belonging to 112 different families participated in this study. The average MEQ score was 63.5 ± 11.2 with a significant (P < 0.0001) linear increase with age. Morningness was significantly (P < 0.0001) higher in the rural (70.2 ± 9.8) than in the municipal zone (62.6 ± 11.1), and was also significantly (P = 0.025) higher in male (64.6 ± 10.9) than in female (62.8 ± 11.2) participants. Thus, in spite of universal access to electricity, the Baependi population was strongly shifted towards morningness, particularly in the rural zone. Heritability of MEQ score was 0.48 when adjusted for sex and age, or 0.38 when adjusted for sex, age, and residential zone. The reported MEQ score heritability is more akin to those of previous twin studies than previous family studies.

Sociosexuality, Morningness–Eveningness, and Sleep Duration

“…For example, morning types reach their highest performance early during the day whereas evening types reach their peak performance in the afternoon, evening, or at night. M/E can be assessed by a set of questionnaires, and M/E is a heritable trait (von Schantz et al, 2015) with a genetic basis (Barclay, Watson, Buchwald, & Goldberg, 2014;Toomey, Panizzon, Kremen, Franz, & Lyons, 2015;Watson, Buchwald, & Harden, 2013). The variance in circadian preference is reflected in diurnal profiles of hormones, such as melatonin (Burgess & Fogg, 2008) or cortisol (Randler & Schaal, 2010) and body temperature (Baehr, Revelle, & Eastman, 2000;Mongrain, Lavoie, Selmaoui, Paquet, & Dumont, 2004).…”

Chronotype and sleep quality as a subphenotype in association studies of clock genes in mood disorders

“…CH is considered as the combination of both biological (genetic factors, aging of the body) and psychosocial (hours of study or work, the rhythm of family life) processes (Allebrandt and Roenneberg 2008). CH is highly heritable (heritability ~50%) (Koskenvuo et al 2007, von Schantz et al 2015. Studies suggested relationships between CH and both differences in the activation level (extraversion/ introversion, novelty seeking, mobility, strength of activation/inhibition of the nervous system) and severity of depression and anxiety (Frank et al 2013, Ottoni et al 2012.…”

Impact of chronotype on athletic performance: current perspectives

“…Most studies that have assessed the heritability of chronotype in populations have estimated it to be ~50%. [49][50][51] However, two studies have arrived at much lower estimates of 14% and 23%, 52,53 and notably chronotype was not normally distributed in these two populations. In the study of an Amazonian …”