Abstract MP29: Chronotype is Associated With Diet Quality and Energy Intake, and Dietary Energy Density Mediates a Relation of Chronotype With Cardiovascular Health in a Diverse Sample of US Women
Authors: Zuraikat Faris M , Makarem Nour , St-Onge Marie-Pierre , LIAO MING , Boege Hedda L , Aggarwal Brooke A 
Published: March 2020

Background:
An individual’s chronotype, the innate preference for the timing of behaviors such as eating and sleeping, has been linked to various health outcomes. Indeed, we recently demonstrated that evening chronotype was related to poorer cardiovascular health (CVH) in US women. However, the associations of chronotype with specific health behaviors are not well characterized in this population. This is particularly true for diet, the CVH metric for which recommendations are least likely to be met. Therefore, the current study examined the association of chronotype with diet and the role of diet in the chronotype-CVH relation in a diverse sample of women.

Hypotheses:
Evening chronotype will be associated with higher energy intake and poorer diet quality, including higher dietary energy density (ED), the total kcal per weight of food consumed and an index of the types and amounts of food eaten; these diet factors will mediate an association of chronotype with CVH.

Methods:
Baseline data from 506 participants enrolled in the AHA Go Red for Women SFRN were examined. Women were 20-76 y of age (mean±SD: 37±16 y); 49% had overweight/obesity and 61% were racial/ethnic minority. Women were categorized as either morning/intermediate or evening chronotype based on their Morningness/Eveningness Questionnaire scores. Dietary ED and daily intakes of food [by weight (g) and energy (kcal)], nutrients (g/1000 kcal), and fruits and vegetables [FV (servings/1000 kcal)] were assessed using the validated Block Brief Food Frequency Questionnaire. Linear regression models were used to examine associations of chronotype with diet. Causal mediation analyses tested whether dietary ED or energy intake mediated a relation between chronotype and CVH (AHA Life’s Simple 7 score). Models were adjusted for age, BMI, race/ethnicity, education, and health insurance.

Results:
On average, women consumed 1433±862 kcal with a dietary ED of 1.44±0.40 kcal/g. Evening (n=64) vs. morning/intermediate (n=442) chronotype was associated with higher dietary ED (β=0.21, P=0.0001), energy intake (β=448, P=0.0001), and weight of food consumed (β=129.3, P=0.06). Evening chronotype was also related to greater consumption of animal protein (β=1.1, P=0.04) and lower intakes of plant protein (β=-0.66, P=0.006), fiber (β=-2.2, P=0.0005), and FV (β=-1.3, P<0.0001). Dietary ED was a significant partial mediator of the association between chronotype and CVH (percent mediated: 28%, P=0.01). Results were similar when chronotype was analyzed on the continuous scale.

Conclusions:
In a diverse sample of women, evening chronotype was associated with a less heart-healthy diet, including greater energy intake and poorer diet quality. Moreover, that dietary ED partially mediated the relation between evening chronotype and poor CVH suggests that behavioral interventions to reduce dietary ED may improve CVH in women with evening chronotype.