ChronotypeDifferencesinEnergyIntake, CardiometabolicRiskParameters,Cancer,and Depression:ASystematicReviewwith Meta-AnalysisofObservationalStudies

Abstract

Chronotypeisabehavioralmanifestationoftheinternalcircadianclocksystem.Itreferstothespecificactivity-restpreferenceofanindividualover a 24-h period and can be assessed using different methodologies that classify individuals into morning or evening chronotype. In recent years, several studies have suggested a relation between individual chronotype, eating habits, and the risk of developing obesity and other conditions. Ouraimwastoevaluatetheassociationbetweenchronotype,energyintake,andhealthstatusthroughameta-analyticapproach.Acomprehensive search of MEDLINE, Embase, Scopus, Web of Science, and Cochrane Database was conducted. Observational studies that reported a measure of associationbetweenchronotype,energyintake,andhealthindicatorswereconsideredeligible.Overall,39observationalstudies(37cross-sectional studies,2prospectivecohortstudies)wereincludedinthesystematicreview,withatotalof377,797subjects.Bycomparingmorningandevening subjects,pooledanalysesofcross-sectionalstudiesshowedsignificantly(P<0.001)higherconcentrationsofbloodglucose[meandifference(MD): 7.82;95%CI:3.18,12.45],glycatedhemoglobin(MD:7.64;95%CI:3.08,12.21),LDLcholesterol(MD:13.69;95%CI:6.84,20.54),andtriglycerides(MD: 12.62; 95% CI: 0.90, 24.35) in evening subjects. Furthermore, an association between evening type and the risk of diabetes (OR: 1.30; 95% CI: 1.20, 1.41), cancer (OR: 1.18; 95% CI: 1.08, 1.30), and depression (OR: 1.86; 95% CI: 1.20, 2.88) was reported. Regarding the other outcomes examined, no significantdifferenceswereobservedbetweenthegroupsintermsofenergyintake,anthropometricparameters,bloodpressure,insulin,totaland HDLcholesterol,andhypertensionrisk.Inconclusion,eveningchronotypewasassociatedwithaworsecardiometabolicriskprofileandhigherrisk ofdiabetes,cancer,anddepression.Furtherstudiesareneededtoconfirmtheseresultsandtobetterelucidatetheinterplaybetweenchronotype, nutrition,andhealthstatus.Thissystematicreviewwasregisteredatwww.crd.york.ac.uk/prospero/asCRD42021231044