Retrospective analysis of serum ferritin, ALAT and gammaGT reported to the typology "morningness / eveningness" assessed using the MEQ questionnaire.

The systematic use of self-questionnaires MEQ scale (1) during sleep consultation allow us to determine chronobiological type of patients : DET (definitely evening type), ET (evening type), NT (neither type), MT (morning type), DMT (definitely morning type). The use of a database containing all patient data (questionnaires, clinical, biology) allows us to analyse biological parameters according to the typologies .

Method :
We have a 6846 patient database (2854 women and 3892 men) integrating typology Morningness / eveningness evaluated using MEQ questionnaire. Inside this base 583 patients had ferritin assay, 571 ALAT and 583 Gamma GT. Withdrawals for bioassays ferritin ALAT and GAMMA GT were carried out in the usual way between 7am and 9am. Assays were reported by ANOVA with groups determined by the MEQ survey (DET, MET, NT, MMT, DMT). We also check the typology by versus average age.

Results :
It is identified significant differences between Average age, Ferritin levels (p <0.05) ALAT (p < 0.05) and gamma GT (p <0.05) in relation to the type (DM, MM, M, MS, DE) and sex (women are more evening type and men more morning type)

Discussion :
The interaction between the typology on physiological (sex, age) and biological parameters which are mainly linked to liver metabolism (Ferritin, ALAT, GGT) lets interrogate ourself on the interaction of the liver metabolism and the typology.
It is necessary to notice than the time of blood sampling is habitually fixed between 7 and 9am and than observed differences depending on the type could be directly related to the typology or to a phase effect in relation to circadian variations of the observed parameters.
It is very difficult to determine if the part of the observed effect is mainly in conjonction with typology, age or time of blood sampling.
In any case, it seems necessary to take into account the sex, age and/or the typology of the patient in terms of Morningness/eveningness for the interpretation of the normality of these biological parameters.

Bibliography :
(1) Taillard J & al ; Validation of Horne and Ostberg morningness-eveningness questionnaire in a middle-aged population of French workers ; J Biol Rhythms. 2004 Feb ;19(1):76-86.