Circadian rhythm of hunger sensation in patients affected by cystic fibrosis.

OBJECTIVE: The aim of this study was to investigate the daily pattern of hunger sensation (HS) in patients affected by a non-advanced form of cystic fibrosis (CF) in order to detect how the orectic stimulus (OS) behaves in fibrocystic patients (FP) who are obliged to eat frequently because of their pancreatic exocrine insufficiency.
MATERIALS AND METHODS: The study involved 27 out-patients (13 males and 14 females; mean age 18 +/- 4 years; mean BMI 18.77 +/- 2.17 kg/m2) with a non-advanced form of CF, and 19 clinically healthy subjects (CHS, 9 males and 10 females; mean age 24 +/- 2 years; mean BMI 21.00 +/- 1.70 kg/m2). The FP were used to eating frequent small meals between the three main meals of breakfast, lunch and dinner. All of the participants were asked to compile an "orexigram"' which was chrono-biometrically analysed by means of: 1) conventional statistical methods; 2) rhythmometric analysis of circadian rhythm (CR); and 3) spectral analysis of the harmonic structure substantiating the within-day variability of HS.
RESULTS: HS in FP had 1) a significantly increased daily mean level; 2) a well-established CR, with a significantly increased oscillatory mesor and amplitude; and 3) a modified orexigram power spectrum affecting the ultradian harmonic components.
CONCLUSIONS: Our results suggest that the orectic perception of CF patients is characterised by "daily hyperorexia", with the maintenance of HS CR. This condition seems to be a structured abnormality insofar as there are visible changes in the orexigram spectral resolution, particular in the ultradian harmonic components whose oscillatory frequency is responsible for the diurnal pattern of HS. The hyperorexia of the investigated FP indicates that their frequent small meals are not sufficient to satisfy their HS, which may cause a vicious circle leading to progressively disrupted mealtime behaviour.