Nocturnal serum leptin values in chronic primary insomnia : A preliminary report

SummaryQuestion of the studySleep loss and weight gain are assumed to be positively correlated, probably mediated by a decreased leptin secretion and/or an increased production of ghrelin. The present study measured evening and nocturnal serum leptin secretion in patients with chronic primary insomnia and healthy controls.MethodsEleven healthy controls (9 females, 2 males) and 11 patients suffering from primary insomnia (matched for age and gender) were studied in the sleep laboratory for 3 consecutive nights. Blood samples were taken in 2-h intervals from 1900 h to 0900 h prior to and during the third night and analyzed for serum leptin levels.ResultsBody mass index (BMI) was significantly higher in insomniac patients compared to healthy subjects. Polysomnography revealed expected differences between control subjects and insomniac patients. Leptin levels did not differ between patients and controls, also when controlling for the potential confounding influence of BMI by analysis of covariance. Leptin levels correlated positively with BMI values in both groups and negatively with the Pittsburgh sleep quality index (PSQI) scores only in the healthy sample.ConclusionPrimary insomnia was not accompanied by an alteration in evening/nocturnal serum leptin levels. Further studies are warranted encompassing 24-h measurements of leptin in larger samples of patients with primary insomnia with varying degrees of BMI (carefully matched to healthy controls) and during different stages of the insomnia.