Hypocretin Deficiency in Narcoleptic Humans Is Associated with Abdominal Obesity

TLDR

The study aimed to assess obesity prevalence and related health risks in narcoleptic patients, distinguishing effects of hypocretin deficiency from those of daytime sleepiness on waist circumference and body mass. A cross‑sectional case‑control study compared 138 narcolepsy patients, 33 idiopathic hypersomnia patients, and 10,526 age‑matched healthy controls from the Dutch population. Narcolepsy patients had higher obesity (33% vs 12.5%) and overweight rates (43% vs 36%) and a mean waist circumference 5 cm larger than controls; idiopathic hypersomnia patients had lower BMI, indicating that excess body fat in narcoleptics is not solely due to inactivity.

Abstract

To determine the prevalence of obesity among patients with narcolepsy, to estimate associated long-term health risks on the basis of waist circumference, and to distinguish the impact of hypocretin deficiency from that of increased daytime sleepiness (i.e., reduced physical activity) on these anthropometric measures.A cross-sectional, case-control study was conducted. Patients with narcolepsy (n = 138) or idiopathic hypersomnia (IH) (n = 33) were included. Age-matched, healthy members of the Dutch population (Monitoring Project on Risk Factors for Chronic Diseases and Doetinchem Project; n = 10,526) were used as controls. BMI and waist circumference were determined.Obesity (BMI > or = 30 kg/m(2)) and overweight (BMI 25 to 30 kg/m(2)) occurred more often among narcolepsy patients [prevalence: 33% (narcoleptics) vs. 12.5% (controls) and 43% (narcoleptics) vs. 36% (controls), respectively; both p < 0.05]. Narcoleptics had a larger waist circumference (mean difference 5 +/- 1.4 cm, p < 0.001). The BMI of patients with IH was significantly lower than that of narcolepsy patients (25.6 +/- 3.6 vs. 28.5 +/- 5.4 kg/m(2); p = 0.004).Overweight and obesity occur frequently in patients with narcolepsy. Moreover, these patients have an increased waist circumference, indicating excess fat storage in abdominal depots. The fact that patients with IH had a lower BMI than narcoleptics supports the notion that excessive daytime sleepiness (i.e., inactivity) cannot account for excess body fat in narcoleptic patients.