Obesity and other medical comorbidities among NT1 patients after the Norwegian H1N1 influenza epidemic and vaccination campaign

Study Objectives: Narcolepsy type 1 (NT1) may be complicated by comorbidities. We aimed to study the extent of obesity and other medical comorbidities in a Norwegian population of NT1 patients with debut of symptoms after the 2009 H1N1 influenza epidemic and vaccination campaign. We also aimed to explore factors associated with obesity. Methods: Ninety-one patients (48 children and 43 adults) were included in this cross-sectional study, 80 of whom were H1N1-vaccinated. All participants were hospitalized and underwent sleep investigation and physical examination, and completed a semi-structured clinical interview. Results: In children, 16 females (70%) and 10 males (40%) were classified as overweight or obese. Twenty children (42%) had a co-existing medical disorder. Medical comorbidity was significantly positively associated with BMI in children (p =.032). In adults, 19 females (58%) and 7 males (70%) were classified as overweight or obese. Twenty-six adults (61%) had a co-existing medical disorder. We found no factors significantly associated with BMI in adults. On a fatigue scale from 0 to 100, lower scores indicating more fatigue, we found a mean (SD) total fatigue score of 50 (17) in children and 39 (16) in adults. Conclusion: In a cohort of predominantly H1N1-vaccinated NT1 patients, we found a high prevalence of overweight or obesity. Half of the cohort presented with one or more additional medical comorbidities, and patients reported a clinically relevant degree of fatigue. Our findings highlight the importance of carefully monitoring patients with NT1 with regard to the development of obesity, which is a significant risk factor for cardiovascular disorders. Statement of Significance Narcolepsy is complicated with a high prevalence of comorbidities, obesity in particular. However, it is poorly understood why some patients are at more risk of developing obesity than others. We found a high prevalence of obesity in patients who developed narcolepsy type-1 (NT1) after the H1N1 vaccination campaign. Medical comorbidity in children, but not in adults, was the only factor significantly associated with obesity, indicating that the development of obesity is not dependent on the age of onset or severity of narcolepsy. Finally, we found severe fatigue both in children and adults. Our study emphasizes the importance of monitoring patients with NT1 in regard to the development of obesity, which is a significant risk factor for secondary medical complications and decreased quality of life.