Prevalence of Obesity in Japanese Individuals with Neurofibromatosis 1

[Abstract] Background: Although much research on the clinical features of neurofibromatosis 1 (NF1) has been published, few studies have investigated the body size of adults with NF1. Additionally, there are very few reports of metabolic syndromes, such as diabetic mellitus, occurring as comorbidities in individuals with NF1. In a previous single institution study, we found that adults with NF1 had a lower body mass index (BMI) than control subjects. Materials and Methods: The study cohort comprised 146 adults with NF1 (61 men, 85 women; age range 20-79 years [mean+-standard deviation] {SD} 42.2+-16.1 years) from two institutions. As a control, we retrieved national reference data (NFD) on BMI from epidemiologic research performed by the Ministry of Health, Labour and Welfare in Japan in 2011-2012. We used the Mantel-Haenszel test to compare the prevalence of obesity (25 kg/m225 kg/m2 was significantly lower in men with NF1 than in the cohort drawn from NFD (p=0.012); however, this difference was not significant for women (p=0.288). Conclusions: Our findings indicate that most men with NF1 are of normal body size and that they have a lower prevalence of obesity than a control group.