SUMMARY Objective To evaluate the body composition and nutritional status of neurofibromatosis type 1 (NF1) adult patients. Method A cross-sectional study of 60 NF1 patients (29 men, 31 women) aged ≥ 18 years who were evaluated from September 2012 to September 2013 in a Neurofibromatosis Outpatient Reference Center. Patients underwent nutritional assessment including measurements of weight, stature, waist circumference (WC), upper-arm circumference (UAC), and skinfolds (biceps, triceps, subscapular, suprailiac). Body mass index (BMI), upper-arm total area (UATA), upper-arm muscle area (UAMA), upper-arm fat area (UAFA), body fat percentage (BFP), fat mass, fat-free mass, fat mass index, and fat-free mass index were also calculated. Results The mean age of the study population was 34.48±10.33 years. The prevalence of short stature was 28.3%. Low weight was present in 10% of the sample and 31.7% of patients had a BMI ≥ 25 kg/m2. Reduced UAMA (<5th percentile) was present in 43.3% and no difference was found in UAFA between the sexes. The BFP was considered high in 30% and 17 (28.3%) patients had a WC above the World Health Organization cutoffs. Conclusion In this study, NF1 patients had a high prevalence of underweight, short stature, and reduced UAMA, with no difference between the sexes. Reduced UAMA was more prevalent in underweight patients; however, this was also observed in the normal and overweight patients. Further studies should investigate the distribution of body tissues in NF1 patients, including differences between men and women, and the influence of diet and nutrition on clinical features in NF1.
