Assessment of nutritional status in adult patients with cystic fibrosis: whole-body bioimpedance vs body mass index, skinfolds, and leg-to-leg bioimpedance

Objective: To investigate whether body mass index (BMI) or body fat percentage estimated from BMI, skinfolds, or leg-to-leg bioimpedance are good indicators of nutritional status in adult patients with cystic fibrosis. Body fat percentage measured by whole-body bioimpedance was used as the reference method. Design: Cross-sectional study using four methods to estimate body fat percentage. All patients filled out a food frequency and a physical activity questionnaire for assessment of their habitual food intake and energy requirements, respectively. Subjects/Setting: Thirty-five adult patients (23 men/12 women) with cystic fibrosis, age range 18 to 46 years, were measured during their yearly visit at the outpatient clinic of the Cystic Fibrosis Center in Utrecht, the Netherlands. Statistical Analysis: Mean±standard deviation was calculated for all measurements and 95% confidence intervals for differences between methods. Bland-Altman plots were used to assess differences between the measures of body composition and Pearson correlation coefficients were calculated to determine the relationships between them, and between the energy requirements and the energy intakes. Results: For men the whole-body body fat percentage reference was 14.1%±3.0, body fat percentage estimated from BMI was 15.8%±4.3, body fat percentage estimated from skinfolds was 8.6%±4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 13.1%±4.9. For women the whole-body body fat percentage reference was 24.0%±5.9, body fat percentage estimated from BMI was 25.1%±4.0, body fat percentage estimated from skinfolds was 17.0%±4.8, and body fat percentage estimated from leg-to-leg bioimpedance was 25.0%±6.9. Body fat percentage estimated from BMI and body fat percentage estimated from skinfolds were significantly different from the reference value for body fat percentage (