Objective: To evaluate whether anthropometric and dietary intake indicators are predictors of pulmonary function in cystic fibrosis (CF) patients. Methods: This was a cross-sectional study involving 69 patients (age range, 5.4-16.5 years) diagnosed with CF under follow-up at the Hospital de Clínicas de Porto Alegre, located in the city of Porto Alegre, Brazil. Anthropometric assessment was based on body mass index (BMI), mid-arm muscle circumference (MAMC), and triceps skinfold thickness (TST). Dietary intake was assessed by using recall data, which were compared with the recommended dietary allowances. Pulmonary function was assessed by ventilatory capacity, expressed as FEV1. Prevalence ratios for the outcome studied (FEV1 < 80% of predicted) were calculated by indicator. Results: In patients with MAMC and TST below the 25th percentile, the prevalence of FEV1 < 80% of predicted was significantly higher than in those with higher MAMC and TST (p < 0.001 and p = 0.011, respectively). In comparison with other patients, those with a BMI below the 50th percentile showed a 4.43 times higher prevalence of FEV1 < 80% of predicted (95% CI: 1.58-12.41), and that prevalence was 2.54 times higher in those colonized with methicillin-resistant Staphylococcus aureus (MRSA) than in those not so colonized (95% CI: 1.43-4.53). The association between dietary intake and the prevalence of FEV1 < 80% of predicted was of only borderline significance (95% CI: 0.95-3.45). Conclusions: Not being colonized with MRSA and having a BMI above the 50th percentile appear to preserve pulmonary function in CF patients.

Keywords: Cystic fibrosis; Respiratory function tests; Nutrition assessment; Energy intake.