Análise das relações entre densidade mineral óssea e composição corporal, marcadores bioquímicos, atividade física, função pulmonar e mutação F508del-CFTR em pessoas com fibrose cística

Abstract

In people with Cystic Fibrosis, Low Bone Mineral Density (BMD) is common in post-pubertal children, adolescents and adults, although the older ones tend to be more affected. The increase in life expectancy of this population has shown the emergence of Bone Disease Related to Cystic Fibrosis (CFOD). The aim of the study is to analyze the association between bone mineral density and body composition, biochemical markers, physical activity, lung function and F508Del-CFTR mutation in patients with cystic fibrosis. Multicenter cross-sectional study with patients with Cystic Fibrosis in Northeastern Brazil. Patients aged 5 and 20 years were selected, and participants who had already undergone organ transplants, had pulmonary exacerbation or had renal or liver dysfunction were excluded. BMD was assessed by dual energy x-ray emission (DXA) in the whole body less head (TBLH) incidence and the TBLH Z-score (Z-TBLH) adjusted for sex, age, height was calculated. and ethnicity. Body composition was identified through DXA. Mid-upper Arm Circumference (MUAC) and Triceps Skinfold (TSF) were identified by anthropometryA blood sample collected for the analysis of vitamin D, calcium, phosphorus, parathyroid hormone and bone alkaline phosphatase. Pulmonary function was assessed by spirometry, observing Forced Vital Capacity (FVC) and Forced Expiratory Volume in the 1st second (FEV1). Identification of the F508del-CFTR mutation was obtained from the medical record. Descriptive analysis presents general data and statistical models of simple linear regression, multiple linear regression and binary logistic regression were created to establish the predictive power of Z-TBLH in the variables. A p value less than 0.05 reflects a statistically significant result. 39 patients with a mean age of 13.31 ± 3.86 years were selected. None of the food consumption or biochemical markers were associated with Z-TBLH. The practice of physical activity (p = 0.022; OR = 6,000), FVC (p = 0.032; OR = 22.856) and FEV1 (p = 0.042; OR = 11.576) were protective factors in relation to Z-TBLH. Furthermore, a final model composed of AMA, DCT and Age (p = 0.001; R² = 0.381) had AMA and Age as significant predictors. AMB was associated with an increase in the BMD Z-score in the patients studied. 66.7% of genetically tested patients had the F508del-CFTR mutation. The presence of the mutated allele F508del-CFTR was associated with worse nutritional status. It was concluded that a statistical model composed by the values of AMB, DCT and Age can predict Z-TBLH in CF patients, aged 5 to 20 years, of both genders. Anthropometric markers, as they are easy measurements and relatively inexpensive to obtain, are a promising alternative to the use of DXA in predicting the BMD of these patients. It was also concluded that the practice of physical activity for at least 30 minutes a day, at least once a week and better lung function, characterized by forced expiratory flow above 75% of FVC and not having moderate to severe lung disease, are protective factors in relation to CFOD in people with CF 5-20 years old of both sexes.