Validation of a Short Food Frequency Questionnaire (FFQ) to Assess Calcium Intake in Children and Adolescents With Cystic Fibrosis (CF)

Abstract

LEARNING OUTCOME: Develop and validate a short FFQ for clinical or research purposes to quantitate calcium intake in children and adolescents with CF. With increasing lifespan of CF patients, published reports of osteopenia and osteoporosis in young adults with CF have emerged. Although the exact mechanisms remain undefined, prolonged steroid use, decreased exercise, decreased lean body mass, and dietary calcium intake could all play a role. Therefore, it is important that children and adolescents with CF maintain a high calcium intake throughout their growth years to maximize peak bone mass. A quick and easy tool to screen for dietary calcium intake during outpatient visits is needed. A previously validated FFQ which determined the amount of calcium consumed daily in perimenopausal women was adapted for use in children and adolescents with CF living in Louisiana. In addition, this FFQ serves as an educational tool in diet counseling to patients and families. The original FFQ was reduced from 53 to 36 items with deletion of food items not commonly eaten by children such as tofu, figs or almonds, and addition of food items usually consumed by CF children such as cereal with milk, milkshakes, and liquid dietary supplements. In addition, food items commonly eaten in Louisiana such as shellfish and oysters were also included. Twenty CF patients (M=12, F= 8; mean age 4.8 yrs, range 2.0-17.5 yrs) were recruited from the CF center. They or their guardians completed the modified FFQ in clinic and within the next two weeks completed a 5-day food record at home using scales and measuring utensils. The mean daily intake of calcium from the 5-day food record was 1476±924 mg. Calcium intake derived from the FFQ was reproducible (n=12; r=0.94) and was highly correlated with the calcium intake from the 5-day food record (r=0.94; p<0.001). We conclude that our modified FFQ offers an easy and reliable means for assessment of calcium intake of CF patients in Louisiana. We postulate that such FFQ may provide an important clinical tool for the longitudinal assessment and maintenance of adquate calcium intake in CF. (Supported in part by a MCH Training Grant MCJ-229163)