title: Children's nutrient intake variability is affected by age and body weight status according to results from a Brazilian multicenter study.
abstract: A major challenge in nutritional studies focusing on children is estimating "true" intake because the type and amount of foods eaten change throughout growth and development, thereby affecting the variability of intake. The present study investigated the hypothesis that age and body weight status affect the ratio of the within- and between-subject variation of intakes (VR) as well as the number of days of dietary assessment (D) of energy and nutrients. A total of 2,981 Brazilian preschoolers aged 1-6 years were evaluated in a cross-sectional study. Weighed food records and estimated food records were used to assess dietary intake inside and outside of school. Within- and between-subject variations of intakes were estimated by multilevel regression models. VR and D were calculated according to age group and body weight status. VR ranged from 1.17 (calcium) to 8.70 (fat) in the 1- to 2-year-old group, and from 1.47 (calcium) to 8.95 (fat) in the 3- to 6-year-old group. Fat, fiber, riboflavin, folate, calcium, phosphorus, and iron exhibited greater VR and D in the 3- to 6-year-old group. For energy, carbohydrates, and protein, both within- and between-subject variation increased with increasing age. In both body weight groups, calcium showed the lowest VR. Fat showed the highest VR in nonoverweight/obese children (9.47), and fiber showed the highest VR in overweight/obese children (8.74). For most nutrients, D = 7 was sufficient to correctly rank preschoolers into tertiles of intake. In conclusion, age and body weight status affected the within- and between-subject variation and the VR of energy and nutrient intakes among Brazilian preschool children.
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, São Paulo, Brazil. Electronic address: michelle.castro@usp.br.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: de Castro
authors.affiliation: Department of Epidemiology, Institute of Social Medicine, State University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: verlyjr@ims.uerj.br.
authors.forename: Eliseu
authors.initials: E
authors.lastname: Verly
authors.affiliation: Department of Pediatrics, Federal University of São Paulo, São Paulo, Brazil. Electronic address: mauro.fisberg@gmail.com.
authors.forename: Mauro
authors.initials: M
authors.lastname: Fisberg
authors.affiliation: Department of Nutrition, School of Public Health, University de São Paulo, Sao Paulo, Brazil. Electronic address: rfisberg@usp.br.
authors.forename: Regina M
authors.initials: RM
authors.lastname: Fisberg
mesh_terms: D000367:Age Factors; D015992:Body Mass Index; D001835:Body Weight; D001938:Brazil; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage; D009752:Nutritional Status; D009765:Obesity; D050177:Overweight
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D018977:Micronutrients
keywords: BMI; CVb; CVw; Children; D; Diet; EFR; Multilevel analysis; Nutrition assessment; SDb; SDw; Sb(2); Sw(2); VR; Variation; WFR; between-subject SD; between-subject coefficient of variation; between-subject variation of intake; body mass index; correlation coefficient; estimated food record; number of days of dietary assessment; r; ratio of the within- to between-subject variation of intake; weighed food record; within-person variation of intake; within-subject SD; within-subject coefficient of variation