Relative validation of a beverage frequency questionnaire in children ages 6 months through 5 years using 3-day food and beverage diaries.

OBJECTIVE

To determine the relative validity of a quantitative beverage frequency questionnaire in assessing beverage, calcium, and vitamin D intakes using 3-day food diaries for reference.

DESIGN

Parents were asked to complete questionnaires for the preceding week and diaries for the following week for their children. Calcium and vitamin D intakes were estimated from human milk, infant formulas, and cow's milk ("beverages") for questionnaires and diaries and from "all foods and beverages" for diaries. Data collected at 6 and 12 months and 3 and 5 years of age as part of the Iowa Fluoride Study (N=700) were analyzed cross-sectionally.

SUBJECTS

Children (N=240); 60 randomly selected from each quartile of energy intake at 6 months of age.

STATISTICAL ANALYSES

Spearman correlation coefficients, weighted kappa statistics, and percentages of exact agreement were used to assess associations between tools.

RESULTS

Correlations between mean daily beverage intakes estimated from questionnaires and diaries ranged from 0.95-0.99 for human milk, 0.84-0.85 for infant formula, 0.63-0.86 for cow's milk, 0.54-0.69 for juice/drinks, 0.26-0.59 for liquid soft drinks, 0.35-0.74 for powdered soft drinks and 0.54-0.70 for water. Correlations between mean daily nutrient intakes estimated from questionnaires and diaries "beverages" ranged from 0.64-0.74 for calcium and 0.60-0.80 for vitamin D; and between questionnaires and diaries "all foods and beverages" ranged from 0.41-0.63 for calcium and 0.43-0.80 for vitamin D.

APPLICATIONS

A quantitative beverage frequency questionnaire can provide a relative estimate of beverage, calcium, and vitamin D intakes.