Development and evaluation of a Brief Calcium Assessment Tool (BCAT) for adolescents
Abstract
Adolescence is a critical time to achieve peak bone mass, but based on adolescents' average calcium intakes, they are potentially vulnerable to osteoporosis later in life. Thus, a brief and valid assessment tool to quickly assess calcium intake in adolescents is needed. The purpose of this study was to develop a Brief Calcium Assessment Tool (BCAT) for assessing calcium intakes among adolescents and evaluate the tool's integrity. Data from 745 females ages 10-14 y in 6 states and 1,426 Asian, Hispanic, and non-Hispanic white youth ages 9-20 y in 10 states were used to select the 15 foods from the 79 foods in the What You Eat and Drink (WYED) food frequency questionnaire (1) and select the best approach explaining total calcium intake and/or the variance of total calcium intake. The approach using weighted frequencies for 15 foods consumed was determined as the best approach to assess calcium intake of adolescents in terms of closest adherence to WYED results and simplicity. The selected foods and the approach explained 92% of the total variance of calcium intake from the WYED. Based on 15 selected foods and the approach, the BCAT was developed. A simple linear regression was used to get an equation to estimate daily food calcium intake from sum of calcium scores for the 15 selected foods. A score was the value of a weighted frequency for each food consumed. BCAT Score Index (BSI) for assessing calcium intakes of respondents was created based on this equation. Reliability of the BCAT was assessed by repeated BCAT administrations 1 week apart among 41 adolescents ages 9 to 17 y. Correlation of BCAT scores between first and second administration was 0.76 (p<0.001). Relative validity of the BCAT was evaluated by comparing the BCAT to the Block 2004 Online Kids food frequency questionnaire (Block online-FFQ) as completed by 176 adolescents ages 10 to 13 y. Correlation between BCAT scores and calcium estimates as estimated by the Block online-FFQ was 0.35 (p<0.001) and cross-classification analysis placed 80% of the subjects in the same or adjacent quartiles. Multivariate models examined the association between bone mineral content (BMC) from dual-energy x-ray absorptiometer (DXA) measurement and BCAT scores among 748 females (9-14 y). BCAT score was associated with total hip BMC (β=0.014, P=0.003) and femoral neck BMC (β=0.002, P=0.006) while adjusting for age, weight, height, race, maturity and physical activity in the cross-sectional study. BCAT score at the baseline was a predictor of total body BMC at the follow-up in the prospective study (β=0.279, P=0.041) with adjustment for post menarche age, change in height, race, and baseline BMC. The BCAT appears to perform well to assess calcium intake among adolescents, thus the tool can be used to estimate calcium intakes among adolescents.
Degree
Ph.D.
Advisors
Boushey, Purdue University.
Subject Area
Nutrition
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