BACKGROUND: A dietary assessment instrument designed for use in a nationally representative pediatric population was required to examine associations between calcium intake and bone mineral accrual in a large, multicenter study. OBJECTIVE: To determine the reproducibility and intermethod reliability of a youth calcium food frequency questionnaire (FFQ) in a multiracial/ethnic sample of children and adolescents. DESIGN: Reproducibility (n=69) and intermethod reliability (n=393) studies were conducted by administering repeat FFQs and three unannounced 24-hour dietary recalls to stratified random samples of individuals participating in the Bone Mineral Density in Childhood Study. PARTICIPANTS/ SETTING: Children and adolescents ages 5 to 21 years. MAIN OUTCOME MEASURES: Calcium intake estimated from the FFQ and 24-hour dietary recalls. STATISTICAL ANALYSIS: Reproducibility was assessed by the intraclass correlation coefficient (ICC). Intermethod reliability was assessed by deattenuated Pearson correlations between the FFQ and 24-hour recalls. Attenuation factors and calibration corrected effect estimates for bone density were calculated to determine the potential influence of measurement error on associations with health outcomes. RESULTS: The ICC (0.61) for repeat administrations and deattenuated Pearson correlation between the FFQ and 24-hour recalls (r=0.60) for all subjects indicated reproducibility and intermethod reliability (Pearson r=0.50 to 0.74 across sex and age groups). Attenuation factors were ≤0.50 for all sex and age groups and lower for non-Hispanic blacks (λ=0.20) and Hispanics (λ=0.26) than for non-Hispanic whites (λ=0.42). CONCLUSIONS: The Bone Mineral Density in Childhood Study calcium FFQ appears to provide a useful tool for assessing calcium intake in children and adolescents drawn from multiracial/ethnic populations and/or spanning a wide age range. However, similar to other FFQs, attenuation factors were substantially <1, indicating the potential for appreciable measurement error bias. Calibration correction should be performed and racial/ethnic differences in performance considered when analyzing and interpreting findings based on this instrument.
BACKGROUND: A dietary assessment instrument designed for use in a nationally representative pediatric population was required to examine associations between calcium intake and bone mineral accrual in a large, multicenter study. OBJECTIVE: To determine the reproducibility and intermethod reliability of a youth calcium food frequency questionnaire (FFQ) in a multiracial/ethnic sample of children and adolescents. DESIGN: Reproducibility (n=69) and intermethod reliability (n=393) studies were conducted by administering repeat FFQs and three unannounced 24-hour dietary recalls to stratified random samples of individuals participating in the Bone Mineral Density in Childhood Study. PARTICIPANTS/ SETTING:Children and adolescents ages 5 to 21 years. MAIN OUTCOME MEASURES: Calcium intake estimated from the FFQ and 24-hour dietary recalls. STATISTICAL ANALYSIS: Reproducibility was assessed by the intraclass correlation coefficient (ICC). Intermethod reliability was assessed by deattenuated Pearson correlations between the FFQ and 24-hour recalls. Attenuation factors and calibration corrected effect estimates for bone density were calculated to determine the potential influence of measurement error on associations with health outcomes. RESULTS: The ICC (0.61) for repeat administrations and deattenuated Pearson correlation between the FFQ and 24-hour recalls (r=0.60) for all subjects indicated reproducibility and intermethod reliability (Pearson r=0.50 to 0.74 across sex and age groups). Attenuation factors were ≤0.50 for all sex and age groups and lower for non-Hispanic blacks (λ=0.20) and Hispanics (λ=0.26) than for non-Hispanic whites (λ=0.42). CONCLUSIONS: The Bone Mineral Density in Childhood Study calcium FFQ appears to provide a useful tool for assessing calcium intake in children and adolescents drawn from multiracial/ethnic populations and/or spanning a wide age range. However, similar to other FFQs, attenuation factors were substantially <1, indicating the potential for appreciable measurement error bias. Calibration correction should be performed and racial/ethnic differences in performance considered when analyzing and interpreting findings based on this instrument.
Authors: H R Rockett; M Breitenbach; A L Frazier; J Witschi; A M Wolf; A E Field; G A Colditz Journal: Prev Med Date: 1997 Nov-Dec Impact factor: 4.018
Authors: Jonathan A Mitchell; Alessandra Chesi; Shana E McCormack; Diana L Cousminer; Heidi J Kalkwarf; Joan M Lappe; Vicente Gilsanz; Sharon E Oberfield; John A Shepherd; Andrea Kelly; Struan F A Grant; Babette S Zemel Journal: Med Sci Sports Exerc Date: 2018-05 Impact factor: 5.411
Authors: Jonathan A Mitchell; Alessandra Chesi; Okan Elci; Shana E McCormack; Sani M Roy; Heidi J Kalkwarf; Joan M Lappe; Vicente Gilsanz; Sharon E Oberfield; John A Shepherd; Andrea Kelly; Struan Fa Grant; Babette S Zemel Journal: J Bone Miner Res Date: 2016-08 Impact factor: 6.741