Peripheral quantitative computed tomography (pQCT) in 12- and 24-month-old children - Practical aspects and descriptive data.

Abstract

Peripheral quantitative computed tomography (pQCT) is a useful tool to assess detailed bone characteristics. Its utility in infants is however limited due to lack of reference data and technical challenges. The purpose of this study was to provide data on length- and weight-adjusted pQCT values and to present a quality grading system for healthy children aged 12 and 24months. As a part of the Vitamin D intervention in Infants (VIDI) trial, we collected pQCT and anthropometric data from 855 children at 12months and from 784 children at 24months. Bone mineral content (BMC; mg/mm), volumetric bone mineral density (vBMD; mg/cm3), cross-sectional area (CSA; mm2), polar-moment of inertia (PMI; mm4), and periosteal circumference (PsC; mm) were assessed for total bone at 20% distal site of the left tibia using pQCT (Stratec XCT2000L). We evaluated the impact of scan quality on bone measures. Total bone parameters were assessed for boys and girls separately. The means of the bone parameters were also compared in relation to age. The associations between bone parameters and weight, length, sex and scan quality were analyzed. We included scans with sufficient quality (Grade 1-5) in the final analyses: 679/855 (79%) at 12months and 709/784 (90%) at 24months. Altogether 39% of the scans at 12months and 51% at 24months were of good or excellent quality (Grade 1-2). Scan quality had an impact on BMCs at 12 and 24months (p=0.001 and p=0.017, respectively) but not on other bone parameters. Boys presented greater total bone BMC, CSA, PMI and PsC values at 12 and 24months but vBMDs were similar. All bone parameters showed a significant increase between 12 and 24months for both sexes. When adjusting bone parameters for weight, length and scan quality, differences between sexes disappeared. Weight was the strongest modifier of BMC, CSA, PMI and PsS at 12 and 24months. This study increases our understanding on bone parameters in young children and demonstrates the suitability of pQCT in bone research in infants. The described pQCT data and scan quality grading system should prove useful in evaluating data reliability in research settings. NCT1723852.