Muscle determinants of bone mass, geometry and strength in prepubertal girls

Purpose: The aim of this study was to compare the relative contribution of peak muscle force (isokinetic peak torque) with surrogate estimates of muscle force, including leg lean tissue mass (LTM) and vertical jump height (VJH), on bone mass, geometry and strength in healthy prepubertal girls (n = 103).

Methods: Total leg and FN BMC and leg LTM were measured by DXA; the hip strength analysis program was used to assess FN diameter, cross-sectional area (CSA) and section modulus (Z). Isokinetic peak torque of the knee extensors and flexors (60°·s-1) were used as direct measures of peak muscle force. VJH was measured as an estimate of neuromuscular function. Total leg length or femoral length was used as a surrogate measure of moment arm length.

Results: All estimates of muscle function, except VJH, were positively associated with leg BMC (r = 0.72 - 0.90) and FN BMC, geometry and strength (r = 0.35-0.65) (all, P < 0.001). Multiple linear regression analyses revealed that leg LTM and isokinetic peak torque were independently and equally predictive of leg BMC and FN BMC, bone geometry and strength, explaining 8 to 28% of the variance in each of the bone traits after accounting for moment arm length. When isokinetic peak torque was corrected for both leg LTM and moment arm length, it remained an independent predictor of BMC, CSA and Z, but only accounted for an additional 2 to 5% of the variance.

Conclusion: These data suggest that DXA-derived leg LTM can be used as a reasonable surrogate for isokinetic peak muscle forces when assessing bone strength in relation to muscular function in healthy pre-pubertal girls.

Feasibility of repeated 24-h dietary recalls combined with a food-recording booklet, using EPIC-Soft, among preschoolers

Background/Objectives: This study evaluates the feasibility among preschoolers of the 224-h dietary recalls (24-HDRs) method combined with a food-recording booklet (FRB), using EPIC-Soft pc-program for the 24-HDR (the software developed to conduct 24-HDRs in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study).
Subjects/Methods: A total of 20 and 25 (4- to 5-year-old) children were recruited, as a convenience sample, through worksites or day or healthcare in Denmark and Spain, respectively. One parent (or both parents together) completed two face-to-face 24- HDR, combined with an optional use of a FRB. Feasibility was evaluated by evaluation questionnaires completed by parents and interviewers.
Results: The face-to-face interviews were primarily conducted with the mothers. The FRB was used by 90% of the participants, and proxy persons, other than the parent, were also involved; involvement of proxy persons seems necessary in a majority of the recalls in both the countries.
Conclusions: The results suggest that 224-HDR with one parent combined with a FRB is feasible for registering preschoolers’ diet. An FRB and/or information from proxy persons, other than the parent, is needed for a majority of the parents. In future studies, it may be beneficial to develop the FRB more like a structured food record (FR), which might, in principle, change the method to a one-day FR method from more than a 24-HDR method. It is recommended then to further investigate the use of EPIC-Soft as a data-entry tool.