Multiple-regression analysis of the independent determination of human long-bone structure by regional muscle mass, body weight, body height, bone length, age, and time since menopause

PAOLA REINA; GUSTAVO ROBERTO COINTRY; SARA FELDMAN; PAMELA RANSDALE; DANIEL SALICA; JOERN RITTWEGER; JOSÉ LUIS FERRETTI; RICARDO FRANCISCO CAPOZZA

Denver (CO)

Congreso; XXXI ANNUAL MEETING, American Society for Bone & Mineral Research (ASBMR).; 2009

Multiple-Regression Analysis of the Independent Determination of Human Long-Bone Structure By Regional Muscle Mass, Body Weight, Body Height, Bone Length, Age, and Time Since Menopause Authors: P. Reina, G. Cointry, S. Feldman, P. Ramsdale, D. Salica, J. Rittweger, J. Ferretti, R. Capozza All the above factors interact as determinants of bone structure. To evaluate their independent influence following biomechanical criteria, pQCT indicators of bone mass (vBMC), material "quality" (cortical vBMD, vCtD), diaphyseal design (moments of inertia) and strength (SSI) of radii and tibiae were determined as dependent variables (yi) in forearms (4 and 66% sites) and legs (4,14,38 and 66% sites) of 60 men, 80 pre-MP women, and 120 post-MP women, all healthy and sedentary, with no history of smoking, alcohol abuse, bone pathology, fractures, or treatments affecting the skeleton. The single or combined determining power of age, time since MP (TMP), body weight (BW), body height (BH), radius or tibia length (bone length, BL), and regional muscle mass (maximal calf or forearm muscle area, MA) as independent variables (xi) on the indicators was analyzed by two different multiple-correlation models (R2=0.3-0.9): Model I compared Yi indicators with age (or TMP), BW, BH, and MA (x1-4), aiming to oppose muscle force to age- or size-related factors. Model II included BL instead of BH as x4, to compare the relevance of bone length and body height. In general, the strong independent influence of MA blunted that of BW. Age was a weak determinant in men and pre-MP women, but TMP impaired significantly every indicator in post-MP women.The vCtD was unaffected by any allometrically-associated parameter in any group, but it decreased with TMP. Excluding vCtD from the analyses, age and TMP had no influence on the studied indicators. Inclusion of BL instead of BH improved the significance of the analyses and enhanced the general influence of MA, more evidently in males than females, for bone design/strength rather than mass indicators, and for the lower than upper limbs. In lower limbs, MA was the chief determinant of bone mass/design/strength in males and pre-MP females. In post-MP women the most relevant determinants were BH and BW. In forearms, only MA was a relevant determinant of bone features. ResultS show that 1. Regional muscles are stronger determinants of long-bone features than age or BW in males and pre-MP females, while TMP is the strongest determinant in post-MP women. 2. In upper (not lower) limbs, muscle influence virtually excludes that of body weight, height, or age. 3. BL is a stronger determinant of bone design than BH in long bones, and 4. Bone material’s "quality" (vCtD) is unaffected by the proposed determinants, excepting TMP in post-MP women.