Association between Bone-Specific Physical Activity Scores and Measures of Areal and Volumetric Bone Mineral Density and Bone Markers in Middle-Aged Premenopausal Women

Abstract

The bone-specific physical activity questionnaire (BPAQ) has been shown to be related to areal bone mineral density (aBMD), but its relation to bone architecture and bone markers has not been well studied. PURPOSE: The purpose of this study was to investigate the relationship between a total BPAQ score (tBPAQ), aBMD, volumetric BMD (vBMD, mg/cm3), and bone markers in middle-aged premenopausal women. METHODS: Thirty-four premenopausal women (44.4 ± 4.1 years; 161.7 ± 5.4 cm; 69.9 ± 11.1 kg) were recruited for this study. aBMD of L1-L4 and dual proximal femur (TH; total hip, FN; femoral neck) were measured using Dual Energy X-ray Absorptiometry. We assessed vBMD of tibia 4% (ToD; total vBMD, trabecular vBMD), 38% (ToD, CoD; cortical vBMD, SSI; strength strain index), and 66% (ToD, CoD, SSI) by peripheral quantitative computed tomography. Bone formation (Bone ALP) and bone resorption (TRAP5b) markers were assessed. The tBPAQ was used to obtain a comprehensive account of lifetime physical activity related to bone health. RESULTS: Spearman’s correlation showed significant (p<0.05) positive relationships between tBPAQ and aBMD of right FN(r=.370) and left femur (TH, r=.373; FN, r=.372) and L1-L4 (r=.371), but no significant relationship was found for the right TH (p>0.05). There were no significant correlations between vBMD variables and tBPAQ. Also, no relationships were found between tBPAQ and bone ALP and TRAP5b (p>0.05). When tBPAQ, bone free lean body mass (BFLBM), calcium intake, and age were included in a stepwise multiple linear regression analysis, BFLBM was the only predictor of tibia 38% and 66% SSI, accounting for 16% (p=0.012) and 27% of the variance (p=0.001), respectively. CONCLUSION: The tBPAQ score-derived physical activity had positive relationships with FN, TH, and L1-L4 aBMD in healthy middle-aged premenopausal women, but no significant associations were found between tBPAQ and both vBMD and bone markers. Table 1. tBPAQ and aBMD (g/cm2).Table: No title available.