Development & cross-validation of anthropometric predictive models to estimate the appendicular skeletal muscle mass in middle-aged women in Sri Lanka

Background & objectives: Attempts have been made to estimate appendicular skeletal muscle mass (ASMM) using anthropometric indices and most of these are country specific. This study was designed to develop and cross-validate simple predictive models to estimate the ASMM based on anthropometry in a group of healthy middle-aged women in Sri Lanka. Methods: The study was conducted on a randomly selected group of community-dwelling women aged 30-60 years. ASMM (kg) quantified with dual-energy X-ray absorptiometry (DXA) (ASMMDXA) was used as the reference standard. Anthropometric measurements such as body weight (kg), height (m), limb circumferences (cm) and skinfold thickness (mm) which showed significant correlations with ASMMDXA, were used to develop the models. The models were developed using a group of 165 women (aged 30-60 yr) and were cross-validated using a separate sample of women (n=167) (mean age: 48.9±8.56 yr), selected randomly. Results: Nine anthropometry-based models were developed using weight, height, skinfold thicknesses, circumferences, body mass index, menopausal status (MS) and age as independent variables. Four models which were based on height, weight, triceps skinfold thickness (TSFT), age and MS met all the validation criteria with high correlations (ranged 0.89-0.92) and high predictive values explaining high variance (80-84%) with low standard error of estimate (1.10-1.24 kg). Interpretation & conclusions: The four models (ASMM 1-ASMM 4) developed based on height, weight, TSFT, age and MS showed a high accuracy in estimating the ASMM in middle-aged women.

Prediction of total and visceral fat contents using anthropometric measures of adiposity in women.

BACKGROUND: Although techniques such as dual energy xray absorptiometry (DXA) and quantitative CT are available to estimate global and regional adiposity, anthropometric measurements are often used to detect adiposity in clinical practice. OBJECTIVES: To assess the association between the anthropometric measurements of obesity with total and regional fat mass determined by DXA. DESIGN: A cross-sectional, descriptive study. Patients and method 106 healthy women volunteers, aged between 30 and 54 years were studied. Anthropometric measurements including body mass index (BMI), waist circumference (WC), hip circumference (HC), height adjusted WC (WC/HT), waist-hip ratio (WHR), and skin-fold thickness (SFT) over triceps, infrascapular, and iliac regions were made. All women underwent assessment of total fat mass (TFM) and visceral fat mass (VFM) using a Hologic DXA scan. RESULTS: TFM and VFM showed positive correlations with all the anthropometric measurements examined, the strongest correlation was with BMI (r = 0.89 and 0.77 for TFM and VFM respectively, p < 0.001). Correlations of TFM with WC, HC, and WC/HT were 0.72, 0.87, and 0.65, (p < 0001 for all) respectively. Corresponding figures for VFM were 0.73, 0.74, and 0.68, (p < 0001 for all). WHR showed a poor correlation with TFM (r = 18, p = 0.09) and VFM (r = 0.33, p = 0.002). SFTs measured at three sites showed less strong correlations with TFM and VFM (r = 0.48 to 0.69, p < 0.001). CONCLUSIONS: BMI has the strongest association with total and visceral fat mass among these women. Waist and hip circumferences showed high correlations with total and visceral fat mass, but adjusting waist circumference for height did not improve the correlation.

Comparison of phalangeal bone mineral content and density between the dominant and non-dominant sides.

OBJECTIVES: Compared to the non-dominant side, higher bone mineral content (BMC) and density (BMD) have been demonstrated in the forearm bones in the dominant side. Clinicians are compelled to scan the dominant side when deformities or artifacts are found in the non-dominant side. This study was done to evaluate the differences in phalangeal BMC and BMD, measured using accuDXA, between the dominant and non-dominant hands. Design and participants A group of 333 subjects, comprising 267 healthy volunteers (185 women and 82 men) and 66 women with rheumatoid arthritis. Phalangeal BMD and BMC, were measured using accuDEXA, both in the non-dominant and dominant hands. Main results BMC and BMD showed strong correlations between the two sides (r = 0.95, p < 0.001 for both). Compared to the non-dominant side, dominant side BMC was 5% higher (mean values =1.54 and 1.47, mean difference = 0.064, 95% CI for the mean difference = 0.048-0.081 g, p < 0.001) and BMD was 4% higher (mean values = 0.480 and 0.463, mean difference = 0.018, 95% CI for the mean difference = 0.014-0.021 g/cm2, p < 0.001). In the subgroup analysis, percentage differences of BMD between the two sides were found to be similar among men (n=82), women (n=251), people below 50 years (n=24), people above 50 years (n=122) and also among patients with rheumatoid arthritis (n=66). Conclusions When the non-dominant hand is not suitable for scanning, the clinician should consider scanning the dominant hand instead. However, the differences in BMD between the two hands should be taken into consideration when interpreting results.