2 + 2 (+ 2) = 4: A new approach for appendicular muscle mass assessment by ultrasound.

OBJECTIVE: The aim of this study was to develop new appendicular lean mass (ALM) prediction models based on ultrasound and anthropometric measurements. METHODS: This was a cross-sectional assessment of a subsample from a population-based study (COMO VAI?), conducted with community-dwelling individuals ≥60 y of age living in a southern Brazilian city. ALM was measured by dual-energy x-ray absorptiometry (DXA). Muscle thickness (MT) from supine participants was assessed by ultrasound on the anterior aspect of both upper and lower limbs. Such measures, along with anthropometric data, were used to develop prediction models (multivariable linear regression) through the backward stepwise method. RESULTS: The study included 190 participants composed mainly of women, white, and middle-class individuals. The best ALM predictive performance was achieved by a model based on two "lengths" (height and arm length), two circumferences (dominant arm and thigh), and two ultrasound-measured MTs (dominant arm and thigh): R2 = 0.90, limits of agreement: ±2.36 kg. Closely satisfactory results were also achieved by an "abbreviated" model composed by the two aforementioned "lengths" and MTs (R2 = 0.89, limits of agreement: ±2.51 kg). ALM estimates from both equations were unbiased and similar to DXA measurements (P = 0.13 and 0.09, respectively). Bootstrap analysis favorably suggested the validity of the models. CONCLUSIONS: Based on two ultrasound assessments and a few anthropometric measurements, the developed equations produced accurate and unbiased ALM estimates in the sample. Hence: 2 MTs + 2 lengths (+ 2 circumferences) = 4 limbs' muscle mass. Such models might represent promising alternatives for muscle assessment among older individuals.

Think Globally, Act Locally: The Importance of Population-Specific Bioelectrical Impedance Analysis Prediction Equations for Muscle Mass Assessment.

BACKGROUND: Bioelectrical impedance analysis (BIA) is a convenient muscle assessment method, but its accuracy highly depends on population-specific aspects of the adopted equation. We aimed to develop appendicular lean mass (ALM) prediction models for older South Americans and to compare their performances to those of reference equations in the same sample. METHODS: Cross-sectional evaluation of 192 community-dwelling Brazilian subjects ≥60 years old from the COMO VAI? STUDY: Using measurements from single-frequency and multifrequency devices (BIASF and BIAMF, respectively), new ALM prediction equations were developed (reference method: dual-energy x-ray absorptiometry [DXA]). Validity was assessed by bootstrapping. Four previously established equations were also tested, and the performances were compared using Bland-Altman analysis. RESULTS: Stepwise variable selection produced the following equations: ALMSF-BIA = (2.08 × sex) + (0.04 × weight) + (0.24 × RI50 ) + (0.07 × Xc50 ) - 0.16; ALMMF-BIA = (1.85 × sex) + (0.03 × weight) + (0.31 × RI50 ) + (0.04 × Xc50 ) + (0.01 × Z5 ) - 8.16, where ALM is estimated in kg; female sex = 0 and male sex = 1; weight is measured in kg; RI50 is the resistance index at 50 kHz measured in cm2 /Ω); Xc50 is the reactance at 50 kHz measured in Ω; and Z5 is impedance at 5 kHz measured in Ω. The equations explained, respectively, 89% and 90% of the variability of ALMDXA in our sample, and their estimates were not significantly different from DXA measurements. Bland-Altman analysis revealed accurate and unbiased performances for both models, with similar limits of agreement (BIASF : ±2.58 kg; BIAMF : ±2.48 kg), and their validity was considered adequate by the bootstrap method. The reference equations, however, systematically overestimated ALM in our sample. CONCLUSION: The proposed equations might represent practical options to estimate ALM in older noninstitutionalized South Americans. Further external validation, though, is required to verify the reproducibility of our findings.

Bioelectrical impedance analysis in the assessment of sarcopenia.

PURPOSE OF REVIEW: Bioelectrical impedance analysis (BIA) is an accepted technique to estimate low muscle mass for sarcopenia diagnosis. However, muscularity assessment from BIA relies on prediction equations, estimating different compartments according to the calibration method. Low muscle mass can be defined using different approaches. RECENT FINDINGS: There is a lack of standardization on how low muscularity is defined in the context of sarcopenia. Recent studies have shown discrepant results for the estimation of low muscle mass when different prediction equations are used in the same BIA device. Different sarcopenia prevalence rates are observed if different definitions are used to identify low muscle mass. Most of the studies using BIA for diagnosing sarcopenia use the incorrect combination of specific population cut-off or a different device from the original equation. SUMMARY: The lack of standardization of BIA use for assessing muscularity results in a wide range of sarcopenia prevalence rates among studies, even when conducted in the same population. As BIA equations and cut-off values are population and device-specific, results should be interpreted with caution when data from different devices are applied in equations or using cut-off values from a different population.

Falls among older adults in the South of Brazil: prevalence and determinants.

OBJECTIVE Evaluate the prevalence and the factors associated with the occurrence of falls among older adults. METHODS A cross-sectional study with a representative sample of 1,451 elderly residents in the urban area of Pelotas, RS, in 2014. A descriptive analysis of the data was performed and the prevalence of falls in the last year was presented. The analysis of demographic, socioeconomic, behavioral and health factors associated with the outcome was performed using Poisson regression with adjustment for robust variance according to the hierarchical model. The variables were adjusted to each other within each level and for the higher level. Those with p ≤ 0.20 were maintained in the model for confounding control and those with p < 0.05 were considered to be associated with the outcome. RESULTS The prevalence of falls among older adults in the last year was 28.1% (95%CI 25.9-30.5), and most occurred in the person's own residence. Among the older adults who fell, 51.5% (95%CI 46.6-56.4) had a single fall and 12.1% (95%CI 8.9-15.3) had a fracture as a consequence, usually in the lower limbs. The prevalence of falls was higher in women, adults of advanced age, with lower income and schooling level, with functional incapacity for instrumental activities, and patients with diseases such as diabetes, heart disease, and arthritis. CONCLUSIONS The occurrence of falls reached almost a third of the older adults, and the prevalence was higher in specific segments of the population in question. About 12% of the older adults who fell fractured some bone. The factors associated with the occurrence of falls identified in this study may guide measures aimed at prevention in the older adult population.

Falls among older adults in the South of Brazil: prevalence and determinants / Quedas em idosos no Sul do Brasil: prevalência e determinantes

ABSTRACT OBJECTIVE Evaluate the prevalence and the factors associated with the occurrence of falls among older adults. METHODS A cross-sectional study with a representative sample of 1,451 elderly residents in the urban area of Pelotas, RS, in 2014. A descriptive analysis of the data was performed and the prevalence of falls in the last year was presented. The analysis of demographic, socioeconomic, behavioral and health factors associated with the outcome was performed using Poisson regression with adjustment for robust variance according to the hierarchical model. The variables were adjusted to each other within each level and for the higher level. Those with p ≤ 0.20 were maintained in the model for confounding control and those with p < 0.05 were considered to be associated with the outcome. RESULTS The prevalence of falls among older adults in the last year was 28.1% (95%CI 25.9-30.5), and most occurred in the person's own residence. Among the older adults who fell, 51.5% (95%CI 46.6-56.4) had a single fall and 12.1% (95%CI 8.9-15.3) had a fracture as a consequence, usually in the lower limbs. The prevalence of falls was higher in women, adults of advanced age, with lower income and schooling level, with functional incapacity for instrumental activities, and patients with diseases such as diabetes, heart disease, and arthritis. CONCLUSIONS The occurrence of falls reached almost a third of the older adults, and the prevalence was higher in specific segments of the population in question. About 12% of the older adults who fell fractured some bone. The factors associated with the occurrence of falls identified in this study may guide measures aimed at prevention in the older adult population.

RESUMO OBJETIVO Avaliar a prevalência e os fatores associados à ocorrência de quedas em idosos. MÉTODOS Estudo transversal com amostra representativa de 1.451 idosos residentes na zona urbana de Pelotas, RS, em 2014. Foi realizada análise descritiva dos dados e apresentada a prevalência de quedas no último ano. A análise de fatores demográficos, socioeconômicos, comportamentais e de saúde associados ao desfecho foi realizada por meio de regressão de Poisson com ajuste para variância robusta conforme modelo hierárquico. As variáveis foram ajustadas entre si dentro de cada nível e para as de nível superior. Aquelas com p ≤ 0,20 foram mantidas no modelo para controle de confusão e aquelas com p < 0,05 foram consideradas associadas ao desfecho. RESULTADOS A prevalência de quedas em idosos no último ano foi de 28,1% (IC95% 25,9-30,5), e a maioria ocorreu na própria residência do idoso. Entre os idosos que sofreram queda, 51,5% (IC95% 46,6-56,4) tiveram uma única queda e 12,1% (IC95% 8,9-15,3) tiveram fratura como consequência, sendo a de membros inferiores a mais relatada. A prevalência de quedas foi maior em mulheres, idosos com idade avançada, de menor renda e escolaridade, com incapacidade funcional para atividades instrumentais e portadores de enfermidades como diabetes, doença cardíaca e artrite. CONCLUSÕES A ocorrência de quedas atingiu quase um terço dos idosos, e a prevalência foi mais elevada em segmentos específicos da população em questão. Cerca de 12% dos idosos que caíram, fraturaram algum osso. Os fatores associados à ocorrência de quedas identificados neste estudo poderão nortear medidas que visem sua prevenção na população de idosos.