Skeletal Muscle Mass Indices in Healthy Young Mexican Adults Aged 20–40 Years: Implications for Diagnoses of Sarcopenia in the Elderly Population

Background and Objectives. Skeletal muscle and skeletal muscle indices in young adults from developing countries are sparse. Indices and the corresponding cut-off points can be a reference for diagnoses of sarcopenia. This study assessed skeletal muscle using dual-energy X-ray absorptiometry (DXA) in healthy male and female subjects aged 20–40 years and compared their appendicular skeletal muscle mass (ASM) and total-body skeletal muscle (TBSM) indices using certain cut-off points published in the literature. Methods. A sample of 216 healthy adults men and women from northwest Mexico was included. Body composition was assessed by DXA and several published DXA-derived skeletal muscle indices were compared. Results. Both, ASM and TBSM were higher in men compared to the women group (23.0 ± 3.4 versus 15.9 ± 1.6 kg; P<0.05 and 26.5 ± 4.1 versus 16.9 ± 1.9 kg; P<0.05, resp.). These differences were also valid for both indices. When derived cut-off points were compared with the most reported indices, significant differences were found. Interpretation and Conclusion. Published cut-off points from Caucasians are higher than cut-off point derived in this sample of Mexican subjects. The new DXA-derived cut-off points for ASM proposed herein may improve diagnoses of sarcopenia in the geriatric Mexican population

Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults

<p>Abstract</p> <p>Background</p> <p>The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women.</p> <p>Methods</p> <p>This study included 155 male and female subjects from northern Mexico, 20–50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM).</p> <p>Results and Discussion</p> <p>The final model was: FFM (kg) = 0.7374 * (Ht²/R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R²was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 ± 10.9 kg) and that measured by ADP (48.43 ± 11.3 kg). The new equation did not differ from the line of identity, had a high R²and a low SRMSE, and showed no significant bias (0.87 ± 2.84 kg).</p> <p>Conclusion</p> <p>The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample.</p

Greater male variability in daily energy expenditure develops through puberty

The authors also gratefully acknowledge funding from the Chinese Academy of Sciences (grant no. CAS153E11KYSB20190045) to J.R.S. and the US National Science Foundation (grant no. BCS-1824466) awarded to H.P. Acknowledgements Yvonne Schönbeck provided important information about morphometric measurements for Dutch children. A chat over dinner with Karsten Koehler, Eimear Dolan and Danny Longman brought up a number of thoughts that influenced this manuscript. The DLW database, which can be found at https://doublylabelled-waterdatabase.iaea.org/home, is hosted by the IAEA and generously supported by Taiyo Nippon Sanso and SERCON. We are grateful to the IAEA and these companies for their support and especially to Takashi Oono for his tremendous efforts at fundraising on our behalf.Peer reviewedPublisher PD

Greater male variability in daily energy expenditure develops through puberty

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decrease in the degree of GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages

Greater male variability in daily energy expenditure develops through puberty

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decrease in the degree of GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages

Nutrient-rich dairy proteins improve appendicular skeletal muscle mass and physical performance, and attenuate the loss of muscle strength in older men and women subjects: a single-blind randomized clinical trial

Heliodoro Alem&aacute;n-Mateo,1 Virginia Ram&iacute;rez Carre&oacute;n,1 Liliana Mac&iacute;as,1 Humberto Astiazaran-Garc&iacute;a,1 Ana Cristina Gallegos-Aguilar,1 Jos&eacute; Rogelio Ramos Enr&iacute;quez2 1Coordinaci&oacute;n de Nutrici&oacute;n, Centro de Investigaci&oacute;n en Alimentaci&oacute;n y Desarrollo, A.C., 2Laboratorio de An&aacute;lisis Cl&iacute;nicos e Investigaci&oacute;n, Departamento de Ciencias Qu&iacute;mico Biol&oacute;gicas, Universidad de Sonora, Hermosillo, Mexico Background: At present, it is unknown whether the use of nutrient-rich dairy proteins improves the markers of sarcopenia syndrome. Therefore, our proposal was to investigate whether &shy;adding 210 g of ricotta cheese daily would improve skeletal muscle mass, handgrip strength, and &shy;physical performance in non-sarcopenic older subjects.Subjects and methods: This was a single-blind randomized clinical trial that included two homogeneous, randomized groups of men and women over 60 years of age. Participants in the intervention group were asked to consume their habitual diet but add 210 g of ricotta cheese (IG/HD + RCH), while the control group was instructed to consume only their habitual diet (CG/HD). Basal and 12-week follow-up measurements included appendicular skeletal muscle mass (ASMM) by dual-energy X-ray absorptiometry, handgrip strength by a handheld dynamometer, and physical performance using the short physical performance battery (SPPB) and the stair-climb power test (SCPT). The main outcomes were relative changes in ASMM, strength, SPPB, and SCPT.Results: ASMM increased in the IG/HD + RCH (0.6&plusmn;3.5 kg), but decreased in the CG/HD (&ndash;1.0&plusmn;2.6). The relative change between groups was statistically significant (P=0.009). The relative change in strength in both groups was negative, but the loss of muscle strength was more pronounced in CG/HD, though in this regard statistical analysis found only a tendency (P=0.07). The relative change in the balance-test scores was positive for the IG/HD + RCH, while in the CG/HD it was negative, as those individuals had poorer balance. In this case, the relative change between groups did reach statistical significance.Conclusion: The addition of 210 g of ricotta cheese improves ASMM and balance-test scores, while attenuating the loss of muscle strength. These results suggest that adding ricotta cheese to the habitual diet is a promising dietetic strategy that may improve the markers of sarcopenia in subjects without a pronounced loss of ASMM or sarcopenia. Keywords: nutritional intervention, nutrient-rich dairy proteins, ricotta cheese, markers of sarcopenia, elderl