Lean Mass In Women Research Articles

Prevalence of Sarcopenia Based on Different Diagnostic Criteria Using DEXA and Appendicular Skeletal Muscle Mass Reference Values in an Italian Population Aged 20 to 80

To identify the mean values and percentiles for ASMM (appendicular skeletal muscle mass) and the prevalence of sarcopenia, in terms of muscle mass reduction, using different cutoffs in a European population. A retrospective analysis on the dataset from a multicenter study on apparently healthy Italian adults conducted between 1999 and 2002. A significant muscle mass loss, necessary to diagnose sarcopenia, was defined in 3 different ways: (1) by subtracting 2 SDs from the mean ASMM index (ASMMI) of a young adult population (20-39 year-olds), as in the Rosetta study and the NHANES survey; (2) by calculating the 15th percentile of the distribution of our young population, corresponding to about 1 SD below the mean ASMMI; (3) by calculating the 20th percentile of the distribution of the ASMMI (as in the Health ABC study) of an elderly population. Five centers for the diagnosis and treatment of osteoporosis in various parts of the country (Padova, Verona, Parma, Roma, Napoli). Participants were 1535 volunteers (1208 women and 327 men) aged 20 to 80 years, drawn from among staff members, university students, lay people contacted by word of mouth, and patients presenting spontaneously for osteoporosis screening. Body weight and height were measured for all participants. Body composition was assessed by DEXA, and the ASMMI was calculated as the ASMM divided by body height in meters squared. Both men's and women's lean mass in the arms and ASMM were highest in the young group and became lower in older age. In men, the ASMMI dropped gradually from age 20 to 29 to age 60 to 69, then remained stable in the oldest group. In women, the ASMMI gradually increased from age 20 to 29 to age 60 to 69, then dropped among the 70- to 80-year-olds. Based on the 15th percentile of the ASMMI for our young adult reference population, the cutoffs for sarcopenia were 7.59 kg/m(2) in men and 5.47 kg/m(2) in women; if the 20th percentile of the ASMMI in our elderly subjects (>65 years) was considered, the cutoffs were 7.64 kg/m(2) in men and 5.78 kg/m(2) in women. Applying the different diagnostic criteria to the those older than 65, the prevalence of sarcopenia ranged from 0% to about 20% in both genders. The 15th percentile (or 1 SD below the mean) of the ASMMI of our young adults, and the 20th percentile of this index for an elderly reference population proved more effective in identifying cases of sarcopenia than subtracting 2 SD from the mean ASMMI of a young adult population.

Association between C-Reactive Protein and Adiposity in Women

The link between C-reactive protein (CRP) and adiposity deserves to be further explored, considering the controversial diabetogenic role of CRP. We explored the potential causal role of CRP on measures of adiposity. We used a Mendelian randomization approach with the CRP and LEPR genes as instrumental variables in a cross-sectional Caucasian population-based study comprising 2526 men and 2836 women. Adiposity was measured using body mass index (BMI), fat and lean mass estimated by bioelectrical impedance, and waist circumference. Log-transformed CRP explained by the rs7553007 single-nucleotide polymorphism tagging the CRP gene was significantly associated with BMI [regression coefficient: 1.22 (0.18; 2.25), P = 0.02] and fat mass [2.67 (0.65; 4.68), P = 0.01] but not with lean mass in women, whereas no association was found in men. Log-transformed CRP explained by the rs1805096 LEPR single-nucleotide polymorphism was also positively associated, although not significantly, with BMI or fat mass. The combined CRP-LEPR instrument explained 2.24 and 0.77% of CRP variance in women and men, respectively. Log-transformed CRP explained by this combined instrument was significantly associated with BMI [0.98 (0.32; 1.63), P = 0.004], fat mass [2.07 (0.79; 3.34), P = 0.001], and waist [2.09 (0.39; 3.78), P = 0.01] in women but not men. Our data suggest that CRP is causally and positively related to BMI in women and that this is mainly due to fat mass. Results on the combined CRP-LEPR instrument suggest that leptin may play a role in the causal association between CRP and adiposity in women. Results in men were not significant.

Androgen Receptor Gene cag and ggn Length Polymorphisms Are Associated With Lean Mass in Women

The androgen-androgen receptors (AR) signalling pathway plays a role in skeletal muscle development and it is necessary for the anabolic effect elicited by androgen stimulation. The AR gene contains a GGN and a CAG repeat polymorphism in exon 1, which length is inversely associated with transcriptional activity of the AR. PURPOSE. The aim of this study was to determine if there is an association between AR CAG and GGN tract polymorphisms repeat length, and lean mass in a cohort of 345 healthy subjects.METHODS. Three-hundred forty five subjects (284 men, 61 women; age: 28.8 ± 7.6; 25.4 ± 6.7 years; height: 176.8 ± 5.5; 165.3 ± 5.8 cm; body mass: 78.1 ± 1; 60.6 ± 7.8 kg, men and women, respectively) agreed to participate in this study. Subjects were genotyped by polymerase chain reaction (PCR) to determine the number of AR CAG and GGN repeats, and grouped as carrying repeat lengths of 21 (i.e. long allele) for males CAG; 22 for females CAG; and 23 for both males and females GGN. Whole body lean mass and the lean mass of the extremities were determined by DXA. Differences in lean mass were determined using ANCOVA with 2 factors gender (male, female) and polymorpism (short, long) with height as covariate. RESULTS. The whole body lean mass was 7% greater in the women with a shorter CAG tract polymorphism (42.5 ± 6.1 vs 39.7 ± 6.1 kg, short and long, respectively, P=0.009). This difference was explained by a greater muscle mass in the extremities of the women with the shorter CAG polymorphisms (17.2 ± 3.4 vs 15.9 ± 3.4 kg, short and long, respectively, P=0.055). Neither GGN nor CAG polymorphism was associated with lean whole body or muscle mass in males.CONCLUSION. Women with a shorter androgen receptor CAG repeat polymorphism (22). Neither GGN nor CAG repeat polymorphisms are associated with muscle mass in healthy males. Supported by a grant from Ministerio de Educación y Ciencia, Spain (DEP2006-56076-C06-04/ACTI).

The Interrelationship between Body Topology and Body Composition Varies with Age among Women

The purpose of this analysis was to evaluate the relationship between age and the size and distribution of the fat and lean tissue compartments in a population-based sample of women. The study population consisted of the 875 women aged 18-94 y in the Iowa Bone Health Study who reported never smoking. Fat mass and lean mass were measured using dual X-ray absorptiometry. Hip and waist circumference and height were measured using standardized protocols. Regression was used to model the associations among age, composition and topology measures. When fat mass was modeled as a function of hip and waist circumference as well as age, age(2) and height, the age x height and age x waist circumference interaction terms remained in the fitted model and collectively accounted for 91% of the variance. In contrast, the quadratic model of age alone accounted for 8% of the observed variance in fat mass. Lean mass was modeled in two segments, with age dichotomized at 58 y. Age alone did not predict lean mass in women <58 y but did predict lean mass in women >/=58 y, with the modeled relationship including interactions with waist circumference and height. These models accounted for 70% of observed variance in lean mass. Age is associated with body composition but explains <10% of variation. When measures of height and circumferences are available, amounts of lean and fat mass are highly predictable. This is particularly important for lean mass because no other surrogate measures exist for lean mass, whereas there are surrogates for fat mass, including body mass index.

Relation of BMI to a dual-energy X-ray absorptiometry measure of fatness.

Dual-energy X-ray absorptiometry (DXA) is a valid technique for measuring the fat, bone and lean (muscle, organs and water) masses of the body. We evaluated relationships of BMI (kg/m2) with independent measurements of fat and lean masses using DXA in 226 adult volunteers. The evaluation was an application of a general approach to compositional data which has not previously been used for describing body composition. Using traditional regression analyses, when lean mass was held constant, BMI varied with fat mass (men r 0.75, P < 0.05; women r 0.85, P < 0.05); when fat mass was held constant, BMI varied with lean mass (men r 0.63, P < 0.05; women r 0.47, P < 0.05). In contrast, a regression model for compositional data revealed that BMI was: (a) strongly associated with log fat mass in both sexes (b1 4.86, P < 0.001 for all women and b1 5.96, P < 0.001 for all men); (b) not associated with bone mass, except in older men; (c) related to lean mass in women but not in men (b3 -4.04, P < 0.001 for all women and b1 -2.59, P < 0.15 for all men). Women with higher BMI tended to have more fat mass and more lean mass than women with lower BMI. Men with higher BMI had more fat mass but similar lean mass to men with lower BMI. Investigators need to be alert to the inaccuracy of BMI to assign a fatness risk factor to individuals, especially among women.