Increased Body Fat Percentage Research Articles

Body surface temperature distribution in relation to body composition in obese women

Adipose tissue levels and human obesity are known to be associated with increased heat production. At the same time, subcutaneous adipose tissue provides an insulating layer that impedes heat loss. The energy implications of obesity and body thermoregulatory mechanisms remain relatively poorly understood. This study attempted to examine the potential relationship between body composition (subcutaneous and visceral fat) determined by bioimpedance as well as BMI (body mass index), and skin surface temperature distribution recorded at rest.One specific aim of this study was to draw a thermal map of body areas in obese women and compare this with women of normal body mass, and thus to identify body regions within which heat transfer is particularly impeded. As high fat content is a good insulator, it could reduce the body‘s ability to respond effectively to changes in environmental temperature, which would be problematic for thermal homeostasis. Our results showed that core temperature did not differ between obese and normal body mass participants, while skin temperature of most body surfaces was lower in obese subjects.The results of regression analysis showed that the mean body surface temperature (Tmean) decreased with increasing percentage of body fat (PBF) of the abdominal area. The opposite relationship was observed for the front area of the hand (simultaneous increase in Tmean and PBF). We also found a negative correlation between BMI and Tmean of the thigh areas, both the front and the back. From this it could be concluded that the mean body surface temperature is dependent on body fat.

Changes in body weight and markers of health following short‐term vacations (811.14)

Longitudinal studies among U.S. adults show that average weight gain is 1kg per year. Recent studies have shown that short periods of time, such as the holiday season, can account for a significant portion of the average yearly weight gain. Objective: (1) to determine if a 1‐3 week vacation will alter body weight and chronic disease risk factors, and (2) to determine if any changes in weight or chronic disease risk factors persist 6 weeks after the vacation. Methods: Seventy‐three adults (31 males, 42 females; age 34±13.6 years) we went on a vacation lasting 1‐3 weeks were recruited. Baseline measurements (visit 1) within 1 week of vacation included height, weight, body composition, waist and hip circumference, and blood pressure. Subjects also completed the International Physical Activity Questionnaire and the Perceived Stress scale. All baseline measurements were repeated within 1 week after the vacation (visit 2) and again 5 weeks after visit 2 (visit 3). Results: There was a significant increase in body weight from visit 1 to visit 2 (76.3±1.9kg to 78.6±2.1kg, p<0.05); however, body weight returned to baseline by visit 3 (76.6±1.8kg). There was a trend for an increase in body fat percentage from visit 1 to visit 2 (25.9±1.0% to 26.4±0.9%, p=0.10) which persisted at visit 3 (26.3±0.8%). No changes in waist or hip circumference or blood pressure were found. Physical activity was highest prior to vacations, trended for a decrease at visit 2 (p=0.09), and had significantly decreased by visit 3 (p=0.02). Finally, perceived stress was highest prior to the vacation but had decreased by visit 3 (p<0.01). Conclusions: Short‐term vacations resulted in significant weight gain (2.3±1.3kg) and decreased physical activity. Body weight returned to baseline levels by 6 weeks post‐vacation. No other changes in health markers were found.

Abstract P174: Increased Cardiovascular Disease Risk Factors in Young Hispanic Women at the High-end of Normal-weight Body Mass Index

BMI is often used to assess risk of cardiovascular disease (CVD); however, current BMI cutpoints may not be accurate for all ethnicities. Given the high prevalence of obesity and type 2 diabetes in Hispanics, it is important to examine whether current BMI cutpoints accurately identify those at healthy weight and those at risk. We examined whether there was a difference in CVD risk factors within the normal-weight BMI category in young, Hispanic women. We hypothesized that women in the highest tertile of normal-weight would have significantly more CVD risk factors than those in the lowest tertile of normal-weight. Sixty nine normal-weight Hispanic women (20-39 y) were divided into tertiles of normal-weight BMI: 18.5-20.9 kg/m2 (NW low, n=17), 21.0-22.9 kg/m2 (NW mid, n=31) and 23.0-24.9 kg/m2 (NW high, n=21). CVD risk factors measured included waist circumference, blood pressure and fasting glucose, triglycerides and high-density and low-density lipoprotein. Glucose tolerance was measured by a 2h oral glucose tolerance test. Body composition was measured by dual-energy x-ray absorptiometry. Intra-abdominal adipose tissue, an estimate of visceral adiposity, was calculated. Data were analyzed using multivariate ANOVA, with Levine’s test indicating homogeneity of variances among groups, and Kruskal-Wallace test. Post hoc tests included Bonferroni and Mann Whitney. Results indicated the prevalence of women who were risk factor free was 65%, 39% and 24% for NW low, mid and high, respectively. The prevalence of women with one or more CVD risk factors was 35%, 61%, and 76% for NW low, mid and high, respectively. The prevalence of women with two or more CVD risk factors was 0%, 3%, and 29% for NW low, mid and high, respectively. The prevalence of women with three or more CVD risk factors was 0%, 0% and 10% for NW low, mid and high, respectively. Overall the prevalence of CVD risk factors was significantly higher in NW high than NW low (p=0.006) and NW mod (p=0.04) and approached significance between NW mid and NW low (p=0.08). There was a significant increase in percentage body fat (27.6±5.1%, 30.7±4.6%, 36.9±4.6%, respectively), intra-abdominal adipose tissue (24.2±7.9 cm2, 45.6±12.2 cm2, 66.5±19.7 cm2, respectively), and waist circumference (71.2±3.1 cm, 76.6±4.8 cm, 81.0±5.8 cm, respectively) from NW low to NW high (p<0,001). NW high had significantly higher triglyceride levels than NW low (86.4±40.0 mg/dL vs. 58.9±20.6 mg/dL, p=0.04) and significantly higher 2h glucose levels than NW mid (120.0±27.9 mg/dL vs. 99.1±17.3 mg/dL, p=0.003). In conclusion, young, Hispanic women at the upper-end of the normal-weight BMI range had a significantly higher prevalence of CVD risk factors, body fat and central obesity than women in the mid and lower end of normal-weight BMI range. These findings suggest that the normal-weight BMI cutpoint may need to be adjusted for Hispanic women.

Relationship between changes in body fat and a decline of renal function in the elderly.

Obesity is a risk factor for chronic kidney disease, and its prevalence among the elderly is increasing. We investigated the effects of changes in body fat percentage (BFP) on the longitudinal changes in the estimated glomerular filtration rate (eGFR) in the elderly. This prospective cohort study included 390 participants aged >65 years who underwent bioelectrical impedance analysis at baseline and follow-up as a part of the Korean Longitudinal Study on Health and Aging. After a median follow-up period of 5.3 years, BFP was significantly higher than that at the start point (P<0.05). Participants who had the largest increase in BFP had the highest BMI and waist circumference (WC) (P<0.001). The highest tertile had the highest white blood cell count and erythrocyte sedimentation rate, incidence of rapid progression, and decline in eGFR >25% (P≤0.017, P = 0.025, P = 0.005, respectively). The lowest tertile had the lowest triglyceride and highest high-density lipoprotein levels (P<0.05). The adjusted decline rate in eGFR was correlated with a change in BFP (P = 0.039), but not with that in BMI or WC. The highest tertile had a 4.875-fold increase in the risk for rapid progression to a decline in eGFR (95% CI: 1.366–17.397) and a 4.931-fold decrease in the risk to a decline in eGFR>25% (95% CI: 1.617–15.037), when compared with the lowest tertile. In subgroup analysis, the incidence of renal outcomes was significantly increased according to the increase in BFP in patients with lower eGFR (P≤0.010). A change in BFP may be associated with inflammation and dyslipidemia development, and longitudinal changes in body fat are related to a decrease in eGFR in the elderly.

PGC1α -1 Nucleosome Position and Splice Variant Expression and Cardiovascular Disease Risk in Overweight and Obese Individuals.

PGC1α, a transcriptional coactivator, interacts with PPARs and others to regulate skeletal muscle metabolism. PGC1α undergoes splicing to produce several mRNA variants, with the NTPGC1α variant having a similar biological function to the full length PGC1α (FLPGC1α). CVD is associated with obesity and T2D and a lower percentage of type 1 oxidative fibers and impaired mitochondrial function in skeletal muscle, characteristics determined by PGC1α expression. PGC1α expression is epigenetically regulated in skeletal muscle to determine mitochondrial adaptations, and epigenetic modifications may regulate mRNA splicing. We report in this paper that skeletal muscle PGC1α −1 nucleosome (−1N) position is associated with splice variant NTPGC1α but not FLPGC1α expression. Division of participants based on the −1N position revealed that those individuals with a −1N phased further upstream from the transcriptional start site (UP) expressed lower levels of NTPGC1α than those with the −1N more proximal to TSS (DN). UP showed an increase in body fat percentage and serum total and LDL cholesterol. These findings suggest that the −1N may be a potential epigenetic regulator of NTPGC1α splice variant expression, and −1N position and NTPGC1α variant expression in skeletal muscle are linked to CVD risk. This trial is registered with clinicaltrials.gov, identifier NCT00458133.

Mice Deficient in Sfrp1 Exhibit Increased Adiposity, Dysregulated Glucose Metabolism, and Enhanced Macrophage Infiltration

The molecular mechanisms involved in the development of obesity and related complications remain unclear. Wnt signaling plays an important role in preadipocyte differentiation and adipogenesis. The expression of a Wnt antagonist, secreted frizzled related protein 1 (SFRP1), is increased in response to initial weight gain, then levels are reduced under conditions of extreme obesity in both humans and animals. Here we report that loss of Sfrp1 exacerbates weight gain, glucose homeostasis and inflammation in mice in response to diet induced obesity (DIO). Sfrp1-/- mice fed a high fat diet (HFD) exhibited an increase in body mass accompanied by increases in body fat percentage, visceral white adipose tissue (WAT) mass, and adipocyte size. Moreover, Sfrp1 deficiency increases the mRNA levels of key de novo lipid synthesis genes (Fasn, Acaca, Acly, Elovl, Scd1) and the transcription factors that regulate their expression (Lxr-α, Srebp1, Chreb, and Nr1h3) in WAT. Fasting glucose levels are elevated, glucose clearance is impaired, hepatic gluconeogenesis regulators are aberrantly upregulated (G6pc and Pck1), and glucose transporters are repressed (Slc2a2 and Slc2a4) in Sfrp1-/- mice fed a HFD. Additionally, we observed increased steatosis in the livers of Sfrp1-/- mice. When there is an expansion of adipose tissue there is a sustained inflammatory response accompanied by adipokine dysregulation, which leads to chronic subclinical inflammation. Thus, we assessed the inflammatory state of different tissues and revealed that Sfrp1-/- mice fed a HFD exhibited increased macrophage infiltration and expression of pro-inflammatory markers including IL-6, Nmnat, Tgf-β2, and SerpinE1. Our findings demonstrate that the expression of Sfrp1 is a critical factor required for maintaining appropriate cellular signaling in response to the onset of obesity.

Orexin Restores Aging-Related Brown Adipose Tissue Dysfunction in Male Mice

The aging process causes an increase in percent body fat, but the mechanism remains unclear. In the present study we examined the impact of aging on brown adipose tissue (BAT) thermogenic activity as potential cause for the increase in adiposity. We show that aging is associated with interscapular BAT morphologic abnormalities and thermogenic dysfunction. In vitro experiments revealed that brown adipocyte differentiation is defective in aged mice. Interscapular brown tissue in aged mice is progressively populated by adipocytes bearing white morphologic characteristics. Aged mice fail to mobilize intracellular fuel reserves from brown adipocytes and exhibit deficiency in homeothermy. Our results suggest a role for orexin (OX) signaling in the regulation of thermogenesis during aging. Brown fat dysfunction and age-related assimilation of fat mass were accelerated in mice in which OX-producing neurons were ablated. Conversely, OX injections in old mice increased multilocular morphology, increased core body temperature, improved cold tolerance, and reduced adiposity. These results argue that BAT can be targeted for interventions to reverse age-associated increase in fat mass.

Longitudinal Changes in the Physical Activity of Adolescents with Anorexia Nervosa and Their Influence on Body Composition and Leptin Serum Levels after Recovery

ObjectivePatients with anorexia nervosa (AN) are often observed to have high levels of physical activity, which do not necessarily diminish after a successful therapy. Previous studies have shown that body fat tissue recovery in these patients is associated with a disproportional restoration of the adipocyte hormone, leptin. Therefore, we wondered whether the individual variation in physical activity in AN patients prior to treatment may be related to body fat percentage and plasma leptin level outcome.MethodBody fat percentage, leptin serum, and physical activity levels (accelerometer) were measured in adolescents with an (n=37, age 13 to 17.5 years) at initial assessment, at the end of study participation (median 12 months), and at one-year follow-up.ResultsAccelerometer data were used to split the patients in two groups: those with low (n=26) and those with high levels of physical activity (HLPA, n=11). These groups did not differ in terms of age, IQ, presence of menses, BMI and season of admission. The HLPA group was characterized by a longer total duration of illness. Physical activity levels during therapy decreased for the group with initially HLPA and increased for the group with low levels of physical activity (to comparable levels). Physical activity remained stable after one year. The increase in body fat percentage and leptin levels were dependent on the recovery status; however, recovered patients with initially HLPA had significantly higher fat mass during the follow-up.DiscussionHLPA, an important modulator of AN progression in adolescents, can be successfully diminished by therapeutic intervention. Among recovered patients, those with initially HLPA had higher fat mass levels than those with low levels of physical activity. This finding suggests that HLPA are an important modulator of the body composition recovery mechanism.

Short Duration of Sleep Is Associated with Hyperleptinemia in Taiwanese Adults

Higher plasma levels of leptin have been associated with increased cardiometabolic risk. The aim of this study was to investigate the association between short duration of sleep and hyperleptinemia in Taiwanese adults. We examined the association between duration of sleep and hyperleptinemia in 254 men and women recruited from the physical examination center at a regional hospital in southern Taiwan. Hyperleptinemia was defined as a plasma leptin level of 8.13 ng/mL and above. Short sleep duration was defined as < 6.5 h/day. Multiple logistic regression analysis was used to assess the association between short duration of sleep and hyperleptinemia. In females, short duration of sleep (< 6.5 h/day; OR = 2.15, 95% CI = 0.99-4.78), greater hip circumference (OR = 3.00, CI = 1.13-8.78), higher percent body fat (OR = 1.75, CI = 1.07-2.95), and higher white blood cell counts (OR = 1.67, CI = 1.26-2.28) were associated with an increased risk of hyperleptinemia. In males, greater body weight was significantly associated with an increased risk of hyperleptinemia (OR = 3.55, 95% CI = 1.46-10.23). There was also a trend of association (p = 0.096) between short duration of sleep and an increased risk of hyperleptinemia (OR = 4.98, 95% CI = 0.80-42.40). In this study of healthy Taiwanese adults, short duration of sleep was significantly associated with hyperleptinemia in women, and the association was independent of adiposity.

Carbohydrate nutrition and development of adiposity during adolescence

To examine the prospective association between glycemic index, glycemic load (GL) of diets and intakes of carbohydrates, sugars, fiber, and the main carbohydrate containing food groups (e.g., soft drinks) with changes in percent body fat, body mass index (BMI), and waist circumference among adolescents. Students aged 12 at baseline (n = 856) were examined both in 2004-2005 and 2009-2011. A semiquantitative food frequency questionnaire was administered. Anthropometric parameters were measured and defined using standardized protocols. After multivariable adjustment, in girls, each 1-SD increase in dietary GL was associated with concurrent 0.77 kg/m2 and 1.45 cm increase in BMI and waist circumference, respectively (both P = 0.01). Conversely, each 1-SD increase in dietary fiber intake was associated with a concurrent 0.44 kg/m2 decrease in mean BMI in girls (P = 0.02) and 1.45 cm decrease in waist circumference in boys (P = 0.002). Girls who consumed soft drinks once or more per day versus those who never/rarely consumed soft drinks, had a 4.45% increase in percent body fat after 5 years (Ptrend = 0.01). High-GL foods might adversely influence development of body composition, particularly in girls, whereas fiber-rich diets could limit excess weight during adolescence.

AB0834-HPR Health-related physical fitness testing in physiotherapy practice – reference values

BackgroundPeople with musculoskeletal conditions (MSCs) tend to be less physically active1 and more deconditioned than healthy controls2. Recommendations for management of MSCs emphasize exercise as an important part of the...

AB0833-HPR Health-related physical fitness testing in physiotherapy practice – reliability and feasibility

BackgroundPeople with musculoskeletal conditions (MSCs) tend to be less physically active1 and more deconditioned than healthy controls2;3. Thus, physiotherapists seeing patients with MSCs should include an individually tailored exercise program...

FRI0598-HPR Patients with musculoskeletal complaints do less vigorous physical activity and have poorer physical fitness than population controls

BackgroundStudies have shown that patients with chronic low back pain and osteoarthritis tend to be less physically active1 or have lower level of physical fitness than healthy controls2;3. It is...

Association of bilateral oophorectomy and body fatness in a representative sample of US women

ObjectivePreclinical studies suggest that abrupt hormone deprivation caused by oophorectomy, leads to obesity and its metabolic sequelae. The purpose of the current study was to examine the association between oophorectomy and body fatness in a nationally representative sample of women. MethodsThe association between prior oophorectomy and nine adiposity measures was examined using data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988–1994). The analytic population included cancer-free women age 40 or older (N=3549) who underwent standardized body measurements and reported on whether or not they had a bilateral oophorectomy. Multivariate linear and polytomous logistic regressions were used to evaluate the association of oophorectomy with multiple measures of adiposity. ResultsMean percent body fat, skinfold thickness, waist circumference and body mass index were significantly higher in women with oophorectomy before age 40 compared to those with intact ovaries, but no difference was observed in women with oophorectomy at an older age. Women who underwent an early oophorectomy were nearly three times more likely than women with intact ovaries to have percent body fat in the highest tertile compared to the lowest tertile (OR=2.82, 95% CI 1.39–5.75). Excluding hormone therapy (HT) users yielded stronger associations. ConclusionBilateral oophorectomy in young women is strongly associated with an increase in percent body fat, a well-established risk factor for cancer and other chronic diseases. Measuring body fat in addition to BMI may provide a more comprehensive assessment of adiposity in these women.

Recommended IGF-I Dosage Causes Greater Fat Accumulation and Osseous Maturation Than Lower Dosage and May Compromise Long-term Growth Effects

The maximum dose of IGF-I recommended for treatment of GH insensitivity is commonly used. The aim was to test the hypothesis that a lower dose is as effective as a high dose of IGF-I in growth promotion and has fewer deleterious effects. Subjects were treated for 3 years with regular examinations including bone age and dual energy x-ray absorptiometry and for 1 year with abdominal ultrasound studies at a clinical research institute in Quito, Ecuador. The study included 21 subjects ages 3.2-15.9 years with GH insensitivity due to the same splice site mutation on the GH receptor gene. Subjects were allocated to receive 120 (n = 14) or 80 (n = 7) μg/kg IGF-I twice daily. Height velocity, osseous maturation, height SD scores (SDS), body composition, abdominal organ growth, and side effects were assessed. There were no differences in growth velocity or height SDS increment by dosage, and the SDS increase was greater than in other reported series. Osseous maturation over 3 years with the high dose was nearly twice as rapid as with the lower dose (P < .001) and correlated with an increase in percentage body fat (r = .64; P < .001) and with adrenal size increase over 1 year (r = .32; P = .03). The ratio of bone age to height age was lower in the high-dose group after 3 years of treatment (P = .007). The commonly used IGF-I dosage of 120 μg/kg twice a day is excessive in comparison to a dose of 80 μg/kg twice a day, disproportionately accelerating osseous maturation, probably from the combined effects of obesity and inappropriate adrenal growth, thus likely compromising adult height potential. Moreover, the lower dose decreases direct treatment cost by one-third.

Fast-Food Restaurant Advertising on Television and its Influence on Youth Body Composition

We examine the effects of fast-food restaurant advertising on television on the body composition of adolescents as measured by percentage body fat (PBF) and to assess the sensitivity of these effects to using conventional measures of youth obesity based on body-mass index (BMI). We merge measures of body composition from bioelectrical-impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA) from the National Health and Nutrition Examination Survey with individual level data from the National Longitudinal Survey of Youth 1997 and data on local fast-food restaurant advertising on television from Competitive Media Reporting.Exposure to fast-food restaurant advertising on television causes statistically significant increases in PBF in adolescents. These results are consistent with those obtained by using BMI-based measures of obesity. The responsiveness to fast-food advertising is greater for PBF than for BMI. Males are more responsive to advertising than females regardless of the measure. A complete advertising ban on fast-food restaurants on television would reduce BMI by 2 percent and PBF by 3 percent. The elimination of the tax deductibility of food advertising costs would still leave a considerable number of youth exposed to fast-food advertising on television but would still result in non-trivial reductions in obesity.

Type 2 Diabetes Risk among Asian Indians in the US: A Pilot Study

The purpose of this pilot study was to investigate type 2 diabetes risk among Asian Indians of Kerala ethnicity living in a West Texas County of the USA. The study used a descriptive correlational design with thirty-seven adult nondiabetic Asian Indian subjects between 20 and 70 years of age. The measurement included nonbiochemical indices of obesity, family history of type 2 diabetes, length of immigration in the US, history of hypertension, physical activity pattern, and fruit and vegetable intake. The majority of the subjects showed an increased nonbiochemical indices corresponding with overweight and obesity, placing them at risk for type 2 diabetes and associated cardiovascular complications. The physical activity pattern indicated a sedentary lifestyle. The decreased physical activity was associated with a higher Body Mass Index (BMI) and body fat percentage; length of residence in the US greater than 10 years was associated with increased body fat percentage and BMI; family history of type 2 diabetes was associated with an increase in body fat percentage. Fruit and vegetable intake pattern was not associated with a risk for type 2 diabetes. Further studies are recommended for risk surveillance among Asian Indian population living in the US.

Effects of a mat Pilates programme on body composition in elderly women.

With ageing, the ability to mobilize fat is reduced and this, coupled with gradual decrease in lean body mass (LBM) from lessened exercise, allows for an increased body fat percentage (%BF). Exercising is considered a key to maintaining an appropriate body mass (BM), as it improves fat oxidation, while maintaining LBM. Although the effects of endurance and/or resistance training on fat mass (FM) and LBM in the elderly have well been established, limited data are forthcoming regarding the effects of Pilates as a training modality on these variables in the elderly. The present study was therefore conducted to determine the effects of a mat Pilates programme on body fat in elderly women. Fifty sedentary, apparently healthy females aged 60 years and older were randomly assigned a control (CG, n = 25) or an intervention (IG, n = 25) group. The IG took part in an eight-week progressive mat Pilates exercise programme, three times weekly while the CG were instructed to maintain their normal daily activities throughout the eight-week experimental period. All subjects underwent pre- and post-test in which FM and LBM were assessed. Eight weeks of mat Pilates demonstrated a significant (p ≤ 0.05) decrease in % BF (p = 0.016) and FM (p = 0.038), with a significant increase in LBM (p = 0.006), while not showing any significant changes (p ≥ 0.05) in BM (p = 0.979) and BMI (p = 0.992). The CG, however, did not produce any significant (p ≥ 0.05) changes in any of the tested anthropometric variables (BM: p = 0.266; BMI: p = 0.123; % BF: p = 0.516; FM: p = 0.937 and LBM: p = 0.522) after completion of the eight-week Pilates programme. An eight-week mat Pilates exercise programme may contradict or even reverse some of the most serious consequences of ageing associated with an increased fat mass and reduced lean body mass in elderly females.

Testosterone is associated with age-related changes in bone health status, muscle strength and body composition in men

Objective: Variations in testosterone levels are associated with several outcomes of aging. The present study aimed to examine the relationship between age-related decline of testosterone levels and changes in bone health status, handgrip strength, body fat percentage and fat-free mass. Materials and methods: A total of 335 Malaysian Chinese and Malay men aged 40 years and above were recruited for this study. Their body compositions, calcaneal speed of sound and handgrip strength were measured and their blood was collected. Linear regression analysis was done to examine the relationship among age, testosterone levels and outcomes of aging. Results: The results indicated significant changes in all testosterone measurements, sex hormone binding globulin level, calcaneal speed of sound, handgrip strength, body fat percentage and fat-free mass with age (p < 0.05). Age-dependent decline in bioavailable and free testosterone levels were significantly associated with reduction in calcaneal speed of sound, fat-free mass and handgrip strength (p < 0.05). Age-dependent decline in the total testosterone level was significantly associated with an increase in body fat percentage among the elderly men (p < 0.05). Conclusion: Testosterone levels are associated with changes in outcome of aging such as bone health status, muscle strength and body composition, and the relationships are age-dependent.

Relationship of sex steroid hormones with body size and with body composition measured by dual-energy X-ray absorptiometry in US men

To evaluate the association of body size-captured via whole-body dual-energy X-ray absorptiometry (DXA) and physical measurement-with serum sex steroid hormones and sex hormone binding globulin (SHBG), we utilized cross-sectional data and serum samples from the National Health and Nutrition Examination Survey (NHANES; 1999-2004). Testosterone, androstanediol glucuronide (3-alpha-diol-G), estradiol, and SHBG were measured via immunoassay in serum samples from a total of 898 adult men (ages 20-90) participating in the morning examination. As part of the NHANES data collection, DXA scans and measurements of weight, height, and waist circumference were performed by trained staff. Linear regression was used to estimate associations between body size and hormone levels adjusted for potential confounders and NHANES sampling procedures. Total bone area (cm(2)) was inversely associated with total testosterone (ng/mL) [beta = -0.12; p value < 0.01], while bone mineral density (g/cm(2)) was inversely associated with SHBG (nmol/L) [beta = -17.16; p value = 0.01]. Increased percent body fat was associated with lower concentrations of total testosterone [beta = -0.16; p value < 0.01] and SHBG [beta = -1.11; p value < 0.01] and higher concentrations of free estradiol (fg/mL) [beta = 12.52; p value < 0.01]. Clinical measures of body fat (measured via DXA scan) and anthropometric measures of body fat (BMI and waist circumference) provided similar inferences regarding the association between increased body fat and hormone levels in men. Increased body fat was associated with lower circulating levels of testosterone (total and free) and SHBG and higher circulating levels of free estradiol in men, while decreased bone mineral density was associated with higher circulating levels of SHBG.