Adjustment For Body Composition Research Articles

#2796 Divergent associations between mortality and different measures of renal function after adjustment for body composition: results from the UK Biobank

Abstract Background and Aims There is data suggesting estimated glomerular filtration rate using Cystatin-C (eGFRCystatin-C) is superior to the creatinine-based (eGFRCreat) method when assessing associations between renal function and mortality (Lees et al. 2019). Given cystatin-C is derived from all nucleated cells and creatinine from skeletal muscle, there remains a need to understand how controlling for multimorbidity, inflammation and estimates of muscle mass will affect the association between mortality and these different measures of renal function. Method An observational study was conducted using the UK Biobank cohort. Adults were recruited between 2007-2010 at 22 UK centres. MM was estimated using bioimpedance defined whole body fat-free mass (BI-FFM: Tanita BC418). The primary outcome was all-cause mortality (ACM—data from NHS Information Centre [England / Wales] and NHS Central Registry [Scotland]). Follow up was defined as the period between the first visit date to either date of death / the latest date for central registry downloads (December 2021). Estimated GFRCreat or eGFRCystatin-C were calculated using the CKD-EPI 2009 equation without ethnicity correction. Albuminuria was defined as a urine albumin / creatinine ratio of >3 mg/mmol. Participants were excluded if they were on dialysis, died from SARS-CoV-2 infection or withdrew consent. Sequences of regressions analyses (SoRA), a graphical Markov modelling technique which assesses complex direct and indirect pathways of association between blocks of variables which are ordered a-priori to reflect postulated directions of association, were constructed for both eGFRCreat and eGFRCystatin-C. Results There were 500,589 participants eligible for analysis (272,623 females / 227,966 males). There were 10,299 and 21,319 participants with eGFRCreat and eGFRCystatin-C < 60 ml/min/1.73 m2 respectively, and 25,308 with a urine albumin/creatinine ratio > 3 mg/mmol. There were 33,755 deaths over a median follow up period of 12.58 (IQR 11.85-13.30) yrs. Higher eGFRCreat was associated with higher odds of ACM in men (OR 1.012, 95% CI 1.004-1.020) and women (OR 1.010, 95% CI 1.001-1.018) in the presence of an interaction with weight in both sexes. Higher eGFRCystatin-C was associated with lower odds of ACM in men (OR 0.978, 95% CI 0.968-0.988) and women (Fig. 1: OR 0.986, 95% CI 0.984-0.987). In men there was an interaction between eGFRCystatin-C and weight observed but no such interaction was observed in women. Interaction plots showed that weight had less influence on the association between ACM and renal function in the eGFRCystatin-C compared to the eGFRCreat sub-models. Conclusion Higher eGFRCreat is associated with higher odds of ACM when controlling for FFM and weight, whereas higher eGFRCystatin-C is associated with lower odds of ACM. This suggests eGFRCystatin-C is more resilient to the effects of variable body composition when compared with eGFRCreat, providing a potential explanation for the stronger association between eGFRCystatin-C and mortality in patients with long term conditions including in chronic kidney disease (CKD). In this model, eGFRCreat should be viewed as a FFM surrogate.

Associations Between Low Serum Urate, Body Composition, and Mortality.

Controversy remains as to whether low serum urate or uric acid (UA) levels contribute to adverse outcomes. We evaluated the relation between low serum UA levels and sarcopenia and assessed whether sarcopenia confounds associations between these low levels and mortality. We utilized data from the National Health and Nutrition Examination Survey (1999-2006). Participants with available whole-body dual x-ray absorptiometry body composition measurements and serum UA concentrations were included. Body composition assessments included body mass index (BMI), waist circumference, maximum lifetime BMI, and age-, sex-, and race-specific appendicular lean mass index (ALMI) and fat mass index (FMI) Z scores. We also calculated Z scores for ALMI relative to FMI (ALMIFMI ). We evaluated associations between serum UA levels and body composition using logistic regression and assessed associations between serum UA levels and mortality before and after adjusting for differences in body composition using Cox proportional hazards regression. Among the 13,979 participants, low serum UA concentrations (<2.5 mg/dl in women, <3.5 mg/dl in men) were associated with low lean mass (ALMI and ALMIFMI Z scores), underweight BMI (<18.5 kg/m2 ), and higher rates of weight loss. The proportion of patients with low ALMI Z scores was 29% in the low serum UA group and 16% in the normal serum UA group (P=0.001). Low serum UA levels were associated with increased mortality before we adjusted for body composition (hazard ratio 1.61 [95% confidence interval 1.14-2.28]; P=0.008) but was attenuated and not significant after adjustment for body composition and weight loss (hazard ratio 1.30 [95% confidence interval 0.92-1.85], P=0.13). Sarcopenia and weight loss are more common among patients with low serum UA concentrations. Differences in body composition may help to explain associations between low levels of serum UA and higher mortality.

Nutrition, Body Composition, and Blood Pressure in Children and Adolescents from the Korea National Health and Nutrition Examination Survey.

We aimed to investigate the association between nutrition and blood pressure and the role that body composition plays in this relationship. Korea National Health and Nutrition Examination Survey data from the years 2008–2020 were reviewed. A total of 11,234 subjects (5974 boys and 5260 girls) aged 10–18 years of age were selected. We analyzed the correlation between nutrition (intakes of energy, protein, fat, carbohydrate, sodium, saturated fatty acid (SFA), unsaturated fatty acid (USFA), and dietary fiber (DF)) and body composition (height, weight, waist circumference (WC), body mass index (BMI), and waist to height ratio (WHtR)), and performed multiple regression analysis to find the independent correlation between body composition and blood pressure (BP). We then compared the correlation between nutrition and BP, with or without adjustment for body composition. The intakes of energy, protein, fat, carbohydrate, sodium, and USFA had positive associations with height, weight, WC, and BMI. Systolic BP (SBP) and diastolic BP (DBP) were independently positively correlated with height and BMI. The intakes of energy, protein, fat, carbohydrate, sodium, and SFA had positive correlations with SBP and DBP, which disappeared when additionally adjusted for BMI and height. In conclusion, nutrition seems to affect BP via height and BMI in Korean children and adolescents.

Body Composition, Eicosapentaenoic Acid, and Vitamin D are Associated with Army Combat Fitness Test Performance.

ABSTRACTBackgroundThe Army Combat Fitness Test (ACFT), an updated and newly developed metric to assess combat readiness, may require specialized exercise and nutritional interventions. The purpose of this cross-sectional study was to investigate the relationship between body composition, erythrocyte long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA), serum vitamin D (VITD) and ACFT performance.MethodsSixty cadets (43 males, 17 females; 20.9 ± 3.8 years; 173.6 ± 10.2 cm; 75.6 ± 13.7 kg) completed the 6-event ACFT (3-repetition maximum trap-bar deadlift [3DL], standing power toss [SPT], hand-release pushups [HRPU], sprint-drag-carry shuttle run [SDC], leg tuck [LTK], or plank [PLK], and 2-mile run [2MR]), body composition analysis via dual-energy x-ray absorptiometry (percent body fat [%BF], lean body mass [LBM], fat-free mass index [FFMI (LBM+bone mineral content)]), and an omega-3 questionnaire. A sub-sample (n = 50) completed blood draws for fatty acid (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) and VITD analysis. Significance was set at p < .05.ResultsLower %BF predicted better performance on all ACFT events (p < .05), except the PLK. Higher LBM was predictive of better performance on the 3DL, SPT, and SDC (p < .05), but no other events. Adjusted FFMI was positively correlated with the 3DL, SPT, HRPU, SDC, and ACFT scores (p < .01 for all). Cadet EPA and DHA dietary intake and omega-3 erythrocyte status was well below established recommendations (25.6 ± 33.9 mg, 58.3 ± 78.1 mg, respectively) and an omega-3 index (O3i = %EPA+%DHA in erythrocytes) of 3.96 ± 1.36%, respectively. EPA was associated with better performance on the 3DL (r = 0.280, p = .049), SPT (r = 0.314, p = .027), LTK (r = 0.316, p = .047), and PLK (r = 0.837, p = .003). After adjusting for body composition, erythrocyte EPA only remained predictive of PLK scores (p = .006). Every 0.1% increase in EPA translated into 5.4 (95% CI: 2.1, 8.8) better PLK score. The O3i or DHA were not associated with any performance variables. Cadets’ average serum VITD status was 38.0 ± 14.9 ng∙ml−1. VITD was associated with 3DL (r = 0.305, p = .031), HRPU (r = 0.355, p = .011), 2MR (r = 0.326, p = .021), and total ACFT score (r = 0.359, p = .011). VITD remained predictive of each event after adjustment for body composition. Every 10 ng∙ml−1 increase in VITD was associated with 3-point increase in 3DL, HRPU, 2MR scores, and a 13-point increase in the total ACFT score.ConclusionsOur data highlight the importance of measures of muscularity, LBM and FFMI, on ACFT performance. Additionally, EPA and VITD status is associated with various strength, power, and muscular and aerobic endurance components of the ACFT. While these results could help professionals better assess and train military personnel, especially since these measures are modifiable through exercise and dietary interventions, they are ultimately hypothesis generating and warrant further exploration.

Longitudinal Associations of Adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Lifestyle Recommendations with Quality of Life and Symptoms in Colorectal Cancer Survivors up to 24 Months Post-Treatment.

Simple SummaryUsing data from 459 colorectal cancer (CRC) survivors, we described how participants adhered to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations and how this adherence was related to quality of life, level of functioning, symptoms of fatigue, and neuropathy symptoms. We found that increases in a lifestyle score was associated with better physical functioning and less fatigue. No relations with neuropathy symptoms were found. In addition, we observed that physical activity played an important role in the lifestyle score with regards to quality of life. In contrast, we observed that body composition and alcohol recommendations had a counteractive influence within the lifestyle score. Our findings suggest that CRC survivors benefit from overall adherence to the WCRF/AICR lifestyle recommendations in terms of quality of life and fatigue. Specific recommendations have a varying influence on these associations, complicating the interpretation and requiring further study.Post-treatment adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations were associated with health-related quality of life (HRQoL), fatigue, and chemotherapy-induced peripheral neuropathy (CIPN) in colorectal cancer (CRC) survivors. In a prospective cohort among CRC survivors (n = 459), repeated home-visits were performed at 6 weeks, 6, 12, and 24 months post-treatment. Dietary intake, body composition, sedentary behaviour, and physical activity were assessed to construct a lifestyle score based on adherence to seven 2018 WCRF/AICR recommendations. Longitudinal associations of the lifestyle score with HRQoL, fatigue, and CIPN were analysed by confounder-adjusted linear mixed models. A higher lifestyle score was associated with better physical functioning and less activity-related fatigue, but not with CIPN. Adjustment for physical activity substantially attenuated observed associations, indicating its importance in the lifestyle score with regards to HRQoL. In contrast, adjustment for body composition and alcohol inflated observed associations, indicating that both recommendations had a counteractive influence within the lifestyle score. Our findings suggest that CRC survivors benefit from an overall adherence to the WCRF/AICR lifestyle recommendations in terms of HRQoL and fatigue, but not CIPN. Specific recommendations have a varying influence on these associations, complicating the interpretation and requiring further study.

Obesity predicts subclinical myocardial injury in men and women of all ages: the Nord-Trondelag Health Study

Abstract Background Obesity strongly associates with subclinical myocardial injury as quantified by concentrations of cardiac troponin. Body mass index (BMI) is the most commonly used index of obesity, but BMI does not take into account the different phenotypes that arise on the basis of age, sex and body composition. We aimed to investigate the influence of these factors on the association of obesity with subclinical myocardial injury. Methods We analyzed total body fat and fat-free mass by bioelectrical impedance analysis and cardiac troponin I (cTnI) with a high-sensitivity assay in 30,778 participants of the prospective observational The Nord-Trøndelag Health Study at study visit 4 (2017–2019). All subjects were free from known cardiovascular disease at baseline, and we excluded subjects with BMI &amp;lt;18.5 kg/m2. Subgroup analyses were performed according to sex and age (&amp;lt;45 years, 45–59 years, ≥60 years). Adjustment was made for established cardiovascular risk factors and indices of body composition. Results Median age was 52.1 (range 16.5 to 98.9) years and 56% were women. Concentrations of cTnI were detectable in 60.6% of study participants, and were median 1.5 (0.6 to 2.9) ng/L. Median BMI was 26.7 (24.0 to 29.9) kg/m2. There was a strong and linear association between BMI and cTnI in adjusted models, with a 37.3 (95% CI, 27.6 to 46.9) % increase in concentrations of cTnI per 10 units of BMI (Figure 1). When adjusting for body composition, strong associations were observed for both sexes. The association between BMI and cTnI was stronger with increasing age (Table 1). Conclusion Obesity is strongly associated with subclinical myocardial injury. The associations are stronger with increasing age and persisted after adjustment for body composition, suggesting a harmful effect of obesity on the myocardium independently of different obesity phenotypes. Figure 1. Association between BMI and cTnI Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): South-Eastern Norway Regional Health Authority

MON-586 Gut Hormones Response to 24-H High Carbohydrate Overfeeding Is a Determinant of Metabolic Adaptation to Carbohydrate Intake in Healthy Individuals

Background: We previously demonstrated that short-term (24h) changes in carbohydrate (CARBOX) or fat oxidation rates in response to overfeeding diets with different macronutrient content are highly correlated within an individual, suggesting the existence of human metabolic phenotypes (carbohydrate vs. fat oxidizers). Gut hormones have a role in feeding and substrate oxidation, thus we investigated if the changes in gut hormones concentration during overfeeding diets or fasting explain the degree of metabolic flexibility in healthy humans.Methods: While residing in our clinical research unit, 67 healthy, weight-stable volunteers (37±10y, BMI: 26±4 kg/m2, body fat: 28±10%; mean±SD, 54 men) with normal glucose regulation had 24-h EE measurements in a whole-room indirect calorimeter during energy balance (EB, diet: 50% carbohydrate, 20% protein), three overfeeding diets, and fasting in a crossover design. The overfeeding diets (200% of weight-maintaining energy requirements) included diets with 20%-protein [50%-carbohydrate (SOF), 75%-carbohydrate (CNP), and 60%-fat (FNP)]. Metabolic flexibility was determined by the difference between respiratory quotient (RQ) during overfeeding/fasting from EB conditions. Plasma GLP-1, PYY, PP, and total ghrelin concentrations were measured by ELISA after an overnight fast the morning of and after each diet. Results: PYY increased after all overfeeding diets (3.4±13.1, 7.0±16.2, and 7.6±14.4 pg/mL; all p<0.05, SOF, CNP and FNP respectively) and decreased with fasting (-11.6±14.2 pg/mL; p<0.001). GLP-1 increased after fasting (2.7±5.8 pg/mL; p<0.001) and FNP (1.3±4.5 pg/mL; p=0.02) and decreased with CNP (-0.9±6.3 pg/mL; p=0.04). PP only increased after fasting (92.8±133.4 pg/mL; p<0.001), while ghrelin decreased with SOF (-31.3±108 pg/mL; p=0.02) and CNP (-43.1±120 pg/dL; p=0.005) but not with FNP (p=0.51). After adjustment for body composition and other known EE determinants, no hormonal changes were associated with the change in 24-h EE in any diet (all p>0.05); however, during CNP greater decreases in GLP1, PYY, and Ghrelin were associated with less increase in 24-h RQ (all r>0.25; all p<0.05) while greater decrease in PP was associated with larger increase in 24-h RQ (r=-0.31, p=0.01). Specifically, greater increase in CARBOX during CNP was positively associated with the changes in GLP-1 (r=0.30; p=0.02) and Ghrelin (r=0.32, p=0.01). In a linear model, only the change in GLP-1, PP, and Ghrelin concentrations during CNP were independent predictors of the change in RQ [β=0.003; -0.0001; and 0.000006 per 1 pg/mL increase each, p=0.008; 0.02 and 0.02 respectively], after accounting for age and sex. Conclusion: In a carbohydrate rich environment, individuals with normal glucose regulation who maintain GLP-1 and ghrelin levels are better adapted to metabolize this type of diet.

SAT-106 Plasma Interleukine-6 (IL-6) Concentration Is a Determinant of Free-Living Weight Change in Healthy Humans

Background: IL-6 is a multifunctional cytokine secreted by leukocytes and endothelial cells in multiple organs. Mice with IL-6 deficiency show mature-onset obesity due to decreased energy expenditure (EE) but no change in food intake. In humans, IL-6 concentration increases with obesity; however, the causal relationship with future weight gain is unclear. We investigated if fasting plasma IL-6 concentration predicts weight change in lean and overweight individuals. Methods: While residing in our clinical research unit, forty-nine healthy, weight-stable volunteers (37.5±10.8 y, 26.7±4.0 kg/m2BMI, 29.7±9.1% body fat; mean±SD, 39 men) with normal glucose regulation had 24-h EE measurements in a whole-room indirect calorimeter during energy balance and consuming a standard diet (50% carbohydrate, 20% protein). After at least 3 days on weight-maintaining diet and an overnight fast, plasma was collected for measurement of IL-6 concentrations by ELISA (Enzo Life Sciences, Farmingdale, NY; intra-assay CV=7.9%, inter-assay CV=10.5%, range=1.52-50 pg/mL) on 6 different days with values averaged to increase precision. Dual-energy X-ray absorptiometry (DXA) was used to measure body composition. Volunteers returned for follow up assessment of body weight and composition by DXA after 6 months (n=38) and 1 year (n=32). Results: Fasting IL-6 concentrations (geometric mean, 95% CI: 11.5, 10.0-13.2 pg/mL) did not differ by gender or race (p>0.05) nor were associated with age, BMI, % body fat, fat mass (FM), or fat-free mass (FFM). After adjustment for body composition and other known EE determinants, fasting IL-6 concentration was not associated with 24-h EE (p=0.33), sleeping EE (p=0.85), or respiratory quotient (p=0.76). However, higher IL-6 concentration was associated with weight gain at 6 months (r=0.51, p=0.001) and at 1 year (r=0.45, p=0.009), reflecting increases in FM (r=0.42, p=0.01 and r=0.50, p=0.04, respectively), but not FFM (p=0.09 and p=0.40). In a linear model, fasting IL-6 concentration at baseline was an independent predictor of weight gain at 6 months and 1 year [β=13.2 (95% CI: 5.7-20.8) and 15.1 kg (1.6-28.7) per 10-fold increase, p=0.001 and 0.03; respectively] after accounting for baseline weight, age, and sex. Conclusion: Although not influencing EE, higher plasma concentration of IL-6 predicts future weight and FM gain in humans, suggesting a potentially novel role of IL-6 in food intake and overeating.

Adiposity-Independent Effects of Aging on Insulin Sensitivity and Clearance in Mice and Humans.

Objective:Aging is associated with impaired insulin sensitivity and increased prevalence of type 2 diabetes. However, it remains unclear whether aging-associated insulin resistance is due to increased adiposity or other age-related factors. To address this question, we investigated the impact of aging on insulin sensitivity independently of changes in body composition.Methods:Cohorts of mice at 4–8 months (‘young’) and 18–27 months (‘aged’) of age exhibiting similar body composition were characterized for glucose metabolism on chow and high-fat diets. Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analyses. The relationship between aging and insulin resistance in humans was investigated in 1,250 non-diabetic Mexican-Americans who underwent hyperinsulinemic-euglycemic clamps.Results:In mice with similar body composition, age had no detrimental effect on plasma glucose and insulin levels. While aging did not diminish glucose tolerance, hyperinsulinemiceuglycemic clamps demonstrated impaired insulin sensitivity and reduced insulin clearance in aged mice on chow and high-fat diets. Consistent with results in the mouse, age remained an independent determinant of insulin resistance after adjustment for body composition in Mexican-American males.Conclusions:This study demonstrates that in addition to altered body composition, adiposity-independent mechanisms also contribute to aging-associated insulin resistance in mice and humans.

Disruption of brain-derived neurotrophic factor production from individual promoters generates distinct body composition phenotypes in mice.

Brain-derived neurotrophic factor (BDNF) is a key neuropeptide in the central regulation of energy balance. The Bdnf gene contains nine promoters, each producing specific mRNA transcripts that encode a common protein. We sought to assess the phenotypic outcomes of disrupting BDNF production from individual Bdnf promoters. Mice with an intact coding region but selective disruption of BDNF production from Bdnf promoters I, II, IV, or VI (Bdnf-e1-/-, -e2-/-, -e4-/-, and -e6-/-) were created by inserting an enhanced green fluorescent protein-STOP cassette upstream of the targeted promoter splice donor site. Body composition was measured by MRI weekly from age 4 to 22 wk. Energy expenditure was measured by indirect calorimetry at 18 wk. Food intake was measured in Bdnf-e1-/- and Bdnf-e2-/- mice, and pair feeding was conducted. Weight gain, lean mass, fat mass, and percent fat of Bdnf-e1-/- and Bdnf-e2-/- mice (both sexes) were significantly increased compared with wild-type littermates. For Bdnf-e4-/- and Bdnf-e6-/- mice, obesity was not observed with either chow or high-fat diet. Food intake was increased in Bdnf-e1-/- and Bdnf-e2-/- mice, and pair feeding prevented obesity. Mutant and wild-type littermates for each strain (both sexes) had similar total energy expenditure after adjustment for body composition. These findings suggest that the obesity phenotype observed in Bdnf-e1-/- and Bdnf-e2-/- mice is attributable to hyperphagia and not altered energy expenditure. Our findings show that disruption of BDNF from specific promoters leads to distinct body composition effects, with disruption from promoters I or II, but not IV or VI, inducing obesity.

Leptin Concentration Predicts Future Metabolic Syndrome Risk in Japanese Americans Independent of Body Composition

Aims: Leptin has been shown to predict risk of metabolic syndrome (MetS), but it is not known whether this association is independent of body composition. Thus, we examined whether plasma leptin concentration predicted risk of MetS after adjustment for body composition measured using imaging. Methods: We used the modified ATP III MetS criteria for an Asian population to classify participants in the longitudinal Japanese-American Community Diabetes Study as to presence of MetS. Participants without MetS at baseline (n=283) were followed for its development over 5 years. CT-measured adipose depots included baseline and 5-year intra-abdominal and abdominal subcutaneous fat areas at the level of the umbilicus, subcutaneous mid-thigh fat area, and subcutaneous thorax fat area at the nipple level. Other measurements included fasting plasma leptin and serum HDL-cholesterol and triglyceride concentrations, fasting and 2 hour glucose from a 75 g OGTT, systolic blood pressure (SBP), and medication use. Logistic regression analysis was used to estimate the odds of incident MetS by leptin concentration, body composition, and baseline MetS features. Results: 65 participants developed MetS at 5-year follow-up. Multivariable logistic regression models showed a lower odds of incident MetS with 1-SD greater leptin concentration (OR = 0.45; 95% CI = 0.25-0.79; p = 0.006) adjusting for age, sex, CT-fat areas at baseline, and 5-year change in CT-fat areas. Additional adjustment for other MetS features at baseline (fasting and 2 hour glucose, triglycerides, HDL-cholesterol, SBP) yielded similar results (OR = 0.38; 95% CI = 0.20-0.71; p = 0.002). Conclusions: Leptin concentration predicts MetS risk in Japanese Americans independent of body composition. Further research is needed to confirm this association in other populations and to understand potential underlying biologic mechanisms. Disclosure C. Liao: None. W.Y. Fujimoto: None. S.E. Kahn: Advisory Panel; Self; Boehringer Ingelheim GmbH, Elcelyx Therapeutics, Inc., Eli Lilly and Company, Intarcia Therapeutics, Inc., Janssen Research &amp; Development, Merck &amp; Co., Inc., Novo Nordisk A/S. D.L. Leonetti: None. E.J. Boyko: None.

Propensity for excess gestational weight gain in African‐American women may be explained by hypometabolic factors in early pregnancy

BackgroundWomen with obesity are at increased risk for excess gestational weight gain. Studies in non‐pregnant women suggest that the etiology of weight gain may be different between African‐American and White women and this may cause higher retention of weight postpartum and the increased prevalence of obesity in offspring.ObjectiveTo conduct a cross‐sectional study in African‐American and White pregnant women to identify metabolic and behavioral risk factors for aberrant weight gain trajectories.DesignMetabolic and behavioral phenotyping was conducted in 66 pregnant women with obesity, expecting a single fetus, between 14 and 16 weeks of gestation. Energy expenditure was measured in free‐living conditions over 7 days using stable isotopes and during sleep in a room calorimeter. Body composition was measured by air displacement plethysmography and physical activity by SenseWear™ accelerometers. Fasting blood was collected to measure markers of metabolic health.ResultsAfrican‐American (AA, n=34) and White women (W, n=32) were comparable in age (27.7±0.6 years) but had a lower socio‐economic status and higher parity. The two groups were matched for BMI (36.9±0.7 kg/m2) and while body fat was not different (55.1±0.6%), AA women had more fat‐free mass (AA: 56.9±1.6 vs W: 51.6±1.1 kg, p=0.009) and tended to be more insulin resistant (HOMA‐IR, AA: 4.0±0.4 vs W: 3.1±0.3, p=0.06). Total daily energy intake was significantly lower in AA women compared to their white counterparts (AA: 2633±88 vs W: 2901±76 kcal/d, p=0.03), while diet composition and absolute total daily energy expenditure (TDEE) were not different between the two ethnic groups (AA: 2590±77 vs W: 2711±56 kcal/d, p=0.21). However, after correction for individual differences in body composition, TDEE was significantly lower in AA women (−231±74kcal/d, p=0.003). Similarly, energy expenditure during sleep was comparable between ethnicities in absolute terms (p=0.77), but lower in AA women after adjustment for body composition (−81±37kcal/d, p=0.03). Physical activity was not significantly different between AA and white women as assessed by calorimetrically data or by accelerometry (eg. time spent in activity, average intensity of activity (METs), or as #steps). We observed no differences in substrate oxidation (12h and sleeping RQ) or metabolic profile (plasma T3 and T4 concentrations, urinary epinephrine and norepinephrine excretion).ConclusionsEarly in pregnancy, African‐American and White women with obesity have similar energy intake and physical activity but energy expenditure per kg of metabolic mass is significantly lower in women who are African‐American. Energy requirements used by clinicians to counsel pregnant women on healthy weight gain are not race‐specific. The lower energy expenditure in African‐American women may therefore lead to unintentional overeating and contribute to the increasing prevalence of excessive gestational weight gain in African‐American women.Support or Funding InformationThis study was funded by the National Institutes of Health (R01DK099175; Redman) and in part by U54GM104940 and P30DK072476.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The relationship between objectively assessed physical activity and bone health in older adults differs by sex and is mediated by lean mass.

To investigate associations of objectively assessed PA and bone health in community-dwelling older adults. This secondary analysis of a subset of the Tasmanian Older Adult Cohort study included participants with PA assessed utilising ActiGraph GT1M accelerometers over 7days (N = 209 participants, 53% female; mean ± SD age 64.5 ± 7.2years). Steps/day and PA intensity were estimated via established thresholds. Bone mineral content (BMC) was acquired at the total hip, lumbar spine, legs and whole body by DXA at baseline and approximately 2.2years later. Relationships between PA and BMC were assessed by multivariable linear regression analyses adjusted for age, smoking status, height and total lean mass. Men with above-median total hip BMC completed significantly less steps per day, but there was no significant difference in PA intensity compared with those with below-median BMC. There were no significant differences in PA in women stratified by median BMC. In women, steps/day were positively associated with leg BMC (B = 0.178; P = 0.017), and sedentary behaviour was negatively associated with leg BMC (- 0.165; 0.016) at baseline. After adjustment for confounders including lean mass and height, higher sedentary behaviour at baseline was associated with declines in femoral neck BMC (- 0.286; 0.011) but also with increases in pelvic BMC (0.246; 0.030) in men and increases in total hip BMC (0.215; 0.032) in women, over 2.2years. No other significant longitudinal associations were observed after adjustment for body composition. Associations of accelerometer-determined sedentary behaviour and PA with bone health in older adults differ by sex and anatomical site and are mediated by body composition.

Insulin Resistance Is Associated With Smaller Cortical Bone Size in Nondiabetic Men at the Age of Peak Bone Mass.

In type 2 diabetes mellitus, fracture risk is increased despite preserved areal bone mineral density. Although this apparent paradox may in part be explained by insulin resistance affecting bone structure and/or material properties, few studies have investigated the association between insulin resistance and bone geometry. We aimed to explore this association in a cohort of nondiabetic men at the age of peak bone mass. Nine hundred ninety-six nondiabetic men aged 25 to 45 years were recruited in a cross-sectional, population-based sibling pair study at a university research center. Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR), with insulin and glucose measured from fasting serum samples. Bone geometry was assessed using peripheral quantitative computed tomography at the distal radius and the radial and tibial shafts. In age-, height-, and weight-adjusted analyses, HOMA-IR was inversely associated with trabecular area at the distal radius and with cortical area, periosteal and endosteal circumference, and polar strength strain index at the radial and tibial shafts (β ≤ -0.13, P < 0.001). These associations remained essentially unchanged after additional adjustment for dual-energy X-ray absorptiometry-derived body composition, bone turnover markers, muscle size or function measurements, or adiponectin, leptin, insulin-like growth factor 1, or sex steroid levels. In this cohort of nondiabetic men at the age of peak bone mass, insulin resistance is inversely associated with trabecular and cortical bone size. These associations persist after adjustment for body composition, muscle size or function, or sex steroid levels, suggesting an independent effect of insulin resistance on bone geometry.

Analysis of Insulin Resistance in Obese Non-Diabetic Candidates for Bariatric Surgery: Adjustment for Body Composition

Analysis of Insulin Resistance in Obese Non-Diabetic Candidates for Bariatric Surgery: Adjustment for Body Composition

Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls

The beef industry has emphasized the improvement of feed utilization, as measured by modeling feed intake through performance traits to calculate residual feed intake (RFI). Evidence supports an inverse relationship between feed efficiency and reproductive function. The objective of this study was to determine the relationship of reproductive assessments and RFI unadjusted (RFIKoch) or adjusted for body composition (RFIus) and the relationship among fertility-related parameters. In total, 34 crossbred bulls were housed together for 112 days of performance evaluation, followed by assessment of scrotum IR imaging, scrotal circumference, testes ultrasonography and semen quality parameters at 377±33.4 days of age. Bulls were slaughtered at 389±34.0 days of age, and analyses of carcass composition, biometrics and histomorphometry of the testis and epididymis were conducted. Bulls were grouped into two subpopulations based on divergence of RFI, and within each RFI model either by including 50% of the population (Halves, high and low RFI, n=17) or 20.6% extremes of the population (Tails, high and low RFI, n=7). The means of productive performance and fertility-related measures were compared through these categories. Pearson’s correlation was calculated among fertility-related measures. In the Halves subpopulation of the RFIus, sperm of low-RFI bulls had decreased progressive motility (47.30% v. 59.90%) and higher abundance of tail abnormalities (4.30% v. 1.80%) than that of high-RFI bulls. In the Tails subpopulation of the RFIKoch, low RFI displayed less variation in the scrotum surface temperature (0.62°C v. 1.16°C), decreased testis echogenicity (175.50 v 198.00 pixels) and larger (60.90 v. 56.80 mm2) but less-developed seminiferous tubules than high-RFI bulls. The evaluation of fertility-related parameters indicated that a higher percentage of immature seminiferous tubules was correlated with occurrence of sperm with distal droplets (r=0.59), a larger temperature variation at the top of the scrotum was correlated with improved sperm progressive motility (r=0.38), a lower occurrence of sperm loose head abnormalities was correlated with larger temperature variation at the lower part of the scrotum (r=−0.43), and a lower minimum testis echogenicity (r=−0.59) and smaller scrotal circumference (r=0.72) were correlated with age. The adjustment for body composition (RFI determination) enabled distinct biological inferences about reproduction and feed efficiency when compared with the non-adjusted model. However, both RFI models and the correlation analysis supported the hypothesis that feed-efficient bulls have features of delayed sexual maturity. Overall, the assessment of fertility-related measurements is important to avoid the improvement of feed efficiency at the expense of reproductive function in young bulls.

Higher Natriuretic Peptide Levels Associate With a Favorable Adipose Tissue Distribution Profile

The goal of this study was to investigate the association between natriuretic peptides and body fat distribution in a multiethnic cohort. Natriuretic peptides stimulate lipolysis, reduce weight gain, and promote adipocyte browning in animal models, but data are lacking in humans. A total of 2,619 participants without heart failure in the Dallas Heart Study underwent measurements of 1) B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP); and 2) body fat distribution by dual energy x-ray absorptiometry and magnetic resonance imaging. Cross-sectional associations of natriuretic peptides with adiposity phenotypes were examined after adjustment for age, sex, race, comorbidities, and body mass index. Median BNP and NT-proBNP levels in the study cohort (mean age 44 years; 56% women, 48% African Americans, 32% obese) were 3.0 and 28.1 pg/ml, respectively. Natriuretic peptide levels above the median were associated with a more favorable body fat profile and less insulin resistance, including lower visceral fat, liver fat, and homeostasis model assessment of insulin resistance index, and increased lower body fat and higher adiponectin (p < 0.05 for each). In multivariable analyses, NT-proBNP remained inversely associated with visceral fat (beta coefficient = -0.08; p < 0.0001) and liver fat (beta coefficient = -0.14; p < 0.0001) and positively associated with lower body fat (beta coefficient = 0.07; p < 0.0001) independent of age, sex, race, and obesity status; findings were similar with BNP. Adjustment for body composition, homeostasis model assessment of insulin resistance index, circulating androgens, and adipocytokines did not attenuate the associations. Higher natriuretic peptide levels were independently associated with a favorable adiposity profile, characterized by decreased visceral and liver fat and increased lower body fat, suggesting a link between the heart and adipose tissue distribution mediated through natriuretic peptides.

Associations of Insulin Resistance With Cardiovascular Risk Factors and Inflammatory Cytokines in Normal-Weight Hispanic Women

OBJECTIVETo investigate the associations of markers of insulin resistance with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women.RESEARCH DESIGN AND METHODSSeventy-one normal-weight (BMI <25 kg/m2) Hispanic women (age, 20–39 years) participated in a fasting blood draw for glucose, insulin, lipids, and inflammatory markers; a glucose tolerance test; anthropometric and blood pressure measurements; body composition by dual-energy x-ray absorptiometry; and measurements of cardiorespiratory fitness via Vo2max and daily physical activity by accelerometer.RESULTSSix percent of participants had impaired fasting glucose, 14% had impaired glucose tolerance, and 48% had at least one cardiovascular disease risk factor. Homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin were positively correlated with glucose, triglycerides, systolic blood pressure, and diastolic blood pressure, and were negatively correlated with adiponectin (P < 0.05). The 2-h insulin was positively correlated with diastolic blood pressure, triglycerides, and high-sensitivity C-reactive protein. HOMA-IR and fasting insulin remained significantly and positively related to glucose, triglycerides, and blood pressure after adjustment for body composition. The relationships between markers of insulin resistance and adiponectin and high-sensitivity C-reactive protein were attenuated after adjustment for body composition.CONCLUSIONSSurrogate markers of insulin resistance were associated with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women. Our findings suggest that HOMA-IR, fasting, and 2-h insulin may be important clinical markers for identifying young, normal-weight, Hispanic women who may be at risk for development of type 2 diabetes and cardiovascular disease. Our findings show the importance of early screening for prevention of type 2 diabetes and cardiovascular disease in this population.

The effect of obesity on the association between liver fat and carotid atherosclerosis in a multi-ethnic cohort

ObjectiveNon-alcoholic fatty liver disease is the most common liver disorder in Western society, increasing in parallel with obesity and the metabolic syndrome. Evidence suggests that there is an independent relationship between liver fat (LF) and atherosclerosis, however it is unknown if this applies to low risk populations. The purpose of this study was to evaluate the association between LF and measures of sub-clinical carotid atherosclerosis in men and women of Aboriginal, Chinese, European, and South Asian origin. Methods and resultsHealthy men and women were assessed for LF (computed tomography scan) and atherosclerosis (carotid ultrasound) in addition to cardiovascular risk factors, demographics, and body composition. Liver Hounsfield units (HU) values were negatively correlated with age, BMI, waist circumference (WC), percent body fat, carotid intima media thickness total plaque area, and total area. LF was significantly associated with carotid IMT and total area after adjustment for sex, age, ethnicity, education, income and smoking status. However after adjusting for BMI and WC, LF was no longer significantly associated with atherosclerosis. ConclusionIncreased LF may be associated with atherosclerosis, however, after adjustment for body composition, LF was not significantly associated with sub-clinical atherosclerosis. BMI and WC are useful anthropometric measures for the evaluation of CVD risk independent of LF.

Endogenous sex hormones and C‐reactive protein in healthy postmenopausal women

Oral oestrogen replacement therapy increases levels of C-reactive protein (CRP). CRP is an established strong predictor of cardiovascular events. It is unknown whether endogenous oestrogen levels are associated with CRP. We therefore studied the relationship between endogenous sex hormones and CRP in healthy postmenopausal women emphasizing the role of body composition as peripheral fat is both a main source of oestrogen production after menopause and an endocrine tissue with inflammatory activities. The study population comprised 889 women participating in the PROSPECT study, an ongoing population-based cohort study. Information on risk factors was collected by questionnaires and clinical examination. Endogenous sex hormone levels and CRP were measured with double antibody radio immuno assay (RIA) from fasting plasma samples. In this cross-sectional study, associations between risk factors and lnCRP were studied using linear regression models. Increases in oestrone and free oestradiol levels and the free androgen index were related to an increase in lnCRP of 1.19, 1.23 and 1.21 mg dL(-1) respectively. Body mass index (BMI), waist circumference and physical activity were strongly related to CRP levels, independent of age and other cardiovascular risk factors. Levels of all sex steroids but dehydroepiandrostenedione decreased with age. In age-adjusted analyses, an increase in waist circumference or BMI by one quartile was associated with a 1.28-fold and 1.26-fold increase in CRP. The relationship between endogenous hormones and CRP was modestly attenuated but remained highly significant after adjustment for body composition, physical activity and other traditional cardiovascular risk factors. Our findings show that in postmenopausal women high levels of endogenous oestrogenic and androgenic sex steroids coincide with high CRP levels. This was only explained in part by markers of body composition or intra-abdominal fat.