Association between Serum Leptin Levels and 24‐Hour Blood Pressure in Obese Women

Objective: To assess the relationship between serum leptin and 24‐hour blood pressure (BP) in obese women, according to body fat distribution. Research Methods and Procedures: A cross‐sectional study was carried out in a population of 70 nondiabetic, normotensive, obese women (40 with android and 30 with gynoid type of obesity) and 20 nonobese healthy women as a control group. All subjects underwent 24‐hour ambulatory BP monitoring. Blood samples were collected for serum leptin and plasma insulin measurements. Total cholesterol and high‐density lipoprotein cholesterol were also measured. Results: Serum leptin levels were significantly higher in obese subjects than in controls, and they were more elevated in android obese women than in gynoid ones. Leptin levels were positively related to body mass index (BMI), insulin, and waist and hip circumferences in the android group. Among gynoid subjects, leptin levels showed positive associations with BMI and insulin. In women with android obesity, strong positive correlations (p < 0.001) were found between leptin levels and 24‐hour systolic BP (SBP), daytime SBP, nighttime SBP, 24‐hour diastolic BP (DBP), and daytime DBP. Multiple regression analyses, including age, insulin and leptin concentrations, BMI, and waist and hip circumferences on 24‐hour and daytime SBP and DBP, showed that only leptin levels contributed to the variability of BP. Conclusions: Our study shows that serum leptin levels are directly related to 24‐hour BP levels in normotensive women with android fat distribution, independently of BMI.     

BMI Is the Main Determinant of the Circulating Leptin in Women after Vertical Banded Gastroplasty

Objective: To assess the main determinant of serum leptin concentration changes in morbidly obese patients treated by banded vertical gastroplasty. Research Methods and Procedures: Serum leptin and insulin concentrations, insulin resistance, BMI, body weight, and body fat mass in 18 obese women and 8 obese men treated by vertical banded gastroplasty were studied. Lean women and men subjects were used as controls. Results: Before surgery, serum leptin and insulin concentrations and insulin resistance index were significantly higher in morbidly obese patients than in control subjects. BMI, body fat mass, and serum triacylglycerol concentrations were also significantly higher in obese than in lean subjects. All of these parameters gradually decreased during 50 weeks after surgery. Univariate regression analysis displayed significant correlations between the following: serum leptin concentration and BMI (and body fat mass), serum leptin concentration and serum insulin concentration, and serum leptin concentration and insulin resistance index. Multivariate regression analysis indicated that only BMI was independently correlated with the decrease in serum leptin concentration. Discussion: Obtained data suggest the following: 1) vertical banded gastroplasty causes reduction of body weight, serum leptin and insulin concentration, insulin resistance, and serum triacylglycerol concentration; and 2) BMI is the main determinant of the circulating leptin concentration in morbidly obese women after anti‐obesity surgery.     

BMI, body composition, and physical functioning in older adults

Objective: Recent studies have emphasized the importance of muscle and fat mass in relation to age‐related decline in physical function. Our objective was to determine whether BMI, as a surrogate measurement of fat mass, may be used as a measure of risk factor for physical functioning in older adults and whether body composition measurements confer any advantage over BMI. Research Methods and Procedures: Four thousand men and women ≥65 years of age living in the community, stratified by age and sex, underwent the following measurements: body composition by DXA; grip strength; and timed 6‐m walk. Subjects were grouped into five categories of BMI using Asian criteria for health‐related risks, and between‐group differences in physical performance measures and body composition were analyzed using analysis of covariance adjusting for age, physical activity level, and presence of chronic disease. Results: Subjects in the two obese categories had a significantly greater number of instrumental activities of daily living (IADL) impairments compared with the underweight and normal‐weight groups. Those with BMI ≥30 kg/m² had the worst walking performance, and the groups with BMI in the normal and overweight range had optimal performance. Fat mass, but not appendicular muscle mass, was associated with walking speed after adjusting for BMI. Discussion: Fat mass seems to be a more important factor than appendicular muscle mass in determining walking speed in community‐living older adults, even after adjusting for BMI.     

Impaired fat-induced thermogenesis in obese subjects: the NUGENOB study

Objectives: To study energy expenditure before and 3 hours after a high‐fat load in a large cohort of obese subjects (n = 701) and a lean reference group (n = 113). Research Methods and Procedures: Subjects from seven European countries underwent a 1‐day clinical study with a liquid test meal challenge containing 95% fat (energy content was 50% of estimated resting energy expenditure). Fasting and 3‐hour postprandial energy expenditures, as well as metabolites and hormones, were determined. Results: Obese subjects had a reduced postprandial energy expenditure after the high‐fat load, independent of body composition, age, sex, research center, and resting energy expenditure, whereas within the obese group, thermogenesis increased again with increasing BMI category. Additionally, insulin resistance, habitual physical activity, postprandial plasma triacylglycerols, and insulin were all independently positively related to the postprandial energy expenditure. Resting energy expenditure, adjusted for fat‐free mass, increased with degree of obesity, a difference that disappeared after adjustment for fat mass. Furthermore, insulin resistance, fasting plasma free fatty acids, and cortisol were positively associated, whereas fasting plasma leptin and insulin‐like growth factor‐1 were negatively associated, with resting energy expenditure. Discussion: The 3‐hour fat‐induced thermogenic response is reduced in obesity. It remains to be determined whether this blunted thermogenic response is a contributory factor or an adaptive response to the obese state.     

Normal vs. high‐protein weight loss diets in men: Effects on body composition and indices of metabolic syndrome

Objective:

This study assessed the effectiveness of a prescribed weight‐loss diet with 0.8 versus 1.4 g protein·kg^?1 day^?1 on changes in weight, body composition, indices of metabolic syndrome, and resting energy expenditure (REE) in overweight and obese men.

Design and Methods:

Men were randomized to groups that consumed diets containing 750 kcal day^?1 less than daily energy needs for weight maintenance with either normal protein (NP, n = 21) or higher protein (HP, n = 22) content for 12 weeks. The macronutrient distributions of the NP and HP diets were 25:60:15, and 25:50:25 percent energy from fat, carbohydrate, and protein, respectively. Assessments were made pre and post intervention. The subjects were retrospectively subgrouped into overweight and obese groups.

Results and Conclusion:

Both diet groups lost comparable body weight and fat. The HP group lost less lean body mass than the NP group (?1.9 ± 0.3 vs. ?3.0 ± 0.4 kg). The effects of protein and BMI status on lean body mass loss were additive. The reductions in total cholesterol, HDL‐C, triacylglycerol, glucose, and insulin, along with LDL‐C, total cholesterol‐to‐HDL‐C ratio, and HOMA‐IR, were not statistically different between NP and HP. Likewise, macronutrient distributions of the diet did not affect the reductions in REE, and blood pressure. In conclusion, energy restriction effectively improves multiple clinical indicators of cardiovascular health and glucose control, and consumption of a higher‐protein diet and accomplishing weight loss when overweight versus obese help men preserve lean body mass over a short period of time.

     

Evaluation of a multisensor armband in estimating energy expenditure in obese individuals

Objective: To examine the reliability and validity of the SenseWear Pro 2 Armband (SWA; Body Media, Pittsburgh, PA) during rest and exercise compared with indirect calorimetry (IC) in obese individuals. Research Methods and Procedures: Energy expenditure was assessed during rest with the SWA and IC in 142 obese adults (37 men and 105 women, BMI = 42.3 ± 7.0) and in 25 lean and overweight adults (BMI = 25.3 ± 3.2) who were used as a comparison group. Twenty‐nine of the obese adults also participated in three separate short exercise sessions including cycle ergometry, stair stepping, and treadmill walking. Results: The repeatability of SWA estimates in obese subjects was high (r = 0.88, p < 0.001). The SWA generally underestimated the resting energy expenditure (REE) (1811 ± 346 vs. 1880 ± 382 kcal/d) and highly overestimated the energy expenditure during the exercise sessions in obese individuals. REE estimations by SWA were significantly correlated with fat‐free mass (r = 0.88, p < 0.001). Bland‐Altman plots based statistical analysis for the estimated REE, and measured IC showed a low agreement (Total Error > 20% but Systematic Error < 5%) between the two methods in obese subjects, although they showed a high correlation and a very good agreement in lean and overweight patients. Discussion: The SWA is an easy to handle, practical, new portable device for measuring energy expenditure. The accuracy of the SWA appeared to be poor in the obese subjects we examined, especially those with high REE both in rest and exercise. We believe that it is necessary to incorporate new, obesity‐specific algorithms in the relative software.     

Leptin, superoxide dismutase, and weight loss: initial leptin predicts weight loss

Objective: Our goal was to study how plasma leptin concentration, superoxide dismutase (SOD) activity, and weight loss are related in obese adults. Research Methods and Procedures: Serum leptin concentration, SOD activities, general biochemical data, and body composition measurements were obtained for 62 overweight and obese subjects before and after an 8‐week body weight reduction (BWR) regimen. The subjects were on dietary control, performed moderate aerobic and strength training exercises, and attended educational lectures. Results: The measurement results indicated that the following criteria were significantly reduced: body weight [84.4 ± 17.0 vs. 79.3 ± 16.1 (standard error) kg, p < 0.001]; BMI (31.5 ± 4.3 vs. 29.4 ± 4.2 kg/m², p < 0.001), and fat mass (33.3 ± 10.0 vs. 29.8 ± 10.4 kg, p < 0.001). Plasma leptin levels also significantly decreased from 31.5 ± 17.6 to 26.5 ± 17.2 ng/mL (p < 0.001). Additionally, SOD activity was significantly increased from 261.4 ± 66.0 to 302.7 ± 30.9 U/mL (p < 0.001). Based on linear regression analysis results, a 3.78‐ to 8.13‐kg reduction in weight can be expected after the 8‐week BWR regimen when initial leptin concentration was 5 to 30 ng/mL. Discussion: We found that an 8‐week exercise and diet program was effective in reducing weight and fat mass and, notably, had further beneficial effects on leptin resistance and SOD activity. Additionally, this study demonstrated that initial plasma leptin concentration may be used as a predictor for weight loss outcome.     

Low Plasma Leptin Concentration and Low Rates of Fat Oxidation in Weight‐Stable Post‐Obese Subjects

Objective: A low resting metabolic rate for a given body size and composition, a low rate of fat oxidation, low levels of physical activity, and low plasma leptin concentrations are all risk factors for body weight gain. The aim of the present investigation was to compare resting metabolic rate (RMR), respiratory quotient (RQ), levels of physical activity, and plasma leptin concentrations in eight post‐obese adults (2 males and 6 females; 48.9 ± 12.2 years; body mass index [BMI]: 24.5 ± 1.0 kg/m²; body fat 33 ± 5%; mean ± SD) who lost 27.1 ± 21.3 kg (16 to 79 kg) and had maintained this weight loss for ≥2 months (2 to 9 months) to eight age‐ and BMI‐matched control never‐obese subjects (1 male and 7 females; 49.1 ± 5.2 years; BMI 24.4 ± 1.0 kg/m²; body fat 33 ± 7%). Research Methods and Procedures: Following 3 days of weight maintenance diet (50% carbohydrate and 30% fat), RMR and RQ were measured after a 10‐hour fast using indirect calorimetry and plasma leptin concentrations were measured using radioimmunoassay. Levels of physical activity were estimated using an accelerometer over a 48‐hour period in free living conditions. Results: After adjustment for fat mass and fat‐free mass, post‐obese subjects had, compared with controls, similar levels of physical activity (4185 ± 205 vs. 4295 ± 204 counts) and similar RMR (1383 ± 268 vs. 1430 ± 104 kcal/day) but higher RQ (0.86 ± 0.04 vs. 0.81 ± 0.03, p < 0.05). Leptin concentration correlated positively with percent body fat (r = 0.57, p < 0.05) and, after adjusting for fat mass and fat‐free mass, was lower in post‐obese than in control subjects (4.5 ± 2.1 vs. 11.6 ± 7.9 ng/mL, p < 0.05). Discussion: The low fat oxidation and low plasma leptin concentrations observed in post‐obese individuals may, in part, explain their propensity to relapse.     

Hyperleptinemia in obese adolescents deregulates neuropeptides during weight loss

Leptin has emerged over the past decade as a key hormone not only in energy balance regulation but also in neuroendocrine and inflammatory processes. The aim of the present study was to evaluate whether hyperleptinemia deregulates neuropeptides during weight loss. A total of 86 post-pubertal obese adolescents (with or without hyperleptinemia) participated in one year of interdisciplinary weight loss therapy (clinical, nutritional, psychological and exercise-related). Adipokine and neuropeptide concentrations were measured by ELISA, visceral fat was measured by ultrasound and body composition was measured by pletismography. The hyperleptinemic patients presented a lower alpha-MSH concentration and higher NPY/AgRP ratio while the adiponectin/leptin (A/L) ratio was lower compared with the non-hyperleptinemic group. After therapy, significant improvements in BM, BMI, body fat mass, visceral and subcutaneous fat, HOMA-IR, QUICKI, total cholesterol and triglycerides were observed in both groups. Indeed, we observed significant increases in adiponectin and A/L as well as reductions in leptin and NPY/AgRP ratio in the hyperleptinemic group. In the stepwise multiple linear regression analysis with leptin concentration as the dependent variable, α-MSH and body fat mass (%) were the independent predictors to explain leptin concentration. For the entire group, we found positive correlations between leptinemia and BMI and body fat mass (%) as well as a negative correlation with free fat mass (%) and alpha-MSH. Finally, we verified negative correlations between adiponectin/leptin ratio with total cholesterol and LDL-c, only in hyperleptinemic patients. In conclusion, the hyperleptinemia in obese adolescents deregulates neuropeptides during weight loss.     

Lower serum leptin concentrations in rugby players in comparison with healthy non-sporting subjects--relationships to anthropometric and biochemical parameters

Leptin is a protein hormone synthesized by adipocytes. Its serum concentrations reflect the total body fat content. Serum leptin concentrations are significantly higher in obese than in lean people and in women than in men. However little information about the influence of physical activity on serum leptin concentrations is available. We have compared the body weight, the body mass index (BMI), the body fat content (measured by caliper as skinfold thickness) and the serum concentrations of leptin, triglycerides, total, high density and low density lipoprotein (LDL) cholesterol in 14 top rugby players and 10 healthy controls. We found that serum leptin, total and LDL cholesterol concentrations were significantly lower in the rugby players group than in the control subjects. The body weight and BMI were significantly higher in the rugby players, while the body fat content was only slightly (non-significantly) higher in the control group. The serum leptin concentrations in both groups positively correlated with the BMI and body fat content and also with LDL concentrations in the control group. The serum leptin concentrations in the rugby players were lower than in the non-sporting subjects despite a similar body fat content in both groups. We would therefore suggest the possibility that regular hard physical training decreases serum leptin concentrations not only by the decrease of total body fat content, but also by a separate mechanism, which is not directly dependent on the changes in the amount of body adipose tissue.     

Cardiac Parasympathetic Activity Is Increased by Weight Loss in Healthy Obese Women

Objective: We studied the effect of weight reduction on cardiac parasympathetic activity (PSA) in obese women. We also studied the relationship between the changes of PSA, resting energy expenditure (REE), and major cardiovascular risk factors. Research Methods and Procedures: Changes of cardiac vagal tone, an index of PSA, REE, and major cardiovascular risk factors, were measured in 52 healthy obese women after a 6‐month weight reduction. Ten of the women were remeasured at 12 and 24 months. Cardiac vagal tone was assessed by a vagal tone monitor and REE by indirect calorimeter. Results: Cardiac vagal tone increased significantly (p = 0.046), averaging a 9.5% weight loss in 6 months. The vagal tone increased further with weight loss during the following 6 months, and thereafter, it declined with weight regain. The increase of cardiac vagal tone correlated significantly with decreases of body weight, fat mass, waist circumference, serum insulin, and heart rate. REE adjusted for fat‐free mass and age did not change with weight loss and was not related to cardiac vagal tone at any time‐point. Discussion: Cardiac PSA activity increases with weight loss in obese women. This increase may not be maintained long‐term if body weight is regained. The rise of cardiac PSA is correlated with decreases of body fat mass, abdominal fat, serum insulin, and heart rate. Cardiac PSA is not related to REE.     

Preliminary findings on the influence of FTO rs9939609 and MC4R rs17782313 polymorphisms on resting energy expenditure,leptin and thyrotropin levels in obese non-morbid premenopausal women

Given that leptin, ghrelin and thyrotropin play a major role in the regulation of resting energy expenditure (REE) and that the FTO rs9939609 and the MC4R rs17782313 polymorphisms have been proposed to affect energy homeostasis, we hypothesized that both polymorphisms are associated with REE and that these relationships can be mediated by leptin, ghrelin and thyrotropin in obesity. Therefore, the present study aimed to examine the relationships between FTO rs9939609 and the MC4R rs17782313 with REE, leptin, ghrelin and thyrotropin levels in obese women. The study comprised 77 obese (body mass index 34.0?±?2.8 kg/m²) women (age 36.7?±?7 years). We measured body composition by dual-energy X-ray absorptiometry and REE by indirect calorimetry. We analysed fasting leptin, ghrelin and thyrotropin levels and the ratio of leptin to fat mass was calculated. Genotype distributions of the polymorphisms did not deviate from Hardy–Weinberg expectations (P values >0.2). Women carrying the A allele of the FTO rs9939609 had lower REE (1,580?±?22 vs. 1,739?±?35 kcal/day, P?<?0.001) and higher leptin to fat mass ratio (1.33?±?0.05 vs. 1.13?±?0.08 ng/ml kg, P?<?0.05) and thyrotropin levels (1.93?±?0.10 vs. 1.53?±?0.16 μU/ml, P?<?0.05) regardless of age and body mass index. We found no significant influence of the MC4R rs17782313 on energy metabolism or biochemical variables. Our findings confirm that the A allele of the FTO rs9939609 is associated with lower REE and increased plasma leptin levels. We also found an association between the FTO rs9939609 and thyrotropin, suggesting the possible influence of FTO in the hypothalamic–pituitary–thyroid axis as a potential mechanism of the increased adiposity.     

Body Weight Loss and Weight Maintenance in Relation to Habitual Caffeine Intake and Green Tea Supplementation

Objective: Investigation of the effect of a green tea‐caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake. Research Methods and Procedures: A randomized placebo‐controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 ± 2.7 kg/m²) matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea‐caffeine mixture (270 mg epigallocatechin gallate + 150 mg caffeine per day) or placebo. Results: Subjects lost 5.9 ±1.8 (SD) kg (7.0 ± 2.1%) of body weight (p < 0.001). At baseline, satiety was positively, and in women, leptin was inversely, related to subjects’ habitual caffeine consumption (p < 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p < 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p < 0.01). In the high caffeine consumers, no effects of the green tea‐caffeine mixture were observed during WM. Discussion: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea‐caffeine mixture improved WM, partly through thermogenesis and fat oxidation.     

Leptin Levels Are Associated with Fat Oxidation and Dietary‐Induced Weight Loss in Obesity

Objective: To examine the relationship between fasting plasma leptin and 24‐hour energy expenditure (EE), substrate oxidation, and spontaneous physical activity (SPA) in obese subjects before and after a major weight reduction compared with normal weight controls. To test fasting plasma leptin, substrate oxidations, and SPA as predictive markers of success during a standardized weight loss intervention. Research Methods and Procedures: Twenty‐one nondiabetic obese (body mass index: 33.9 to 43.8 kg/m²) and 13 lean (body mass index: 20.4 to 24.7 kg/m²) men matched for age and height were included in the study. All obese subjects were reexamined after a mean weight loss of 19.2 kg (95% confidence interval: 15.1–23.4 kg) achieved by 16 weeks of dietary intervention followed by 8 weeks of weight stability. Twenty‐four‐hour EE and substrate oxidations were measured by whole‐body indirect calorimetry. SPA was assessed by microwave radar. Results: In lean subjects, leptin adjusted for fat mass (FM) was correlated to 24‐hour EE before (r = ?0.56, p < 0.05) but not after adjustment for fat free mass. In obese subjects, leptin correlated inversely with 24‐hour and resting nonprotein respiratory quotient (r = ?0.47, p < 0.05 and r = ?0.50, p < 0.05) both before and after adjustments for energy balance. Baseline plasma leptin concentration, adjusted for differences in FM, was inversely related to the size of weight loss after 8 weeks (r = ?0.41, p = 0.07), 16 weeks (r = ?0.51, p < 0.05), and 24 weeks (r = ?0.50, p < 0.05). Discussion: The present study suggests that leptin may have a stimulating effect on fat oxidation in obese subjects. A low leptin level for a given FM was associated with a greater weight loss, suggesting that obese subjects with greater leptin sensitivities are more successful in reducing weight.     

The influence of body composition, fat distribution, and sustained weight loss on left ventricular mass and geometry in obesity

Alterations in left ventricular mass and geometry vary along with the degree of obesity, but mechanisms underlying such covariation are not clear. In a case–control study, we examined how body composition and fat distribution relate to left ventricular structure and examine how sustained weight loss affects left ventricular mass and geometry. At the 10‐year follow‐up of the Swedish obese subjects (SOS) study cohort, we identified 44 patients with sustained weight losses after bariatric surgery (surgery group) and 44 matched obese control patients who remained weight stable (obese group). We also recruited 44 matched normal weight subjects (lean group). Dual‐energy X‐ray absorptiometry, computed tomography, and echocardiography were performed to evaluate body composition, fat distribution, and left ventricular structure. BMI was 42.5 kg/m², 31.5 kg/m², and 24.4 kg/m² for the obese, surgery, and lean groups, respectively. Corresponding values for left ventricular mass were 201.4 g, 157.7 g, and 133.9 g (P < 0.001). In multivariate analyses, left ventricular diastolic dimension was predicted by lean body mass (β = 0.03, P < 0.001); left ventricular wall thickness by visceral adipose tissue (β = 0.11, P < 0.001) and systolic blood pressure (β = 0.02, P = 0.019); left ventricular mass by lean body mass (β = 1.23, P < 0.001), total body fat (β = 1.15, P < 0.001) and systolic blood pressure (β = 2.72, P = 0.047); and relative wall thickness by visceral adipose tissue (β = 0.02, P < 0.001). Left ventricular adjustment to body size is dependent on body composition and fat distribution, regardless of blood pressure levels. Obesity is associated with concentric left ventricular remodeling and sustained 10‐year weight loss results in lower cavity size, wall thickness and mass.     

Effect of Glucose Tolerance Status on PAI‐1 Plasma Levels in Overweight and Obese Subjects

Objective: The aim of our study was to examine whether plasminogen activator inhibitor‐1 (PAI‐1) plasma levels varied as a function of differences in glucose tolerance status independently of body fatness, body‐fat distribution, and insulin sensitivity. Research Methods and Procedures: Plasma PAI‐1 antigen levels, along with insulin resistance [measured by homeostatic model assessment (HOMA_IR)], central fat accumulation, body composition, blood pressure, and fasting concentrations of glucose, insulin, and lipids, were measured in 229 overweight and obese [body mass index (BMI) ≥25 kg/m²) subjects with normal glucose tolerance (NGT) and in 44 age‐ and BMI‐matched subjects with impaired glucose tolerance (IGT). Results: Plasma PAI‐1 antigen levels were significantly higher in IGT than in NGT subjects. Log PAI‐1 was positively correlated with BMI, HOMA_IR, and log insulin, and inversely associated with high‐density lipoprotein‐cholesterol both in IGT and in NGT individuals. On the other hand, log PAI‐1 was positively correlated with waist circumference, fat mass (FM), fat‐free mass, systolic and diastolic blood pressure, and log triglycerides only in the NGT group. After multivariate analyses, the strongest determinants of PAI‐1 levels were BMI, FM, waist circumference, and high‐density lipoprotein cholesterol in the NGT group and only HOMA_IR in the IGT cohort. Discussion: This study demonstrates that PAI‐1 concentrations are higher in IGT than in NGT subjects. Furthermore, we suggest that the influences of total adiposity, central fat, and insulin resistance, main determinants of PAI‐1 concentrations, are different according to the degree of glucose tolerance.     

Association Between the 4 bp Proinsulin Gene Insertion Polymorphism (IVS‐69) and Body Composition in Black South African Women

The objective of the study was to examine the association between a functional 4 bp proinsulin gene insertion polymorphism (IVS‐69), fasting insulin concentrations, and body composition in black South African women. Body composition, body fat distribution, fasting glucose and insulin concentrations, and IVS‐69 genotype were measured in 115 normal‐weight (BMI <25 kg/m²) and 138 obese (BMI ≥30 kg/m²) premenopausal women. The frequency of the insertion allele was significantly higher in the class 2 obese (BMI ≥35kg/m²) compared with the normal‐weight group (P = 0.029). Obese subjects with the insertion allele had greater fat mass (42.3 ± 0.9 vs. 38.9 ± 0.9 kg, P = 0.034) and fat‐free soft tissue mass (47.4 ± 0.6 vs. 45.1 ± 0.6 kg, P = 0.014), and more abdominal subcutaneous adipose tissue (SAT, 595 ± 17 vs. 531 ± 17 cm², P = 0.025) but not visceral fat (P = 0.739), than obese homozygotes for the wild‐type allele. Only SAT was greater in normal‐weight subjects with the insertion allele (P = 0.048). There were no differences in fasting insulin or glucose levels between subjects with the insertion allele or homozygotes for the wild‐type allele in the normal‐weight or obese groups. In conclusion, the 4 bp proinsulin gene insertion allele is associated with extreme obesity, reflected by greater fat‐free soft tissue mass and fat mass, particularly SAT, in obese black South African women.     

DXA measurements confirm that parental perceptions of elevated adiposity in young children are poor

Objective: To compare parental assessments of child body weight status with BMI measurements and determine whether children who are incorrectly classified differ in body composition from those whose parents correctly rate child weight. Also to ascertain whether children of obese parents differ from those of non‐obese parents in actual or perceived body weight. Research Methods and Procedures: Weights, heights, BMI, and waist girths of New Zealand children ages 3 to 8 years were determined. Fat mass, fat percentage, and lean mass were measured by DXA (n = 96). Parents classified child weight status as underweight, normal‐weight, slightly overweight, or overweight. Centers for Disease Control and Prevention 2000 percentiles of BMI were used. Results: Parents underestimated child weight status. Despite having 83% more fat mass than children with BMI values below the 85th percentile, only 7 of 31 children with BMI values at or above the 85th percentile were rated as slightly overweight or overweight. In the whole sample, participants whose weight status was underestimated by parents (40 of the 96 children) had l9% less fat mass but similar lean mass as children whose weight status was correctly classified. However, children of obese and non‐obese parents did not differ in body composition or anthropometry, and obese parents did not underestimate child weight more than non‐obese parents. Discussion: Because parents underestimate child weight, but BMI values at or above the 85th percentile identify high body fat well, advising parents of the BMI status of their children should improve strategies to prevent excessive fat gain in young children.     

Resting Energy Expenditure Changes With Weight Loss: Racial Differences

It is controversial whether weight loss reduces resting energy expenditure (REE) to a different magnitude in black and white women. This aim of this study was to determine whether changes in REE with weight loss were different between black and white postmenopausal women, and whether changes in body composition (including regional lean and fat mass) were associated with REE changes within each race. Black (n = 26) and white (n = 65) women (age = 58.2 ± 5.4 years, 25 < BMI < 40 kg/m²) completed a 20‐week weight‐loss intervention. Body weight, lean and fat mass (total body, limb, and trunk) via dual‐energy X‐ray absorptiometry, and REE via indirect calorimetry were measured before and after the intervention. We found that baseline REE positively correlated with body weight, lean and fat mass (total, limb, and trunk) in white women only (P < 0.05 for all). The intervention decreased absolute REE in both races similarly (1,279 ± 162 to 1,204 ± 169 kcal/day in blacks; 1,315 ± 200 to 1,209 ± 185 kcal/day in whites). REE remained decreased after adjusting for changes in total or limb lean mass in black (1,302–1,182 kcal/day, P = 0.043; 1,298–1,144 kcal/day, P = 0.006, respectively), but not in white, women. Changes in REE correlated with changes in body weight (partial r = 0.277) and fat mass (partial r = 0.295, 0.275, and 0.254 for total, limb, and trunk, respectively; P < 0.05) independent of baseline REE in white women. Therefore, with weight loss, REE decreased in proportion to the amount of fat and lean mass lost in white, but not black, women.     

Serum Leptin Concentrations and Weight Gain in Postobese,Postmenopausal Women

Objective : This study was designed to determine if serum leptin concentrations (adjusted for fat mass) after weight loss on a low-calorie diet predict subsequent weight gain. Research Methods and Procedures : Body composition and serum leptin concentrations were determined on 14 moderately obese, postmenopausal, nondiabetic women with a familial predisposition to obesity. Assessments were obtained under tightly controlled metabolic ward conditions of macronutrient intake and weight maintenance both before (obese state) and after a mean weight loss of 12.0 kg to normal body weight (postobese state). Four years later, without intervention, body weight and body composition were reassessed. Results : Weight loss resulted in significant decreases in fat mass (29.7 ± 5.4 vs. 20.3 ± 4.7; kg), body mass index (27.7 ± 1.6 vs. 23.0 ± 1.5; kg/m2), percent body fat (40.7 ± 4.3 vs. 33.1 ± 5.0), and serum leptin concentrations (31.8 ± 16.0 vs. 11.5 ± 5.4; ng/mL). Serum leptin concentrations were positively correlated (p<<0.05) with fat mass in both the obese and postobese states (r = 0.67 and r = 0.56, respectively). However, residual serum leptin concentrations (adjusted for fat mass) in the obese and postobese states were not related to changes in body weight (p<= 0.61 and 0.52), fat mass (p = 0.72 and 0.42), body mass index (p = 0.59 and 0.33), or percent body fat (p = 0.84 and 0.46) over the follow-up period. Discussion : These finding do not support the hypothesis that relatively low concentrations of leptin predict weight regain after weight loss. However, because the number of subjects in this study was limited, further studies are warranted.