Cardiometabolic risks during anabolic hormone supplementation in older men

Objective:

To determine the cardiometabolic risks of testosterone and growth hormone (GH) replacement therapy to youthful levels during aging.

Design and Methods:

A double‐masked, partially placebo controlled study in 112 men 65‐90 years‐old was conducted. Transdermal testosterone (5 g vs. 10 g/day) using a Leydig Cell Clamp and subcutaneous recombinant GH (rhGH) (0 vs. 3 vs. 5 μg/kg/day) were administered for 16‐weeks. Measurements included testosterone and IGF‐1 levels, body composition by DEXA, and cardiometabolic risk factors (upper body fat, blood pressure, insulin sensitivity, fasting triglycerides, HDL‐cholesterol, and serum adiponectin) at baseline and after 16 weeks of treatment.

Results:

Some cardiometabolic factors improved (total and trunk fat, triglycerides, HDL‐cholesterol) and others worsened (systolic blood pressure, insulin sensitivity index [QUICKI], adiponectin). Cardiometabolic risk composite scores (CRCSs) improved (?0.69 ± 1.55, P < 0.001). In multivariate analyses, QUICKI, triglycerides, and HDL‐cholesterol contributed 33%, 16%, and 14% of the variance in CRCS, respectively. Pathway analyses indicated that changes in fat and lean mass were related to individual cardiometabolic variables and CRCS in a complex manner. Changes in BMI, reflecting composite effects of changes in fat and lean mass, were more robustly associated with cardiometabolic risks than changes in fat mass or LBM individually.

Conclusions:

Testosterone and rhGH administration was associated with diverse changes in individual cardiometabolic risk factors, but in aggregate appeared not to worsen cardiometabolic risk in healthy older men after 4‐months. The long‐term effects of these and similar anabolic therapies on cardiovascular events should be investigated in populations with greater functional limitations along with important health disabilities including upper body obesity and other cardiometabolic risks.

     

Dynamics of Change in Total and Regional Body Composition After Gastric Bypass in Obese Patients

Little is known on patterns of change over time in body composition, especially lean body mass (LBM), during massive weight loss after Roux‐en‐Y gastric bypass (RYGB) in obese patients. We performed sequential measurements of total and regional body composition in patients after RYGB, and we compared a subsample of patients after surgery to a nonsurgical control group of similar age and body fatness. We used dual‐energy X‐ray absorptiometry (DXA) before and at 3, 6, and 12 months after RYGB in 42 obese women (before surgery: age 39.5 ± 11.6 years; BMI 44.6 ± 6.1 kg/m²; mean ± s.d.) and in 48 control obese women referred for nonsurgical weight management, before weight loss. During 1‐year follow‐up after RYGB, there was a continuous decrease in body weight (?36.0 ± 12.5 kg at 1 year), total fat mass (FM) (?26.0 ± 9.1 kg), as well as in trunk and appendicular FM. In contrast, the decrease in total LBM (?9.8 ± 4.8 kg at 1 year), as well as in trunk and appendicular LBM, plateaued after 3–6 months. Rates of loss in weight, FM, and LBM were highest during the first 3‐month period after RYGB (6.4 ± 1.8, 4.1 ± 1.7, and 2.3 ± 1.2 kg/month, respectively), then decreased continuously for FM but plateaued for LBM. There was no evidence of a decrease in total, trunk, or appendicular LBM in weight‐reduced subjects compared to the control group. In conclusion, follow‐up of these obese women revealed a differential pattern of change in FM and LBM after RYGB. Despite an important loss in LBM, especially during the 3–6 months of initial period, LBM appears to be spared thereafter.     

Body composition and cardiometabolic disease risk factors in captive baboons (Papio hamadryas sp.): Sexual dimorphism

Baboons (Papio hamadryas sp.) exhibit significant sexual dimorphism in body size. Sexual dimorphism is also exhibited in a number of circulating factors associated with risk of cardiometabolic disease. We investigated whether sexual dimorphism in body size and composition underlie these differences. We examined data from 28 male and 24 female outdoor group‐housed young adult baboons enrolled in a longitudinal observational study of cardiometabolic disease risk factors. Animals were sedated with ketamine HCl (10 mg/kg) before undergoing venous blood draws, basic body measurements, and dual‐energy X‐ray absorptiometry body composition scans. Percentage glycated hemoglobin A_1c (%HbA_1c) was measured in whole blood. Serum samples were analyzed for glucose, insulin, C‐peptide, high‐density lipoprotein, and triglyceride concentrations. Males were heavier and had greater body length and lean tissue mass than females. Females had a greater body fat percentage relative to males (10.8 ± 6.4 vs. 6.9 ± 4.0, P = 0.01). Although C‐peptide, fasting glucose, and %HbA_1c did not differ between the sexes, females had greater fasting insulin and triglyceride compared to their male counterparts. Insulin and percentage body fat were significantly correlated in males (r = 0.61, P = 0.001) and to a lesser extent in females (r = 0.43, P = 0.04). Overall, relations between adiposity and fasting insulin and fasting triglyceride were stronger in males. After accounting for differences in percentage body fat, fasting insulin and triglyceride were no longer statistically different between males and females. Despite stronger correlations between relative adiposity and insulin and triglyceride in males, the higher fasting insulin and triglyceride of female baboons may be underlain by their greater relative body fat masses. Am J Phys Anthropol 153:9–14, 2014. © 2013 Wiley Periodicals, Inc.     

Ethnic group differences in cardiometabolic disease risk factors independent of body mass index among American youth

Objective: The purpose of this analysis was to identify any ethnic group differences in the prevalence of cardiometabolic disease risk factors independent of BMI in United States youth. Design and Methods: Data on 3,510 boys and girls aged 8‐11 years from the 1999‐2008 National Health and Nutrition Examination Surveys were analyzed to determine the prevalence of 1 or ≥3 cardiometabolic disease risk factors: abnormal waist circumference and systolic (SBP) and diastolic blood pressure (DBP), increased concentrations of fasting triglyceride, and decreased concentrations of high‐density lipoprotein (HDL) cholesterol before and after adjusting for BMI. Results: Abnormal waist circumference and HDL‐cholesterol significantly differed by ethnic group before and after adjusting for BMI (P < 0.01). Non‐Hispanic blacks were significantly less likely to have abnormal HDL‐cholesterol concentrations than were Hispanics and non‐Hispanic whites, but non‐Hispanic whites were significantly more likely to have elevated triglycerides and three or more abnormal cardiometabolic risk factors than non‐Hispanic blacks. Conclusion: These findings point to ethnic group disparities not related to BMI alone, even in children as young as 8‐11 years. Programs to prevent and treat eventual cardiometabolic disease in children could be tailored for specific ethnic backgrounds as a result.     

Relationships of BMI to Cardiovascular Risk Factors Differ by Ethnicity

The burden of cardiovascular risk associated with obesity disproportionately affects African Americans and little is known about ethnic/racial differences in the relationship of obesity to cardiometabolic risk. This report assesses whether obesity is similarly associated with cardiometabolic risk factors in African Americans and whites of European ancestry. Cross‐sectional observational data from the Jackson Heart Study (JHS) and the Framingham Heart Study (FHS) were compared. This analysis uses participants aged 35–74 years with BMI >18.5 kg/m², and free of prevalent cardiovascular disease (CVD), from the initial JHS clinical examination (2000–2004) and the FHS Offspring (1998–2001) and Third Generation (2002–2005) cohorts. Participants were evaluated for the presence of lipid abnormalities, hypertension, and diabetes. Overall, 4,030 JHS (mean age 54 years, 64% women) and 5,245 FHS (mean age 51 years, 54% women) participants were available for analysis. The prevalence of all risk factors except high triglycerides and low high‐density lipoprotein (HDL) was substantially higher in JHS (all P < 0.001) and BMI was associated with increasing prevalence of most CVD risk factors within each race. For diabetes mellitus, hypertension, and low HDL, steeper relationships to BMI were observed in FHS than in JHS (P values <0.001–0.016). There were larger proportional increases in risk factor prevalence with increasing BMI in whites than in African Americans. The higher prevalence rates of cardiometabolic risk factors at nearly all levels of BMI in African Americans, however, suggest that additional factors contribute to the burden of CVD risk in African Americans.     

Calcium and dairy product modulation of lipid utilization and energy expenditure

Objective: The purpose of this study was to investigate the impact of dietary calcium or dairy product intake on total energy expenditure (TEE), fat oxidation, and thermic effect of a meal (TEM) during a weight loss trial. Methods and Procedures: The intervention included a prescribed 500‐kcal deficit diet in a randomized placebo‐controlled calcium or dairy product intervention employing twenty‐four 18 to 31‐year‐old (22.2 ± 3.1 years, mean ± s.d.) overweight women (75.5 ± 9.6 kg). TEM and fat oxidation were measured using respiratory gas exchange after a meal challenge, and TEE was measured by doubly labeled water. Fat mass (FM) and lean mass (fat‐free mass (FFM)) were measured by dual‐energy X‐ray absorptiometry. Subjects were randomized into one of these three intervention groups: (i) placebo (<800 mg/day calcium intake); (ii) 900 mg/day calcium supplement; (iii) three servings of dairy products/day to achieve an additional 900 mg/day. Results: There were no group effects observed in change in TEE; however, a group effect was observed for fat oxidation after adjusting for FFM (P = 0.02). The treatment effect was due to an increase in fat oxidation in the calcium‐supplemented group of 1.5 ± 0.6 g/h, P = 0.02. Baseline 25‐hydroxyvitamin D (25OHD) was positively correlated with TEM (R = 0.31, P = 0.004), and trended toward a correlation with fat oxidation (P = 0.06), independent of group assignment. Finally, the change in log parathyroid hormone (PTH) was positively correlated with the change in trunk FM (R = 0.27, P = 0.03). Discussion: These results support that calcium intake increases fat oxidation, but does not change TEE and that adequate vitamin D status may enhance TEM and fat oxidation.     

The Terneuzen Birth Cohort: BMI change between 2 and 6 years is most predictive of adult cardiometabolic risk

Background

We recently reported the age interval 2–6y being the earliest and most critical for adult overweight. We now aim to determine which age intervals are predictive of cardiometabolic risk at young adulthood.

Methods and Findings

We analyzed data from 642 18–28 years olds from the Terneuzen Birth Cohort. Individual BMI SDS trajectories were fitted by a piecewise linear model. By multiple regression analyses relationships were assessed between subsequent conditional BMI SDS changes and components of the metabolic syndrome (MetS), skinfold thickness and hsCRP at young adulthood. Results were adjusted for gender and age, and other confounders. Gender was studied as an effect modifier. All BMI SDS changes throughout childhood were related to waist circumference and skinfold thickness. No other significant relationship was found before the age of 2 years, except between the BMI SDS change 0–1y and hsCRP. Fasting blood glucose was not predicted by any BMI SDS change. BMI SDS change 2–6y was strongly related to most outcome variables, especially to waist circumference (ß 0.47, SE 0.02), systolic and diastolic blood pressure (ß 0.20 SE 0.04 and ß 0.19 SE 0.03), and hsCRP (ß 0.16 SE 0.04). The BMI SDS change 10–18y was most strongly related to HDL cholesterol (ß -0.10, SE 0.03), and triglycerides (ß 0.21, SE 0.03). To a lesser degree, the BMI SDS change 6–10y was related to most outcome variables. BMI SDS changes 2–6y and 10–18y were significantly related to MetS: the OR was respectively 3.39 (95%CI 2.33–4.94) and 2.84 (95%CI 1.94–4.15).

Conclusion

BMI SDS changes from 2y onwards were related to cardiometabolic risk at young adulthood, the age interval 2–6y being the most predictive. Monitoring and stabilizing the BMI SDS of children as young as 2–6y may not only reverse the progression towards adult overweight, but it may also safeguard cardiometabolic status.     

Sex Differences in the Association of Thigh Fat and Metabolic Risk in Older Adults

We have previously shown a favorable association of subcutaneous leg fat with markers of insulin resistance and dyslipidemia in postmenopausal women. It is not known whether there is a sex dimorphism in the association of lower‐body adiposity with reduced metabolic risk. Thus, our primary aim was to determine whether the favorable association of thigh subcutaneous fat, independent of abdominal fat, is also observed in older men. Mid‐thigh and abdominal fat areas were measured by computed tomography (CT) in 108 older men and postmenopausal women (mean ± s.d.; 69 ± 7 years). Additionally, trunk and leg fat mass (FM) were measured by dual‐energy X‐ray absorptiometry (DXA). Markers of insulin resistance and dyslipidemia were determined from oral glucose tolerance tests and lipid and lipoprotein measurements, respectively. Outcomes were fasted and postchallenge (area under the curve, AUC) insulin (INS_AUC) and glucose (GLU_AUC), product of the insulin and glucose AUC (INS_AUC × GLU_AUC), triglycerides (TG), and high‐density lipoprotein (HDL)‐cholesterol. Consistent with our previous findings in postmenopausal women, adjusting for DXA trunk FM revealed a favorable association of DXA leg FM with the metabolic risk outcomes in both older men and postmenopausal women. Likewise, adjusting for CT abdominal visceral fat generally revealed a favorable association of CT thigh fat with metabolic risk outcomes in women, but not men. The discordance between the DXA and CT results in men is unclear but may be due to sex differences in visceral fat accrual. The mechanisms underlying the protective effect of thigh fat on metabolic risk factors need to be elucidated.     

Physical Activity Levels Are Low in Free‐Living Adults with Chronic Paraplegia

Objectives: To compare physical activity levels (PALs) of free‐living adults with chronic paraplegia with World Health Organization recommendations and to compare energy expenditure between persons with complete vs. incomplete paraplegia. Research Methods and Procedures: Twenty‐seven euthyroid adults (17 men and 10 women) with paraplegia (12.5 ± 9.5 years since onset; 17 with complete lesions and 10 with incomplete lesions) participated in this cross‐sectional study. Resting metabolic rate was measured by indirect calorimetry and total daily energy expenditure (TDEE) by heart rate monitoring. PAL was calculated as TDEE/resting metabolic rate. Total body water was measured by deuterium dilution and fat‐free mass (FFM) and fat mass (FM) by calculation (FFM = total body water/0.732; FM = weight ? FFM). Obesity was defined using the following percentage FM cutoffs: men 18 to 40 years >22% and 41 to 60 years >25%; and women 18 to 40 years >35% and 41 to 60 years >38%. Results: Nineteen subjects (70.4%; 13 men and six women) were obese. Fifteen subjects (56%) engaged in structured physical activity 1.46 ± 0.85 times during the observation period for a mean of 49.4 ± 31.0 minutes per session. Despite this, mean PAL of the group was 1.56 ± 0.34, indicative of limited physical activity. TDEE was 24.6% lower in subjects with complete paraplegia (2072 ± 505 vs. 2582 ± 852 kcal/d, p = 0.0372). Discussion: PAL of the group was low, indicating that persons with paraplegia need to engage in increased frequency, intensity, and/or duration of structured physical activity to achieve a PAL ≥1.75 and, thereby, to offset sedentary activities of daily living.     

Effect of sarcopenia on cardiovascular disease risk factors in obese postmenopausal women

Objective: To compare sarcopenic‐obese and obese postmenopausal women for risk factors predisposing to cardiovascular disease (CVD) and determine whether there may be a relationship between muscle mass and metabolic risk in obese postmenopausal women. Research Methods and Procedures: In this cross‐sectional study, 22 healthy obese postmenopausal women (mean age, 66 ± 5 years; mean BMI, 27 ± 3 kg/m²) were divided into two groups matched for age (±2 years) and fat mass (FM) (±2%). Sarcopenia was defined as a muscle mass index of <14.30 kg fat‐free mass (FFM)/m² (which corresponds to 1 standard deviation below the values of a young reference population), and obesity was defined as an FM of >35% (which corresponds to the World Health Organization guidelines). FM, FFM (measured by DXA), daily energy expenditure (accelerometry), dietary intake (3‐day dietary record), and blood biochemical analyses (lipid profile, insulin, glucose, and C‐reactive protein) were obtained. Visceral fat mass (VFM) was calculated by the equation of Bertin, which estimates VFM from DXA measurements. Results: Obese women had more FFM (p = 0.006), abdominal FM (p = 0.047), and VFM (p = 0.041) and a worse lipid profile [p = 0.040 for triglycerides; p = 0.004 for high‐density lipoprotein (HDL); p = 0.026 for total cholesterol/HDL] than sarcopenic‐obese postmenopausal women. Obese women also ingested significantly more animal (p = 0.001) and less vegetal proteins (p = 0.013), although both groups had a similar total protein intake (p = 0.967). Discussion: Sarcopenia seems to be associated with lower risk factors predisposing to CVD in obese postmenopausal women. With the increase in the number of aging people, the health implications of being sarcopenic‐obese merit more attention.     

Short‐Term Effects of Weight Loss on the Cardiovascular Risk Factors in Morbidly Obese Patients

Objective: To analyze the short‐term effects of weight loss on the cardiovascular risk factors in morbidly obese patients. Research Methods and Procedures: Five metabolic cardiovascular risk factors (blood glucose, blood pressure, total cholesterol, high‐density lipoprotein (HDL)‐cholesterol, and triglycerides) were determined before and 15.3 ± 2.1 months after laparoscopic gastric banding in 650 morbidly obese patients. Global cardiovascular risk was calculated according to the Prospective Cardiovascular Münster (PROCAM) scoring system. Results: Mean weight loss was 22.7 ± 20.4 kg. Normalization of the metabolic alteration was observed in 67.3% of patients with diabetes, 38.3% of patients with hypercholesterolemia, 72.5% of patients with low HDL‐cholesterol, 72.3% of patients with hypertriglyceridemia, and 46.7% of patients with hypertension. PROCAM score fell from 31.4 ± 11.6 to 28.0 ± 12.0 points (p < 0.001). The modifications of total cholesterol and blood pressure were unrelated to percentage weight loss. Percentage weight loss was significantly related to the reductions of fasting blood glucose, triglyceride level, and the PROCAM score and to the increase of HDL‐cholesterol concentrations observed after surgery. However, the strength of these four relationships was generally low. The variations of HDL‐cholesterol concentrations and blood pressure levels were more influenced by actual energy balance than by the extent of weight loss. Discussion: Weight loss observed in the first 12 to 18 months after gastric banding was associated with a significant improvement of single cardiovascular risk factors and global risk. On the other hand, the extent of weight loss was poorly related to the magnitude of improvement in cardiovascular risk.     

Associations of leg fat accumulation with adiposity‐related biological factors and risk of metabolic syndrome

Objective:

To examine associations between regional fat mass (FM) distribution and cardiometabolic risk factors among ethnic minority groups, such as non‐Hispanic blacks and Hispanics.

Design and Methods:

The associations among 8,802 US residents who participated in the 1999‐2004 US National Health and Nutrition Examination Survey were examined. Body composition was measured using dual‐energy X‐ray absorptiometry. Leg fat indices included leg FM, leg FM percent (FM%), leg to whole body FM ratio (leg/whole), and leg to trunk FM ratio (leg/trunk). The correlation between leg fat indices and adiposity‐related risk factors, as well as the association of these indices with metabolic syndrome (MetS) was evaluated.

Results:

After adjusting for covariates including age, gender, and trunk FM or trunk FM%, higher leg FM and leg FM% were, in general, correlated favorably with adiposity‐related risk factors and associated with lower odds of MetS in all ethnicities, including non‐Hispanic whites and blacks and Hispanic groups. In addition, in all multivariate‐adjusted models, leg/whole and leg/trunk ratios were strongly associated with lower levels of most risk factors and decreased odds of MetS in these ethnicities (all odds ratios comparing extreme quintiles < 0.1).

Conclusions:

Results show that leg fat accumulation is inversely associated with adiposity‐related biological factors and risk of MetS in both whites and ethnic groups, suggesting that regional fat distribution plays an important role in the etiology of adiposity‐related diseases in these populations.     

From metabolic normality to cardiometabolic risk factors in subjects with obesity

The aim of the study was to evaluate the 3 years incidence of cardiometabolic risk factors, such as impaired fasting glucose, reduced high-density lipoprotein (HDL)-cholesterol, increased plasma triglycerides or blood pressure as well as impaired glucose tolerance in overweight or obese (ow/ob) and normal body weight (nbw) subjects metabolically normal at baseline. Subjects from the Relationship between Insulin Sensitivity and Cardiovascular Disease (RISC) study were analyzed. We analyzed 284 nbw and 152 ow/ob subjects who, at baseline, did not show any of the above-mentioned cardiometabolic risk factors. At 3 years, these parameters were re-evaluated. Intima-media thickness (IMT) of the common carotid artery (CCA) was echographically measured. At follow-up, the incidence of one or more cardiometabolic risk factors was 57.2% in ow/ob vs. 31.7% in nbw (P < 0.0001). After adjustment for age, sex, menopause status, lifestyle parameters, insulin sensitivity, and fasting insulinemia, BMI remained significantly linked to the development of one or more cardiometabolic risk factors (P = 0.02). An increased BMI at follow-up was significantly associated with the development of cardiometabolic alterations, in both nbw and ow/ob groups (P = 0.04). Ow/ob subjects who, at 3 years follow-up, remained metabolically normal, showed a less favourable cardiometabolic profile, when compared to nbw counterparts. In ow/ob metabolically normal males and females, intima-media of the common carotid at follow-up was thicker than in nbw (P = 0.03 for males, P = 0.04 for females). In conclusion, metabolically normal obese subjects show a higher incidence of cardiometabolic risk factors, in a short follow-up period. Weight gain is significantly associated with the development of these factors, in both nbw and ow/ob subjects.     

Structural-functional changes in the cardiovascular system during high athletic activity in aboriginals of Yakutia

To study structural-functional changes in the cardiovascular system and metabolic characteristics in residents of Yakutia who were engaged in sports activities, 146 Yakut men 18–29 years old living in Yakutsk were examined. The basic group consisted of elite athletes (free-style wrestling and boxing) (n = 108; average age, 20.2 ± 0.2 years). The control group consisted of untrained healthy men (n = 38; average age, 24.5 ± 0.4 years). The examination included primary inspection, anthropometry, echocardiography, integral rheography of the body, measurement of blood pressure (BP), and biochemical analysis of blood serum. The basic group was divided into two subgroups depending on the BP level (Ia, with optimal and normal BP; Ib, with high normal BP).     

Isoprostanes and isofurans as non-traditional risk factors for cardiovascular disease among Canadian Inuit

Abstract

Objectives: The aim of the present study was to investigate the potential importance of oxidative stress, measured by isoprostanes-related compounds, as non-traditional risk factor for cardiovascular disease. We planned to examine the relationship between concentrations of plasma F₂-isoprostanes (F₂-IsoPs), isofurans (IsoFs), measures of obesity and various cardiometabolic risk factors. Materials and methods: Cross-sectional study using a sub-sample from the population of a survey conducted in the summer and fall 2007 and 2008 by Canadian Coastguard Ship Amundsen in 36 Canadian Arctic Inuit communities. Subjects included a subset (n =?233) of a total study population (n =?2595) with a mean age 42.56 ± 15.39 years and body mass index 27.78 ± 5.65 kg/m². Plasma levels of F₂-IsoPs and IsoFs was determined by gas chromatography/negative ion chemical ionization/mass spectrometry (GC/NICI/MS) method; and their relationships to waist circumference (WC), blood pressure C reactive proteins (CRP), blood lipids and fasting glucose were assessed by multivariate analyses. Results: Plasma F₂-IsoPs correlated positively with CRP (r =.132, P =.048) and systolic blood pressure (SBP) (r =.157, P =.024) after adjustment for age, sex and body mass index. IsoFs correlated with WC (r =.190, P =.005) and SBP (r =.137, P =.048). F2-IsoPs were not found elevated in smokers (P =.034), whereas IsoFs were decreased in smokers (P =.001). WC, SBP and sex were found to be major correlates of oxidative stress in Canadian Inuit. Conclusions: Plasma measures of F₂-IsoPs and IsoFs increase with increased obesity and associated cardiometabolic risk factors, including CRP and blood pressure. Simultaneous measurement of IsoFs provides an advantageous mechanistic insight into oxidative stress not captured by F₂-IsoPs alone.     

The Predatory Mite Phytoseiulus persimilis Adjusts Patch-leaving to Own and Progeny Prey Needs

Integration of optimal foraging and optimal oviposition theories suggests that predator females should adjust patch leaving to own and progeny prey needs to maximize current and future reproductive success. We tested this hypothesis in the predatory mite Phytoseiulus persimilis and its patchily distributed prey, the two-spotted spider mite Tetranychus urticae. In three separate experiments we assessed (1) the minimum number of prey needed to complete juvenile development, (2) the minimum number of prey needed to produce an egg, and (3) the ratio between eggs laid and spider mites left when a gravid P. persimilis female leaves a patch. Experiments (1) and (2) were the pre-requirements to assess the fitness costs associated with staying or leaving a prey patch. Immature P. persimilis needed at least 7 and on average 14±3.6 (SD) T. urticae eggs to reach adulthood. Gravid females needed at least 5 and on average 8.5±3.1 (SD) T. urticae eggs to produce an egg. Most females left the initial patch before spider mite extinction, leaving prey for progeny to develop to adulthood. Females placed in a low density patch left 5.6±6.1 (SD) eggs per egg laid, whereas those placed in a high density patch left 15.8±13.7 (SD) eggs per egg laid. The three experiments in concert suggest that gravid P. persimilis females are able to balance the trade off between optimal foraging and optimal oviposition and adjust patch-leaving to own and progeny prey needs.     

A cross‐sectional study of osteocalcin and body fat measures among obese adolescents

Osteocalcin (OCN), a marker of osteoblast activity, has been implicated in the regulation of energy metabolism by the skeleton and thus may affect body fat measures.

Objective:

To examine the relationships of OCN to body fat measures and whether they vary according to markers of energy and vitamin D metabolism.

Design and Methods:

Data were obtained from 58 obese adolescents aged 13‐17.9 years (38 females, 8 black or African‐American). Total fat mass (FM) [dual X‐ray absorptiometry (DXA)] and visceral adipose tissue (VAT) [computerized axial tomography (CT)] were calculated. Blood tests included leptin, OCN, 25‐hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), thyroid function tests, and triglycerides. Markers of glucose metabolism were obtained from fasting and OGTT samples.

Results and Conclusions:

Adolescents with 25(OH)D <20 ng mL^?1 were considered deficient (n = 17/58); none had high PTH (PTH ≥ 65 pg mL^?1). OCN was associated with lower VAT (?84.27 ± 33.89 mm²) and BMI (?0.10 ± 0.05 kg m^?2), not FM (P = 0.597) in a core model including age, sex, race, geographic latitude, summer, height z‐score, and tanner stage. Adding 25(OH)D deficiency and PTH attenuated the inverse association of OCN to VAT. There was a significant interaction of OCN and 25(OH)D deficiency on FM (0.37 ± 0.18 kg, P = 0.041) and BMI (0.28 ± 0.10 kg m^?2, P = 0.007) in this adjusted model, which was further explained by leptin. Adding A1C to the core model modified the relationship of OCN to VAT (?93.08 ± 35.05 mm², P = 0.011), which was further explained by HOMA‐IR. In summary, these findings provide initial evidence for a relationship between OCN and body fat measures that is dependent on energy metabolism and vitamin D status among obese adolescents.

     

Birth weight is inversely associated with central adipose tissue in healthy children and adolescents

Objective: Previous studies have explored the association between birth weight and excess childhood body fat, but few have used precise measures of body composition, leading to equivocal and sometimes contradictory results. Research Methods and Procedures: Subjects included 101 children who underwent DXA measurements between 1995 and 2000. Birth weight and gestational age were assessed using maternal recall. Multiple linear regression analysis was used to determine the relationship between birth weight and the following four outcome variables: total fat mass (FM), truncal fat mass (TrFM), percentage body fat (%BF), and TrFM adjusted for FM (TrFMadj), controlling for current weight and Tanner stage. Results: The mean age of the children studied was 12.9 ± 2.4 years, and the mean birth weight reported by subjects’ mothers was 3.3 ± 0.5 kg. The FM and TrFM were 12.8 ± 8.7 kg and 5.1 ± 4.1 kg, respectively, and the mean %BF was 22.9 ± 10.3%. Birth weight was a significant predictor of FM (p = 0.02) and %BF (p = 0.038). However, birth weight adjusted for gestational age (BWTadj) was a significant (p = 0.03) negative predictor of TrFMadj, independently of race, sex, Tanner stage, and current weight. Discussion: These results provide evidence that, even in childhood and adolescence, a higher birth weight is associated with higher FM and %BF, while a low birth weight is associated with TrFM, adjusted for FM.     

The beneficial effects of α-cyclodextrin on blood lipids and weight loss in healthy humans

α‐Cyclodextrin (α‐CD) is a soluble fiber derived from corn. It has previously been reported that early intervention with Mirafit fbcx, a trademarked name for α‐CD, has beneficial effects on weight management in obese individuals with type 2 diabetes, and that it preferentially reduces blood levels of saturated and trans fats in the LDL receptor knockout mice. The current investigation involves overweight but not obese nondiabetic individuals and was intended to confirm the effects of α‐CD on both weight management and improving blood lipid levels. Forty‐one healthy adults (age: 41.4 ± 13.6 years) participated in this 2‐month, double‐blinded, crossover study. In 28 compliant participants (8 males and 20 females), when the active phase was compared to the control phase, there were significant decreases in body weight (?0.4 ± 0.2 kg, P < 0.05), serum total cholesterol (mean ± s.e.m., ?0.295 ± 0.10 mmol/l, 5.3%, P < 0.02) and low‐density lipoprotein (LDL) cholesterol (?0.23 ± 0.11 mmol/l, ?6.7%, P < 0.05). Apolipoprotein B (Apo B) (?0.0404 ± 0.02 g/l, ?5.6%, P = 0.06) and insulin levels also decreased by 9.5% (?0.16 ± 0.08 pmol/l, P = 0.06) while blood glucose and leptin levels did not change. These results suggest that α‐CD exerts its beneficial health effects on body weight and blood lipid profile in healthy nonobese individuals, as previously reported in obese individuals with type 2 diabetes.     

Duration of obesity exposure between ages 10 and 40 years and its relationship with cardiometabolic disease risk factors: A cohort study

BackgroundIndividuals with obesity do not represent a homogeneous group in terms of cardiometabolic risk. Using 3 nationally representative British birth cohorts, we investigated whether the duration of obesity was related to heterogeneity in cardiometabolic risk.Methods and findingsWe used harmonised body mass index (BMI) and cardiometabolic disease risk factor data from 20,746 participants (49.1% male and 97.2% white British) enrolled in 3 British birth cohort studies: the 1946 National Survey of Health and Development (NSHD), the 1958 National Child Development Study (NCDS), and the 1970 British Cohort Study (BCS70). Within each cohort, individual life course BMI trajectories were created between 10 and 40 years of age, and from these, age of obesity onset, duration spent obese (range 0 to 30 years), and cumulative obesity severity were derived. Obesity duration was examined in relation to a number of cardiometabolic disease risk factors collected in mid-adulthood: systolic (SBP) and diastolic blood pressure (DBP), high-density-lipoprotein cholesterol (HDL-C), and glycated haemoglobin (HbA1c).A greater obesity duration was associated with worse values for all cardiometabolic disease risk factors. The strongest association with obesity duration was for HbA1c: HbA1c levels in those with obesity for <5 years were relatively higher by 5% (95% CI: 4, 6), compared with never obese, increasing to 20% (95% CI: 17, 23) higher in those with obesity for 20 to 30 years. When adjustment was made for obesity severity, the association with obesity duration was largely attenuated for SBP, DBP, and HDL-C. For HbA1c, however, the association with obesity duration persisted, independent of obesity severity. Due to pooling of 3 cohorts and thus the availability of only a limited number harmonised variables across cohorts, our models included adjustment for only a small number of potential confounding variables, meaning there is a possibility of residual confounding.ConclusionsGiven that the obesity epidemic is characterised by a much earlier onset of obesity and consequently a greater lifetime exposure, our findings suggest that health policy recommendations aimed at preventing early obesity onset, and therefore reducing lifetime exposure, may help reduce the risk of diabetes, independently of obesity severity. However, to test the robustness of our observed associations, triangulation of evidence from different epidemiological approaches (e.g., mendelian randomization and negative control studies) should be obtained.

Tom Norris and colleagues investigate how obesity duration and obesity severity throughout a person''s lifetime may affect cardiometabolic risk factors such as blood pressure, cholesterol, and glycated haemoglobin.