Plasma stearoyl‐CoA desaturase indices: Association with lifestyle,diet, and body composition

Objective:

Stearoyl‐coenzyme A desaturase‐1 (SCD1) is a key enzyme in fatty acid and energy metabolism. Increased hepatic SCD1 activity is associated with obesity and obesity‐related diseases. We examined the relations of two plasma SCD activity indices (16:1n‐7/16:0, 18:1n‐9/18:0) with body composition, and the association of lifestyle and dietary variables with the plasma SCD indices.

Design and Methods:

This population‐based, cross‐sectional study of 2021 elderly (71–74 y) men and women from the Hordaland Health Study in Western Norway was conducted using a validated food frequency questionnaire, body composition measurements by dual‐energy X‐ray absorptiometry and determination of the plasma fatty acid profile.

Results:

In multivariate regression analyses, plasma SCD indices were positively associated with BMI and body fat (P < 0.001 for both). From the 2.5th to 97.5th percentiles of plasma SCD‐16 and SCD‐18 indices, fat mass differed by about 8 kg and 5 kg, respectively. Intake of polyunsaturated fatty acids were negatively associated with SCD‐16 (partial r = ?0.30) and SCD‐18 (partial r = ?0.24) (P < 0.001 for both). Alcohol intake was positively associated with SCD‐16 (partial r = 0.26) and SCD‐18 (partial r = 0.16) (P < 0.001 for both), whereas coffee consumption and physical activity were inversely associated with SCD‐16 (P = 0.026 and P = 0.006, respectively) and SCD‐18 (P = 0.001 and P = 0.022, respectively).

Conclusions:

In this elderly population, plasma markers of SCD1 activity are associated with increased adiposity. Furthermore, modifiable dietary habits and lifestyle are associated with plasma SCD indices. These results suggest that SCD1 activity may be a promising target for weight control.

     

High‐normal tsh values in obesity: Is it insulin resistance or adipose tissue's guilt?

Objective:

Clinical evidences reported subclinical alterations of thyroid function in obesity, although the relationship between thyroid status and obesity remains unclear. We cross‐sectionally investigated the influence of metabolic features on hypothalamic–pituitary–thyroid axis in obesity.

Design and Methods:

We enrolled 60 euthyroid subjects with no history of type 2 diabetes mellitus and assessed the relationship of thyroid function with insulin resistance, measured using euglycemic clamp, and abdominal fat volume, quantified by computed tomography scan (CT scan). Thyroid stimulating hormone (TSH) correlated with BMI (r = 0.46; P = 0.02), both visceral (r = 0.58; P = 0.02) and subcutaneous adipose tissue volumes (r = 0.43; P = 0.03) and insulin resistance (inverse relationship with insulin sensitivity–glucose uptake: r = ?0.40; P = 0.04).

Results:

After performing multivariate regression, visceral adipose tissue volume was found to be the most powerful predictor of TSH (β = 3.05; P = 0.01), whereas glucose uptake, high‐density lipoprotein (HDL) cholesterol, low‐density lipoprotein (LDL) cholesterol, subcutaneous adipose tissue volume, and triglycerides were not. To further confirm the hypothesis that high‐normal TSH values could be dependent on adipose tissue, and not on insulin resistance, we restricted our analyses to moderately obese subjects' BMI ranging 30‐35 kg/m². This subgroup was then divided as insulin resistant and insulin sensitive according to the glucose uptake (≤ or >5 mg·kg^?1·min^?1, respectively). We did not find any statistical difference in TSH (insulin resistant: 1.62 ± 0.65 µU/ml vs. insulin sensitive: 1.46 ± 0.48; P = not significant) and BMI (insulin resistant: 32.2 ± 1.6 kg/m² vs. insulin sensitive: 32.4 ± 1.4; P = not significant), thus confirming absence of correlation between thyroid function and insulin sensitivity per se.

Conclusion:

Our study suggests that the increase in visceral adipose tissue is the best predictor of TSH concentration in obesity, independently from the eventual concurrent presence of insulin resistance.

     

Circulating regulatory T cells are reduced in obesity and may identify subjects at increased metabolic and cardiovascular risk

Objective:

Reduced numbers of regulatory T (T_reg) cells have been observed in visceral adipose tissue of obese mice and humans. However, it is unknown whether human obesity affects circulating Treg cells and whether their number is associated with markers of systemic inflammation or glucose intolerance.

Design and Methods:

Peripheral blood mononuclear cells were isolated from venous blood of obese (BMI ≥ 27 kg/m²; n = 30) and nonobese (BMI ≥ 27 kg/m²; n = 13) individuals and analyzed using flow cytometry for the expression of CD4, CD25, and Foxp3.

Results:

Reduced circulating T_reg‐cell numbers were detected in obese compared with nonobese study participants (P = 0.038). Circulating CD4⁺CD25⁺CD127^?Foxp3 T_reg cells inversely correlated with body weight (P = 0.009), BMI (P = 0.004) and plasma leptin levels (P = 0.004) and were reduced in subjects with hsCRP ≥ 3.0 mg/L (P = 0.034) or HbA1c ≥ 5.5% (P < 0.005). Receiver operating characteristic curve analysis revealed a cutoff of circulating Treg cells < 1.06% to be predictive for hsCRP levels ≥ 3.0 mg/L, and logistic regression showed that the risk of having hsCRP levels ≥ 3.0 mg/L was increased 9.6‐fold (P = 0.008), if T_reg cells were below this threshold. The T_reg cutoff for HbA1c levels ≥ 5.5% was 0.73%, and this cutoff also predicted an increased risk of having elevated levels of both hsCRP and HbA1c, if only obese subjects were examined.

Conclusion:

Our findings thus reveal an association between circulating T_reg cells and measures of adiposity, inflammation, and glucose intolerance. Although further prospective studies are needed, we present data suggesting that the determination of T_reg cells might be useful to identify obese subjects at increased risk of developing cardiovascular and/or metabolic complications.

     

Sleep apnea modifies the long‐term impact of surgically induced weight loss on cardiac function and inflammation

Objective:

Obesity is frequently associated with obstructive sleep apnea (OSA). Both conditions are proinflammatory and proposed to deteriorate cardiac function. We used a nested cohort study design to evaluate the long‐term impact of bariatric surgery on OSA and how weight loss and OSA relate to inflammation and cardiac performance.

Design and Methods:

At 10‐year follow‐up in the Swedish Obese Subjects (SOS) study, we identified 19 obese subjects (BMI 31.2 ± 5.3 kg m^?2), who following bariatric surgery at SOS‐baseline had displayed sustained weight losses (surgery group), and 20 obese controls (BMI 42.0 ± 6.2 kg m^?2), who during the same time‐period had maintained stable weight (control group). All study participants underwent overnight polysomnography examination, echocardiography and analysis of inflammatory markers.

Results:

The surgery group displayed a lower apnea hypopnea index (AHI) (19.9 ± 21.5 vs. 37.8 ± 27.7 n/h, P = 0.013), lower inflammatory activity (hsCRP 2.3 ± 3.0 vs. 7.2 ± 5.0 mg L^?1, P < 0.001), reduced left ventricular mass (165 ± 22 vs. 207 ± 22 g, P < 0.001) and superior left ventricular diastolic function (E/A ratio 1.24 ± 1.10 vs. 1.05 ± 0.20, P = 0.006) as compared with weight stable obese controls. In multiple regression analyses including all subjects (n = 39) and controlling for BMI, the AHI remained independently associated with hsCRP (β = 0.09, P < 0.001), TNF‐α (β = 0.03, P = 0.031), IL‐6 (β = 0.01, P = 0.007), IL 10 (β = ?0.06; P = 0.018), left ventricular mass (β = 0.64, P < 0.001), left atrial area (β = 0.08, P = 0.002), pulmonary artery pressure (β = 0.08, P = 0.011) and E/E_a ratio (β = 0.04, P = 0.021).

Conclusions:

Patients with sustained weight loss after bariatric surgery display less severe sleep apnea, reduced inflammatory activity, and enhanced cardiac function. Persisting sleep apnea appears to limit the beneficial effect of weight loss on inflammation and cardiac performance.

     

Liver fat and SHBG affect insulin resistance in midlife women: The Study of Women's Health Across the Nation (SWAN)

Objective:

The liver is an insulin‐responsive organ that contributes significantly to both whole body insulin sensitivity and availability of sex steroids through the production of sex hormone binding globulin (SHBG). Our objective was to explore whether lower SHBG was associated with ectopic liver fat and mediated its effect on insulin resistance in The Study of Women's Health Across the Nation (SWAN).

Design and Methods:

A subset of midlife African American and Caucasian women from SWAN (n = 208; 50.9 ± 0.18 yrs; 71% Caucasian) had computed tomography scans to quantify visceral, subcutaneous and liver fat. Blood samples were collected and assayed for hormonal and metabolic markers.

Results:

The cohort, while overweight, was generally healthy, and both liver fat and SHBG were unaffected by menopausal stage or race. Both higher liver fat and lower SHBG levels were significantly associated with higher insulin concentrations after adjustment for adiposity (r = ?0.25, P < 0.001 and r = ?0.18, P = 0.01). SHBG and liver fat had additive effects on insulin concentrations such that women with the lowest SHBG and the highest fat levels had the highest values (interaction P = 0.09). The association between SHBG and insulin was more apparent among women with fattier livers. SHBG and liver fat appear to have independent effects on insulin levels as adjustment for each other did not diminish the strength of either association (P = 0.023 and 0.001 respectively).

Conclusion:

These results confirmed the strong independent associations between increased liver fat and decreased SHBG with increased metabolic risk in midlife women. Further these data underscore the need for additional research into the role of liver fat in modifying SHBG's influence on insulin levels.

     

Associations of testosterone and sex hormone binding globulin with adipose tissue hormones in midlife women

Objective:

Regulators of adipose tissue hormones remain incompletely understood, but may include sex hormones. As adipose tissue hormones have been shown to contribute to numerous metabolic and cardiovascular disorders, understanding their regulation in midlife women is of clinical importance. Therefore, we assessed the associations between testosterone (T) and sex hormone binding globulin (SHBG) with leptin, high molecular weight (HMW) adiponectin, and the soluble form of the leptin receptor (sOB‐R) in healthy midlife women.

Design and Methods:

Cross‐sectional analyses were performed using data from 1,881 midlife women (average age 52.6 (±2.7) years) attending the sixth Annual follow‐up visit of the multiethnic Study of Women's Health Across the Nation.

Results:

T was weakly negatively associated with both HMW adiponectin and sOB‐R (r = ?0.12 and r = ?0.10, respectively; P < 0.001 for both), and positively associated with leptin (r = 0.17; P < 0.001). SHBG was more strongly and positively associated with both HMW adiponectin and sOB‐R (r = 0.29 and r = 0.24, respectively; P < 0.001 for both), and more strongly and negatively associated with leptin (r = ?0.27; P < 0.001). Adjustment for fat mass, insulin resistance, or waist circumference only partially diminished associations with HMW adiponectin and sOB‐R, but attenuated associations with leptin. In conclusion, in these midlife women, lower SHBG values, and to a lesser extent, higher T levels, were associated with lower, or less favorable, levels of adiponectin and sOB‐R, independent of fat mass.

Conclusions:

These data suggest that variation in these adipose hormones resulting from lower SHBG levels, and possibly, though less likely, greater androgenicity, may contribute to susceptibility for metabolic and cardiovascular outcomes during midlife in women.

     

Effect of dietary composition of weight loss diets on high‐sensitivity c‐reactive protein: The Randomized POUNDS LOST trial

Objective:

Overweight and obesity are associated with increased high‐sensitivity C‐reactive protein (hsCRP) levels. The purpose of this study was to determine if weight loss diets differing in fat, protein, or carbohydrate composition differentially reduce hsCRP.

Design and Methods:

POUNDS (preventing overweight using novel dietary strategies) LOST was a 2‐year trial of overweight and obese adults randomly allocated to one of four weight loss diets with targeted percentages of energy derived from fat, protein, and carbohydrates (20, 15, 65%; 20, 25, 55%; 40, 15, 45%; 40, 25, 35%, respectively). hsCRP was measured at baseline, 6, and 24 months among 710 participants, and adiposity as measured by dual X‐ray absorptiometry (N = 340) or abdominal computed tomography (N = 126) was correlated with hsCRP change.

Results:

At 6 months, hsCRP was reduced in all trial participants by ?24.7% (Interquartile range (IQR) +7%, ?50%), weight by ?6.7% (IQR ?3%, ?11%), and waist circumference by ?6.0% (IQR ?3%, ?10%) (all P < 0.002), with no significant differences according to dietary composition. The percent change in hsCRP at 6 and 24 months correlated modestly with change in weight, waist circumference, fasting insulin, fasting glucose, HOMA, and most lipid levels. Reductions in hsCRP persisted despite ～ 50% regain of weight by 24 months. The percent change in hsCRP at 24 months significantly correlated with changes in total body fat (r = 0.42), total abdominal adiposity (r = 0.52), subcutaneous abdominal adiposity (r = 0.52), visceral adiposity (r = 0.47), and hepatic tissue density (r = ?0.34) (all P < 0.0006).

Conclusion:

Weight loss decreased hsCRP by similar magnitude, irrespective of dietary composition. Clinicians concerned about inflammation and cardiovascular risk should recommend weight loss diets most likely to succeed for their patients.

     

Objectively measured sedentary behavior,physical activity,and plasma lipids in overweight and obese children

Objective:

This study examines the associations between objectively measured sedentary behavior, light physical activity (LPA), and moderate‐to‐vigorous physical activity (MVPA), and plasma lipids in overweight and obese children.

Design and Methods:

Cross‐sectional analyses were conducted among 126 children aged 5.5‐9.9 years. Sedentary behavior, LPA, and MVPA were assessed using accelerometry. Fasting blood samples were analyzed for plasma lipids (high‐density lipoprotein cholesterol [HDL‐C], low‐density lipoprotein cholesterol [LDL‐C], total cholesterol [TC], and triglycerides [TG]).

Results:

MVPA was not related to plasma lipids (P > 0.05). Independent of age, sex, energy intake, and waist circumference z‐score, sedentary behavior and LPA were associated with HDL‐C (β = ?0.23, 95% CI ?0.42 to ?0.04, P = 0.020; β = 0.20, 95% CI 0.14 to 0.39, P = 0.036, respectively). The strength of the associations remained after additionally adjusting for MVPA (sedentary behavior: β = ?0.22, 95% CI ?0.44 to 0.006, P = 0.056; LPA: β = 0.19, 95% CI ?0.005 to 0.38, P = 0.056, respectively).

Conclusion:

Substituting at least LPA for sedentary time may contribute to the development of healthy HDL‐C levels among overweight and obese children, independent of their adiposity. Comprehensive prevention and treatment strategies to improve plasma HDL‐C among overweight and obese children should target reductions in total sedentary time and promote the benefits of LPA, in addition to promoting healthy levels of adiposity, healthy dietary behaviors, and MVPA.

     

Body adiposity index assess body fat with high accuracy in nondialyzed chronic kidney disease patients

Objective:

High body fat (BF) is an alarming condition that also affects nondialyzed chronic kidney disease (CKD) patients. Distinct methods are used to evaluate BF; however, in CKD population it remains unclear which one is more reliable showing high accuracy. Dual‐energy X‐ray absorptiometry (DXA), used as reference method to estimate adiposity, is expensive and time consuming to be applied in clinical settings. Recently, a new body adiposity index (BAI), that estimates BF from easily accessible measures, was validated in the general population. The aim of this study was to evaluate which simple and practical method, routinely used to estimate BF, shows the highest accuracy compared with DXA, in nondialyzed CKD patients.

Design and Methods:

In this cross‐sectional study BF was estimated by DXA, bioelectrical impedance analysis (BIA), anthropometry (ANTHRO), and BAI. Serum leptin levels were determined.

Results:

Studied patients (n = 134) were 55% males, 54% overweight/obese, and 64.9 ± 12.5 years old, with estimated glomerular filtration rate (eGFR) = 29.0 ± 12.7 ml/min. The correlation coefficient was higher between DXA vs. ANTHRO (r = 0.76) and BAI (r = 0.61) than with BIA (r = 0.57), after adjusting for gender, age, and eGFR (P < 0.0001). Therefore, the Lin's concordance correlation coefficient and Bland–Altman plots were performed to measure the accuracy (C_b) between DXA with both ANTHRO and BAI. A higher accuracy (C_b = 0.82) and lower mean difference (?3.4%) was observed for BAI than for ANTHRO (C_b = 0.61; ?8.4%). Leptin levels correlated (P < 0.0001) with DXA (r = 0.56) and BAI (r = 0.59).

Conclusions:

These findings suggest that BAI estimates BF with high accuracy in nondialyzed CKD patients and may be helpful in the treatment of this population with increased BF.

     

VAT=TAAT‐SAAT: Innovative anthropometric model to predict visceral adipose tissue without resort to CT‐Scan or DXA

Objective:

To investigate whether a combination of a selected but limited number of anthropometric measurements predicts visceral adipose tissue (VAT) better than other anthropometric measurements, without resort to medical imaging.

Hypothesis:

Abdominal anthropometric measurements are total abdominal adipose tissue indicators and global measures of VAT and SAAT (subcutaneous abdominal adipose tissue). Therefore, subtracting the anthropometric measurement the more correlated possible with SAAT while being the least correlated possible with VAT, from the most correlated abdominal anthropometric measurement with VAT while being highly correlated with TAAT, may better predict VAT.

Design and Methods:

BMI participants' range was from 16.3 to 52.9 kg m^?2. Anthropometric and abdominal adipose tissues data by computed tomography (CT‐Scan) were available in 253 patients (18‐78 years) (CHU Nord, Marseille) and used to develop the anthropometric VAT prediction models.

Results:

Subtraction of proximal thigh circumference from waist circumference, adjusted to age and/or BMI, predicts better VAT (Women: VAT = 2.15 × Waist C ? 3.63 × Proximal Thigh C + 1.46 × Age + 6.22 × BMI ? 92.713; R² = 0.836. Men: VAT = 6 × Waist C ? 4.41 × proximal thigh C + 1.19 × Age ? 213.65; R² = 0.803) than the best single anthropometric measurement or the association of two anthropometric measurements highly correlated with VAT. Both multivariate models showed no collinearity problem. Selected models demonstrate high sensitivity (97.7% in women, 100% in men). Similar predictive abilities were observed in the validation sample (Women: R² = 76%; Men: R² = 70%). Bland and Altman method showed no systematic estimation error of VAT.

Conclusion:

Validated in a large range of age and BMI, our results suggest the usefulness of the anthropometric selected models to predict VAT in Europides (South of France).

     

Racial/ethnic differences in the prevalence of gestational diabetes mellitus and maternal overweight and obesity,by Nativity,Florida, 2004‐2007

Objective:

We examined the risk of gestational diabetes mellitus (GDM) among foreign‐born and U.S.‐born mothers by race/ethnicity and BMI category.

Design and Method:

We used 2004‐2007 linked birth certificate and maternal hospital discharge data of live, singleton deliveries in Florida to compare GDM risk among foreign‐born and U.S.‐born mothers by race/ethnicity and BMI category. We examined maternal BMI and controlled for maternal age, parity, and height.

Results:

Overall, 22.4% of the women in our study were foreign born. The relative risk (RR) of GDM among women who were overweight or obese (BMI ≥ 25.0 kg m^?2) was higher than among women with normal BMI (18.5‐24.9 kg m^?2) regardless of nativity, ranging from 1.3 (95% confidence interval (CI) = 1.0, 1.9) to 3.8 (95% CI = 2.1, 7.2).Foreign‐born women also had a higher GDM risk than U.S.‐born women, with RR ranging from 1.1 (95% CI = 1.1, 1.2) to 2.1 (95% CI = 1.4, 3.1). This finding was independent of BMI, age, parity, and height for all racial/ethnicity groups.

Conclusions:

Although we found differences in age, parity, and height by nativity, these differences did not substantially reduce the increased risk of GDM among foreign‐born mothers. Health practitioners should be aware of and have a better understanding of how race/ethnicity and nativity can affect women with a high risk of GDM. Although BMI is a major risk factor for GDM, it does not appear to be associated with race/ethnicity or nativity.

     

Prediction of measured weight from self‐reported weight was not improved after stratification by body mass index

Objective:

Self‐reported weight may underestimate measured weight. Researchers have tried to reduce the error using statistical models to predict weight from self‐reported weight. We investigate whether deriving equations within separate BMI categories improves the prediction of weight compared with an equation derived regardless of an individual's BMI.

Design and Methods:

The analysis included self‐reported and measured data from 20,536 individuals participating in the EPIC‐Norfolk study. In a derivation set (n = 15,381) two approaches were used to predict weight from self‐reported weight: (1) using a linear regression model with measured weight as outcome and self‐reported weight and age as predictors, and (2) using the same model fit separately within 3 strata defined by BMI (< 25, 25‐30, ≥30 kg m^?2). The performance of these approaches was assessed in a validation set (n = 5,155). Measured weight was compared to self‐reported weight and predicted weight.

Results:

Self‐reported weight underestimated measured weight (P < 0.0001): mean difference ?1.2 ± 3.1 kg (men), ?1.3 ± 2.5 kg (women). Underestimation was greater in obese participants (P < 0.0001). Predicted weight using approach 1 was not significantly different from measured weight (P < 0.05). However, in individuals with BMI < 25 kg m^?2, weight was overestimated in men (0.90 ± 3.87 kg) and women (0.57 ± 2.06 kg), but underestimated in overweight (?0.29 ± 3.58, ?0.20 ± 2.62 kg) and obese (?1.46 ± 5.05 kg, ?0.73 ± 3.54 kg) men and women.

Conclusions:

Using separate prediction equations in strata of BMI did not further improve prediction of weight. In conclusion, predicted weight was closer to measured weight compared with self‐reported weight, but using equations derived in strata of BMI did not further improve the prediction and are not recommended for prediction of weight.

     

Measurements of total and regional body composition in preschool children: A comparison of MRI,DXA, and anthropometric data

Objective:

There are clear sex differences in the distribution of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in adults, with males having more VAT and less SAT than females. This study assessed whether these differences between the sexes were already present in preschool children. It also evaluated which measures of body composition were most appropriate for assessing abdominal obesity in this age group.

Design and Methods:

One‐hundred and five children (57 boys and 48 girls) participated in the study. Body composition was measured using dual‐energy X‐ray absorptiometry (DXA). Weight, height, and waist circumference (WC) were also recorded. Magnetic resonance imaging (MRI) of the entire abdomen using sixteen 10‐mm‐thick T₁‐weighted slices was performed in a subgroup of 48 children (30 boys and 18 girls); SAT and VAT volumes were measured using semiautomated segmentation.

Results:

Boys had significantly more VAT than girls (0.17 versus 0.10 l, P < 0.001). Results showed that VAT correlated significantly with all measurements of anthropometry (P < 0.01) after adjusting for SAT and for total fat mass measured with DXA. The mean limits of agreement between DXA and MRI regarding truncal FM were calculated to be ?11.4 (range ?17.8 to ?3.6), using a Bland–Altman plot.

Conclusion:

Sex differences in adipose tissue distribution are apparent at an early age. MRI is the best method with which to study abdominal fat distribution in young children.

     

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.

     

Psychosocial predictors of 4‐year BMI change in overweight and obese children in primary care

Objective:

This study aimed to determine whether (( 1 ) ) initial and/or (( 2 ) ) changes in psychosocial functioning predict body mass index (BMI) z‐score change over 4 years in overweight/mildly obese 5‐ to 9‐year old children presenting to primary care.

Design and Methods:

Eligible participants (n = 258) were overweight/mildly obese children (IOTF criteria) recruited into the LEAP2 trial (ISRCTN52511065) from 3,958 children visiting general practitioners in Melbourne, Australia from May 2005 to July 2006. Predictors were change scores calculated from repeated measures of parent‐ and child‐reported child health‐related quality of life (PedsQL) and self‐esteem; child‐reported desire to be thinner; and parent‐reported child weight concern. Outcome was measured BMI z‐score change from baseline to 4 years.

Results:

The 189 respondents (61% female; 73% retention) showed little mean change in BMI z‐score (?0.08) but wide variation (standard deviation 0.50, range ?1.32 to 1.20). Only one baseline measure (better parent‐reported PedsQL School Functioning) predicted improving BMI z‐score. However, parents and children consistently reported that changes in psychosocial functioning (i.e., PedsQL Social and Global Self‐esteem) were inversely related to BMI z‐score change scores. The strongest predictors of decreases in BMI z‐scores were changes in child‐reported body‐image variables, i.e., improvements in Physical Appearance Self‐esteem (β =0.40, 95% CI ?0.98 to ?0.15, P < 0.01) and declines in Desire to be Thinner (β = 0.33, 95% CI 0.04 to 0.23, P < 0.01).

Conclusions:

At presentation to primary care, it seems unlikely that targeting the psychosocial factors measured in this study would influence BMI z‐score change in overweight/mildly obese children. Subsequent change in psychosocial well‐being covaries with BMI z‐score change and may have important adolescent ramifications; the causal directions for these associations require further research.

     

Nonalcoholic fatty liver disease in severely obese adolescent and adult patients

Objectives:

Nonalcoholic fatty liver disease (NAFLD) is increasingly an indication for liver transplantation in adults. While severe obesity (SO, BMI ≥40 kg m^?2) in adults is long standing, it is recent in duration in adolescents. With adolescent obesity on the rise, NAFLD is becoming the most frequent liver disease in adolescents. The hypothesis that SO adolescents and adults have different severity of NAFLD because of longer duration of obesity in SO adults was tested.

Design and Methods:

Preoperative clinical data, NAFLD activity and NASH (Nonalcoholic steatohepatitis) scores from intraoperative liver biopsies were extracted from a prospective database of consecutively operated SO adolescents and adults (n = 24 each). Fasting preoperative serum inflammatory mediators were evaluated by ELISA.

Results:

Other than age, baseline BMI, ethnicity and gender distribution, the incidence and extent of dyslipidemia, hypertension, and metabolic syndrome were comparable between groups. Histologic scores for steatosis and inflammation were similar. Adolescents have significantly higher NASH incidence, hepatocyte injury scores and fibrosis. This was associated with higher serum C‐reactive protein and sCD14 levels.

Conclusion:

For comparable BMI and metabolic profile, SO adolescents have more advanced liver damage, more severe systemic inflammation, suggesting differences in NAFLD etiologies and more aggressive disease progression in the young obese population.

     

Influence of calendar period on the association between BMI and coronary heart disease: A meta‐analysis of 31 cohorts

Objective:

The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta‐analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI).

Design and Methods:

The relative risks (RRs) of CHD for a five‐BMI‐unit increment and BMI categories were pooled by means of random effects models. Meta‐regression analysis was used to examine the influence of calendar period (>1985 v ≤1985) in univariate and multivariate analyses (including mean population age as a covariate).

Results:

The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five‐BMI‐unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: ?56:0) lower RR of CHD associated with a five‐BMI‐unit increment and a 51% (95%CI: ?78: ?14)) lower RR associated with obesity in studies starting after 1985 (n = 15 and 10, respectively) compared to studies starting in or before 1985 (n = 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five‐BMI‐unit increment and obesity (?29(95%CI: ?55: ?5)) and ?31(95%CI: ?66:3), respectively) per 10‐year increment in mean age).

Conclusion:

This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age.

     

Greater screen time is associated with adolescent obesity: A longitudinal study of the BMI distribution from Ages 14 to 18

Objective:

Previous research has examined the association between screen time and average changes in adolescent body mass index (BMI). Until now, no study has evaluated the longitudinal relationship between screen time and changes in the BMI distribution across mid to late adolescence.

Design and Methods:

Participants (n = 1,336) were adolescents who were followed from age 14 to age 18 and surveyed every 6 months. Time spent watching television/videos and playing video games was self‐reported (<1 h day^?1, 1 h day^?1, 2 h day^?1, 3 h day^?1, 4 h day^?1, or 5+ h day^?1). BMI (kg m^?2) was calculated from self‐reported height and weight. Longitudinal quantile regression was used to model the 10th, 25th, 50th, 75th, and 90th BMI percentiles as dependent variables. Study wave and screen time were the main predictors, and adjustment was made for gender, race, maternal education, hours of sleep, and physical activity.

Results:

Increases at all the BMI percentiles over time were observed, with the greatest increase observed at the 90th BMI percentile. Screen time was positively associated with changes in BMI at the 50th (0.17, 95% CI: 0.06, 0.27), 75th (0.31, 95% CI: 0.10, 0.52), and 90th BMI percentiles (0.56, 95% CI: 0.27, 0.82). No associations were observed between screen time and changes at the 10th and 25th BMI percentiles.

Conclusions:

Positive associations between screen time and changes in the BMI at the upper tail of the BMI distribution were observed. Therefore, lowering screen time, especially among overweight and obese adolescents, could contribute to reducing the prevalence of adolescent obesity.

     

Effects of taspoglutide on glycemic control and body weight in obese patients with type 2 diabetes (T‐emerge 7 study)

Objective:

Therapies that lower blood glucose and provide weight loss may provide meaningful benefits for obese patients with type 2 diabetes mellitus (T2DM). This study assessed the efficacy of taspoglutide compared with placebo on glycemic control and weight in obese patients with T2DM inadequately controlled with metformin monotherapy.

Design and Methods:

In a 24‐week, randomized, double‐blind, placebo‐controlled, multicenter trial, obese adults with T2DM were randomized (1:1) to weekly subcutaneous taspoglutide 20 mg (10 mg for first 4 weeks) (n = 154) or placebo (n = 151) for 24 weeks. Efficacy measures included hemoglobin A1c (HbA1c) levels, body weight, percentage of patients achieving HbA1c ≤6.5 and ≤7.0%, and fasting plasma glucose (FPG). Adverse events (AEs) were assessed.

Results:

Mean baseline HbA1c was 7.55% and mean baseline BMI was 36.7 kg/m². HbA1c reductions from baseline were significantly greater with taspoglutide than placebo (least square mean [LSMean], ?0.81% vs. ?0.09%; P < 0.0001). Weight loss at week 24 was significantly greater with taspoglutide than placebo (LSMean, ?3.16 vs. ?1.85 kg; P < 0.01). In the taspoglutide and placebo groups, target HbA1c levels (≤6.5%) were achieved by 49 and 16% of patients, respectively, while 72 and 36% achieved HbA1c levels ≤7%. Decreases in FPG were significantly greater with taspoglutide than placebo (?23.59 vs. 0.09 mg/dl; P < 0.0001). Nausea and vomiting were the most common AEs associated with taspoglutide, but tended to be transient and generally mild or moderate.

Conclusions:

In obese patients with T2DM, once‐weekly taspoglutide provided the combined benefits of glycemic control and weight loss.