Distribution of plasma levels of adiponectin and leptin in an adult Caucasian population

Sex-Specific Associations between Adiponectin and Leptin Signaling and Pancreatic Cancer Survival

BACKGROUND

Circulating adiponectin and leptin have been associated with risk of pancreatic cancer. However, the relationship between long-term exposure to these adipokines in the prediagnostic period with patient survival has not been investigated.

METHODS

Adipokine levels were measured in prospectively collected samples from 472 patients with pancreatic cancer. Because of sex-specific differences in adipokine levels, associations were evaluated separately for men and women. In a subset of 415 patients, we genotyped 23 SNPs in adiponectin receptor genes (ADIPOR1 and ADIPOR2) and 30 SNPs in the leptin receptor gene (LEPR).

RESULTS

Adiponectin levels were inversely associated with survival in women [HR, 1.71; 95% confidence interval (CI), 1.15-2.54]; comparing top with bottom quartile but not in men (HR, 0.89; 95% CI, 0.46-1.70). The SNPs rs10753929 and rs1418445 in ADIPOR1 were associated with survival in the combined population (per minor allele HR, 0.66; 95% CI, 0.51-0.84, and HR, 1.33; 95% CI, 1.12-1.58, respectively). Among SNPs in LEPR, rs12025906, rs3790431, and rs17127601 were associated with survival in the combined population [HRs, 1.54 (95% CI, 1.25-1.90), 0.72 (95% CI, 0.59-0.88), and 0.70 (95% CI, 0.56-0.89), respectively], whereas rs11585329 was associated with survival in men only (HR, 0.39; 95% CI, 0.23-0.66; Pinteraction = 0.0002).

CONCLUSIONS

High levels of adiponectin in the prediagnostic period were associated with shorter survival among women, but not among men with pancreatic cancer. Several polymorphisms in ADIPOR1 and LEPR are associated with patient survival.

IMPACT

Our findings reveal the association between adipokine signaling and pancreatic cancer survival and demonstrate the importance of examining obesity-associated pathways in relation to pancreatic cancer in a sex-specific manner.

Alterations in metabolic status of healthy individuals with and without obesity during transition from adolescence to young adulthood

Aim: Extensive research is carried out throughout the world in healthy persons with obesity phenotype in concern with prevalence, metabolic profiling, etc. To the best of the authors’ knowledge, not many studies have investigated the status of adiponectin, specific inflammatory changes, oxidative damage in healthy adolescents and young adults with obesity. Present study was undertaken in adolescents and young adults of urban population in a district of North Karnataka, India, in a view to understand relationship between hormone adiponectin, oxidative stress markers like C3, C4, high sensitivity C-reactive protein (hs-CRP) in non-hypertensive, non-diabetic, euthyroid individuals with and without obesity. Methods: Participant selection was done using cluster sampling technique. Participating adolescents and young adults, each with and without obesity were included in the study. Screening of participants for diabetes, hypertension, and thyroid disorders was done, their serum level of adiponectin, hs-CRP, C3, C4, ceruloplasmin (Cp), thiobarbituric acid reactive substances (TBARS), and total antioxidant capacity (TAC) were estimated using standardized methods in National Accreditation Board for Testing and Calibration Laboratories (NABL) laboratory. Results: Adiponectin (young adults lower than adolescents, P = 0.01) levels were low, while hs-CRP and Cp (young adults higher than adolescents, P = 0.01) levels were high with increasing age in non-obese. While in persons having obesity, aging adiponectin levels were low while hs-CRP, C3, Cp levels were high significantly. Females without obesity had significantly higher values of C3 than males. Adiponectin showed higher levels in females than males, however, statistical significance could not be achieved (P = 0.308). While females with obesity, exhibited statistically lower levels of adiponectin, and higher levels of C3 and C4. Conclusions: Being non-diabetic and non-hypertensive yet obese, tagged by one time of assay, does not suffice to be categorized as healthy. Healthy young adults with obesity are exhibiting lower levels of adiponectin and higher levels of inflammatory and oxidative stress markers compared to adolescents with obesity. This implies, the so categorized “healthy obese” participants are in a phase of transition towards an unhealthy state.

Preconceptual leptin levels in gestational diabetes and hypertensive pregnancy

Pregnancy - induced hypertension (PIH), preeclampsia (PE), and gestational diabetes (GDM) are common adverse outcomes in pregnancy.

OBJECTIVE

To find out whether preconceptual leptin levels differ in subsequent pregnancy between control vs. GDM and hypertensive pregnancy groups.

MATERIALS AND METHODS

Data was from The Cardiovascular Risk in Young Finns Study and The Medical Birth Register of Finland. Of 293 subjects 71 developed GDM, 27 PIH/PE and 201 were controls.

RESULTS

Leptin was higher in GDM (p < 0.0001) and PIH/PE (p = 0.0002) groups compared to control. GDM group was robust to BMI matching (p = 0,0081).

CONCLUSION

Leptin was higher in GDM (p < 0.0001) and PIH/PE (p = 0.0002) groups compared to control. GDM group was robust to BMI matching (p = 0,0081).

Lower leptin level at discharge in acute anorexia nervosa is associated with early weight-loss

OBJECTIVE

Predictive values of acute phase metabolic abnormalities of anorexia nervosa (AN) have seldom been studied. As early postrestoration weight loss is associated with poor outcome, discharge biologic parameters were assessed to detect an association with 2-month follow-up weight loss as a proxy to poor outcome.

METHOD

Fasting plasma levels of leptin, acyl-ghrelin, obestatin, PYY, oxytocin and BDNF were measured in 26 inpatients, at inclusion, at discharge and 2 months later. A body mass index less than 18 2-month postdischarge was considered a poor outcome.

RESULTS

Nineteen patients (73%) had a fair outcome and seven (27%) had a poor one with a mean loss of 0.69 versus 4.54 kg, respectively. Only discharge leptin levels were significantly higher in fair versus poor outcome patients (14.1 vs. 7.0 ng/ml, p = 0.006). The logistic regression model using discharge leptin, acyl-ghrelin, obestatin, oxytocin, PYY and BDNF levels as predictors of outcome disclosed a nearly significant effect of leptin (p < 0.10). Receiver operating characteristic analysis showed 11.9 ng/ml was the best value of threshold. Neither clinical variables differed according to outcome.

CONCLUSION

Leptin level may be a biomarker of early weight relapse after acute inpatient treatment of AN. Its clinical usefulness in monitoring care in AN should further be determined.

A Cross-Sectional Study on the Combined Effect of Body Weight and Coffee Consumption on Serum Levels of Leptin, Vitamin B12, and Folic Acid in Healthy Young Adult Males

Purpose

Studies on the effect of body weight and coffee consumption on leptin, vitamin B12, and folic acid are scarce and conflicting. This study investigates the effect of body weight and/or coffee consumption rate on the serum levels of these molecules in healthy young adult males.

Patients and Methods

This observational cross-sectional study was carried out at the faculty of pharmacy, Applied Science Private University (ASU), Amman, Jordan, from July to September 2020. Young healthy males were invited to participate in the study and fill a questionnaire regarding lifestyle habits including coffee consumption during the last 3 months, medical history, and anthropometric measurements. Depending on BMI and extent of coffee consumption, participants were divided into 4 groups; normal body weight and moderate coffee consumption (NW/MCC) group; normal body weight and heavy coffee consumption (NW/HCC) group; overweight and moderate coffee consumption (OW/MCC) group; overweight and heavy coffee consumption (OW/HCC) group. Serum samples were taken to measure leptin, vitamin B12, and folic acid levels in addition to morning and midnight salivary cortisol and dehydroepiandrosterone (DHEA) samples.

Results

Healthy males (n = 122) aged 18 to 26 years continued participation in this study. Serum levels of leptin in NW/MCC, NW/HCC, OW/MCC, OW/HCC groups were 5.93, 5.75, 14.86, 16.79 ng/mL, respectively. Serum levels of vitamin B12 in these groups were 356.09, 402.71, 334.25, 331.05 pg/mL, respectively. While, the serum levels of folic acid were 8.92, 10.27, 10.12, 10.47 ng/mL, respectively. Body weight was positively associated with leptin (p = 0.00), negatively associated with vitamin B12 (p = 0.047), and not associated with folic acid (p = 0.235). Coffee consumption rate had no significant effect on leptin, vitamin B12, or folic acid. Finally, the combination of body weight and coffee consumption had no significant effect on leptin, vitamin B12, or folic acid.

Conclusion

There was no possible synergistic effect between body weight and coffee consumption rate on leptin, vitamin B12, or folic acid levels. However, overweight was associated with higher leptin, lower vitamin B12, and no change in folic acid levels.

Trial Registration

This trial was registered at clinicaltrials.gov as NCT04488731.

Dysfunctional Eating Behaviour and Leptin in Middle-Aged Women: Role of Menopause and a History of Anorexia Nervosa

BACKGROUND

Weight gain is common as women approach mid-life. Reduced levels of leptin, an anorexigenic hormone, may facilitate this. Studies in middle-aged women with obesity have shown that dysfunctional eating behaviour, such as restrained eating, is linked to lower leptin. Furthermore, states of low oestradiol signalling, as are found in post-menopause or anorexia nervosa, have been found to impact leptin levels. The aim of this study was to investigate, for the first time, how different aspects of dysfunctional eating, menopausal status, and a history of anorexia nervosa relate to leptin levels in normal-weight middle-aged women.

METHODS

A total of N = 57 women were recruited. Thirty-one were post-menopausal, and 27 had a history of anorexia nervosa. Dysfunctional eating behaviour was measured by the Three-Factor Eating Questionnaire, which contains three subscales: susceptibility/responsiveness to hunger, restraint, and disinhibition. Body composition was assessed by bioelectrical impedance analysis. A fasting blood sample was obtained to determine leptin.

RESULTS

Controlling for age, body mass index, and fat mass, susceptibility/responsiveness to hunger was positively associated with leptin (β = 0.267, p = 0.031), whereas restrained eating (β = - 0.183, p = 0.079) and a history of anorexia nervosa (β = - 0.221, p = 0.059) were, by trend, negatively associated with leptin. Neither disinhibited eating nor menopausal status was related to leptin.

CONCLUSIONS

Leptin may decline as a response to repeated states of a negative energy balance. A possible implication is that mid-life weight management should avoid extreme changes in eating behaviour and instead focus on the macronutrient composition of diet and physical activity. Further, longitudinal enquiries are warranted to investigate these relationships.

Associations of a Panel of Adipokines with Fat Deposits and Metabolic Phenotypes in a General Population

OBJECTIVE

This study provides a comprehensive overview of the associations of five adipokines (adiponectin, chemerin, galectin-3, leptin, and resistin) with fat deposits, behavioral risk factors, and metabolic phenotypes.

METHODS

Using multivariable linear and logistic regression models, cross-sectional data from 4,116 participants of the population-based Study of Health in Pomerania were analyzed.

RESULTS

Participants with obesity showed higher chemerin, galectin-3, and leptin but showed lower adiponectin concentrations. Independently of other fat compounds, liver fat content, visceral adipose tissue, and subcutaneous adipose tissue (SAT) were inversely associated with adiponectin. Independent positive associations of liver fat content and SAT with chemerin as well as of SAT with galectin-3 and leptin were observed. Physically inactive participants had higher chemerin and leptin concentrations. Smokers had higher chemerin and galectin-3 as well as lower leptin. Alcohol consumption was associated with adiponectin (positive) and resistin (inverse). All adipokines were associated with at least one lipid marker. Associations with glucose metabolism were seen for adiponectin, chemerin, galectin-3, and leptin.

CONCLUSIONS

High adiponectin concentrations were related to favorable metabolic conditions, whereas high chemerin, galectin-3, and leptin were associated with an unfavorable metabolic profile. High leptin seems to be primarily indicative of obesity, whereas high adiponectin and chemerin are associated with a broader range of metabolic phenotypes.

Coffee consumption and plasma biomarkers of metabolic and inflammatory pathways in US health professionals

BACKGROUND

Coffee consumption has been linked to lower risk of various health outcomes. However, the biological pathways mediating the associations remain poorly understood.

OBJECTIVES

The aim of this study was to assess the association between coffee consumption and concentrations of plasma biomarkers in key metabolic and inflammatory pathways underlying common chronic diseases.

METHODS

We investigated the associations of total, caffeinated, and decaffeinated coffee consumption with 14 plasma biomarkers, including C-peptide, insulin-like growth factor 1 (IGF-1), IGF binding protein (IGFBP) 1, IGFBP-3, estrone, total and free estradiol, total and free testosterone, sex hormone-binding globulin (SHBG), total adiponectin, high-molecular-weight (HMW) adiponectin, leptin, C-reactive protein (CRP), interleukin 6 (IL-6), and soluble tumor necrosis factor receptor 2 (sTNFR-2). Data were derived from 2 cohorts of 15,551 women (Nurses' Health Study) and 7397 men (Health Professionals Follow-Up Study), who provided detailed dietary data before blood draw and were free of diabetes, cardiovascular disease, or cancer at the time of blood draw. Multivariable linear regression was used to calculate the percentage difference of biomarker concentrations comparing coffee drinkers with nondrinkers, after adjusting for a variety of demographic, clinical, and lifestyle factors.

RESULTS

Compared with nondrinkers, participants who drank ≥4 cups of total coffee/d had lower concentrations of C-peptide (-8.7%), IGFBP-3 (-2.2%), estrone (-6.4%), total estradiol (-5.7%), free estradiol (-8.1%), leptin (-6.4%), CRP (-16.6%), IL-6 (-8.1%), and sTNFR-2 (-5.8%) and higher concentrations of SHBG (5.0%), total testosterone (7.3% in women and 5.3% in men), total adiponectin (9.3%), and HMW adiponectin (17.2%). The results were largely similar for caffeinated and decaffeinated coffee.

CONCLUSION

Our data indicate that coffee consumption is associated with favorable profiles of numerous biomarkers in key metabolic and inflammatory pathways. This trial was registered at clinicaltrials.gov as NCT03419455.

Adipokine levels in overweight women with early-onset gestational diabetes mellitus

PURPOSE

The study of adipokines in overweight women with early-onset (diagnosed before 20 weeks) gestational diabetes mellitus (GDM) could help to understand the ethiopathological mechanisms of this disorder. Our aim was to assess adipokine levels in overweight pregnant women with early-onset GDM compared to patients with standard-onset (diagnosed at 24-28 weeks) GDM and to glucose-tolerant women at the same gestational ages.

METHODS

This nested case-control study included 133 overweight pregnant women: 33 with early-onset (diagnosed < 20 weeks) GDM; 40 with standard-onset (diagnosed ≥ 24 weeks) GDM and 60 glucose-tolerant (normal oral glucose tolerance tests < 20 and ≥ 24 weeks). Adiponectin, leptin, resistin, visfatin and ghrelin serum levels were measured by ELISA.

RESULTS

Adiponectin serum levels were significantly lower in early-onset GDM women than in standard-onset GDM patients or controls matched for gestational age. Leptin serum levels were significantly higher in women with early-onset GDM than in controls. Women with early-onset GDM had lower adiponectin/leptin ratio than those with standard-onset GDM. There were no significant differences in resistin, ghrelin and visfatin serum levels among the participants.

CONCLUSIONS

Our results suggest that, compared to overweight glucose-tolerant women and patients with standard-onset GDM, overweight women with early-onset GDM have unbalanced adipokine levels, suggesting that they have a more inflammatory profile.

Depressive symptoms and adipokines in women: Study of women's health across the nation

Small clinical studies suggest depression is associated with alterations in adiponectin and leptin, adipocyte-derived secretory proteins involved in metabolic regulation; however, longitudinal data on these association are lacking. This study examined cross-sectional and longitudinal associations of depressive symptoms and major depressive disorder (MDD) with adiponectin and leptin in healthy middle-aged women (mean (SD) age, 45.6 (2.5) years). Cross-sectional analyses included 575 women with baseline adipokine data; longitudinal analyses included 262 women with 2-4 adipokine measurements over 5 years. The 20-item Center for Epidemiologic Studies Depression scale (CES-D) was used to assess depressive symptoms; history of MDD was determined by the Structured Clinical Interview for DSM-IV. Adipokines were assayed from stored serum specimens; values were log-transformed for analyses. Linear and repeated measure random effects regression models evaluated associations of baseline CES-D scores with baseline adipokine concentrations and changes over time, respectively. Secondary analyses evaluated the relation of MDD history with adipokine concentrations. Mean (SD) baseline concentrations of adiponectin and leptin were 9.90 (4.92) μg/mL and 27.02 (20.06) ng/mL; both increased over time (p < .0001). CES-D scores were associated with lower adiponectin at baseline (per 1-SD: estimate=-0.04, SE=.02, p=.03) and over time (per 1-SD: estimate=-0.055, SE = .024, p=.02). Associations were unchanged in risk factor-adjusted models. Women with elevated CES-D scores (≥16) had 6.9% (95% CI: -1.1%, 14.3%; p = .089) lower median adiponectin at baseline and 11.5% (95% CI: 1.5%, 20.4%, p = .025) lower median adiponectin over time in adjusted models, compared to women with CES-D<16. Rate of change in adipokines did not vary by baseline depressive symptoms or MDD history. Depressive symptoms and MDD history were unrelated to leptin. In women at midlife, depressive symptoms are associated with lower adiponectin, a critical anti-inflammatory biomarker involved in metabolic and cardiovascular conditions.

The association between circulating adiponectin levels, lung function and adiposity in subjects from the general population; data from the Akershus Sleep Apnea Project

BACKGROUND

Circulating adiponectin (ADPN) levels are inversely associated with disease severity in patients with chronic obstructive pulmonary disease (COPD), while studies assessing the relationship between ADPN and lung function in subjects from the general population have shown diverging results. Accordingly, we hypothesized that ADPN would be associated with lung function in a population-based sample and tested how abdominal adiposity, metabolic syndrome, and systemic inflammation influenced this association.

METHODS

We measured total ADPN in serum, forced vital capacity (FVC) and forced expiratory volume during the 1st second (FEV1) in 529 participants (median 50 years, 54.6% males) recruited from the general population. We assessed the association between ADPN and lung function by multivariate linear regression analyses and adjusted for age, gender, height, smoking habits, weight, body mass index, waist-hip ratio, metabolic syndrome, obstructive sleep apnoea (OSA) and C-reactive protein.

RESULTS

The median (interquartile range) level of serum ADPN was 7.6 (5.4-10.4) mg/L. ADPN levels were positively associated with FVC % of predicted (beta 3.4 per SD adiponectin, p < 0.001)) in univariate linear regression analysis, but the association was attenuated in multivariate analysis (standardized beta 0.03, p = 0.573)). Among co-variates only WHR significantly attenuated the relationship. ADPN levels were also associated with FEV1% of predicted in bivariate analysis that adjusted for smoking (beta 1.4, p = 0.042)), but this association was attenuated and no longer significant in multivariate analysis (standardized beta -0.06, p = 0.254)).

CONCLUSION

In this population-based sample no association between ADPN and lung function was evident after adjustment for covariates related to adiposity.

Targeted proteomic analysis of habitual coffee consumption

BACKGROUND

Coffee drinking has been implicated in mortality and a variety of diseases but potential mechanisms underlying these associations are unclear. Large-scale systems epidemiological approaches may offer novel insights to mechanisms underlying associations of coffee with health.

OBJECTIVE

We performed an analysis of known and novel protein markers linked to cardiovascular disease and their association with habitual coffee intake in the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, n = 816) and followed up top proteins in the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 635) and EpiHealth (n = 2418).

METHODS

In PIVUS and ULSAM, coffee intake was measured by 7-day dietary records whilst a computer-based food frequency questionnaire was used in EpiHealth. Levels of up to 80 proteins were assessed in plasma by a proximity extension assay.

RESULTS

Four protein-coffee associations adjusted for age, sex, smoking and BMI, met statistical significance in PIVUS (FDR < 5%, P < 2.31 × 10^-3 ): leptin (LEP), chitinase-3-like protein 1 (CHI3L), tumour necrosis factor (TNF) receptor 6 and TNF-related apoptosis-inducing ligand. The inverse association between coffee intake and LEP replicated in ULSAM (β, -0.042 SD per cup of coffee, P = 0.028) and EpiHealth (β, -0.025 SD per time of coffee, P = 0.004). The negative coffee-CHI3L association replicated in EpiHealth (β, -0.07, P = 1.15 × 10^-7 ), but not in ULSAM (β, -0.034, P = 0.16).

CONCLUSIONS

The current study supports an inverse association between coffee intake and plasma LEP and CHI3L1 levels. The coffee-CHI3L1 association is novel and warrants further investigation given links between CHI3L1 and health conditions that are also potentially influenced by coffee.

Relationship Between Adiponectin and apoB in Individuals With Diabetes in the Atlantic PATH Cohort

Context

The increasing prevalence of obesity and diabetes greatly influences the risk for cardiovascular (CV) comorbidities and affects the quality of life of many people. However, the relationship among diabetes, obesity, and cardiovascular risk is complex and requires further investigation to understand the biological milieu connecting these conditions.

Objective

The aim of the current study was to explore the relationship between biological markers of adipose tissue function (adiponectin) and CV risk (apolipoprotein B) in body mass index (BMI)-matched participants with and without diabetes.

Design

Nested case-control study.

Setting

The Atlantic Partnership for Tomorrow's Health (PATH) cohort represents four Atlantic Canadian provinces: Newfoundland and Labrador, New Brunswick; Nova Scotia; and Prince Edward Island.

Participants

The study population (n = 480) was aged 35 to 69 years, 240 with diabetes and 240 without diabetes.

Main Outcome Measures

Groups with and without diabetes were matched for sex and BMI. Both measured and self-reported data were used to examine disease status, adiposity, and lifestyle factors. Immunoassays were used to measure plasma markers.

Results

In these participants, plasma adiponectin levels were lower among those with diabetes than those without diabetes; these results were sex-specific, with a strong relationship seen in women. In contrast, in participants matched for sex and adiposity, plasma apoB levels were similar between participants with and those without diabetes.

Conclusion

Measures of adiposity were higher in participants with diabetes. However, when matched for adiposity, the adipokine adiponectin exhibited a strong inverse association with diabetes.

Association Between Peripheral Adipokines and Inflammation Markers: A Systematic Review and Meta-Analysis

OBJECTIVE

Obesity-induced inflammation potentially promotes a variety of chronic conditions. This study aimed to summarize cross-sectional associations between adipose tissue-derived hormones (leptin and adiponectin) and inflammatory biomarkers (C-reactive protein [CRP], interleukin [IL]-6, and tumor necrosis factor [TNF]-α) by means of meta-analysis.

METHODS

A systematic search of the databases EMBASE and MEDLINE (PubMed) up to January 2017 was conducted. Data were independently extracted and evaluated by two reviewers. Pooled effect sizes and 95% confidence intervals were calculated using random-effects models.

RESULTS

After the initial search, 5,907 publications were retrieved; of these, an overall 60 studies with 45,210 participants were deemed eligible for inclusion in the meta-analysis. Positive correlations with inflammatory biomarkers were observed for leptin (pooled R_ho  = 0.35, 0.20, and 0.20 for CRP, IL-6, and TNF-α, respectively), whereas the respective correlations with adiponectin were negative (pooled R_ho  = -0.18, -0.14, and -0.12 for CRP, IL-6, and TNF-α, respectively). Stratification by age showed that the observed correlations tended to be weaker with the increasing age of participants. No apparent differences were observed by sex and adiposity status.

CONCLUSIONS

This is the first quantitative synthesis of human studies on the association between circulating adipokines and inflammation biomarkers. Potential influence of age on these associations requires further evaluation.

Serum leptin level positively correlates with metabolic syndrome among elderly Taiwanese

Objective:

Leptin is an adipocyte-derived hormone and has shown positive correlation with obesity and metabolic syndrome (MetS) in many studies. However, there are few studies investigating this relation in elderly people. Therefore, we aimed to investigate the correlation between the fasting serum leptin level and MetS among older Taiwanese.

Materials and Methods:

The fasting serum leptin level was obtained from 62 Taiwanese participants over 65 years old and was measured using a commercially available enzyme immunoassay kit. MetS and its components were defined using diagnostic criteria from the International Diabetes Federation.

Results:

Thirty elderly participants (48.4%) had MetS. The serum leptin level was positively correlated with MetS (P < 0.001). Multivariate logistic regression analysis of the factors significantly associated with MetS showed that logarithmically transformed leptin (log-leptin, each increase 0.1 ng/mL log-leptin, odds ratio: 1.276, 95% confidence interval: 1.015–1.603, P = 0.037) was still an independent predictor of MetS in elderly persons. Univariable linear analysis showed that body weight (r = 0280, P = 0.028), body mass index (r = 0.417, P = 0.001), waist circumference (r = 0.419, P = 0.001), blood urea nitrogen (r = 0255, P = 0.046), log-insulin (r = 0436, P < 0.001), and logarithmically transformed homeostasis model assessment of insulin resistance (r = 0359, P = 0.004) positively correlated with fasting serum log-leptin levels. Multivariate forward stepwise linear regression analysis of the factors significantly associated with fasting serum log-leptin levels revealed that waist circumference (adjusted R² = 0.083, P = 0.002), statin use (adjusted R² = 0.058, P = 0.016), and female gender (adjusted R² = 0.041, P = 0.034) were independent predictors of fasting serum log-leptin levels among elderly participants.

Conclusion:

In elderly Taiwanese, the serum leptin level was positively correlated with MetS. Waist circumference, statin use, and female gender were independent predictors of the fasting serum leptin level in elderly participants.

Leptin Level and Skipping Breakfast: The National Health and Nutrition Examination Survey III (NHANES III)

Skipping breakfast is a common dietary habit considered to be unhealthy. However, the mechanisms underlying skipping breakfast have not been fully explored. Leptin is a hormone that regulates food intake and energy storage and secretes in a diurnal rhythm with lowest levels in the morning. We examined the association between the serum leptin level and skipping breakfast in 5714 adults in the U.S. National Health and Nutrition Examination Survey III, 1988-1994. We defined breakfast as any food or beverage consumed between 5:00 a.m. and 10:00 a.m. using a single 24-h recall. Skipped breakfast was seen in 13.1%. In the logistic regression models with and without adjusting for adiposity and sex, leptin levels were not associated with skipping breakfast. After adjusting for age, race/ethnicity, and time of venipuncture, the association remained insignificant. After further adjusting for potential confounders: physical activity, alcohol intake, smoking and diabetes and after further adjusting for: dietary factors, insulin and glucose levels, there was a 9% and 11%-12%, respectively, statistically significantly higher likelihood of skipping breakfast if the leptin level was more than 50% greater. Further investigation into the biological reasons for skipping breakfast may be useful for promoting healthy lifestyles.

Overweight across the life course and adipokines, inflammatory and endothelial markers at age 60-64 years: evidence from the 1946 birth cohort

Background/Objectives:

There is growing evidence that early development of obesity increases cardiovascular risk later in life, but less is known about whether there are effects of long-term excess body weight on the biological drivers associated with the atherosclerotic pathway, particularly adipokines, inflammatory and endothelial markers. This paper therefore investigates the influence of overweight across the life course on levels of these markers at retirement age.

Subjects/Methods:

Data from the Medical Research Council National Survey of Health and Development (n=1784) were used to examine the associations between overweight status at 2, 4, 6, 7, 11, 15, 20, 26, 36, 43, 53 and 60–64 years (body mass index (BMI)⩾25 kg m⁻² for adult ages and gender-specific cut-points for childhood ages equivalent to BMI⩾25 kg m⁻²) and measurements of adipokines (leptin and adiponectin), inflammatory markers (C-reactive protein (CRP), interleukin-6 (IL-6)) and endothelial markers (E-selectin, tissue plasminogen activator (t-PA) and von Willebrand factor) at 60–64 years. In addition, the fit of different life course models (sensitive periods/accumulation) were compared using partial F-tests.

Results:

In age- and sex-adjusted models, overweight at 11 years and onwards was associated with higher leptin, CRP and IL-6 and lower adiponectin; overweight at 15 years and onwards was associated with higher E-selectin and t-PA. Associations between overweight at all ages earlier than 60–64 with leptin, adiponectin, CRP and IL-6 were reduced but remained apparent after adjustment for overweight at 60–64 years; whereas those with E-selectin and t-PA were entirely explained. An accumulation model best described the associations between overweight across the life course with adipokines and inflammatory markers, whereas for the endothelial markers, the sensitive period model for 60–64 years provided a slightly better fit than the accumulation model.

Conclusions:

Overweight across the life course has a cumulative influence on adipokines, inflammatory and possibly endothelial markers. Avoidance of overweight from adolescence onwards is likely important for cardiovascular disease prevention.

Liver function parameters in hip fracture patients: relations to age, adipokines, comorbidities and outcomes

AIM

To asses liver markers in older patients with hip fracture (HF) in relation to age, comorbidities, metabolic characteristics and short-term outcomes.

METHODS

In 294 patients with HF (mean age 82.0±7.9 years, 72.1% women) serum alanine aminotransferase (ALT), gammaglutamyltransferase (GGT), alkaline phosphatase (ALP), albumin, bilirubin, 25(OH)vitaminD, PTH, calcium, phosphate, magnesium, adiponectin, leptin, resistin, thyroid function and cardiac troponin I were measured.

RESULTS

Elevated ALT, GGT, ALP or bilirubin levels on admission were observed in 1.7%-9.9% of patients. With age GGT, ALT and leptin decrease, while PTH and adiponectin concentrations increase. Higher GGT (>30 U/L, median level) was associated with coronary artery disease (CAD), diabetes mellitus (DM), and alcohol overuse; lower ALT (≤20 U/L, median level) with dementia; total bilirubin>20 μmol/L with CAD and alcohol overuse; and albumin>33 g/L with CAD. Multivariate adjusted regression analyses revealed ALT, ALP, adiponectin, alcohol overuse and DM as independent and significant determinants of GGT (as continuous or categorical variable); GGT for each other liver marker; and PTH for adiponectin. The risk of prolonged hospital stay (>20 days) was about two times higher in patients with GGT>30 U/L or adiponectin>17.14 ng/L (median level) and 4.7 times higher if both conditions coexisted. The risk of in-hospital death was 3 times higher if albumin was <33 g/L.

CONCLUSIONS

In older HF patients liver markers even within the normal range are associated with age-related disorders and outcomes. Adiponectin (but not 25(OH)vitaminD, PTH, leptin or resistin) is an independent contributor to higher GGT. Serum GGT and albumin predict prolonged hospital stay and in-hospital death, respectively. A unifying hypothesis of the findings presented.

Menopause Analytical Hormonal Correlate Outcome Study (MAHCOS) and the association to brain electrophysiology (P300) in a clinical setting

Various studies have demonstrated that increased leptin levels and obesity are inversely related to cognitive decline in menopausal women. It is hypothesized that adiposity is inversely correlated with cognitive decline, as women with increased weight are less vulnerable to diminishing cognition. However, it is increasingly observed that menopausal women, even with increased adiposity, experience significant cognitive decline. Positron emission tomography (PET) has been used to analyze cognitive function and processing in menopausal women. Evoked potentials (P300) and neurophysiologic tests have validated brain metabolism in cognitively impaired patients. Post-hoc analyses of 796 female patients entering PATH Medical Clinic, between January 4, 2009 and February 24, 2013, were performed as part of the "Menopause Analytical Hormonal Correlate Outcome Study" (MAHCOS). Patient age range was 39-76 years (46.7 ± 0.2). P300 latency and amplitude correlated with a number of hormones: follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, estrone, estriol, DHEA, pregnenolone, progesterone, free and total testosterone, thyroid stimulating hormone (TSH), Vitamins D 1.25 and D 25OH, leptin, and insulin-like growth factor-binding protein 3 (IGF-BP3). Corrected statistics did not reveal significant associations with P300 latency or amplitude for these hormones except for leptin plasma levels. However, factor analysis showed that FSH and LH clustered together with Vitamin D1.25 and Vitamin D25OH, P300 latency (not amplitude), and log leptin were found to be associated in the same cluster. Utilizing regression analysis, once age adjusted, leptin was the only significant predictor for latency or speed (p = 0.03) with an effect size of 0.23. Higher plasma leptin levels were associated with abnormal P300 speed (OR = 0.98). Our findings show a significant relationship of higher plasma leptin levels, potentially due to leptin resistance, and prolonged P300 latency. This suggests leptin resistance may delay electrophysiological processing of memory and attention, which appears to be the first of such an association.

Habitual consumption of coffee and green tea in relation to serum adipokines: a cross-sectional study

PURPOSE

Coffee and green tea consumption may be associated with circulating adipokines, but data are inconsistent, scarce or lacking. We examined the association of coffee and green tea consumption with serum adiponectin, leptin, visfatin, resistin and plasminogen activator inhibitor-1 (PAI-1) among a Japanese working population.

METHODS

The authors analyzed data (n = 509) from a cross-sectional survey among Japanese workers aged 20-68 years. Serum adipokines were measured using a Luminex suspension bead-based multiplexed array. Coffee and green tea consumption was assessed using a validated diet history questionnaire, and caffeine consumption from these beverages was estimated. Multiple regression analysis was performed with adjustment for potential confounding variables.

RESULTS

Coffee consumption was significantly, inversely associated with leptin and PAI-1 (P for trend = 0.007 and 0.02, respectively); compared with subjects consuming <1 cup per day, those consuming ≥4 cups per day had 13 and 10 % lower means of leptin and PAI-1, respectively. Similar associations were observed for caffeine consumption (P for trend = 0.02 for both leptin and PAI-1). Additionally, we noted a significant positive association between coffee consumption and adiponectin in men (P for trend = 0.046), but not in women (P for trend = 0.43, P for interaction = 0.11). Moreover, there was a positive association between coffee consumption and resistin in current male smokers (P for trend = 0.01), but not in male non-smokers (P for trend = 0.35, P for interaction = 0.11). Green tea consumption was not associated with any adipokine.

CONCLUSIONS

Higher consumption of coffee and caffeine but not green tea was associated with lower serum levels of leptin and PAI-1 in Japanese adults.

Adiponectin gene variant interacts with fish oil supplementation to influence serum adiponectin in older individuals

Marine n3 polyunsaturated fatty acids (PUFAs) activate the transcription factor peroxisome proliferator-activated receptor (PPARγ), which modulates the expression of adiponectin. We investigated the interaction of dietary n3 PUFAs with adiponectin gene (ADIPOQ) single nucleotide polymorphism (SNP) genotypes as a determinant of serum adiponectin concentration. The Modulation of Atherosclerosis Risk by Increasing Doses of n3 Fatty Acids study is a parallel design, double-blind, controlled trial. Serum adiponectin was measured in 142 healthy men and 225 women aged 45-70 y randomized to treatment with doses of 0.45, 0.9, and 1.8 g/d 20:5n3 and 22:6n3 (1.51:1), or placebo for 12 mo. The 310 participants who completed the study were genotyped for 5 SNPs at the ADIPOQ locus: -11391 G/A (rs17300539), -11377 C/G (rs266729), -10066 G/A (rs182052), +45 T/G (rs2241766), and +276 G/T (rs1501299). The -11391 A-allele was associated with a higher serum adiponectin concentration at baseline (n = 290; P < 0.001). The interaction between treatment and age as a determinant of adiponectin was significant in participants aged >58 y after the highest dose (n = 92; P = 0.020). The interaction between +45 T/G and treatment and age was a nominally significant determinant of serum adiponectin after adjustment for BMI, gender, and ethnicity (P = 0.029). Individuals homozygous for the +45 T-allele aged >58 y had a 22% increase in serum adiponectin concentration compared with baseline after the highest dose (P-treatment effect = 0.008). If substantiated in a larger sample, a diet high in n3 PUFAs may be recommended for older individuals, especially those of the +45 TT genotype who have reported increased risk of hypoadiponectinemia, type 2 diabetes, and obesity.

Unchanged serum adipokine concentrations in the setting of short-term thyroidectomy-induced hypothyroidism

OBJECTIVE

To investigate short-term effects of thyroidectomy-induced hypothyroidism on leptin, adiponectin, and resistin concentrations in association with anthropometric data.

METHODS

Thirty premenopausal women with euthyroid nodular goiter-mean age, 44.0 ± 11.6 years; mean body mass index (BMI), 28.6 ± 5.9 kg/m2; 13 obese, 7 overweight, and 10 normal weight subjects-scheduled for total thyroidectomy were included in the study. Serum leptin, adiponectin, resistin, free triiodothyronine, free thyroxine, thyroid-stimulating hormone, glucose, insulin, and C-reactive protein concentrations, lipid profile, and anthropometric variables were determined in the euthyroid state (preoperatively) and the hypothyroid state (postoperatively, with a thyroid-stimulating hormone concentration >30 mIU/L).

RESULTS

Body weight, BMI, waist and hip circumferences, body fat mass, and serum lipid concentrations increased significantly after thyroidectomy. No significant difference was found between preoperative and postoperative serum leptin, adiponectin, and resistin concentrations. Fat tissue mass-corrected leptin, adiponectin, and resistin concentrations did not differ significantly between euthyroid and hypothyroid periods. Thyroid hormone concentrations showed no significant correlations with adipokine levels.

CONCLUSION

Serum adipokine concentrations seem not to change significantly during short-term thyroidectomy-induced hypothyroidism despite significant increases in body weight, BMI, fat mass, and lipid concentrations.

The relationship between longitudinal serum leptin measures and measures of magnetic resonance imaging-assessed knee joint damage in a population of mid-life women

BACKGROUND AND OBJECTIVE

Serum leptin measures are associated with radiographic knee osteoarthritis, but no studies have examined leptin levels with respect to different measures of knee joint damage from MRI.

METHODS

Participants in the Michigan Study of Women's Health Across the Nation underwent bilateral knee MRIs at follow-up visit 11 for assessment of cartilage defects, bone marrow lesions, osteophytes, meniscal tears, synovitis and joint effusion. Serum leptin measures were available from baseline, follow-up visits 1 and 3-7.

RESULTS

Baseline serum leptin levels were associated with greater odds of having more severe knee joint damage at follow-up visit 11 after adjustment for age, smoking status, menopause status and body mass index residuals. The greatest effect was observed for osteophytes; a 5 ng/ml increase in baseline leptin was associated with 24% higher odds of having larger osteophytes (95% CI 1.17 to 1.32). Correlations with baseline serum leptin were greatest for MRI-assessed osteophytes (r=0.41), followed by effusion (r=0.32), synovitis (r=0.30), cartilage defects (r=0.28), bone marrow lesions (r=0.24) and meniscal abnormalities (r=0.21).

CONCLUSIONS

Leptin levels 10 years prior to MRI assessment were associated with the presence of cartilage defects, bone marrow lesions, osteophytes, meniscal tears, synovitis and effusion among a population of middle-aged women. Understanding the role that leptin plays in the joint degradation process is critical for development of more targeted interventions for osteoarthritis.

Relation of absolute or relative adiposity to insulin resistance, retinol binding protein-4, leptin, and adiponectin in type 2 diabetes

BACKGROUND

Central fat mass (CFM) correlates with insulin resistance and increases the risk of type 2 diabetes and cardiovascular complications; however, peripheral fat mass (PFM) is associated with insulin sensitivity. The aim of this study was to investigate the relation of absolute and relative regional adiposity to insulin resistance index and adipokines in type 2 diabetes.

METHODS

Total of 83 overweighted-Korean women with type 2 diabetes were enrolled, and rate constants for plasma glucose disappearance (K(ITT)) and serum adipokines, such as retinol binding protein-4 (RBP4), leptin, and adiponectin, were measured. Using dual X-ray absorptiometry, trunk fat mass (in kilograms) was defined as CFM, sum of fat mass on the lower extremities (in kilograms) as PFM, and sum of CFM and PFM as total fat mass (TFM). PFM/TFM ratio, CFM/TFM ratio, and PFM/CFM ratio were defined as relative adiposity.

RESULTS

Median age was 55.9 years, mean body mass index 27.2 kg/m(2), and mean HbA1c level 7.12±0.84%. K(ITT) was positively associated with PMF/TFM ratio, PMF/CFM ratio, and negatively with CFM/TFM ratio, but was not associated with TFM, PFM, or CFM. RBP4 levels also had a significant relationship with PMF/TFM ratio and PMF/CFM ratio. Adiponectin, leptin, and apolipoprotein A levels were related to absolute adiposity, while only adiponectin to relative adiposity. In correlation analysis, K(ITT) in type 2 diabetes was positively related with HbA1c, fasting glucose, RBP4, and free fatty acid.

CONCLUSION

These results suggest that increased relative amount of peripheral fat mass may aggravate insulin resistance in type 2 diabetes.

Dysregulated adipokine metabolism in chronic obstructive pulmonary disease

BACKGROUND

Research concerning the involvement of body composition and systemic inflammatory markers in adipokine metabolism in chronic obstructive pulmonary disease (COPD) is still limited. Therefore, we primarily aimed to investigate the adipokine metabolism in relation to these systemic inflammatory biomarkers and to evaluate possible gender-related differences in the adipokine metabolism in patients with COPD.

MATERIALS AND METHODS

One hundred and eighty-six subjects with COPD [mean (SD) FEV(1) %pred: 50 (±16)] and 113 controls, matched for age, gender and body composition were selected from the ECLIPSE cohort. The following serological data were collected: serum levels of leptin, adiponectin and systemic inflammatory biomarkers such as C-reactive protein (CRP), Interleukin-6 (IL-6) and fibrinogen.

RESULTS

Compared with controls, patients with COPD had higher levels of CRP, IL-6, fibrinogen and adiponectin. After stratification for gender, men with COPD had higher CRP, IL6 and fibrinogen levels compared with male controls, while women with COPD had higher levels of CRP and fibrinogen compared with the female controls. Moreover, in both female controls and patients with COPD, leptin correlated with CRP and fibrinogen, while leptin only correlated with CRP in male controls. Adiponectin correlated negatively with CRP, only in patients with COPD. Body mass index and gender were the strongest determinants for both leptin and adiponectin.

CONCLUSIONS

This study shows a gender-dependent dysregulation of adipokine metabolism in patients with COPD compared with BMI-matched controls. Furthermore, results from this study suggest a more prominent role of adiponectin in the systemic response to COPD.

Impact of age on leptin and adiponectin independent of adiposity

Age-related changes in leptin and adiponectin levels remain controversial, being affected by inconsistent normalisation for adiposity and body fat distribution in the literature. In a cross-sectional study on 210 Caucasians (127 women, eighty-three men, 18-78 years, BMI 16.8-46.8 kg/m²), we investigated the effect of age on adipokine levels independent of fat mass (FM measured by densitometry), visceral and subcutaneous adipose tissue volumes (VAT and SAT assessed by whole-body MRI). Adiponectin levels increased with age in both sexes, whereas leptin levels decreased with age in women only. There was an age-related increase in VAT (as a percentage of total adipose tissue, VAT%TAT), associated with a decrease in SAT(legs)%TAT. Adiposity was the main predictor of leptin levels, with 75.1 % of the variance explained by %FM in women and 76.6 % in men. Independent of adiposity, age had a minor contribution to the variance in leptin levels (5.2 % in women only). The variance in adiponectin levels explained by age was 14.1 % in women and 5.1 % in men. In addition, independent and inverse contributions to the variance in adiponectin levels were found for truncal SAT (explaining additional 3.0 % in women and 9.1 % in men) and VAT%TAT (explaining additional 13.0 % in men). In conclusion, age-related changes in leptin and adiponectin levels are opposite to each other and partly independent of adiposity and body fat distribution. Normalisation for adiposity but not for body fat distribution is required for leptin. Adiponectin levels are adversely affected by subcutaneous and visceral trunk fat.

Differences in the association between serum leptin levels and body mass index in black and white women: a report from the Southern Community Cohort Study

BACKGROUND/AIMS

Leptin may be an important link between obesity and many high-burden diseases, including cancer and cardiovascular disease, but leptin levels and correlates in individuals of diverse racial backgrounds have not been well characterized despite racial differences in incidence and mortality patterns for many obesity-related diseases.

METHODS

In a cross-sectional study of 915 white and 892 black women enrolled in the Southern Community Cohort Study (age 40-79 years, half postmenopausal), serum leptin levels were compared between the race groups and across categories of body mass index (BMI). Potential correlates of leptin were assessed via race-stratified linear regression models.

RESULTS

Blacks had higher unadjusted leptin levels than whites (geometric mean 22.4 vs. 19.0 ng/ml; p < 0.0001). Leptin increased with increasing BMI, and racial differences in leptin were most pronounced in women with BMI ≥25. Significant correlates of leptin included BMI, age, alcohol consumption, cigarette smoking, diabetes (both races) and fat consumption (black women only). Leptin remained higher in black women (22.7 vs. 18.8 ng/ml) after adjustment for these factors.

CONCLUSIONS

Persistent racial differences in leptin concentrations exist after adjustment for BMI and other factors. Leptin assessment may be informative in future studies that investigate racial differences in the development of obesity-related diseases.

Effect of interaction between PPARG, PPARA and ADIPOQ gene variants and dietary fatty acids on plasma lipid profile and adiponectin concentration in a large intervention study

Unsaturated fatty acids are ligands of PPAR-γ, which up-regulates genes involved in fatty acid transport and TAG synthesis and the insulin-sensitising adipokine adiponectin, which activates fatty acid β-oxidation via PPAR-α action in liver. We investigated the effect of dietary fatty acid interaction with PPARG, PPARA and ADIPOQ gene variants on plasma lipid and adiponectin concentrations in the Reading Imperial Surrey Cambridge King's study, a five-centre, parallel design, randomised controlled trial of 466 subjects at increased cardiometabolic risk. After a 4-week run-in to baseline, SFA was replaced by MUFA or carbohydrate (low fat) in isoenergetic diets for 24 weeks. Habitual dietary PUFA:SFA ratio×PPARG Pro12Ala genotype interaction influenced plasma total cholesterol (P=0·02), LDL-cholesterol (P=0·002) and TAG (P=0·02) concentrations in White subjects. PPARA Val162Leu×PPARG Pro12Ala genotype interaction influenced total cholesterol (P=0·04) and TAG (P=0·03) concentrations at baseline. After high-MUFA and low-fat diets, total cholesterol and LDL-cholesterol were reduced (P<0·001) and gene×gene interaction determined LDL-cholesterol (P=0·003) and small dense LDL as a proportion of LDL (P=0·012). At baseline, ADIPOQ -10066 G/A A-allele was associated with lower serum adiponectin (n 360; P=0·03) in White subjects. After the high-MUFA diet, serum adiponectin increased in GG subjects and decreased in A-allele carriers (P=0·006 for difference). In GG, adiponectin increased with age after the high MUFA and decreased after the low-fat diet (P=0·003 for difference at 60 years). In conclusion, in Whites, high dietary PUFA:SFA would help to reduce plasma cholesterol and TAG in PPARG Ala12 carriers. In ADIPOQ -10066 GG homozygotes, a high-MUFA diet may help to increase adiponectin with advancing age.

Single nucleotide polymorphisms at the ADIPOQ gene locus interact with age and dietary intake of fat to determine serum adiponectin in subjects at risk of the metabolic syndrome

BACKGROUND

Adiponectin gene expression is modulated by peroxisome proliferator-activated receptor γ, which is a transcription factor activated by unsaturated fatty acids.

OBJECTIVE

We investigated the effect of the interaction between variants at the ADIPOQ gene locus, age, sex, body mass index (BMI), ethnicity, and the replacement of dietary saturated fatty acids (SFAs) with monounsaturated fatty acids (MUFAs) or carbohydrates on serum adiponectin concentrations.

DESIGN

The RISCK (Reading, Imperial, Surrey, Cambridge, and Kings) study is a parallel-design, randomized controlled trial. Serum adiponectin concentrations were measured after a 4-wk high-SFA (HS) diet and a 24-wk intervention with reference (HS), high-MUFA (HM), and low-fat (LF) diets. Single nucleotide polymorphisms at the ADIPOQ locus -11391 G/A (rs17300539), -10066 G/A (rs182052), -7734 A/C (rs16861209), and +276 G/T (rs1501299) were genotyped in 448 participants.

RESULTS

In white Europeans, +276 T was associated with higher serum adiponectin concentrations (n = 340; P = 0.006) and -10066 A was associated with lower serum adiponectin concentrations (n = 360; P = 0.03), after adjustment for age, BMI, and sex. After the HM diet, -10066 G/G subjects showed a 3.8% increase (95% CI: -0.1%, 7.7%) and G/A+A/A subjects a 2.6% decrease (95% CI: -5.6%, 0.4%) in serum adiponectin (P = 0.006 for difference after adjustment for the change in BMI, age, and sex). In -10066 G/G homozygotes, serum adiponectin increased with age after the HM diet and decreased after the LF diet.

CONCLUSION

In white -10066 G/G homozygotes, an HM diet may help to increase adiponectin concentrations with advancing age. This trial was registered at clinicaltrials.gov as ISRCTN29111298.

The influence of body mass index and renin-angiotensin-aldosterone system activity on the relationship between 25-hydroxyvitamin D and adiponectin in Caucasian men

OBJECTIVE

Previous studies have suggested that circulating adiponectin concentrations are associated positively with vitamin D and negatively with body mass index (BMI) but have not accounted for the influence of the renin-angiotensin-aldosterone system (RAAS) in this relationship. This is particularly relevant because increased RAAS activity is associated with obesity and is known to lower adiponectin levels. We evaluated the association between adiponectin and 25-hydroxyvitamin D (25(OH)D) after controlling RAAS activity with dietary sodium equilibration and also evaluated whether this relationship was influenced by BMI.

DESIGN

Cross-sectional study of 115 hypertensive Caucasian men from the Hypertensive Pathotype Consortium.

METHODS

To manipulate RAAS activity, all subjects underwent 1 week of high dietary sodium (HS) diet to suppress RAAS and 1 week of low dietary sodium (LS) diet to stimulate RAAS. Linear regression was used to evaluate the association between adiponectin and 25(OH)D, and the effect of BMI on this relationship, in each dietary condition.

RESULTS

Adiponectin was higher on HS, where circulating RAAS activity was low, when compared with LS (HS=2.9 versus LS=2.4 μg/ml, P<0.0001). 25(OH)D levels were positively associated with adiponectin, and BMI was a statistically significant effect modifier of the relationship between 25(OH)D and adiponectin on both diets (P interaction <0.01 between BMI and 25(OH)D).

CONCLUSIONS

Higher 25(OH)D concentrations were independently associated with higher adiponectin levels, particularly when BMI was high. Dietary sodium balance and circulating RAAS activity did not appear to affect this relationship. Future studies should explore whether vitamin D supplementation increases adiponectin levels in obesity.

Pharmacodynamic effects of rosiglitazone in nondiabetic patients with metabolic syndrome

STUDY OBJECTIVES

To determine the effects of the thiazolidinedione rosiglitazone on the adipocyte-derived cytokines adiponectin (an antiinflammatory and insulin-sensitizing cytokine; low levels have been associated with metabolic syndrome) and resistin (an inflammation mediator; high levels have been associated with metabolic syndrome) in nondiabetic patients with metabolic syndrome, and to characterize the effects of rosiglitazone on other components of the metabolic syndrome phenotype in this population.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study.

SETTING

Outpatient general clinical research center.

PATIENTS

Thirty-two nondiabetic men and women with a clinical diagnosis of metabolic syndrome (as defined in the American Heart Association-National Heart, Lung, and Blood Institute scientific statement).

INTERVENTION

Patients were randomly assigned to receive either oral rosiglitazone 4 mg/day or matching placebo for 12 weeks.

MEASUREMENTS AND MAIN RESULTS

The primary end point was change in serum adiponectin concentrations from baseline to week 12. Secondary end points were changes in serum resistin concentrations, insulin resistance, fasting glucose level, fasting insulin level, body weight, lipid levels, systolic and diastolic blood pressure, and waist circumference from baseline to week 12. Also, changes from baseline in adiponectin and resistin concentrations and insulin resistance were assessed over time at weeks 2, 4, 8, and 12. Rosiglitazone was associated with a significant increase in serum adiponectin concentration after 12 weeks compared with placebo (45.8% vs 2.6%, p=0.002). The increase in adiponectin concentration occurred quickly, with a significant difference observed after 2 weeks of therapy. Compared with placebo, rosiglitazone was not associated with significant 12-week changes in serum resistin concentrations, insulin resistance, fasting glucose level, fasting insulin level, body weight, lipid levels, systolic or diastolic blood pressure, or waist circumference.

CONCLUSION

Rosiglitazone had beneficial effects on adiponectin concentrations without significantly affecting other components of the metabolic syndrome phenotype. Additional studies that further elucidate the time course of thiazolidinedione pharmacodynamic effects, along with their effects on cardiovascular end points, are warranted in nondiabetic patients with metabolic syndrome.