Abdominal adiposity is associated with elevated C-reactive protein independent of BMI in healthy nonobese people

Obesity, anthropometric measures and chronic kidney disease complications

BACKGROUND/AIMS

Anthropometric measures such as body mass index (BMI) and waist circumference (WC) have differential associations with incident chronic kidney disease (CKD) and mortality. We examined the associations of BMI and WC with various CKD complications.

METHODS

We conducted a cross-sectional analysis of 2,853 adult participants with CKD in the National Health and Nutrition Examination Surveys 1999-2006. The associations of BMI and WC (both as categorical and continuous variables) with CKD complications such as anemia, secondary hyperparathyroidism, hyperphosphatemia, metabolic acidosis, hypoalbuminemia and hypertension were examined using logistic regression models while adjusting for relevant confounding variables.

RESULTS

When examined as a continuous variable, an increase in BMI by 2 points and in WC by 5 cm was associated with higher odds of secondary hyperparathyroidism, hypoalbuminemia and hypertension among those with CKD. CKD participants with BMI ≥30 have higher odds of hypoalbuminemia and hypertension than those with BMI <30. CKD participants with high WC (>102 cm in men and >88 cm in women) have higher odds of hypoalbuminemia and hypertension and lower odds of having anemia than those with low WC. CKD participants with BMI <30 and high WC (vs. BMI <30 and low WC) were not associated with any increase in CKD complications.

CONCLUSIONS

Anthropometric measures such as BMI and WC are associated with secondary hyperparathyroidism, hypoalbuminemia and hypertension among adults with CKD. Higher WC among those with BMI <30 is not associated with CKD complications.

Association of high-sensitivity C-reactive protein with cardiometabolic risk factors and micronutrient deficiencies in adults of Ouagadougou, Burkina Faso

Increasing evidence suggests that high-sensitivity C-reactive protein (hs-CRP) is associated with cardiometabolic risk factors (CMRF) while being also related to micronutrient deficiencies. As part of a project on the double burden of under- and overnutrition in sub-Saharan Africa, we assessed the relationship between hs-CRP and both CMRF and micronutrient deficiencies in a population-based cross-sectional study carried out in the Northern district of Ouagadougou, the capital city of Burkina Faso. We randomly selected 330 households stratified by income tertile. In each income stratum, 110 individuals aged 25-60 years and having lived in Ouagadougou for at least 6 months were randomly selected, and underwent anthropometric measurements and blood sample collection. The prevalence of high hs-CRP was 39.4 %, with no sex difference. Vitamin A-deficient subjects (12.7 %) exhibited significant risk of elevated hs-CRP (OR 2.5; P= 0.015). Serum ferritin was positively correlated with log hs-CRP (r 0.194; P= 0.002). The risk of elevated hs-CRP was significant in subjects with BMI ≥ 25 kg/m² (OR 6.9; 95 % CI 3.6, 13.3), abdominal obesity (OR 4.6; 95 % CI 2.2, 7.3) and high body fat (OR 10.2; 95 % CI 5.1, 20.3) (P< 0.001, respectively). Independent predictors of hs-CRP in linear regression models were waist circumference (β = 0.306; P= 0.018) and serum TAG (β = 0.158; P= 0.027). In this sub-Saharan population, hs-CRP was consistently associated with adiposity. Assuming that plasma hs-CRP reflects future risk of cardiovascular events, intervention which reduces CRP, or chronic and acute nutrition conditions associated with it, could be effective in preventing their occurrence particularly in sub-Saharan Africa.

High sensitivity C-reactive protein associated with different health predictors in middle-aged and oldest old Chinese

OBJECTIVE

To describe the distribution of plasma high sensitivity C-reactive protein (hsCRP) and explore the relationship between hsCRP and metabolic risk factors among residents living in longevity areas of China.

METHODS

268 individuals aged between 40 and 59 years and 506 individuals aged over 90 years were selected from 5 longevity areas of China to participate in a cross section longitudinal cohort study. The participants were interviewed with general health related questionnaire to collect their demographic, behavioral and lifestyle data, as well as their chronic conditions, and meanwhile their physical and biomedical parameters including waist circumference (WC), blood pressure (BP), hsCRP, plasma lipids, and fasting blood glucose (FBG) were measured.

RESULTS

The median of hsCRP was 0.99 mg/L in the middle-aged group and 1.76 mg/L in the oldest old group. No significant gender difference was observed between the above two groups. Among the oldest old individuals, 36.56% had an hsCRP level >3.0 mg/L. The prevalence of high hsCRP was 16.79% in the middle-aged group. The results of stepwise multiple linear regression analyses showed that HDL-C was independently associated with ln (hsCRP) concentration in the middle-aged group, whereas ln (TG), HDL-C and FBG were correlated after adjustment for gender, study site, smoking, drinking, education and BMI in the oldest old group.

CONCLUSION

HDL-C is a stronger predictor of elevated hsCRP than other metabolic factors in the middle-aged population. For the oldest old persons, high TG, low HDL-C, and FBG predict elevated plasma hsCRP.

Hyperadiponectinemia protects against premature death in metabolic syndrome model mice by inhibiting AKT signaling and chronic inflammation

We previously reported that transgenic (Tg) expression of adiponectin significantly prolonged the lifespan of normal mice. The aim of this study was to elucidate the mechanism involved in the longevity effects of adiponectin using KK/Ta mice, a murine model of metabolic syndrome. We established a Tg line of KK/Ta (Tg-KK/Ta) mice expressing human adiponectin in the liver, and assessed their lifespan. The cause of death was determined by macroscopic and microscopic examinations immediately after death. The expressions of SIRT1, C-reactive protein (CRP), inflammatory cytokines, AMPK, and AKT were measured by quantitative real-time PCR, ELISAs, and/or western blotting. KK/Ta mice had lower serum adiponectin levels and shorter lifespan (57.6±13.9 vs 106.5±18.3 weeks, P<0.0001) than C57BL/6N mice. Tg adiponectin expression significantly extended the lifespan of KK/Ta mice (73.6±16.6 weeks, P<0.001) without affecting body weight, daily food consumption, or plasma glucose levels. Neoplasms were observed in only three of 22 KK/Ta mice that died spontaneously because of tumors. Atherosclerotic lesions were not detected in any mice. SIRT1 levels were not significantly different between KK/Ta and Tg-KK/Ta mice. Gene expressions of Crp, Tnfα, Il6, and Nfκb were increased in KK/Ta mice, but they were significantly attenuated in Tg-KK/Ta mice. Phosphorylated AMPK levels were increased and phosphorylated AKT levels were decreased in Tg-KK/Ta mice. The anti-inflammatory effects of adiponectin, achieved by inhibiting the AKT signaling pathway, may explain how adiponectin slows the accelerated aging process associated with the metabolic syndrome.

Obesity, inflammation and the immune system

Obesity shares with most chronic diseases the presence of an inflammatory component, which accounts for the development of metabolic disease and other associated health alterations. This inflammatory state is reflected in increased circulating levels of pro-inflammatory proteins, and it occurs not only in adults but also in adolescents and children. The chronic inflammatory response has its origin in the links existing between the adipose tissue and the immune system. Obesity, like other states of malnutrition, is known to impair the immune function, altering leucocyte counts as well as cell-mediated immune responses. In addition, evidence has arisen that an altered immune function contributes to the pathogenesis of obesity. This review attempts to briefly comment on the various plausible explanations that have been proposed for the phenomenon: (1) the obesity-associated increase in the production of leptin (pro-inflammatory) and the reduction in adiponectin (anti-inflammatory) seem to affect the activation of immune cells; (2) NEFA can induce inflammation through various mechanisms (such as modulation of adipokine production or activation of Toll-like receptors); (3) nutrient excess and adipocyte expansion trigger endoplasmic reticulum stress; and (4) hypoxia occurring in hypertrophied adipose tissue stimulates the expression of inflammatory genes and activates immune cells. Interestingly, data suggest a greater impact of visceral adipose tissue and central obesity, rather than total body fat, on the inflammatory process. In summary, there is a positive feedback loop between local inflammation in adipose tissue and altered immune response in obesity, both contributing to the development of related metabolic complications.

Contribution of gender and body fat distribution to inflammatory marker concentrations in apparently healthy young adults

OBJECTIVE

This cross-sectional study assessed the potential contribution of gender, body fat distribution, and their interactions to some inflammatory marker concentrations [C-reactive protein (CRP), complement factor 3 (C3), and ceruloplasmin (Cp)] in young adults.

METHODS

Measurements included body composition, lifestyle features, blood biochemical and selected inflammatory markers on 317 healthy subjects [122 males/195 females; 22 ± 3 years; 22.1 ± 2.8 kg/m(2) (mean ± SD)].

RESULTS

Women had significantly higher CRP and Cp concentrations than men. No gender difference was noted in C3 concentrations. In a multivariate model of the whole sample, body fat (BF), waist circumference (WC) and the sex × WC interaction term presented the highest R (2) for variance of CRP (11%), C3 (2%), and Cp (12%), respectively. In regression models separated by sex, BF was the adiposity indicator that explained the variability of CRP in men (13%) and women (7%). WC was the only variable significantly associated with C3 concentrations in women (3%). BF presented the highest partial R (2) for Cp in men (8%) and WC in women (16%).

CONCLUSION

Our findings indicate a relevant interaction between gender and body fat distribution on the variance of CRP, C3, and Cp concentrations in apparently healthy young adults.

Comparison of adiposity measures as risk factors in postmenopausal women

CONTEXT

There is a continuing debate about which adiposity measure is the best risk factor.

OBJECTIVES

This study compared the associations of 14 health outcomes with combinations of four adiposity measures: body mass index (BMI), waist to hip ratio (WHR), waist, and waist to height ratio.

DESIGN

Data were from the Women's Health Initiative, a prospective study of women enrolled from 1993-1998 with a median follow-up time of 8 yr. Regression models were used to test the association of adiposity measures with outcome after adjusting for a number of variables related to demographic characteristics and health behavior.

SETTING

The women were recruited from 40 clinical centers throughout the United States.

PARTICIPANTS

The sample analyzed included 141,652 postmenopausal women age 50-79 yr who met the criteria for the Women's Health Initiative randomized control trials.

MAIN OUTCOME MEASURES

Outcomes included death and eight medical conditions.

RESULTS

Adiposity measures were most strongly associated with diabetes, hypertension, joint replacement, and gallbladder disease; moderately associated with myocardial infarction, endometrial cancer, and death; and least strongly associated with colon cancer, stroke, and breast cancer. Associations were nearly identical for waist and waist to height ratio. For most outcomes, waist was a stronger individual risk factor than BMI or WHR. However, BMI and WHR were the most useful combination of adiposity measures for stratifying participants according to risk of hypertension or diabetes.

CONCLUSIONS

The adiposity measure most useful for stratifying persons on the basis of risk depends on the outcome of interest. When the outcome is diabetes or hypertension in postmenopausal women, the best indication of risk is a combination BMI and WHR.

Centrally located body fat is associated with lower bone mineral density in older Puerto Rican adults

BACKGROUND

Fat mass is thought to be protective against osteoporosis, primarily because of its weight-bearing effect. Few studies have evaluated the association between abdominal fat mass (AFM) and bone health beyond its weight-bearing effect.

OBJECTIVE

We tested the hypothesis that higher body weight-adjusted AFM is associated with poor bone health.

DESIGN

A cross-sectional study was conducted in 629 Puerto Rican adults aged 47-79 y. Bone mineral density (BMD) of the femoral neck, trochanter, total femur, and lumbar spine (L2-L4) were measured by using dual-energy X-ray absorptiometry (DXA). AFM and total fat mass (TFM) were assessed by using body-composition software from whole-body DXA scans. Osteoporosis and osteopenia were defined as T-scores ≤ -2.5 and -1.0 to -2.5 SD, respectively, at the respective bone site.

RESULTS

After confounders were controlled for, body weight-adjusted AFM was inversely associated with BMD at all 4 bone sites in women and at the femoral neck in men. For TFM, small inverse associations were seen at the trochanter and total femur in women. In men, similar associations were seen at the 3 femur sites. In both sexes, the odds for osteoporosis or osteopenia at each of the femoral sites increased by 10-16% for every 100-g increase in body weight-adjusted AFM.

CONCLUSIONS

Higher AFM was associated with poor bone health in this Puerto Rican sample. Efforts to reduce abdominal obesity will not only reduce the risk of chronic disease but may also improve bone health. This trial is registered at clinicaltrials.gov as NCT01231958.

Uncoupling protein 2 G(-866)A polymorphism: a new gene polymorphism associated with C-reactive protein in type 2 diabetic patients

Background

This study evaluated the relationship between the G(-866)A polymorphism of the uncoupling protein 2 (UCP2) gene and high-sensitivity C reactive protein (hs-CRP) plasma levels in diabetic patients.

Methods

We studied 383 unrelated people with type 2 diabetes aged 40-70 years. Anthropometry, fasting lipids, glucose, HbA1c, and hs-CRP were measured. Participants were genotyped for the G (-866)A polymorphism of the uncoupling protein 2 gene.

Results

Hs-CRP (mg/L) increased progressively across the three genotype groups AA, AG, or GG, being respectively 3.0 ± 3.2, 3.6 ± 5.0, and 4.8 ± 5.3 (p for trend = 0.03). Since hs-CRP values were not significantly different between AA and AG genotype, these two groups were pooled for further analyses. Compared to participants with the AA/AG genotypes, homozygotes for the G allele (GG genotype) had significantly higher hs-CRP levels (4.8 ± 5.3 vs 3.5 ± 4.7 mg/L, p = 0.01) and a larger proportion (53.9% vs 46.1%, p = 0.013) of elevated hs-CRP (> 2 mg/L). This was not explained by major confounders such as age, gender, BMI, waist circumference, HbA1c, smoking, or medications use which were comparable in the two genotype groups.

Conclusions

The study shows for the first time, in type 2 diabetic patients, a significant association of hs-CRP levels with the G(-866)A polymorphism of UCP2 beyond the effect of major confounders.

Cardiovascular risk in women with diabetes

Women with diabetes have a high risk of cardiovascular disease that, almost completely eliminates the gender difference in cardiovascular morbidity and mortality between non-diabetic men and women. In this chapter we have reviewed data showing that cardiovascular risk factors are more common, more likely to cluster, or more severe in diabetic women than men; this may be due to biological or behavioural factors. Disparities in accessibility, quality and, possibly, effectiveness of care further disadvantage diabetic women. Based on available data it can be concluded that a large number of CVD deaths are preventable in diabetic women; therefore special attention should be paid to risk factors detection and correction, as well as timely CHD diagnosis and treatment in diabetic women. To meet these needs gender specific guidelines and implementation measures may be in order.

Relation of C-reactive protein to abdominal adiposity

Inflammation is a crucial element in the development of cardiovascular disease. Serum measurements of inflammation through high-sensitivity C-reactive protein (hsCRP) can lead to improved risk stratification of patients for risk for hard cardiovascular events. There is evidence that anthropomorphic measurements of obesity are important determinants of systemic inflammation. Online databases (e.g., PubMed and Medline) were searched for original research reports published in English from June 1990 to June 2009 examining the relations between hsCRP; anthropomorphic measurements of obesity including body mass index, waist-to-hip ratio, waist circumference, and visceral adiposity; and cardiovascular disease. When possible, correlation coefficients were used to compare data among studies. Measurements of abdominal obesity are associated with systemic inflammation as measured by hsCRP (r = 0.40 to 0.61). The association between hsCRP and abdominal adiposity persists when taking into account body mass index. Elevation of hsCRP might be reversible with weight loss and exercise. In conclusion, clinical measurements of abdominal adiposity readily provide data elucidating the systemic inflammatory state of patients and can help guide intensity of lifestyle modifications, thus leading to reduction of this inflammation.

Circulating brain-derived neurotrophic factor and indices of metabolic and cardiovascular health: data from the Baltimore Longitudinal Study of Aging

BACKGROUND

Besides its well-established role in nerve cell survival and adaptive plasticity, brain-derived neurotrophic factor (BDNF) is also involved in energy homeostasis and cardiovascular regulation. Although BDNF is present in the systemic circulation, it is unknown whether plasma BDNF correlates with circulating markers of dysregulated metabolism and an adverse cardiovascular profile.

METHODOLOGY/PRINCIPAL FINDINGS

To determine whether circulating BDNF correlates with indices of metabolic and cardiovascular health, we measured plasma BDNF levels in 496 middle-age and elderly subjects (mean age approximately 70), in the Baltimore Longitudinal Study of Aging. Linear regression analysis revealed that plasma BDNF is associated with risk factors for cardiovascular disease and metabolic syndrome, regardless of age. In females, BDNF was positively correlated with BMI, fat mass, diastolic blood pressure, total cholesterol, and LDL-cholesterol, and inversely correlated with folate. In males, BDNF was positively correlated with diastolic blood pressure, triglycerides, free thiiodo-thyronine (FT3), and bioavailable testosterone, and inversely correlated with sex-hormone binding globulin, and adiponectin.

CONCLUSION/SIGNIFICANCE

Plasma BDNF significantly correlates with multiple risk factors for metabolic syndrome and cardiovascular dysfunction. Whether BDNF contributes to the pathogenesis of these disorders or functions in adaptive responses to cellular stress (as occurs in the brain) remains to be determined.