Body Fat Distribution and Total Body Fat as Risk Factors for Microalbuminuria in the Obese

Visceral adipose tissue and residual cardiovascular risk: a pathological link and new therapeutic options

Obesity is a heterogeneous disease that affects almost one-third of the global population. A clear association has been established between obesity and cardiovascular disease (CVD). However, CVD risk is known to be related more to the local distribution of fat than to total body fat. Visceral adipose tissue (VAT) in particular has a high impact on CVD risk. This manuscript reviews the role of VAT in residual CV risk and the available therapeutic strategies for decreasing residual CV risk related to VAT accumulation. Among the many pathways involved in residual CV risk, obesity and particularly VAT accumulation play a major role by generating low-grade systemic inflammation, which in turn has a high prognostic impact on all-cause mortality and myocardial infarction. In recent years, many therapeutic approaches have been developed to reduce body weight. Orlistat was shown to reduce both weight and VAT but has low tolerability and many drug-drug interactions. Naltrexone-bupropion combination lowers body weight but has frequent side effects and is contraindicated in patients with uncontrolled hypertension. Liraglutide and semaglutide, glucagon-like peptide 1 (GLP-1) agonists, are the latest drugs approved for the treatment of obesity, and both have been shown to induce significant body weight loss. Liraglutide, semaglutide and other GLP-1 agonists also showed a positive effect on CV outcomes in diabetic patients. In addition, liraglutide showed to specifically reduce VAT and inflammatory biomarkers in obese patients without diabetes. GLP-1 agonists are promising compounds to limit inflammation in human visceral adipocytes.

Obesity is a risk factor for progression to kidney transplant waitlisting after liver transplantation

BACKGROUND

Non-alcoholic steatohepatitis has emerged as a leading cause of cirrhosis, and obesity-associated comorbidities, including renal disease, have increased in prevalence. Obesity predisposes the kidney to hyperfiltration injury, potentially impairing acute kidney injury recovery. Identification of patients at risk for renal dysfunction is impeded by poor performance of renal function estimating equations among cirrhotics. To better understand obesity among cirrhotics and renal disease progression, we examined likelihood of kidney transplantation (KT) waitlisting after liver transplant alone (LTA) by obesity class.

METHODS

68 607 LTA recipients were identified in SRTR (2005-2018). Fine and Gray competing risks models were used to analyze likelihood of KT waitlisting.

RESULTS

27.4% of recipients were obese (BMI ≥ 30 kg/m² ) and were 10% more likely to require KT waitlisting (aHR: 1.10, 95%CI: 1.01-1.20). Risk was highest among recipients with Classes II and III obesity (BMI: ≥35 kg/m² ) (aHR: 1.37, 95%CI: 1.17-1.56). Moreover, recipients with Classes II and III obesity were 57% more likely to require KT waitlisting within one year post-LTA (aHR: 1.57, 95%CI: 1.18-2.10) compared to non-obese recipients.

DISCUSSION

These findings suggest obesity was a risk factor for renal recovery failure and/or renal disease progression post-LTA and may confound identification of renal dysfunction and/or prediction of renal recovery among cirrhotics.

Microalbuminuria and Serum Cystatin C in Prediction of Early-Renal Insufficiency in Children with Obesity

OBJECTIVE

Serum cystatin-C (SCysC) and microalbuminuria are well-recognized early markers of renal damage. This study aims to assess whether these early markers are elevated in children with obesity and normal serum creatinine (SCr).

METHODS

Pediatric patients diagnosed with obesity were included (n = 105, ages 4-18 y) in this study. The patients were divided into three groups as follows: solely obese, metabolic syndrome and type 2 diabetes. Serum cystatin-C, 24-h microalbuminuria, SCr and glomerular filtration rate (GFR) were evaluated in all patients. All patients were examined with history, physical examination, laboratory analysis and ultrasonography evaluation.

RESULTS

The findings showed that renal function, GFR and SCr levels were normal in all patients. There was microalbuminuria in six patients and SCysC was elevated in eight patients. There were also both elevated SCysC and microalbuminuria in eight patients. Significant elevations of both microalbuminuria and SCysC were detected in cases with type 2 diabetes (p < 0.05).

CONCLUSIONS

The findings suggest that SCysC may have a diagnostic value in early-renal insufficiency. Although there was not any statistically significant difference between groups in GFR, significant elevations for both microalbuminuria and SCysC in patients with type 2 diabetes were detected. This suggests that the risk factors of diabetes may have a direct relation with renal damage. Regarding renal function in type 2 diabetic and obese pediatric patients, microalbuminuria and SCysC may be screened to observe early-renal damage, even in cases with normal GFR and SCr levels.

Renoprotection with SGLT2 inhibitors in type 2 diabetes over a spectrum of cardiovascular and renal risk

Approximately half of all patients with type 2 diabetes (T2D) develop a certain degree of renal impairment. In many of them, chronic kidney disease (CKD) progresses over time, eventually leading to end-stage kidney disease (ESKD) requiring dialysis and conveying a substantially increased risk of cardiovascular morbidity and mortality. Even with widespread use of renin-angiotensin system blockers and tight glycemic control, a substantial residual risk of nephropathy progression remains. Recent cardiovascular outcomes trials investigating sodium-glucose cotransporter 2 (SGLT2) inhibitors have suggested that these therapies have renoprotective effects distinct from their glucose-lowering action, including the potential to reduce the rates of ESKD and acute kidney injury. Although patients in most cardiovascular outcomes trials had higher prevalence of existing cardiovascular disease compared with those normally seen in clinical practice, the proportion of patients with renal impairment was similar to that observed in a real-world context. Patient cardiovascular risk profiles did not relevantly impact the renoprotective benefits observed in these studies. Benefits were observed in patients across a spectrum of renal risk, but were evident also in those without renal damage, suggesting a role for SGLT2 inhibition in the prevention of CKD in people with T2D. In addition, recent studies such as CREDENCE and DAPA-CKD offer a greater insight into the renoprotective effects of SGLT2 inhibitors in patients with moderate-to-severe CKD. This review outlines the evidence that SGLT2 inhibitors may prevent the development of CKD and prevent and delay the worsening of CKD in people with T2D at different levels of renal risk.

Cardiovascular protection with sodium-glucose co-transporter-2 inhibitors in type 2 diabetes: Does it apply to all patients?

Patients with type 2 diabetes (T2D) are at an increased risk of cardiovascular disease (CVD). Cardiovascular risk in these patients should be considered as a continuum, and comprehensive treatment strategies should aim to target multiple disease risk factors. Large-scale clinical trials of sodium-glucose co-transporter-2 (SGLT2) inhibitors have shown an impact on cardiovascular outcomes, including heart failure hospitalization and cardiovascular death, which appears to be independent of their glucose-lowering efficacy. Reductions in major cardiovascular events appear to be greatest in patients with established CVD, particularly those with prior myocardial infarction, but are independent of heart failure or renal risk. Most large-scale trials of SGLT2 inhibitors predominantly include patients with T2D with pre-existing CVD and high cardiovascular risk at baseline, limiting their applicability to patients typically observed in clinical practice. Real-world evidence from observational studies suggests that there might also be beneficial effects of SGLT2 inhibitors on heart failure hospitalization and all-cause mortality in various cohorts of lower risk patients. The most common adverse events reported in clinical and observational studies are genital infections; however, the overall risk of these events appears to be low and easily managed. Similar safety profiles have been reported for elderly and younger patients. There is still some debate regarding the safety of canagliflozin in patients at high risk of fracture and amputation. Outstanding questions include specific patterns of cardiovascular protection according to baseline risk.

Osteopontin: The Molecular Bridge between Fat and Cardiac-Renal Disorders

Osteopontin (OPN) is a multifaceted matricellular protein, with well-recognized roles in both the physiological and pathological processes in the body. OPN is expressed in the main organs and cell types, in which it induces different biological actions. During physiological conditioning, OPN acts as both an intracellular protein and soluble excreted cytokine, regulating tissue remodeling and immune-infiltrate in adipose tissue the heart and the kidney. In contrast, the increased expression of OPN has been correlated with the severity of the cardiovascular and renal outcomes associated with obesity. Indeed, OPN expression is at the “cross roads” of visceral fat extension, cardiovascular diseases (CVDs) and renal disorders, in which OPN orchestrates the molecular interactions, leading to chronic low-grade inflammation. The common factor associated with OPN overexpression in adipose, cardiac and renal tissues seems attributable to the concomitant increase in visceral fat size and the increase in infiltrated OPN⁺ macrophages. This review underlines the current knowledge on the molecular interactions between obesity and the cardiac–renal disorders ruled by OPN.

Gender- and Age-Specific Associations between Visceral Obesity and Renal Function Impairment

OBJECTIVE

Although obesity is associated with an increased risk of chronic kidney disease, this trend becomes nonsignificant following adjustment for cardiovascular risk factors. The present study aims to investigate whether visceral obesity is independently associated with renal function impairment.

METHOD

The medical records of 14,529 male and 10,561 female Chinese adults undergoing health check-ups during 2013-2015 were retrospectively collected. The baseline characteristics, including the degree of visceral fat and the percentage of body fat, were compared. The association between study groups and renal function impairment was investigated using regression models adjusted for confounding factors.

RESULTS

All variables differed significantly among non-obese, peripheral, and central type obese subjects, both younger and older, and of both genders, except for hsCRP in older male subjects (p = 0.053) and eGFR in older female subjects (p = 0.098). Unadjusted univariate analysis showed that central obesity contributed significantly to renal function impairment in all age groups and in both genders. After adjusting for possible confounding factors, only central obesity was found to be an independent factor of renal function impairment in all groups, except for men under 45 years of age.

CONCLUSION

Visceral obesity is independently associated with renal function impairment in all ages and both genders, except for males younger than 45 years.

Metabolic syndrome and its components are related to a higher risk for albuminuria and proteinuria: Evidence from a meta-analysis on 10,603,067 subjects from 57 studies

BACKGROUND & AIM

Previous studies have explored the relation of metabolic syndrome (MetS), its components and the risk of albuminuria/proteinuria but their results are inconsistent. Then, we aimed to conduct a meta-analysis in order to resolve these controversies.

METHOD

PubMed and Scopus were systematically searched from their inception to 1 march 2018. Risk estimates and their 95% confidence intervals were extracted and pooled using the random-effects approach.

RESULT

A total of 57 studies, 44 studies on albuminuria and 13 studies on proteinuria, with a total sample size of 10,603,067 participants, were included in this meta-analysis. Overall, MetS was contributed to higher risks of proteinuria (OR = 2.08, 95%CI = 1.85-2.34) and albuminuria (OR = 1.92, 95%CI = 1.71-2.15), independent of diabetes status; although, this relationship was more noticeable in studies that used the WHO definition of MetS and in non-East Asian populations. Also, the relationship between MetS and proteinuria was sex independent, while, for albuminuria was significant only in men. MetS components such as obesity, impaired fasting glucose, elevated blood pressure and hypertriglyceridemia were associated with significant increases in proteinuria and albuminuria risk, while lower HDL-Cholesterol was only linked to greater risk of proteinuria. Moreover, the total impact of MetS on proteinuria was more remarkable than each component of the syndrome and an escalating dose-response association was found between the number of MetS components and albuminuria risk.

CONCLUSION

MetS and its components are potential risk factors for albuminuria and proteinuria.

Association Between Body Mass Index Combined with Albumin: creatinine Ratio and All-cause Mortality in Chinese Population

The association between body mass index (BMI) combined with albumin: creatinine ratio (ACR) and all-cause mortality in the general population has not been established. To address this, we examined a representative sample from the general population of China. The study included 46,854 participants with a follow-up of 4.6 years. Compared to the normal weight with ACR <10 mg/g group (the reference group), the crude hazard ratios (HRs) for all-cause mortality for the underweight with ACR >10 mg/g, normal weight with ACR >10 mg/g, overweight with ACR >10 mg/g, and obese with ACR >10 mg/g groups, were 2.22 (95% CI, 1.41 to 3.49), 1.70 (95% CI, 1.42 to 2.04), 1.52 (95% CI, 1.22 to 1.89), and 2.05 (95% CI, 1.45 to 2.89), respectively. After multivariable adjustments for age, race, comorbidities, and baseline eGFR, the HRs for the underweight with ACR >10 mg/g and normal weight with ACR >10 mg/g groups were 1.85 (95% CI, 1.17 to 2.91) and 1.36 (95% CI, 1.13 to 1.63), respectively. The results indicate that BMI combined with ACR can better predict all-cause mortality than BMI alone in the general Chinese population. Underweight and normal weight people with elevated ACR are at a higher risk of all-cause mortality than those in the same BMI category with ACR <10 mg/g.

The Relationship between Serum Bilirubin and Elevated Fibrotic Indices among HBV Carriers: A Cross-Sectional Study of a Chinese Population

The study probed the association between bilirubin and hepatitis B virus (HBV) infection and progression. A cross-sectional analysis of 28,500 middle aged and elderly Chinese participants was performed to analyze the differences of bilirubin in terms of hepatitis B surface antigen (HBsAg) positive or negative and the correlation between bilirubin and severity of hepatic fibrosis estimated by non-invasive indices. Bilirubin was significantly higher in the HBsAg (+) group than the HBsAg (−) group. Higher bilirubin levels were consistently associated with elevated liver fibrosis indices among HBsAg carriers. Compared with quartile 1 of total bilirubin (TBil), the multivariable-adjusted ORs (95% CIs) for elevated fibrosis indices of quartile 4 were 2.24 (95% CIs, 1.57–3.21) estimated by fibrosis 4 score (FIB-4) and 2.22 (95% CIs, 1.60–3.08) estimated by aspartate transaminase to platelet ratio index (APRI). In addition, direct bilirubin (DBil) had a stronger association with elevated liver fibrosis indices than did indirect bilirubin (IBil). Furthermore, the relationship between DBil and elevated fibrosis indices was more robust among participants who were female, overweight or had central fat distribution. These findings suggested that bilirubin levels, especially DBil, were independently associated with an increased risk of increased fibrosis indices.

U-shaped association between central body fat and the urinary albumin-to-creatinine ratio and microalbuminuria

BACKGROUND

The prevalence of obese and overweight patients has increased dramatically worldwide. Both are common risk factors for chronic kidney disease (CKD) as indicated by a diminished estimated glomerular filtration rate (eGFR) or microalbuminuria. This study aimed to investigate whether anthropometric parameters [waist circumference (WC), waist-to-height ratio (WHtR) and body mass index (BMI)] are associated with renal function in a population-based study of Caucasian subjects.

METHODS

Data from 3749 subjects (1825 women) aged 20 to 81 years from the Study of Health in Pomerania (SHIP) were analysed. Renal indices, including the urinary albumin-to-creatinine ratio (uACR), microalbuminuria, eGFR and CKD, were studied. Parameters of anthropometry (WC, WHtR and BMI) were categorised into sex-specific quintiles.

RESULTS

Analysis of variance (ANOVA) models, adjusting for age, sex, type 2 diabetes mellitus and hypertension, revealed that a high and low WC or WHtR and low BMI were independently related to a higher uACR. Logistic regression models confirmed these results with respect to uACR and showed that subjects with a high or low WC or a high WHtR had increased odds of microalbuminuria. The ANOVA models revealed no relations of the investigated anthropometric parameters with eGFR. However, subjects with high values for these parameters had increased odds of CKD.

CONCLUSIONS

Our results demonstrate U-shaped associations between markers of central fat distribution and uACR or microalbuminuria in the general population, suggesting that both obese and very thin subjects have a higher risk of renal impairment.

Central body fat distribution associates with unfavorable renal hemodynamics independent of body mass index

Central distribution of body fat is associated with a higher risk of renal disease, but whether it is the distribution pattern or the overall excess weight that underlies this association is not well understood. Here, we studied the association between waist-to-hip ratio (WHR), which reflects central adiposity, and renal hemodynamics in 315 healthy persons with a mean body mass index (BMI) of 24.9 kg/m(2) and a mean (125)I-iothalamate GFR of 109 ml/min per 1.73 m(2). In multivariate analyses, WHR was associated with lower GFR, lower effective renal plasma flow, and higher filtration fraction, even after adjustment for sex, age, mean arterial pressure, and BMI. Multivariate models produced similar results regardless of whether the hemodynamic measures were indexed to body surface area. Thus, these results suggest that central body fat distribution, independent of BMI, is associated with an unfavorable pattern of renal hemodynamic measures that could underlie the increased renal risk reported in observational studies.

Association of subcutaneous and visceral adiposity with albuminuria: the Framingham Heart Study

Microalbuminuria is a common condition associated with increased incidence of cardiovascular events and mortality. Abdominal obesity is associated with microalbuminuria, but studies linking visceral adipose tissue (VAT) and microalbuminuria are limited. Our objective was to determine the associations of albuminuria with VAT and subcutaneous adipose tissue (SAT). We performed a cross-sectional study in the Framingham Multi-Detector Computed Tomography (MDCT) cohort (n = 3099, 48.2% women, mean age 53 years). VAT and SAT volumes were measured using computed tomography. Urinary albumin-to-creatinine ratio (UACR) was calculated from spot urine samples. Microalbuminuria was defined as a UACR >25 mg/g in women or >17 mg/g in men. Overall, 7.9% (n = 244) of the sample had microalbuminuria. Among men, VAT (odds ratio (OR) 1.48 per s.d., P < 0.0001) and SAT (OR 1.37 per s.d., P = 0.0002) were associated with microalbuminuria in minimally adjusted models, which remained significant after multivariable adjustment (VAT OR 1.34 per s.d., P = 0.001; SAT OR 1.28 per s.d., P = 0.005). Additionally, when considered jointly, VAT (P = 0.002) but not SAT (P = 0.2) was associated with microalbuminuria. In women, VAT was associated with microalbuminuria after minimal adjustment (OR 1.28, P = 0.01), but not after multivariable adjustment (OR 1.03, P = 0.8). In multivariable models in women, SAT was associated with a decreased odds of having microalbuminuria (OR 0.75 per s.d., P = 0.03). In conclusion, VAT is associated with microalbuminuria in men but not women. Albuminuria may be a manifestation of visceral adiposity.

Effects of Anthropometric Measurements on Renal Function

Although the negative effect of increased body mass index on kidney has been examined, the relation between other anthropometric measurements and kidney functions has not been investigated sufficiently. This study looks at the influence of anthropometric measurements on kidney functions. Forty patients were included in the study. Patients who had increased or normal anthropometric measurements were compared by serum levels of the urea, creatinine, albumin, 24 hr urine creatinine clearance, and urinary albumin excretion rate (UAER). Of all patients, 22 (55%) had an increased body mass index (BMI), 19 (47.5%) had an increased waist circumference (WC), and 24 (60%) had an increased waist-hip ratio (WHR). Subjects with increased BMI, WC, and WHR had significantly higher levels of serum creatinine and UAER than the subjects with normal measurements. The relation between CC and BMI was statistically significant only among the anthropometric measurements (p = 0.026). The ratio of microalbuminuria was 27.3%, 21.1%, and 29.2% in persons with increased BMI, WC, and WHR, respectively. Increases of anthropometric measurements affect kidney functions negatively. However, the influence of BMI on kidney function is more prominent. For this reason; individuals with increased anthropometric measurements should be monitored closely in terms of renal functions additional to cardiovascular risk factors.

Prevalence and determinants of microalbuminuria among diabetic patients in the United Arab Emirates

BACKGROUND

Microalbuminuria (MA) represents the earliest clinical evidence of diabetic nephropathy and is a predictor of increased cardiovascular morbidity and mortality. The aim of this study was to determine the prevalence of MA among diabetic patients in the Al-Ain district of the United Arab Emirates (UAE).

METHODS

The study was part of a general cross-sectional survey carried out to assess the prevalence of diabetes mellitus (DM) complications in Al-Ain district, UAE and was the first to assess the prevalence of MA among diabetic patients. A sample of 513 diabetic patients with a mean age of 53 years (SD: +/- 13) was randomly selected during 2003/2004. All patients completed an interviewer-administered questionnaire and underwent medical assessment. First morning urine collections were obtained and were tested for clinical proteinuria using urine dipsticks and for MA using the single Micral-Test II strips.

RESULTS

MA was found in 61% (95% CI: 56.7-65.7) of the sample and the rate was significantly higher among males, positively related to body mass index (BMI), type 2 DM and presence of other DM complications such as diabetic retinopathy and neuropathy. Of the total sample population, 12.5% (95% CI: 8.1-14.1) had clinical proteinuria.

CONCLUSION

The prevalence rate of MA was considerably high ( 61%) among diabetic patients in the UAE. Therefore, regular screening for MA is recommended for all diabetic patients, as early treatment is critical for reducing cardiovascular risks and slowing the progression to late stages of diabetic nephropathy (overt proteinuria and end-stage renal disease).

Abdominal obesity, systolic blood pressure, and microalbuminuria in normotensive and euglycemic Korean men

OBJECTIVES

To evaluate the relationship between abdominal obesity and microalbuminuria (MA) in normotensive, euglycemic Korean men.

DESIGN

A cross-sectional study at a health screening center.

SUBJECTS

A total of 1321 healthy, normotensive Korean men, aged 20-78 years, with a fasting plasma glucose level <100 mg/dl.

MEASUREMENTS

Height, weight, and waist; systolic blood pressure (SBP); diastolic blood pressures (DBP); urinary albumin to creatinine ratio (ACR); fasting glucose, insulin, lipids, C-reactive protein (CRP), and white blood cell count. Waist circumference (WC) was used to indicate abdominal obesity and a single measurement of ACR was used to estimate MA. We also calculated body mass index (BMI) based on weight and height.

RESULTS

Mean BMI, WC, and SBP were significantly higher in subjects with MA than in those without (24.8+/-4.1 vs 23.8+/-2.7 kg/m2, 86+/-9 vs 83+/-8 cm, and 115+/-5 vs 112+/-7 mmHg, respectively). Multiple logistic regression analyses showed that only WC and SBP were independent predictors of MA.

CONCLUSION

WC and SBP were positively associated with MA in normotensive and euglycemic Korean men.

Visceral obesity is associated with higher urinary albumin excretion levels in normoalbuminuric type 2 diabetic patients

AIM: To analyze the relationship between visceral obesity and urinary albumin excretion rate (UAER). METHODS: A cross-sectional study of 73 normoalbuminuric (urinary albumin excretion rate < 20 µg/min) type 2 patients was performed. Patients were divided into two groups according to the median of UAER (7.5 µg/min). Office auscultatory blood pressure was measured in sitting position after a 10-min rest. RESULTS: Waist to hip ratio was higher in the group with UAER > 7.0 µg/min (0.98 ± 0.08), when compared to the other group (0.93 ± 0.08, p= 0.01). Waist to hip ratio significantly correlated with UAER (r= 0.28; p= 0.018). In multiple linear regression analysis, only waist to hip ratio was associated with UAER (r= 0.29; p= 0.04). A1c, DM duration and systolic BP levels were excluded from the model. CONCLUSIONS: Type 2 normoalbuminuric diabetic patients with higher levels of UAER could represent a group with an elevated risk for the development of cardiovascular diseases.

Kidney Disease and the Metabolic Syndrome

The epidemic of metabolic syndrome contributes to the rapid growth of cardiovascular and renal diseases. Hyper-hemodynamics, impaired pressure natriuresis, excess excretory load, insulin resistance, endothelial dysfunction, chronic inflammation, and prothrombotic status individually and interdependently initiate renal injury in metabolic syndrome. The prevention and treatment of kidney disease require a multifactorial approach. Weight loss through diet control and exercise can reverse many pathophysiologic processes. Pharmacologic intervention includes insulin sensitizers, tight glycemic and lipid control, blockage of renin angiotensin aldosterone system, and anti-inflammatory and antithrombotic therapies. Each peroxisome proliferator-activated receptor isoform plays a distinct role in metabolic syndrome, and their agonists may prevent or reverse the early renal injuries.

Association between body mass index and CKD in apparently healthy men

BACKGROUND

Overweight and obesity are well-established risk factors for cardiovascular disease and decline in kidney function in individuals with existing chronic kidney disease (CKD). Conversely, their association with the development of CKD is less clear.

METHODS

We evaluated the association between body mass index (BMI) and risk for CKD in a cohort of 11,104 initially healthy men who participated in the Physicians' Health Study and provided a blood sample after 14 years. BMI was calculated from self-reported weight and height. We estimated glomerular filtration rate (GFR) by using the abbreviated equation from the Modification of Diet in Renal Disease Study and defined CKD as GFR less than 60 mL/min/1.73 m2 (<1 mL/s/1.73 m2).

RESULTS

After an average 14-year follow-up, 1,377 participants (12.4%) had a GFR less than 60 mL/min/1.73 m2 (<1 mL/s/1.73 m2). Higher baseline BMI was associated consistently with increased risk for CKD. Compared with participants in the lowest BMI quintile (<22.7 kg/m2), those in the highest quintile (>26.6 kg/m2) had an odds ratio (OR) of 1.45 (95% confidence interval [CI], 1.19 to 1.76; P trend <0.001) after adjusting for potential confounders. We found similar associations by using different categories of BMI. Compared with men who remained within a +/-5% range of their baseline BMI, those who reported a BMI increase greater than 10% had a significant increase in risk for CKD (OR, 1.27; 95% CI, 1.06 to 1.53).

CONCLUSION

In this large cohort of initially healthy men, BMI was associated significantly with increased risk for CKD after 14 years. Strategies to decrease CKD risk might include prevention of overweight and obesity.

Obesidade visceral, hipertensão arterial e risco cárdio-renal: uma revisão

A maior parte da adversidade atribuída à obesidade é dada pelo risco cardiovascular/coronariano imputado à mesma, particularmente presente nos obesos com distribuição visceral de gordura corporal. O acúmulo de gordura visceral está sabidamente associado à maior prevalência de desarranjos metabólicos, hormonais, inflamatórios e hemodinâmicos, que no conjunto implicarão em maior acometimento da microvasculatura e impacto negativo sobre os órgãos-alvo, particularmente sobre o eixo cárdio-renal. Neste sentido, além da associação clássica com a doença coronariana, têm-se verificado uma associação maior da obesidade visceral com a hipertrofia ventricular esquerda e microalbuminúria, ambos fatores de risco cardiovascular e nefrológico reconhecidos. Assim, a abordagem terapêutica dos pacientes obesos, particularmente dos hipertensos, deve levar em conta a estratificação de risco baseada na distribuição de gordura corporal, o que permitirá uma terapêutica mais adequada, visando-se não só o controle dos fatores de risco como a monitorização do acometimento de órgãos-alvo nestas populações.

Risk factors for coronary heart disease in two similar Indian population groups, one residing in India, and the other in Sydney, Australia

OBJECTIVE

To identify the prevalence of coronary risk factors among South Asian Indians in Australia and India.

DESIGN

Cross-sectional intercountry comparison.

SUBJECTS

Healthy volunteers aged 23-75 y recruited from the Indian community in Sydney Australia (n=125), and their nominated relatives in India, (n=125).

RESULTS

The two groups were of similar background with over 90% of the group in India being siblings, parents or relatives of the group in Australia. There was no difference in the populations between India and Australia with regard to mean age (40+/-11.5 vs 39+/-10.3 y), body mass index (BMI) (25+/-3.3 vs 25+/-3.5 kg/m(2)), lipoprotein (a) (178 vs 202 mg/l), total cholesterol (5.3+/-1.3 vs 5.3+/-1.2 mmol/l) or triglyceride (1.7+/-0.8 vs 1.7+/-0.8 mmol/l). The group in India had higher insulin (median values) (139 vs 83 pmol/l, P=0.0001), waist-to-hip ratio (WHR) (0.88+/-0.08 vs 0.85+/-0.09, P=0.01), exercise time (23.7+/-32.7 vs 17.2+/-23.2 h/week, P=0.07), lower waist (83+/-10.0 vs 85+/-11.1 cm, P=0.05) and high-density lipoprotein (0.9+/-0.3 vs 1.1+/-0.6 mmol/l, P=0.02). Women in India had lower BMI (22.7+/-2.9 vs 25.3+/-4.2 kg/m(2), P<0.001), higher insulin (182 vs 90 pmol/l, P<0.001), WHR (0.86+/-0.08 vs 0.77+/-0.06, P<0.001)) and prevalence of abdominal obesity (% WHR >0.8, 73 vs 23%, P<0.001; odds of waist >90 cm=2.3, P<0.05). Men in India had the same BMI, lower waist (85.5+/-8.8 vs 92.9+/-7.2 cm, P<0.001) and WHR (0.89+/-0.09 vs 0.93+/-0.05, P<0.01) but higher insulin (137 vs 76 pmol/l).

CONCLUSION

The group in Australia (especially women) have a more favourable disease risk profile than those in India. The fact that the groups are of such similar background and partly related, make it unlikely that changes due to migration have a strong genetic bias. In contrast to other studies, the absence here of excessive weight gain on migration may be a key factor in disease risk prevention.

Comparison of a footpad analyser with a tetrapolar model for the determination of percent body fat in young men

Since excess weight in adolescence predisposes to overweight and obesity in adulthood, a simple measure of excess adiposity in adolescents is important. Fast, inexpensive, bioelectric impedance analysers (BIA) which rely on two foot pad electrodes are now available to measure % total body fat (TBF), but are less well investigated than conventional tetrapolar models which require the subject to lie prone with four electrodes attached to hands and feet. The aim of this study was to compare the estimation of % TBF by a foot pad analyser and a tetrapolar model. Male students, n = 35, 17-19 years had height, weight, waist and hip circumferences measured and completed a questionnaire regarding age, ethnicity and time of last eating and drinking. Percent TBF was measured by a Tanita stand-on analyser (Tanita 105, Tanita Corporation, Japan) and a SEAC tetrapolar model (SEAC, SFB3, QUT, Australia). Mean age (+/- SD) of subjects = 18.2 +/- 0.6 years, BMI = 24.4 +/- 3.5 kg/m2, WHR = 0.81 +/- 0.04, % TBF, Tanita = 18.2 +/- 6.2 and SEAC = 20.4+/-4.8. Both measures of fat were correlated (r = 0.84, p<0.0001). A plot of the average versus the difference of the two analysers found the majority of differences were above zero, especially for measures of fat below 22%, indicating a negative bias for the Tanita. The limits of agreement are between -5.4 and 9% TBF. Information provided by this study will guide gymnasium operators and health professionals to comment on a relative degree of adiposity with greater confidence of data reliability.

Prevention of hypertension and its complications: theoretical basis and guidelines for treatment

Hypertension is a nutritional-hygienic disease. Long-term caloric intake in excess of energy expenditures, chronic supraphysiological intake of dietary sodium, excessive alcohol consumption, and psychosocial stressors all contribute to the development of hypertension throughout the world. Elevated BP, particularly systolic BP, has been linked to multiple adverse clinical outcomes including stroke, heart failure, myocardial infarction, renal insufficiency/failure, peripheral vascular disease, retinopathy, dementia, and premature mortality. These undesirable clinical outcomes are typically, although not invariably, preceded by pressure-related target-organ injury such as left ventricular hypertrophy, renal insufficiency and proteinuria. The relation of BP and CKD and, in turn, the prevention of CKD or forestalling its progression by hypertension treatment, will be the focus of this manuscript. In hypertensive persons with reduced kidney function and/or proteinuria, lowering BP with multidrug therapy that is inclusive of pharmacologic modulators of the renin-angiotensin-aldosterone-kinin system is an effective strategy to forestall the progressive loss of kidney function. The totality of data support low therapeutic BP targets for persons with proteinuria >1 g/d. Nevertheless, in persons with CKD, even those with proteinuria below the dipstick positive level (approximately 300 mg/d or urine protein to creatinine ratio of 0.22), aggressive BP control also may be warranted because of the high risk of nonrenal cardiovascular disease. Multiple antihypertensive drugs will be required in the vast majority of patients with diabetes and/or reduced kidney function to attain BP goal. Renin-angiotensin system (RAS) modulator therapy is indicated among persons with diabetes mellitus and CKD. Available data support the use of angiotensin receptor blockers in persons with type 2 diabetes and overt nephropathy for preservation of kidney function. Among persons with type I diabetes with or without overt nephropathy, type 2 diabetes without overt nephropathy and in nondiabetic CKD, the available clinical data support the use of angiotensin-converting enzyme inhibitors as the RAS modulator of choice. Low therapeutic target BP levels <130/80 mmHg in persons with type 2 diabetes mellitus also appear warranted based on available data mostly for reducing the risk of nonrenal cardiovascular disease and overall mortality.

Clinical and pathophysiological consequences of abdominal adiposity and abdominal adipose tissue depots

OBJECTIVES

To highlight the clinical and metabolic correlates of abdominal obesity and various abdominal adipose tissue depots.

METHODS

We researched the topic using the search terms abdominal obesity, central obesity, visceral obesity, regional obesity, and subcutaneous adipose tissue from MEDLINE (National Library of Medicine, Bethesda, MD), PubMed (National Library of Medicine, Bethesda, MD), Current Contents (Institute for Scientific Information, Thomson Scientific, Philadelphia, PA), and using manual search for the cited references.

RESULTS

Abdominal obesity contributes significantly to the metabolic perturbations and cardiovascular risk in human beings. Abdominal adipose tissue depots (intraabdominal and subcutaneous [deep subcutaneous, posterior subcutaneous]) are metabolically active and appear to be important for the pathogenesis of insulin resistance, dyslipidemia, glucose intolerance, hypertension, hypercoagulable state, and cardiovascular risk. Adipocyte anatomy (size), physiology (growth, catecholamine sensitivity, lipolysis, insulin action), and biochemistry (leptin, plasminogen activator inhibitor-1, cytokines, renin-angiotensin system) are reported to be relatively site-specific, highlighting unique roles of regional adipose tissue depots.

CONCLUSIONS

Several physiological and metabolic parameters are site-specific in abdominal adipose tissue. The epidemiological, clinical, and prognostic significance and relative importance of the regional adipose tissue depots, however, remain to be ascertained.

Optimizing blood pressure control in the obese patient

Obesity is a major public health issue, and hypertension is one of the most common associated comorbidities. Current guidelines for optimal blood pressure levels in obese patients or for the treatment of obesity-hypertension do not provide specific recommendations that go beyond the rather general recommendation to lose weight. Based on the strong ties between obesity, hypertension, and type 2 diabetes, and the similarity of complications that occur in obesity-related hypertension and in hypertension associated with type 2 diabetes, it seems appropriate to explore the optimal blood pressure levels for obese hypertensive patients. Recently published studies underline the importance of weight reduction to reach this goal. Several lines of reasoning support the use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers as the appropriate first-line therapy in obese patients with uncomplicated hypertension. Nondihydropyridine calcium channel blockers, a-blockers, or low-dose diuretics may be added when necessary. Clearly, further studies are needed to define target blood pressure levels in obese patients and to clarify the value of established and newer drugs, like angiotensin receptor blockers, for the treatment of obese hypertensive patients. The role of antiobesity drugs in the management of the obese hypertensive patient also remains to be defined.

Obesity and renal disease

Obesity, which has reached epidemic proportions in the United States and other western countries, may be complicated by hypertension, an increased incidence of renal cancer or proteinuria. Patients with obesity-associated proteinuria show focal glomerulosclerosis and glomerulomegaly on biopsy, usually have minimal clinical edema and relatively normal levels of serum albumin, cholesterol and blood pressure, and can progress to end-stage renal disease. Severe obesity may also be an additive risk factor in patients with preexisting nephropathy or reduced renal mass. The pathophysiology of obesity-associated proteinuria is unclear but may include hyperfiltration, increased renal venous pressure, glomerular hypertrophy, hyperlipidemia and increased synthesis of vasoactive and fibrogenic substances, including angiotensin II, insulin, leptin and transforming growth factor-beta1. These substances may individually or interactively affect glomerular hyperfiltration, mesangial cell hypertrophy and matrix production, and the production of collagen, fibronectin, transforming growth factor-beta and other fibrogenic mediators of change. Although angiotensin-converting enzyme inhibition has proven to have an impact, perhaps temporarily, on obesity-associated proteinuria in humans, weight reduction early in the course of the disease would appear the most important therapeutic approach.