Association Of Visceral Adiposity With Urinary Albumin Excretion In Patients With Type 2 Diabetes

Objective: Obesity, especially abdominal obesity, which has obvious metabolic abnormalities, is risk factor for the occurrence of diabetes, hypertension, dyslipidemia and other chronic diseases. Typical signs of the Chinese people are abdominal obesity, or central obesity. Quantitative analysis of CT is currently the gold standard for the distribution of visceral fat. Diabetic nephropathy (DN) is one of the most common and serious microvascular complication of diabetes mellitus, which characterized by glomerular sclerosis, thickening of basement membrane, extracellular matrix deposition. 24-hour urinary albumin excretion (24h-UAE) is the indicators to determine kidney damage in DN, which represents the simplest and the most sensitive prognostic factor to evaluate the risk of overt nephropathy in diabetes. In this study, we measured Visceral Adiposity (VA) by CT, collected the clinical data, VA, 24h-UAE, blood lipids, creatinine, blood urea nitrogen, fasting blood glucose, glycosylated hemoglobin, insulin and tumor necrosis factor-αof hospitalized patients with type 2 diabetes. According to the quartile of VA, we divided the patients into four groups and compared 24h-UAE level with incidence of heavy proteinuria among the 4 groups, simultaneously we analyzed the relative intensity and linear relationship between VA and LG (24h-UAE). We explored the relationship between VA and LG (24h-UAE) in progressing to DN and provided guidance to overall control risk factors in patients with DN.Methods: All patients were asked face to face detailed demographic data, including gender (SEX), Age (AGE), smoking (SMOKING) history, alcohol consumption (ALCOHOL) history, coronary heart disease (CHD) history, hypertension and so on. 222 patients were collected (male 136 cases), mean age 57 years (30-78 years), from September 2009 to September 2010 of hospitalized in Endocrinoloy, Third Clinical Hospital of Hebei Medical University. Everyone were measured the systolic blood pressure (SBP), diastolic blood pressure (DBP), VA, 24h-UAE, fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), serum creatinine (Scr), blood urea nitrogen(BUN), glycosylated hemoglobin (HbA₁c), fasting insulin (FINS) and tumor necrosis factor (TNF)-α. we calculated body mass index (BMI), waist-hip ratio (WHR), waist height ratio (WHtR) and homeostasis model assessment insulin resistance index (HOMA-IR) (formula, HOMA-IR= FPG×FINS/22.5) and used chronic kidney disease Epidemiology (CKD-Epi) formula to estimates glomerular filtration rate (eGFR). Spiral CT was used to scan the level of umbilical plane in breathholding state and measure the area of intraabdominal adipose. According to the quartile of VA,we divided the data into 1st, 2nd, 3rd, 4th four groups and compared 24h-UAE level with incidence of heavy proteinuria among the 4 groups,while we did correlation and regression analysis between 24h-UAE and VA, BMI, WHR, WHtR, SBP, DBP, TC, TG, HDL-C, LDL-C, eGFR, LG (HOMA-IR), LG (TNF-α) and analyzed the relative intensity and linear relationship between VA and LG (24h-UAE).Statistical analysis: All analyses were performed using SPSS 13.0 software. Baseline characteristics were expressed as mean and standard deviation ( x±s) for continuous variables, and frequencies and percentages for categorical ones. Because of the positively skewed distribution, 24h-UAE, HOMA-IR and TNF-αwere log-transformed before statistical testing to obtain a normal distribution. Analysis of variance (ANOVA) was used to compare multi-group variables, LSD test was used to compare inter-group variables. chi-square test and trend chi-square test were used to Count data. Correlations were evaluated by Pearson's or Spearman's test as appropriate. Regression analysis by simple regression, multiple linear regression and Logistic regression analysis. p<0.05 (two-sided test) was considered statistically significant. Results:1 There was no significant difference in HbA₁c and CHD history among the four groups. There were significant difference in WC and WHtR among the four groups. WHR of group 1st and 2nd were significantly lower than 3rd and 4th. LG (24h-UAE), SBP and ALCOHOL of group 1st and 2nd were significantly lower than group 3rd and 4th. Scr, BUN, DBP, LDL-C and LG (TNF-α) of group 1st, 2nd, 3rd were significantly lower than group 4th. TG of group 2nd, 3rd, 4th were significantly higher than group 1st. There was no significant difference in AGE, HDL-C, eGFR and LG (HOMA-IR) among the 2st, 3rd and 4th. There was no significant difference in TC, BMI of group 2nd and 3rd, but higher than the 1st group and lower than the 4th group. Prevalence of heavy albuminuria increased with the expansion of VA.2 There were certain linear correlation among LG (24h-UAE) and VA, WC, WHR, WHtR, DBP, SBP, BMI, eGFR, TC, LG (HOMA-IR), LDL-C, LG (TNF-α), TG, HDL-c.There were relative medium intensity (r=0.51) between VA and LG (24h-UAE). After DBP, SBP, BMI, TC, LG, HDL-C, LDL-C, eGFR, LG (HOMA-IR) and LG (TNF-α) adjusting, partial correlation coefficient for 0.257 (p<0.001). Regression analysis showed that LG (24h-UAE) increased 0.26 units as VA expanded per dm² (p<0.001), and that was 0.15 units after relative factors adjusting (p=0.001).3 Logistic regression model 1, among the risk factors of heavy albuminuria, women were protective factors and VA was risk factor. After gender adjusting, the odds ratio of heavy albuminuria in 3rd group was 3.21 compared with that in 1st group, and the OR was 4.94 in 4th group.4 Logistic regression model 2, among the risk factors of heavy albuminuria, gender and triglyceride were confounding factors, women were protective factors, triglyceride was a risk factor. After gender and triglyceride adjusting, the odds ratio of heavy albuminuria in 3rd group was 2.75 compared with that in 1st group, and the OR was 3.87 in 4th group.Conclusions: 1 Urinary albumin excretion obviously increased with the expansion of abdominal obesity. Simultaneously the prevalence of heavy albuminuria increased. Expansion of visceral adiposity was a risk factor for an increased risk of urinary albumin excretion, indicating that visceral adiposity particip- ated development of microvascular complications.2 Blood lipids and blood pressure increased with the expansion of visceral adiposity, meanwhile there were relative intensity among blood lipids, blood pressure and urinary albumin excretion, indicating that abdominal obesity, hypertension and dyslipidemia participated development of vascular complica- tions.