Anemia and reduced renal function are independent predictors of elevated serum adiponectin in elderly women

New Insights into Adiponectin and Leptin Roles in Chronic Kidney Disease

Chronic kidney disease (CKD) is commonly associated with a high burden of comorbidities and poor clinical outcomes. Malnutrition–inflammation–atherosclerosis syndrome is common in the more severe stages of CKD, suggesting a close interplay for these three comorbid conditions. Both malnutrition and obesity are associated with a disturbed adipokine profile and inflammation, contributing to a higher risk of cardiovascular disease (CVD) events. Adiponectin and leptin have important roles in carbohydrate and lipid metabolism, and in the inflammatory process. The effects of adiponectin and leptin alterations in CKD, which are usually increased, and their association with the different comorbidities found in CKD, will be focused on to understand their crosstalk with the risk of CVD events. Nonetheless, although adiponectin and leptin contribute to a higher risk of CVD events, further studies are warranted to fully clarify their roles, especially when different comorbidities exist.

Associations of serum transthyretin with triglyceride in non-obese elderly Japanese women independently of insulin resistance, HDL cholesterol, and adiponectin

Objective

Studies are limited on the association between serum transthyretin (TTR), a negative acute phase reactant, and triglyceride (TG).

Research design and methods

TG, TTR, and insulin resistance-related cardiometabolic variables were measured in 159 fasting and 185 nonfasting community-dwelling elderly women aged 50-96 years. Pearson correlation analysis and then stepwise multiple regression analyses were performed to further identify the most significant variables contributing to the variation of fasting and nonfasting TG.

Results

Multiple regression analysis for fasting TG as a dependent variable revealed that TTR (standardized β: 0.299) and HDL cholesterol (standardized β: -0.545) emerged as determinants of TG independently of percentage of body fat, homeostasis model assessment insulin resistance, serum leptin and adiponectin, and plasminogen activator inhibitor-1 (PAI-1) (R ² = 0.36). For nonfasting TG, HDL cholesterol (standardized β: - 0.461), TTR (standardized β: 0.231), nonfasting insulin, a marker of insulin resistance, (standardized β: 0.202), and PAI-1 (standardized β: 0.187) emerged as determinants independently of percentage of body fat, nonfasting glucose, serum leptin and adiponectin, and high-sensitivity C-reactive protein (R ² = 0.45).

Conclusions

Fasting and nonfasting TG showed positive association with TTR in community-dwelling elderly non-obese women independently of insulin resistance, HDL cholesterol, and adiponectin. These findings may provide a clue as to a physiological function of circulating TTR in human: an influence factor of TG-rich lipoproteins in the circulation.

Association of Age and Anemia With Adiponectin Serum Levels in Normal-Weight Japanese Women

BACKGROUND

Adiponectin serum levels are affected by sex, ethnicities, adiposity, age and several pathological conditions such as anemia. The prevalence of hyperadiponectinemia (≥ 20 mg/L) in relation to anemia (hemoglobin < 12 g/dL) was examined in normal-weight Japanese women.

METHODS

Serum adiponectin and blood hemoglobin were measured in 311 young women aged 18 - 24 years (A), 148 of their middle-aged mothers aged 39 - 60 years (B) and 322 community-dwelling women aged ≥ 65 years (C) with a mean body mass index (BMI) of 20.4, 22.0 and 22.4 kg/m2, respectively. Elderly women were subdivided into three age groups: between 65 and 74 years (n = 95, X), between 75 and 84 years (n = 176, Y) and older than 85 years (n = 51, Z).

RESULTS

The prevalence of hyperadiponectinemia (A: 3.9%, B: 3.4%, C: 22.7%, P < 0.001) was low and serum adiponectin (A: 11.5 ± 4.3 mg/L, B: 11.8 ± 4.9 mg/L, C: 15.3 ± 7.8 mg/L, P < 0.001) did not change until middle-aged but increased thereafter in a stepwise fashion (X: 18.9%, Y: 22.7%, Z: 35.3%, P = 0.07 and X: 13.9 ± 6.9 mg/L, Y: 15.1 ± 7.7 mg/L, Z: 18.7 ± 8.6 mg/L, P = 0.001, respectively). There were inverse associations of adiponectin with age (r = -0.201, P < 0.001) and hemoglobin (r = -0.318, P < 0.001) in elderly women but not even in young and middle-aged women combined. Furthermore, anemia was associated with higher prevalence of hyperadiponectinemia (34.8% vs. 20.6%, P = 0.01) and higher serum adiponectin (18.3 ± 9.4 mg/L vs. 14.5 ± 7.1 mg/L, P < 0.001) in elderly women but not in younger and middle-aged women.

CONCLUSIONS

In normal-weight Japanese women, the prevalence of hyperadiponectinemia and serum adiponectin were increased and associated with anemia at 65 years of age and older.

Elevated serum adiponectin and tumor necrosis factor-α and decreased transthyretin in Japanese elderly women with low grip strength and preserved muscle mass and insulin sensitivity

OBJECTIVE

To determine if adiponectin levels are associated with low grip strength among the elderly independently of insulin resistance and inflammation.

RESEARCH DESIGN AND METHODS

Cross-sectional associations were analyzed by logistic regression between low grip strength and body composition, elevated serum adiponectin (≥20 mg/L), and biomarkers of nutritious stasis, insulin resistance and inflammation in 179 community-living Japanese women. Sarcopenia was evaluated using the Asian criteria.

RESULTS

No women had sarcopenia. In bivariate analyses, low grip strength (n=68) was positively associated with age, log tumor necrosis factor-α (TNF-α) and hyperadiponectinemia (n=37) and inversely with body weight, height, skeletal muscle mass, serum albumin, transthyretin (TTR), fat mass, serum zinc and hemoglobin (all p<0.01). In a fully adjusted model, TTR (0.90: 0.83-0.98, p=0.01) in addition to age (p=0.007), height (p=0.004) and skeletal muscle mass (p=0.008) emerged as independent determinants of low grip strength. When TTR was removed from the full model, TNF-α was associated with low grip strength (7.7; 1.3-45.8, p=0.02). Mean waist circumference and high-density lipoprotein cholesterol did not differ between women with and without low grip strength and were within the respective normal range. Women with hyperadiponectinemia had higher percentage of women with low grip strength and lower grip strength (both p<0.01).

CONCLUSIONS

Hyperadiponectinemia and elevated TNF-α in addition to decreased TTR, a biomarker of age-related catabolic states, were found in community-living Japanese elderly women with low grip strength and preserved muscle mass and insulin sensitivity.

High serum adiponectin is associated with low blood haemoglobin in elderly men: the Swedish MrOS study

OBJECTIVES

Blood haemoglobin (Hb) concentration declines in elderly men, whilst the level of the adipocyte-derived protein adiponectin increases with age. The association between erythropoiesis and adiponectin in elderly men is unclear. The aim of this study was to determine whether adipokines such as adiponectin and leptin are associated with anaemia and Hb concentration in elderly community-dwelling men.

DESIGN AND SETTING

The Gothenburg part of the population-based Swedish Osteoporotic Fractures in Men (MrOS) cohort (n = 1010; median age 75.3 years, range 69-81).

MAIN OUTCOME MEASURES

We investigated the associations between levels of adiponectin and Hb before and after adjusting for potential confounders [i.e. age, body composition, erythropoietin (EPO), total oestradiol, leptin, cystatin C and iron and B vitamin status].

RESULTS

In these elderly men, age was negatively associated with Hb (r = -0.12, P < 0.001) and positively associated with adiponectin level (r = 0.13, P < 0.001). In age-adjusted partial correlations, Hb and adiponectin levels were negatively correlated (r = -0.20, P < 0.001); this association remained significant after multivariable adjustment for age, body composition, EPO, fasting insulin, sex hormones, leptin and ferritin. Age-adjusted mean adiponectin concentrations were significantly higher in anaemic men (66/1005; Hb <130 g L(-1) ) compared to nonanaemic men (14.0 vs. 11.7 μg mL(-1) , P < 0.05). In multivariate analysis, adiponectin together with EPO, total oestradiol, insulin, albumin, transferrin saturation, HDL cholesterol, cystatin C, total body fat mass and free thyroxine, but not leptin, explained 35% of the variation in Hb level. These results remained essentially unchanged after exclusion of men with diabetes.

CONCLUSIONS

Serum adiponectin, but not leptin, was negatively and independently associated with Hb. This finding suggests a possible role of adiponectin in the age-related decline in Hb level observed in apparently healthy elderly men.

Elevated serum leptin, adiponectin and leptin to adiponectin ratio is associated with chronic kidney disease in Asian adults

Background

Adiponectin and leptin, two of the key cytokines secreted by adipocytes, have been shown to be associated with cardiovascular disease. However, the association of these adipocytokines with chronic kidney disease (CKD) is not clear. We examined the association of serum adiponectin, leptin levels and leptin to adiponectin ratio (LAR) with CKD in a population-based sample of Asian adults.

Methods

We conducted a case-control study (450 CKD cases and 920 controls matched for age, sex and ethnicity) involving Chinese and Indian adults aged 40–80 years who participated in the Singapore Epidemiology of Eye Diseases Study (2007–2011). CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73m² from serum creatinine. Serum adiponectin and leptin levels were measured using commercially available ELISA. Odds ratio of CKD associated with elevated adiponectin and leptin levels were estimated using logistic regression models adjusted for age, gender, ethnicity, education, smoking, body mass index, diabetes, blood pressure, total and HDL cholesterol.

Results

CKD cases had higher levels of leptin (mean [SD] 9.7 [11.5] vs.16.9 [20.2] ng/mL, p<0.0001) and adiponectin (10.4 [7.4] vs. 9.2 [4.2], p = 0.001) compared to controls. In multi-variable models, compared to those in the lowest quartile, the OR (95% confidence interval) of CKD among those in the highest quartile were: 6.46 (3.84, 10.88), 1.94 (1.32–2.85) and 2.88 (1.78–4.64) for leptin, adiponectin and LAR. Similar associations were also observed when adiponectin and leptin were analyzed as continuous variables. This positive association of serum adiponectin, leptin and LAR with CKD was consistently present in subgroups of gender, ethnicity, diabetes, hypertension and overweight status (all P-interaction >0.1).

Conclusions

Higher levels of serum adiponectin, leptin and LAR were positively associated with CKD independent of traditional risk factors in this Asian population.

Association of pulse pressure with serum TNF-α and neutrophil count in the elderly

AIMS

Elevated pulse pressure (PP) has been reported to be a risk factor for type 2 diabetes in elderly patients with hypertension.

METHODS

Cross-sectional relationships of PP with known risk factors for type 2 diabetes and inflammatory markers were examined in 150 elderly community-dwelling women, 79 women (52.7%) of whom had hypertension.

RESULTS

Systolic blood pressure (standardized β, 0.775), log tumor necrosis factor-α (TNF-α, standardized β, 0.110), age (standardized β, 0.140), and neutrophil count (standardized β, 0.114) emerged as determinants of PP independent of high-sensitivity C-reactive protein, interleukin-6, monocyte count, plasminogen activator inhibitor-1, homeostasis model assessment of insulin resistance, HDL-cholesterol, and adiponectin (R(2) = 0.772).

CONCLUSIONS

The present studies have demonstrated an independent association of higher PP with higher TNF-α, a marker of insulin resistance, and neutrophil count in community-living elderly women and suggest that insulin resistance and chronic low-grade inflammation may in part be responsible for the association between high PP and incident type 2 diabetes found in elderly patients with hypertension.

Association of low serum iron levels with low-grade inflammation and hyperadiponectinemia in community-living elderly women

AIM

There have been inconsistent reports regarding the relationship between the iron status and coronary vascular diseases (CVD). Recently, low serum iron levels have been shown to be associated with mortality from CVD in women.

METHODS

The relationships between the serum iron levels and traditional and nontraditional risk factors for CVD were examined in 202 community-living elderly Japanese women.

RESULTS

The women in the lowest iron tertile had higher high-sensitivity C-reactive protein (hsCRP) and tumor necrosis factor-α (TNF-α) levels than the women in the top iron tertile (p<0.01 or less for both). In addition, the women in the lowest tertile had higher serum levels of adiponectin and copper and ratios of serum copper to zinc and lower serum levels of albumin, hemoglobin and hematocrit. Furthermore, the women in the lowest tertile had higher creatinine levels and lower eGFR values, although there were no significant differences in the prevalence of chronic kidney disease between the three tertile groups. In a multiple regression analysis including the levels of hsCRP, TNF-α, adiponectin and serum creatinine and the ratio of serum copper to zinc as independent variables, the levels of hsCRP, TNF-α and adiponectin emerged as independent determinants of the serum iron level (R(2)= 0.106). In the model to which the hemoglobin level was added as an independent variable, the levels of hemoglobin, hsCRP and TNF-α emerged as independent determinants of the serum iron level (R(2)= 0.192).

CONCLUSIONS

The present study demonstrated that community-living elderly Japanese women with low serum iron levels have nontraditional risk factors for CVD, including low-grade inflammation and higher levels of serum adiponectin.