Impact of C-reactive protein on the likelihood of carotid atherosclerosis in Japanese adults

Increased C-reactive protein associates with elevated carotid intima-media thickness in Chinese adults with normal low density lipoprotein cholesterol levels

AIM

We aimed to study the relationship of elevated C reactive protein (CRP) levels (1.0-2.9 or ≥3.0 mg/L) with carotid intima-media thickness (IMT) in Chinese adults with normal low-density lipoprotein (LDL) cholesterol (<100 mg/dL).

METHODS

Cross-sectional analysis was performed using 2499 eligible subjects recruited from a single community in Shanghai in 2008. These subjects were divided into three groups according to their serum CRP levels (<1.0 mg/L, 1.0-2.9 and ≥3.0 mg/L). IMT was measured using a high-resolution tomographic ultrasound system.

RESULTS

As compared to CRP <1.0 mg/L (n= 1994), subjects with CRP 1.0-2.9 (n=265) and ≥3.0 mg/L (n= 240) were much older and had higher body mass index, waist circumference, systolic and diastolic blood pressure, hemoglobin A1c and serum triglycerides; IMT was significantly elevated in CRP ≥3.0 or 1.0-2.9 mg/L (0.66 or 0.65 vs 0.61 mm, p<0.0001). Subjects with CRP ≥3 mg/L were associated with 1.45-fold risk for elevated IMT (≥0.7 mm) (95% confidence interval, 1.02-2.06) after full adjustment. The association was more prominent in subjects with aged <60 (odds ratio (OR)= 2.04; p= 0.04), in diabetic patients (OR= 1.79; p= 0.04) and obese subjects (OR= 1.55; p= 0.006).

CONCLUSIONS

Increased CRP is associated with elevated IMT in Chinese adults with normal LDL. Low-grade inflammation plays an independent and important role in atherosclerosis.

Evaluation of clinical variables associated with increased carotid intima-media thickness in middle-aged hypertensive women

It has been previously documented that carotid intima-media thickness (cIMT) is a predictor of cardiovascular disease. The aim of this study was to identify clinical parameters associated with an increased cIMT treated hypertensive women. Female patients (n = 116) with essential hypertension, aged 40–65 years, were included in this study. Vascular ultrasound was performed and the patients were divided into two groups according to the values of cIMT (< or ≥0.9 mm). Patients with greater cIMT presented significantly higher systolic blood pressure and pulse pressure. Serum HDL-cholesterol was significantly lower and CRP was significantly higher in the same group. There was a significant correlation between cIMT and age (r = 0.25, P = 0.007), systolic blood pressure (r = 0.19, P = 0.009), pulse pressure (r = 0.30, P = 0.001), and LDL-cholesterol (r = 0.19, P = 0.043). cIMT was correlated to CRP (r = 0.31, P = 0.007) and negatively correlated to HDL-cholesterol (r = 0.33, P = 0.001). In logistic regression, only HDL-cholesterol, CRP, and pulse pressure were shown to be independent variables associated to increased cIMT. In conclusion, pulse pressure, HDL-cholesterol, and CRP are variables correlated with cIMT in treated hypertensive women.

High-sensitivity CRP reflects insulin resistance in smokers

AIM

The elevation of high-sensitivity C-reactive protein (hs-CRP) is a strong risk factor for cardio-vascular disease (CVD) and is associated with insulin resistance. The hs-CRP concentration also increases in smokers known to be at a high risk for CVD. We examined whether hs-CRP concentra-tion reflects insulin resistance in smokers.

METHODS

The hs-CRP levels were measured in 121 male subjects (54 nonsmokers and 67 smokers) with a normal glucose tolerance. The hs-CRP concentration was compared to the homeostasis model assessment of insulin resistance (HOMA-IR) and other clinical variables related to insulin resistance.

RESULTS

Smokers had a 64.5% higher hs-CRP concentration than nonsmokers (p<0.0001). In both nonsmokers and smokers, hs-CRP positively correlated with HOMA-IR (r=0.301, p<0.05 and r=0.312, p<0.01) and fasting insulin (r=0.281, p<0.05 and r=0.356, p<0.01). The correlation between hs-CRP and HOMA-IR or fasting insulin was stronger in smokers than in nonsmokers. In smokers, hs-CRP significantly correlated with BMI and HDL-cholesterol (r=0.386, p<0.01 and r=-0.307, p<0.05). Stepwise regression analysis revealed that BMI and HOMA-IR were significant predictors of hs-CRP in smokers (r=0.423, p<0.01).

CONCLUSIONS

The hs-CRP concentration reflects insulin resistance in smokers. It would be preferable to consider insulin resistance in evaluating hs-CRP concentrations, even in smokers.

Relationship of socioeconomic status to C-reactive protein and arterial stiffness in urban Japanese civil servants

This study investigates whether the two socioeconomic status indicators, educational level and employment grade, are associated with C-reactive protein (CRP) levels and arterial stiffness among Japanese urban civil servants. Brachial-ankle pulse-wave velocity (baPWV) as an indicator of arterial stiffness, CRP, occupational stress and conventional risk factors were evaluated in 3412 men and 854 women. Although the socioeconomic gradient showed a significant association with the CRP levels in men after adjustment for age, the significance disappeared after multivariate adjustment, whereas in women, the socioeconomic gradient showed no significant association with the CRP levels. In men, educational level was significantly associated with the baPWV value after adjustment for conventional risk factors, CRP and occupational stress (P for trend <0.0001). With regards to employment grade, only low-level non-manual workers had a significantly lower baPWV value as compared to manual workers at a fully adjusted model, and trend significance disappeared. However, in women, neither educational level nor employment grade was associated with the baPWV value. In summary, the socioeconomic gradient, especially the educational level, was significantly inversely related to the baPWV value in men. In women, the socioeconomic gradient was not related to the baPWV value. An inverse relationship between the socioeconomic gradient and CRP levels was found in men only after age adjustment. We suggest that because the educational level is an important aspect in the adolescent environment and hence might influence the future lifestyle, early health education should be provided to prevent an unfavourable lifestyle and atherosclerotic diseases in later life.

Intra-individual variation of plasma adipokine levels and utility of single measurement of these biomarkers in population-based studies

Adipokines, soluble mediators produced by adipocytes, may link adipose tissue to the inflammatory, metabolic, and immune dysregulation that characterize many obesity-related diseases. The stability of plasma adipokine levels within individuals, their seasonal variability, intercorrelations, and relationships to well-established measures of adiposity are incompletely defined. We measured levels of 12 adipokines [interleukin 1beta (IL-1beta), IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha), plasminogen activator inhibitor-1 (PAI-1), high-sensitivity C-reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor (NGF), leptin, adiponectin, hepatocyte growth factor (HGF), and resistin] in four seasonal random plasma samples of 48 male participants of a population-based cohort study. The representativeness of single measurements was assessed by correlating the adipokine levels of a single, random sample with the mean levels from the remaining three samples using a bootstrap approach and using intra-class correlation coefficients (ICC). Spearman correlations between adipokine levels, age, body mass index (BMI), and waist-to-hip ratio (WHR) were estimated. Correlations between plasma adipokine levels from one random sample and the mean of the remaining three seasonal samples ranged from 0.57 to 0.89. Over the 1-year study period, the ICCs for adipokine levels ranged from 0.44 (PAI-1) to 0.83 (HGF). IL-8, MCP-1, and resistin levels were positively associated with age; HGF and PAI-1 levels were correlated with BMI and WHR. This study suggests that adipokine levels in a single blood sample may be useful biomarkers of inflammation in population-based studies of obesity-related disease.