Different associations of C-reactive protein, fibrinogen and C3 with traditional risk factors in middle-aged men

Associations of immunological factors with metabolic syndrome and its characteristic elements in Chinese centenarians

BACKGROUND

Metabolic syndrome (MetS) has an increased prevalence (approximately 20-25% of the adult population) all over the world. Immunological function is significantly associated with the development of MetS, and MetS is beginning to be considered as a chronic immune-related disease. The present study addressed on the associations of immunological factors with MetS and its characteristic elements in Chinese centenarians.

METHODS

Hainan is a longevity region with the highest population density of centenarians in China. The China Hainan Centenarian Cohort Study has a considerable sample size, and provides a significant population-based sample of centenarians. Home interview, physical examination and blood analysis were conducted following standard procedures.

RESULTS

All centenarians had a median age of 102 (100-115) years, and the proportion of females was 80.8%. The proportion of centenarians with MetS was 16.0% (135 centenarians). Abdominal obesity, hypertension, dyslipidemia and diabetes mellitus had a prevalence of 26.4% (223 centenarians), 73.7% (623 centenarians), 40.4% (341 centenarians) and 10.7% (90 centenarians), respectively. In Logistic regression analyses, MetS was significantly associated with immunoglobulin E and complement C3 levels (P < 0.05 for all). Abdominal obesity was significantly associated with immunoglobulin E and complement C3 levels (P < 0.05 for all).

CONCLUSIONS

The present study provides epidemiological evidence that MetS has significant associations with immunoglobulin E and complement C3 levels, and demonstrates that abdominal obesity is significantly associated with immunoglobulin E and complement C3 levels in Chinese centenarians.

High sensitivity C-reactive protein in systemic lupus erythematosus: relation to disease activity, clinical presentation and implications for cardiovascular risk

Measurement of high sensitivity C-reactive protein (hs-CRP), has been used in the assessment of disease activity in numerous rheumatic conditions including systemic lupus erythematosus (SLE). However, the utility of hs-CRP measurement in patients with lupus is uncertain. This study examined if hs-CRP can be used to assess disease activity, severity and cardiovascular risk in SLE. Serum samples from 601 visits of 213 SLE patients and 134 controls were analysed for hs-CRP by nephelometry. Detailed demographic data were obtained from all subjects and medication history and key laboratory parameters were collected. Disease activity was assessed using the SLEDAI. High sensitivity CRP was not associated with disease activity (SLEDAI), number of ACR SLE criteria or presence of any particular organ involvement. hs-CRP levels were significantly correlated with standard cardiovascular risk factors including body weight ( P = 0.0002), hypertension ( P = 0.001), and apolipoprotein A-I ( P < 0.0001). Interestingly an inverse correlation was seen between hs-CRP levels and antimalarial use ( P = 0.0018). Our results suggest that measurement of hs-CRP, though not valuable as marker of disease activity in SLE may be of some use in the assessment of cardiovascular risk. We speculate that antimalarials may help to reduce cardiovascular risk in patients with SLE.

Influence of hypertension, obesity and nicotine abuse on quantitative and qualitative changes in acute-phase proteins in patients with essential hypertension

Background

Hypertension is a powerful risk factor for cardiovascular disease and frequently occurs in conjunction with obesity. Accumulative evidence suggests a link between inflammation and hypertension. The aim of study was to evaluate whether blood pressure, obesity and smoking may influence acute-phase response.

Material/Methods

Ninety-two patients with essential hypertension and 75 healthy volunteers as a control group were studied. In all subjects assessment of hsCRP, α1-acid glycoprotein (AGP), α1-antichymotrypsin, transferrin, α1-antitrypsin, and C3 and C4 complement were performed. Evaluation of glycosylation profile and reactivity coefficient (RC) for AGP was done by means of affinity immunoelectrophoresis with concanavalin A as a ligand.

Results

When compared to the controls, hypertensive subjects presented significantly higher hsCRP concentrations and lower transferrin level. Hypertensive patients had elevated AGP-AC. The intensification of the inflammatory reaction was greater in the subgroup of hypertensive patients smoking cigarettes. In obese hypertensives, elevated serum C3 complement level was found.

Conclusions

We conclude that arterial hypertension may evoke the acute-phase response in humans. Markers of acute-phase response are particularly strongly expressed in smokers. Serum C 3 complement, but not other APPs, is elevated in hypertension coexisting with obesity.

Metabolic impact on serum levels of complement component 3 in Japanese patients

The aim of this study was to explore the association between the serum concentration of complement component 3 (C3) and a variety of metabolic parameters. The study involved 125 patients in our outpatient clinic. Anthropometric and clinical laboratory data were collected and statistical associations between the serum concentration of C3 and other parameters were evaluated in a cross-sectional as well as a prospective manner. A group of male patients with metabolic syndrome (Mets, n=35) were characterized by marked increase in serum concentrations of C3, body mass index (BMI), waist circumference, hemoglobin (Hb) A1c, insulin resistance (HOMA-IR), triglyceride, uric acid, urinary protein, and Hb. In a one-way analysis of variance of all subjects, the serum concentration of C3 was significantly elevated as the number of items of complying with the Mets diagnostic criteria increased. In 60 of 125 patients who did not have diabetes and were given anti-lipogenetic medication, the serum concentration of C3 showed significant positive associations with serum levels of CH50, insulin, HOMA-IR, total cholesterol, hematocrit, LDL-c, C4, Hb, triglyceride, BMI, and albumin. In a prospective follow-up evaluation (n=35), there was a significant positive association between DeltaC3 (the second concentration of serum C3 minus the first concentration of serum C3)and DeltaHOMA-IR (the second concentration of HOMA-IR minus the first concentration of HOMA-IR). In conclusion, in Japanese patients, there is evidence implicating C3 concentration as a marker of Mets coinciding with insulin resistance.

Waist circumference and BMI in relation to serum high sensitivity C-reactive protein (hs-CRP) in Cuban Americans with and without type 2 diabetes

Relationship between high-sensitivity C-reactive protein (hs-CRP) and adiposity by diabetes status and gender in Cuban-Americans with and without type 2 diabetes (T2D) was studied. Adult subjects, 226 females, 129 males participated in a case control, single time point study. Subjects with T2D were older, had higher waist circumference (WC) and body mass index (BMI). WC and BMI were associated with ln hs-CRP (P < 0.001). An interaction with diabetes status was found for BMI (P = 0.037). Gender showed a strong relationship with ln hs-CRP (P < 0.001), which was moderated by diabetes status. Only males without diabetes exhibited a significant relationship for both WC and BMI with ln hs-CRP. In this sample of Cuban-Americans, WC and BMI had stronger associations with ln hs-CRP but not with diabetes status. Obesity prevention and controlling for CRP levels may be necessary to eliminate its contributions to develop diabetes and cardiovascular disease (CVD).

Early life origins of low-grade inflammation and atherosclerosis risk in children and adolescents

OBJECTIVE

To examine the relationship between birth weight and later low-grade inflammation in children and adolescents.

STUDY DESIGN

We selected 166 children (49.4% boys; aged, 9.5 +/- 0.3 years) and 126 adolescents (43.7% males; aged, 15.5 +/- 0.4 years) from the Swedish part of the European Youth Heart Study. Birth weight data were collected from parental recall. Low-grade inflammatory markers include C-reactive protein, fibrinogen, and complement factors C3 and C4. Fatness was measured by the sum of 5 skinfold thicknesses. Cardiorespiratory fitness was measured with a maximal ergometer bike test. The association between birth weight and low-grade inflammatory markers was examined with multiple regression analyses.

RESULTS

Birth weight was negatively associated with fibrinogen (beta = -0.059; P = .036), C3 (beta = -0.019; P = .010), and C4 (beta = -0.024; P = .031), after controlling for sex, pubertal status, mother's body mass index and socioeconomic status, fatness and fitness. Birth weight was not associated to later C-reactive protein level (all P > .1).

CONCLUSIONS

Our results showed that smaller birth weight is associated with chronic low-grade inflammation in children and adolescents. Because of the implication of complement factors on atherosclerosis process, these results contribute to explain the increased cardiovascular risk associated with low birth weight.

Association of common variants of UCP2 gene with low-grade inflammation in Swedish children and adolescents; the European Youth Heart Study

We examined the associations of two functional variants 866G>A and DEL/INS polymorphisms of UCP2 gene with low-grade inflammatory proteins (C-reactive protein, fibrinogen, complement C3 [C3], and complement C4 [C4]) in 131 children (52.7% boys, aged 9.5 +/- 0.4 y) and 118 adolescents (44.1% males, aged 15.5 +/- 0.4 y) selected from the European Youth Heart Study. Differences in inflammatory markers among the genotype variants of the two UCP2 gene polymorphisms were analyzed after adjusting for sex, age, pubertal stage, fitness, and fatness. The results showed that fibrinogen, C3, and C4 were higher in GG carriers than in subjects carrying the A allele of the 866G>A polymorphism of the UCP2 gene (UCP2 -866G>A) polymorphism (all p < 0.05). The DEL/DEL genotype of 45nt deletion/insertion variant polymorphism of the UCP2 gene (UCP2 DEL/INS) was associated with higher C3 (p < 0.05) than DEL/INS and INS/INS genotypes. This study provides evidence of a role of UCP2 -866G>A in modifying low-grade inflammatory state in apparently healthy children and adolescents. Given the implication of complement factors on atherosclerosis process, these results contribute to explain the reduced cardiovascular risk associated with the A allele of the UCP2 -866G>A polymorphism.

Air pollution and serum C-reactive protein concentration in children

BACKGROUND

Few biological markers that allow evaluation of the effects of air pollution on human health have been identified. This study evaluated the association of serum C-reactive protein (CRP) concentration in children with their respiratory symptoms and air pollution.

METHODS

Respiratory symptoms and serum concentrations of CRP were examined in 2,094 school children living in 3 communities with different concentrations of air pollutants in Chiba Prefecture, Japan in 2001. The relationships between serum CRP concentration and sex, age, respiratory symptoms, and various environmental factors were analyzed.

RESULTS

Serum CRP concentration decreased with age, and was significantly higher both in children who were bottle-fed in infancy and whose mothers smoked. Children with wheeze had significantly higher serum CRP concentration than those without wheeze. After adjustment for potential confounding factors, increased serum CRP concentrations of the 90th percentile (1.4 mg/L) or above were significantly associated with atmospheric concentration of suspended particulate matter (SPM) (odds ratio [OR] =1.49 for the range of observed concentrations, 95% confidence interval [CI]: 1.07-2.06) and sulfur dioxide (SO(2)) (OR =1.45, 95% CI: 1.04-2.03). In a two-pollutant model including SPM and nitrogen dioxide (NO(2)) concentrations, increased serum CRP concentrations were also associated with SPM (OR =1.94, 95% CI: 1.08-3.50), but no such association was found with NO(2) (OR =0.62, 95% CI: 0.26-1.48).

CONCLUSION

Serum CRP concentration is related to wheezing and the degree of air pollution. Because the concentrations of air pollutants are highly correlated, it is difficult to elaborate on which pollutant has a stronger effect on serum CRP concentrations.

Serum C3 is a stronger inflammatory marker of insulin resistance than C-reactive protein, leukocyte count, and erythrocyte sedimentation rate: comparison study in an elderly population

OBJECTIVE

This study was performed to ascertain the relative relevance of some inflammatory markers in insulin resistance.

RESEARCH DESIGN AND METHODS

Four inflammatory markers (leukocyte count, erythrocyte sedimentation rate [ESR], high-sensitivity C-reactive protein [CRP], and C3 complement) were assessed as possible determinants of the homeostasis model assessment (HOMA) index, together with the five elements of the metabolic syndrome (National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults [Adult Treatment Panel III] definition), total cholesterol, physical activity, and four indicators of adiposity (BMI, waist circumference, percent body fat, and hepatic steatosis) in an unselected population of 990 subjects aged 65-91 years (the Pianoro Study).

RESULTS

In univariable analysis, C3, CRP, and leukocyte count, but not ESR, were significantly correlated with HOMA index. In multivariable analysis, C3 remained associated with insulin resistance with the highest partial R(2) value (0.049), independently of all other covariates. The other most significant (P < 0.0001) determinants of HOMA index were total cholesterol (inverse association, R(2) = 0.026), waist circumference (R(2) = 0.023), triglycerides (R(2) = 0.022), and hepatic steatosis (R(2) = 0.021) (R(2) = 0.450 for the whole model). The adjusted relative risks of having the metabolic syndrome for the subjects with inflammatory markers in the high tertile, with respect to those with lower values, were (prevalence ratio [95% CI]): 1.77 (1.41-2.22) for C3, 1.38 (1.12-1.70) for leukocyte count, 1.17 (0.94-1.46) for CRP, and 1.13 (0.91-1.40) for ESR.

CONCLUSIONS

Of the four inflammatory markers simultaneously assessed in our elderly population, only C3 was strongly associated with insulin resistance, independently of the components of the metabolic syndrome and the main indexes of abdominal and general obesity.

Inflammatory proteins are related to total and abdominal adiposity in a healthy adolescent population: the AVENA Study

BACKGROUND

In adults, obesity is characterized by a state of chronic low-grade inflammation accompanied by moderately high concentrations of acute phase inflammatory proteins. Recent results regarding C-reactive protein (CRP) point to a similar status in adolescents; however, studies of associations of the serum inflammatory proteins CRP, ceruloplasmin, and complement factors C3 and C4 with body fat distribution remain scarce.

OBJECTIVE

We aimed to establish the possible relations of serum inflammatory proteins with body fat estimates and body fat distribution in an apparently healthy adolescent population.

DESIGN

This report included 472 adolescents (248 males and 224 females) aged 13-18.5 y who were recruited from the Spanish cross-sectional multicenter AVENA Study for whom anthropometric and immunologic data were complete. The concentrations of the serum proteins and the in vitro production of cytokines (interleukin 6 and tumor necrosis factor alpha) by isolated and stimulated white blood cells were measured. Relations with anthropometric measurements were explored by using simple and partial correlations.

RESULTS

CRP, C3, and C4 were correlated with central obesity (as measured by waist circumference) and total body fat in both sexes (P < 0.01) and with ceruloplasmin in females only. After further adjustment for BMI, C3 remained independently associated with central obesity (P < 0.05). Production of the cytokines by white blood cells did not seem to be affected by an excess of body fat.

CONCLUSIONS

Total body fat seems to be associated with a chronic low-grade systemic inflammation in apparently healthy adolescents. Central obesity is independently associated with C3 concentrations, which makes this marker especially interesting for further studies of obesity-related diseases.

Complement C3 and C-Reactive Protein Are Elevated in South Asians Independent of a Family History of Stroke

BACKGROUND AND PURPOSE

Complement components are emerging risk factors for cardiovascular disease. In this study, we examined the relation among C3, C-reactive protein (CRP), factor B, and features of the insulin resistance (IR) syndrome in 143 first-degree relatives of South Asian subjects with ischemic stroke, 141 South Asian controls, and 121 white controls.

METHODS

C3, CRP (high-sensitivity assay), and factor B levels were measured by ELISAs, and their relation to features of the IR syndrome were assessed. Data are presented as geometric mean (95% CI).

RESULTS

There was no significant difference in the levels of C3 between South Asian relatives (1.25 [1.21, 1.29] g/L) and South Asian controls (1.20 [1.15, 1.24] g/L, P=0.2). Levels in both South Asian groups were significantly higher than in white controls (0.95 [0.92, 0.98] g/L; P<0.001 for both comparisons). These differences remained significant after adjustment for covariates. Similarly, levels of CRP were not different between the 2 South Asian groups, but levels in both South Asian groups, after adjustment for covariates, were significantly higher than in white controls. There was no difference in the levels of factor B among the 3 groups. South Asian subjects with elevated C3 levels clustered risk factors associated with IR to a greater extent than those with high CRP.

CONCLUSIONS

These results suggest that South Asians have a greater level of chronic subclinical inflammation than do whites, independent of a family history of stroke. In addition, C3 is more likely to cluster with features of the IR syndrome compared with CRP in South Asians.

Effects of weight loss and risk factor treatment in subjects with elevated serum C3, an inflammatory predictor of myocardial infarction

BACKGROUND

Serum C3 is an inflammatory predictor of myocardial infarction and a covariate of fasting insulin and several endogenous risk factors. This study was performed to ascertain whether risk factor control may reduce elevated C3 concentrations.

METHODS

After traditional risk factor and C3 assessment in 1100 unselected men aged 55-64 years, 238 men with persistently elevated C3 levels (>=1.19 g/l, high tertile) were randomised into 2 groups: 43 controls, who were referred to their general practitioner, and 195 subjects who were intensively treated with diet, and anti-hypertensive or antidiabetic drugs according to specific indications, without anti-dyslipidemic drugs.

RESULTS

After three months in the treated subjects significant decrements of body weight, blood pressure, blood glucose and serum lipids were obtained, with stable C3 levels (while in controls a 3.3% increase occurred, P=0.02). The factors associated with a C3 decrement >5% were a high baseline C3 level, a recent acute inflammation, physical activity, belonging to the treated group, and a significant reduction in body weight, triglycerides or blood glucose. However, in multivariate analysis only an elevated baseline C3 (P<0.0001), a weight loss >2% (P=0.0009) and physical activity (P=0.02) remained independently associated with a C3 decrement >5% (R(2)=0.14).

CONCLUSIONS

Only weight loss and physical activity, but not traditional risk factor lowering, could independently induce a significant C3 decrease. Thus, C3 elevation is associated with, but probably not caused by, traditional risk factors.

Cross-sectional study of complement C3 as a coronary risk factor among men and women

In the present study, we examined (i) whether C3 (complement C3) was an independent marker of prevalent CHD (coronary heart disease), and (ii) which preferential associations existed between C3 and some cardiovascular risk factors when jointly analysed with CRP (C-reactive protein) and fibrinogen. In a cohort of 756 unselected adults, 39% of whom had the metabolic syndrome, C3 and other risk variables were evaluated in a cross-sectional manner. In a logistic regression model for the likelihood of CHD, a significant OR (odds ratio) of 3.5 [95% CI (confidence intervals), 1.27 and 9.62)] for C3 was obtained after adjustment for smoking status, TC (total cholesterol) and usage of statins. A similar model, also comprising systolic blood pressure, with a cut-off point of >or=1.6 g/l C3 exhibited a 1.9-fold risk (95% CI, 1.01 and 3.58) compared with individuals below the cut-off point. Both analyses displayed an adjusted OR of 1.37 for each S.D. increment in C3. The significant relationship of C3 with a likelihood of CHD also proved to be independent of CRP. In multiple linear regression models, associations were tested for each acute-phase protein with measures of obesity, fasting insulin, triacylglycerols (triglycerides), TC, HDL (high-density lipoprotein)-cholesterol, physical activity, smoking status, diagnosis of metabolic syndrome and family income. When both genders were combined, C3 was independently associated with serum triacylglycerols, waist circumference, BMI (body mass index) and TC. CRP was independently associated with waist circumference, TC, family income (inversely) and physical activity, and fibrinogen with BMI, TC, smoking status and metabolic syndrome. In summary, elevated levels of complement C3 are associated with an increased likelihood of CHD independent of standard risk factors and regardless of the presence of acute coronary events, suggesting that C3 might be actively involved in coronary atherothrombosis. Unlike CRP and fibrinogen, C3 was preferentially associated with waist girth and serum triacylglycerols.

Dietary alpha-linolenic acid reduces inflammatory and lipid cardiovascular risk factors in hypercholesterolemic men and women

Alpha-linolenic acid (ALA) reduces cardiovascular disease (CVD) risk, possibly by favorably changing vascular inflammation and endothelial dysfunction. Inflammatory markers and lipids and lipoproteins were assessed in hypercholesterolemic subjects (n = 23) fed 2 diets low in saturated fat and cholesterol, and high in PUFA varying in ALA (ALA Diet) and linoleic acid (LA Diet) compared with an average American diet (AAD). The ALA Diet provided 17% energy from PUFA (10.5% LA; 6.5% ALA); the LA Diet provided 16.4% energy from PUFA (12.6% LA; 3.6% ALA); and the AAD provided 8.7% energy from PUFA (7.7% LA; 0.8% ALA). The ALA Diet decreased C-reactive protein (CRP, P < 0.01), whereas the LA Diet tended to decrease CRP (P = 0.08). Although the 2 high-PUFA diets similarly decreased intercellular cell adhesion molecule-1 vs. AAD (-19.1% by the ALA Diet, P < 0.01; -11.0% by the LA Diet, P < 0.01), the ALA Diet decreased vascular cell adhesion molecule-1 (VCAM-1, -15.6% vs. -3.1%, P < 0.01) and E-selectin (-14.6% vs. -8.1%, P < 0.01) more than the LA Diet. Changes in CRP and VCAM-1 were inversely associated with changes in serum eicosapentaenoic acid (EPA) (r = -0.496, P = 0.016; r = -0.418, P = 0.047), or EPA plus docosapentaenoic acid (r = -0.409, P = 0.053; r = -0.357, P = 0.091) after subjects consumed the ALA Diet. The 2 high-PUFA diets decreased serum total cholesterol, LDL cholesterol and triglycerides similarly (P < 0.05); the ALA Diet decreased HDL cholesterol and apolipoprotein AI compared with the AAD (P < 0.05). ALA appears to decrease CVD risk by inhibiting vascular inflammation and endothelial activation beyond its lipid-lowering effects.

Relationship between depression and C-reactive protein in a screening population

BACKGROUND

Both depression and C-reactive protein (CRP) are markers of increased risk for cardiovascular events. This study examined the relationship between CRP and depression in a cohort of participants undergoing a periodic physical to assess potential for interaction as either mediation or confounding of effect on cardiovascular risk.

METHODS

We conducted a cross-sectional study of a cohort of 696 consenting, active duty US Army personnel undergoing a periodic physical. We measured depression using the Patient Health Questionnaire-9, the depression module of the self-administered version of the Primary Care Evaluation of Mental Disorders (PRIME-MD). We used a highly sensitive assay to measure CRP.

RESULTS

The mean age in the cohort was 44 years (SD +/- 3; 82% male). The mean CRP level was 1.7 mg/l (range, 0.3-9.9; SD +/- 1.6 mg/l). Depression scores ranged from 0 to 26 with a mean of 2 (SD +/- 3). Depression scores correlated with prevalences of major depressive disorder and of any depressive disorder of 3.3% and 15%, respectively. Depression scores correlated positively with CRP levels (r = 0.085; p =.028), as did other variables known to be associated with CRP: body mass index (BMI; r = 0.36), insulin levels (r = 0.22), mean arterial pressure (r = 0.21), triglycerides (r = 0.18), exercise (r = -0.12), female sex (r = 0.097), current smoking status (r = 0.08), and high density lipoprotein (r = -0.09). After controlling only for BMI, the relationship between depression and CRP lost statistical significance among women (adjusted r = 0.08; p =.37), among men (adjusted r = -0.11; p =.8), and overall (adjusted r = 0.047; p =.219).

CONCLUSION

Depressive symptoms are only weakly correlated with CRP. However, after adjusting for BMI, we found no significant relationship between CRP and depression. The relationship between depression and clinical coronary disease is unlikely to be explained through direct effects on CRP levels, but may be mediated by BMI.

Fibrinogen--marker or mediator of vascular disease?

Fibrinogen plays a key role in platelet aggregation, the final step of the coagulation cascade, i.e. the formation of fibrin, and it is a major determinant of plasma viscosity and erythrocyte aggregation. It is both constitutively expressed and inducible during an acute phase reaction. Increased plasma fibrinogen levels are associated with an increased risk of coronary heart disease and myocardial infarction. The question as to whether fibrinogen is only a marker of the inflammatory process involved in atherosclerosis or a mediator, i.e. a pathogenic factor, has not yet been answered. Human in vivo studies do not permit a conclusive answer to this question. If it is a pathogenic factor, fibrinogen lowering would be a therapeutic option. Selective fibrinogen-lowering agents do not exist however. All agents that lower fibrinogen also have other cardiovascular effects such as a decrease in cholesterol or inflammation. Newer information stems from molecular biology. Polymorphisms in the human fibrinogen gene with higher fibrinogen levels do not increase the risk for myocardial infarction. Fibrinogen knockout mice crossed with an atherosclerosis-susceptible strain (apoprotein E null mice) did not show a decreased extent of atherosclerosis despite the absence of fibrinogen, and a mouse strain over-expressing fibrinogen did not show an increased degree of atherosclerosis. Thus, fibrinogen seems to be a marker rather than a mediator of vascular disease, which would make selective fibrinogen lowering a useless preventive or therapeutic strategy.

Effects of estrogen and medroxyprogesterone acetate on subpopulations of triglyceride-rich lipoproteins and high-density lipoproteins

Hormonal replacement therapy (HRT) in postmenopausal women has been shown to increase both triglyceride (TG) and high-density lipoprotein (HDL) cholesterol levels. To better understand the effects of conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA), the 2 most commonly prescribed hormones in HRT, on the different subpopulations of TG-rich and HDL lipoproteins, we conducted a placebo-controlled, double-blind, randomized, crossover study consisting of 3 different phases in 14 postmenopausal women. The 3 phases, each 8-week long, included: (1) placebo, (2) CEE 0.625 mg/d, and (3) CEE 0.625 mg/d and MPA 2.5 mg/d. Slight and statistically nonsignificant elevations in TG levels were observed during the CEE treatment. While very-low-density lipoprotein (VLDL) cholesterol levels were not significantly affected by CEE and CEE + MPA, both HRT treatments lowered remnant lipoprotein (RLP) cholesterol (-14% and -37%, respectively). Compared with placebo, CEE caused a significant increase in HDL, HDL(2), apolipoprotein (apo) A-I, LpAI, alpha1, and prealpha1 levels (12%, 27%, 17%, 26%, 60%, and 102%, respectively). The combination therapy blunted the CEE effect on all HDL parameters, resulting in HDL, HDL(2), and LpAI levels being no longer significantly different from placebo. Apo A-I levels and alpha1, and prealpha1 levels were still significantly higher than placebo (+11%, +50%, and +112%, respectively). These results indicate that HRT has beneficial effects on RLP levels and that, while the estrogen component of HRT has a beneficial effect on the HDL subpopulations mostly associated with coronary heart disease (CHD) protection, MPA partially inhibits this effect.

The prevalence of elevated serum C-reactive protein levels in inflammatory and noninflammatory thyroid disease

C-reactive protein (CRP) levels have not been routinely used to diagnose thyroid disease, although many thyroid conditions involve inflammation. This study was intended to determine whether CRP levels could differentiate between inflammatory and noninflammatory thyroid conditions, especially between type II inflammatory amiodarone-induced thyrotoxicosis (AIT) and type I iodine-induced AIT. Serum high-sensitivity CRP levels were measured in 100 euthyroid controls (7 taking amiodarone) and 353 patients with one of the following thyroid conditions: AIT, subacute thyroiditis, toxic diffuse goiter, nodular goiter, Hashimoto's thyroiditis, shortterm hypothyroidism, or postpartum thyroiditis. No patients with nontoxic multinodular goiter (n = 34), toxic nodular goiter (n = 23), or toxic diffuse goiter, either untreated (n = 49) or euthyroid while taking methimazole (n = 33), had positive CRP levels (>10 mg/L). The occurrence of positive CRP levels among patients with Hashimoto's thyroiditis (n = 35), short-term hypothyroidism (n = 38), and postpartum thyroiditis (n = 70) did not differ significantly from controls. The occurrence of positive CRP values did not differ significantly between patients with type I and type II AIT and controls. Six of 7 patients (86%) with untreated subacute thyroiditis had positive CRP levels (p < 0.00001). These results indicate that there is only a limited role for measurement of CRP levels in the diagnosis of thyroid diseases other than subacute thyroiditis.

A comparison of acute phase proteins and traditional risk factors as markers of combined plaque and intima-media thickness and plaque density in carotid and femoral arteries

OBJECTIVES

To test the hypothesis that some acute phase proteins may be better independent predictors of objective measures of arterial wall impairment than traditional risk factors.

DESIGN

Cross-sectional study.

MATERIALS AND METHODS

C-reactive protein (CRP), fibrinogen, C3 complement and traditional risk factors were measured in 288 men aged 55-64 years, randomly chosen from the local registry lists. By ultrasound assessment of the bifurcations of carotid and femoral arteries, maximum combined plaque/intima-media thickness (CPIMTmax) and mean plaque density (MPD, in a grey scale from 0 to 255) were also measured.

RESULTS

In multivariate analysis only traditional risk factors remained associated with the overall CPIMTmax: smoking (r = 0.35, p < 0.0001), cholesterol (r = 0.23, p = 0.0001), age (r = 0.22, p = 0.0002), glucose (r = 0.18, p = 0.002) and systolic blood pressure (r = 0.13, p = 0.02). However, with regard to carotid disease only, fibrinogen was the strongest covariate of CPIMT (r = 0.18, p = 0.002). The overall MPD was independently associated with CRP (r = 0.25, p = 0.0008), physical activity (r = 0.19, p = 0.009), triglycerides (r = -0.18, p = 0.02) and body mass index (r = 0.15, p = 0.04). CRP was mainly associated with femoral MPD, while triglycerides were the major (inverse) covariate of carotid MPD.

CONCLUSIONS

Traditional risk factors are the main determinants of CPIMTmax, although fibrinogen seems to play a role in carotids. CRP was associated with high density femoral plaques. Finally, no acute phase protein was independently associated with low density, potentially vulnerable, plaques.