C-reactive Protein Levels In Men Research Articles

(068) Total Testosterone is Inversely Associated with C-reactive Protein Levels in Men: Findings from the Baltimore Longitudinal Study of Aging

Abstract Introduction Elevated C-Reactive Protein (CRP) and testosterone deficiency are associated with advanced age and chronic inflammatory diseases, such as cancer, obesity, diabetes, and cardiovascular disease. Further, serum CRP has proven to be a robust predictor of major adverse cardiovascular events. Testosterone decreases inflammation through several mechanisms, and testosterone replacement therapy (TRT) has been shown to consistently lower CRP levels in aging, hypogonadal men. While cross-sectional studies have shown an inverse relationship between CRP and total testosterone (TT) levels, mixed findings have been reported when individual components of metabolic syndrome and additional comorbidities are considered. Given that androgens have been implicated in anti-inflammatory pathways, we hypothesize that men with testosterone deficiency will have low CRP levels, independent of added comorbidities. Objective We evaluated the relationship between CRP and TT levels in men from 2004-2018 using the Baltimore Longitudinal Study of Aging. Methods Male participants with a documented serum TT level measured via mass spectroscopy during two separate visits >3 years apart were included in our cohort. CRP, High-Density Lipoprotein (HDL), and Triglyceride levels were collected via blood specimens. Comorbidity data were documented for all participants at each follow-up visit. Patients with serum TT or CRP levels >3 standard deviations from the mean of each respective variable were removed. Men with documented use of any form of TRT or a history of prostate cancer were excluded. Panel regression, a statistical technique implemented to analyze the relationship of a series of independent variables collected in pooled cross-sectional observations over time with a dependent variable, was used for univariable and multivariable modeling of CRP. P-value < 0.05 was considered statistically significant. Results A total of 347 patients (694 visits) met the inclusion criteria of this study. The median age of our sample was 71 years with a follow-up time of 8 years (range: 3-13 years). Participants had a median CRP level of 1.03 mg/dL [0.52, 2.11] and a median TT level of 446 ng/dL [339, 560]. In terms of comorbidities, diabetes was documented most frequently, followed by congestive heart failure (CHF) and cancer (Table 1). On univariable analysis TT, cancer, and HDL were associated with a decline in CRP, while BMI, CHF, Diabetes, and Triglycerides were associated with increased CRP. Age was not associated with CRP (Table 2). On multivariable analysis, we found that increasing TT was associated with a decline in CRP levels, independent of comorbidities (p = 0.022; Table 2). The strengths of our study include having well-documented laboratory values and comorbidity information for patients at multiple visits. However, causal associations cannot be inferred due to the retrospective nature of the data. Conclusions We report that an increase in TT is associated with a decline in CRP levels, after controlling for components of metabolic syndrome and other related comorbidities. This finding is consistent with the anti-inflammatory effects of androgens, which decrease pro-inflammatory mediators and leukotriene biosynthesis. Our study further highlights the benefits of restoring eugonadal testosterone levels in older, hypogonadal men via hormone replacement, potentially lowering CRP levels and reducing cardiovascular risk. Disclosure No

Depression symptoms mediate the association between workplace stress and interleukin 6 in women, but not men: The Whitehall II study

Workplace stress and depression are positively related with inflammation, and each other. Low-grade inflammation and concurrent high levels of workplace stress or depression has been related with future morbidity. The potential pathway between constructs however, remains elusive. For the first time, this study explored the concurrent relationship between workplace stress, depressive symptomology and low-grade inflammation, and considered the role of gender in these relationships. Data from the Whitehall II cohort study (N ​= ​2528, Mage ​= ​57.01, 23.7% females) provided measures of workplace stress (job demand-control; JDC), depressive symptomology (Centre for Epidemiological Studies Depression scale; CES-D) and circulating inflammatory markers, interleukin-6 (IL-6) and C-reactive protein (CRP) collected on the same day from a single time point. Females had higher workplace stress, depressive symptoms and lower serum IL-6 concentrations. For males, higher workplace stress was associated with higher depressive symptoms. For females, higher depressive symptoms were related with elevated IL-6 levels, and both higher workplace stress and IL-6 levels were associated with higher depressive symptoms. Higher depressive symptoms were related with higher CRP levels in men only. Higher depressive symptoms statistically mediated the relationship between higher workplace stress and IL-6 levels in females only, b ​= ​0.016, CI [0.002, 0.039]. Females in this large cohort had higher levels of job strain, depression and lower IL-6 concentrations than males. In females, higher depressive symptoms were associated with higher serum IL-6 levels and workplace stress was not. Considered together, these findings suggest that low job control may be more apparent in females than males, but it is primarily negative affect that drives the positive relationship between work stress and serum IL-6 concentrations in females. Replicating the current design with a suitably proximal follow-up is required to determine if the associations identified are causal.

Impact of Obesity and Adiposity on Inflammatory Markers in Patients With Rheumatoid Arthritis.

The C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) are important disease activity biomarkers in rheumatoid arthritis (RA). This study aimed to determine to what extent obesity biases these biomarkers. Body mass index (BMI) associations with CRP level and ESR were assessed in 2 RA cohorts: the cross-sectional Body Composition (BC) cohort (n = 451), including whole-body dual x-ray absorptiometry measures of fat mass index; and the longitudinal Veterans Affairs Rheumatoid Arthritis (VARA) registry (n = 1,652), using multivariable models stratified by sex. For comparison, associations were evaluated in the general population using the National Health and Nutrition Examination Survey. Among women with RA and in the general population, greater BMI was associated with greater CRP levels, especially among women with severe obesity (P < 0.001 for BMI ≥35 kg/m2 versus 20-25 kg/m2 ). This association remained after adjustment for joint counts and patient global health scores (P < 0.001 in BC and P < 0.01 in VARA), but was attenuated after adjustment for fat mass index (P = 0.17). Positive associations between BMI and ESR in women were more modest. In men with RA, lower BMI was associated with higher CRP levels and ESR, contrasting with positive associations among men in the general population. Obesity is associated with higher CRP levels and ESR in women with RA. This association is related to fat mass and not RA disease activity. Low BMI is associated with higher CRP levels in men with RA; this unexpected finding remains incompletely explained but likely is not a direct effect of adiposity.

Is There a Relationship between Lower Urinary Tract Symptoms and C-reactive Protein Levels in Men? A Cross-Sectional Study

Is There a Relationship between Lower Urinary Tract Symptoms and C-reactive Protein Levels in Men? A Cross-Sectional Study

Effect of body shape and inflammation on tooth loss in men and women.

Android and gynoid adiposity is differently involved on inflammatory responses in men or women in periodontitis and tooth loss. We tested the hypothesis whether identical waist-to-hip ratios (WHR) in men and women could abolish this disparity. Data of 2746 participants from the Study of Health in Pomerania (SHIP) were analysed. Men and women were 1:1 matched, N=344:344, in three age strata for waist-to-hip ratio. We determined anthropometric measures, attachment loss, tooth loss and markers of systemic inflammation. Women matched with men by WHR had increased periodontal measures as compared to women of the general population. Nevertheless, in the matched pairs incidence risk (IRR) ratios for any tooth loss associated with elevated C-reactive protein were IRR=2.15 (CI 1.33-3.40) and 1.04 (0.66-1.66) in men and women, respectively. Regression with tooth loss due to any cause as dependent variable showed dose dependency on C-reactive protein levels in men but not in women. The adjusted IRR associated with high C-reactive protein in men was 1.37 (CI 1.05-1.78) and 2.63 (1.58-4.38) in general and in matched subjects, respectively. Systemic inflammation was associated with tooth loss in men but not in women even in women with wide girth. Despite worsened periodontal measures and inflammation in women matched for body shape with men, these women do not lose more teeth even when they are exposed to increased markers of systemic inflammation. This is an attempt to disentangle the unclear relationship between obesity and periodontitis, both of them having public health relevance.

Gender-Specific Associations of Perceived Stress and Coping Strategies with C-Reactive Protein in Middle-Aged and Older Men and Women

Perceived stress and coping strategies may influence the risk of cardiovascular disease through their possible association with inflammation, but data remain controversial for perceived stress or scanty for coping strategies. We examined the associations of perceived stress and coping strategies with serum high-sensitivity C-reactive protein (CRP) in a Japanese general population. This cross-sectional study included 2,971 men and 4,902 women aged 40-69 years who were enrolled between 2005 and 2007. Subjects with possible inflammation-related disease, CRP levels ≥3,000 ng/mL, or currently used analgesics or lipid-lowering drugs were excluded. Analyses were performed by gender with adjustment for lifestyle, socioeconomic, and psychosocial factors. Unexpectedly, elevated perceived stress was significantly associated with lower CRP levels in men (P trend < 0.001) but not in women (P trend = 0.90) after adjustment for age and covariates. Among five items of coping strategies evaluated, "disengagement" showed a significant inverse association with CRP in men only (P trend = 0.027). In addition, a possible interaction between "emotional support seeking" and perceived stress on CRP was detected in men (P interaction = 0.021); "emotional support seeking" was associated with lower CRP at the high stress level only (P trend = 0.028). Both perceived stress and coping strategies may be associated with systemic inflammation in Japanese men, yet caution must be exercised before accepting the stress-inflammation-disease pathway.

Temporal Association of Elevated C‐Reactive Protein and Periodontal Disease in Men

Most studies on the relationship between serum C-reactive protein (CRP) and periodontal disease have been cross-sectional. In this study, we investigated the temporal association between CRP and periodontal disease by following a large number of subjects for 1 year. We studied 11,162 men in Nagoya, Japan, who had an initial dental examination as part of a complete physical examination and then underwent the same examination 1 year later. For the 4,997 men without periodontal disease at baseline, logistic regression analysis was performed to examine the relationship between baseline CRP and periodontal disease 1 year later, adjusting for age, body mass index, glycosylated hemoglobin A1c level, and smoking status. Similarly, logistic regression analysis was performed to examine the relationship between periodontal disease at baseline and CRP 1 year later for the 10,376 men with normal baseline CRP, adjusting for the same confounding factors. Among men without high CRP at baseline, periodontal disease at baseline correlated to CRP 1 year later. The odds ratio was 1.336 (95% confidence interval [CI]: 1.115 to 1.674). However, in the men without periodontal disease, no significant correlations were seen with baseline CRP or periodontal disease 1 year later. The odds ratio was 1.163 (95% CI: 0.894 to 1.513). Periodontal disease increased the risk for high serum CRP levels in men after 1 year of follow-up.

Association of C-reactive protein (CRP) gene allelic variants with serum CRP levels and hypertension in Turkish adults

Objective Serum C-reactive protein (CRP) is an independent risk factor for cardiovascular disease and metabolic syndrome (MetS). The aim of this study was to analyze the CRP gene allelic variations in the Turkish adult risk factor (TARF) study and relate them with serum CRP levels as well as MetS and its components. Methods We analyzed CRP gene polymorphisms (−286C > T > A [rs3091244], +1444C > T [rs1130864], +1059G > C [rs1800947], and +1846G > A [rs1205]) as well as their haplotypes, in addition to measuring CRP levels ( n = 1138) and collecting risk factor data from 1987 adults (mean age 54.3 ± 11.9 years, 51.3% women) participating in the TARF Study. MetS was defined by using the criteria of the National Cholesterol Education Program modified for pre-diabetes and in men for abdominal obesity. Results After adjustment for the major cardiovascular risk factors, four CRP SNPs (−286C > T > A, +1059G > C, +1444C > T, and +1846G > A) were significantly associated with serum CRP levels in women ( p < 0.05), whereas the −286C > T > A and +1444C > T polymorphisms were associated with CRP levels in men ( p < 0.05). The haplotype analyses revealed four common CRP haplotypes. The haplotype 1 (CGCA) in women and the haplotype 3 (TGTG) in men were associated with serum CRP levels and hypertension ( p < 0.05). However, no haplotype association was observed for MetS or its components. Conclusion CRP gene allelic variation is associated with serum CRP levels as well as hypertension in Turkish adults.

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.

No Reduction in C-Reactive Protein following a 12-Month Randomized Controlled Trial of Exercise in Men and Women

Low-grade systemic inflammation is suggested to play a role in the development of several chronic diseases including cancer. Higher levels of physical activity and lower adiposity have been associated with reduced levels of markers of systemic inflammation, such as C-reactive protein (CRP); however, reductions in CRP have not been consistently observed in randomized controlled trials of exercise. To examine the effect of a 12-month aerobic exercise intervention on CRP levels in men and women. One hundred two men and 100 women, sedentary and of ages 40 to 75 years, with mean body mass index (BMI) of 29.9 and 28.7 kg/m(2), respectively, were randomly assigned to a 12-month moderate-to-vigorous aerobic exercise intervention (6 d/wk, 60 min/d, 60-85% maximum heart rate) or control group. Fasting blood samples were collected at baseline and at 12 months. CRP levels were measured by high-sensitivity latex-enhanced nephelometry. At baseline, CRP was 1.16 and 2.11 mg/L for men and women, respectively, and CRP was correlated with percent body fat (r = 0.48, P < or =0.001), BMI (r = 0.37, P < or = 0.001), and aerobic fitness (r = -0.49, P < or = 0.001). No intervention effects were observed for CRP in men or women, or when stratified by baseline BMI (<30 versus > or =30 kg/m(2)), baseline CRP (<3 versus > or =3 mg/L), or change in body weight, body composition, or aerobic fitness. A 12-month moderate-to-vigorous aerobic exercise intervention did not affect CRP levels in previously sedentary men or women with average-risk CRP values at baseline.

Association of HIV Infection and HIV/HCV Coinfection With C-Reactive Protein Levels

Inflammation is a potential mechanism to explain the accelerated atherosclerosis observed in HIV- and hepatitis C virus (HCV)-infected persons. We evaluated C-reactive protein (CRP) in HIV-infected and HIV/HCV-coinfected individuals in the era of effective antiretroviral (ARV) therapy. Cross-sectional study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) cohort and controls from the Coronary Artery Risk Development in Young Adults (CARDIA) study. CRP levels were measured in 1135 HIV-infected participants from the FRAM cohort and 281 controls from the CARDIA study. The associations of HIV and HIV/HCV infection with CRP levels were estimated by multivariable linear regression. Compared with controls, HIV monoinfection was associated with an 88% higher CRP level in men (P < 0.0001) but with no difference in women (5%; P = 0.80) in multivariate analysis. CRP levels were not associated with ARV therapy, HIV RNA level, or CD4 cell count. Compared with controls, HIV/HCV coinfection was associated with a 41% lower CRP level in women (P = 0.012) but with no difference in men (+4%; P = 0.90). Among HIV-infected participants, HCV coinfection was associated with 50% lower CRP levels after multivariable analysis (P < 0.0001) in men and women. Greater visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were strongly associated with CRP levels. Among HIV-infected participants, CRP levels were 17% (P < 0.001) and 21% (P = 0.002) higher per doubling of VAT and SAT; among controls, CRP levels were 34% (P < 0.001) and 61% (P = 0.009) higher, respectively. In the absence of HCV coinfection, HIV infection is associated with higher CRP levels in men. HCV coinfection is associated with lower CRP levels in men and women.

Association Between Mobility Mode and C-Reactive Protein Levels in Men With Chronic Spinal Cord Injury

Morse LR, Stolzmann K, Nguyen HP, Jain NB, Zayac C, Gagnon D, Tun CG, Garshick E. Association between mobility mode and C-reactive protein levels in men with chronic spinal cord injury. Objective To assess clinical determinants of systemic inflammation in persons with chronic spinal cord injury (SCI). Design Cross-sectional survey. Setting Veterans Affairs medical center. Participants As part of an epidemiologic study assessing SCI-related health conditions, 63 men with chronic SCI provided a blood sample and information regarding locomotive mode and personal habits. Interventions Not applicable. Main Outcome Measure Plasma high-sensitivity C-reactive protein (CRP). Results The mean ± standard deviation age was 56±14y, and participants were assessed 21±13y after injury. Adjusting for heart disease, hypertension, and body mass index (BMI), the mean CRP in 12 motorized wheelchair users (5.11mg/L) was not significantly greater than 23 participants who used a manual wheelchair (2.19mg/L) ( P=.085) but was significantly greater than the 17 who walked with an assistive device (1.41mg/L) ( P=.005) and the 12 who walked independently (1.63mg/L) ( P=.027). CRP was significantly greater in participants with obesity but was not related to age, smoking, or SCI level and severity. CRP was elevated in participants reporting a urinary tract infection (UTI) or pressure ulcer within a year, but adjustment for this did not account for the elevated CRP in motorized wheelchair users. Conclusions These results suggest that CRP in chronic SCI is independently related to locomotive mode, BMI, and a history of pressure ulcers and UTI. It is suggested that future studies in SCI investigate whether modifying these factors influence systemic inflammation and cardiovascular health.

Body weight and oral contraceptives are the most important modulators of serum CRP levels

Background. C‐reactive protein (CRP) levels are modulated by endogenous and exogenous factors independently of inflammation. The present study investigated the impact of oral contraceptives, endogenous oestrogens, age, gender, smoking, body mass index (BMI) and lipid levels on CRP concentrations in a healthy collective. Methods. Highly sensitive CRP, total cholesterol, HDL‐cholesterol and LDL‐cholesterol levels were measured in 850 blood donors (438 M, 412 F); 227 women in this group used oral contraceptive formulations (OC). Additionally, serum samples from 58 women undergoing in vitro fertilization cycles (IVF) were tested for CRP. Results. The 97.5th percentile of CRP levels of the blood donors was 4.91 mg/L in men, 7.52 mg/L in OC non‐users and 11.95 mg/L in OC users. Overweight gives a 2‐fold increase of median CRP levels in men and women. The combination of overweight and OC use in women resulted in 6‐fold median CRP levels. Age, smoking and lipid levels were influencing factors of lower significance. In IVF patients the elevated oestradiol levels had no influence on CRP concentrations in multivariance analysis. Conclusion. The diagnostic and predictive value of CRP levels is most affected by BMI and oral contraceptive use, which suggests the need for further investigations into the role of CRP modulating factors in monitoring infectious diseases.

Relation of Microalbuminuria to Adiponectin and Augmented C-Reactive Protein Levels in Men With Essential Hypertension

Microalbuminuria, and recently, hypoadiponectinemia, have been associated with progression of atherosclerotic disease and increased cardiovascular risk. We examined the possible associations of urinary albumin excretion, expressed as the ratio of albumin to creatinine (ACR), with plasma adiponectin and high-sensitivity C-reactive protein (hs-CRP) levels in men who had essential hypertension. The study population consisted of 108 men who did not have diabetes and were newly diagnosed with stage I to II essential hypertension (age 44.6 years, office blood pressure 148/95 mm Hg) and 110 men matched according to age and body mass index as controls. According to ACR values, which were determined as the average of 2 nonconsecutive overnight spot urine samples, subjects who had hypertension were categorized into 2 groups: those who had microalbuminuria (n = 28; mean ACR 30 to 300 mg/g) and those who had normal albuminuria (n = 80; mean ACR <30 mg/g). Subjects who had hypertension compared with controls exhibited higher ACR and log hs-CRP levels and a trend toward lower log adiponectin values (p = 0.062), whereas those who had normal albuminuria compared with controls had similar log adiponectin levels but significantly higher levels of ACR and log hs-CRP. Moreover, subjects who had hypertension and microalbuminuria compared with those who had hypertension and normal albuminuria had higher log hs-CRP and lower log adiponectin concentrations independently of confounding factors. Among those who had hypertension, ACR exhibited an independent positive correlation with log hs-CRP and a negative correlation with log adiponectin. Multiple linear regression analysis showed that age, body mass index, systolic blood pressure, log hs-CRP, and log adiponectin were significant independent predictors of the ACR. In conclusion, microalbuminuria is accompanied by decreased adiponectin and increased hs-CRP levels in the setting of essential hypertension, reflecting a rather diffuse atherosclerotic process.

C‐reactive protein is significantly associated with prostate‐specific antigen and metastatic disease in prostate cancer

To further analyse the relationship of c-reactive protein (CRP) levels to prostate cancer, by measuring CRP in men with prostate cancer and benign prostatic hypertrophy (BPH), as chronic inflammation has long been linked to cancers with an infectious cause and CRP is a nonspecific marker for inflammation, associated with prostate cancer incidence and progression. Data from 114 men, most of whom had had radioactive seeds implanted, were evaluated from November 1990 to April 2002. In addition, 27 men were included who had biopsy-confirmed BPH. CRP was assessed with an automated chemiluminometric high-sensitivity assay kit. There was no significant difference in CRP levels in men with localized prostate cancer or BPH but levels were significantly higher in men with bone metastases. There was also a significant correlation of CRP level with prostate-specific antigen (PSA) in those with cancer. Because PSA is correlated with disease stage, multiple linear regression was used with CRP as the dependent variable, and PSA and disease stage as independent variables. The regression was significant overall (P < 0.001) and the effect of disease stage on CRP (P < 0.001) was independent of the effect of PSA level (P = 0.001). The strong association of CRP with PSA, independent of tumour stage, suggests that inflammation might be fundamental in prostate cancer, and that chronic inflammation may be a legitimate target for prostate cancer chemoprevention and treatment.

Age and duration of follow-up as modulators of the risk for ischemic heart disease associated with high plasma C-reactive protein levels in men.

Plasma C-reactive protein (CRP) levels recently have been identified as an emerging risk factor for ischemic heart disease (IHD). However, whether plasma CRP levels predict an increased risk for future IHD beyond traditional risk factors has yet to be evaluated in a large prospective, population-based study. The association between elevated plasma CRP levels and the risk for future IHD was investigated in the prospective, population-based cohort of 2037 IHD-free middle-aged men from the Quebec Cardiovascular Study. During a 5-year follow-up, 105 first IHD events were recorded. Baseline plasma CRP levels were measured using a highly sensitive assay. High plasma CRP concentrations (equal to or above vs below the median level of 1.77 mg/L) were associated with a significant 1.8-fold increase in IHD risk (95% confidence interval [CI], 1.2-2.7). This association remained significant after adjustment for lipid risk factors but not when the simultaneous contribution of nonlipid traditional risk factors was taken into account. Multivariate analyses indicated that CRP level predicted short-term risk for IHD (events that occurred < or =2 years after the baseline evaluation), but not long-term risk (>2 years). Moreover, high plasma CRP levels predicted an increased risk for IHD, independent of any other confounder, in younger (< or =55 years) but not in older (>55 years) individuals. Plasma CRP levels may provide independent information on IHD risk only in younger middle-aged men and in the case of IHD events that may occur relatively soon after the baseline evaluation.

Effects of low-dose aspirin on serum C-reactive protein and thromboxane B2concentrations: a placebo-controlled study using a highly sensitive C-reactive protein assay

OBJECTIVESWe performed a placebo-controlled study to evaluate the effect of low-dose aspirin on serum C-reactive protein (CRP) levels.BACKGROUNDElevated circulating concentrations of CRP, an inflammatory marker, increase the risk of thrombotic cardiovascular diseases such as myocardial infarction (MI). Moreover, low-dose aspirin therapy has been reported to be more effective in preventing MI in men with higher CRP levels than it is in those with lower levels, raising the possibility that aspirin prevents thrombosis by reducing vascular inflammation. The effect of low-dose aspirin therapy on serum CRP levels in men has been addressed recently, but the results of the two studies conflict.METHODSEffects of aspirin (81 mg every day or 325, 81 or 40 mg every-third-day given for 31 days) on serum CRP, using a highly-sensitive assay, and on serum platelet-cyclo-oxygenase (COX)-1-derived thromboxane (Tx) B2concentrations were studied simultaneously in 57 healthy volunteers (30 men and 27 women).RESULTSTrough platelet COX-1-derived serum Tx B2concentrations decreased by 100% with daily aspirin and by 90%, 84% and 78% with 325, 81 and 40 mg aspirin every-third-day (p < 0.001). However, there were no significant changes in serum CRP levels from baseline with daily low-dose aspirin therapy, with any of the every-third-day aspirin regimens or with placebo treatment.CONCLUSIONSLow doses of aspirin that markedly inhibit platelet COX-1 activity, as manifested by a profound decline in platelet-derived serum Tx B2concentrations, have no detectable effect on serum CRP levels in healthy men and women.