These associations remained statistically significant after adjusting for age, body mass index (BMI), comorbid conditions, and lifestyle factors. A multistage stratified design was used to recruit a random sample of 2,301 racially and ethnically diverse men age 30–79 years. Low-grade inflammation may be involved in the pathogenesis of subjective symptoms of androgen deficiency in ageing men. Over half of the analysis sample reported use of anti-inflammatory or other medications that could affect CRP levels. Analyses were conducted on a sample of 1,559 men with complete data on sex hormones and CRP. Serum testosterone (T) and sex hormone-binding globulin (SHBG) levels were measured by competitive electrochemiluminescence immunoassays on the 2010 Elecsys system (Roche Diagnostics, Indianapolis, IN). A robust, inverse dose-response correlation between testosterone and SHBG levels with CRP levels provides further evidence of a potential role of androgens in inflammatory processes. The association between CRP and sex hormone levels was assessed using multiple linear regression models. However, CRP is known to be unspecific, and the use of other inflammatory markers such as IL-6 might provide a more precise estimate of inflammation (3, 36). In our study, questionnaires on clinical symptoms were included only at the second visit. Another limitation of the study is the possibility of evaluation of body composition with radiological techniques that could have given a more precise estimation of abdominal obesity. According to the European Urology Association guidelines on testosterone measurement, both immuno-assay and mass spectrometry, providing a reference range for normal men, would be applicable with reliable results (6). Scatter plots of Log10 transformed C-reactive protein levels by Log10 transformed sex hormone levels with LOESS curve Additional covariates did not further attenuate the observed association. These observed associations were robust and remained statistically significant in multivariate models. Table 3 presents crude and adjusted correlations between sex-hormones and CRP levels. Of the 1,559 men included in the analysis, 87 (5.6%) had missing data on one or more covariates. As results for T and SHBG were similar when conducted on the larger group of men with these measures available compared to the subgroup of men with complete data on all hormones and CRP, results are presented for the subgroup of 1,559 men. A total of 12 men with missing or extreme values for T and SHBG were excluded from the analysis. Of the 2,301 men in BACH, blood samples were obtained for 1,899 (82.5%). Similar to their findings, we observed a substantial change in the estimates when WHR or BMI was added to the models. Linear regression analyses were computed and two theoretical models were built. Association between C-reactive protein and calculated bioavailable testosterone.
