C-reactive protein concentration and risk of selected obesity-related cancers in the Women's Health Initiative.

Background: Obesity is a chronic inflammatory condition strongly associated with the risk of numerous cancers. We examined the association between circulating high-sensitivity C-reactive protein (hsCRP), a biomarker of inflammation and strong correlate of obesity, and the risk of three understudied obesity-related cancers in postmenopausal women: ovarian cancer, kidney cancer, and multiple myeloma.
Methods: Participants were 24,205 postmenopausal women who had measurements of baseline serum hsCRP (mg/L) in the Women's Health Initiative (WHI) CVD Biomarkers Cohort, a collection of four sub-studies within the WHI. Incident cancers were identified over 17.9 years of follow-up (n = 153 ovarian, n = 110 kidney, n = 137 multiple myeloma). hsCRP was categorized into study-specific quartiles. Adjusted Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations of baseline hsCRP with the risk of these cancers.
Results: There was no clear association between baseline hsCRP concentration and the risk of ovarian cancer (quartile 4 vs. 1: HR 0.87, 95% CI 0.56-1.37), kidney cancer (HR 0.95, 95% CI 0.56-1.61), or multiple myeloma (HR 0.82, 95% CI 0.52-1.29). HRs for 1 mg/L increases in hsCRP also approximated the null value for each cancer.
Conclusions: The results of this study suggest that elevated CRP is not a major risk factor for these obesity-related cancers (ovarian or kidney cancers, or multiple myeloma) among postmenopausal women. Given the importance of elucidating the mechanisms underlying the association of obesity with cancer risk, further analysis with expanded biomarkers and in larger or pooled prospective cohorts is warranted.