Abstrak: C-reactive protein (CRP) is a well-known biomarker of systemic inflammation and cardiovascular disease. We investigated the trends in prevalence of elevated CRP levels (>3.0 mg/L) in a general population of US adults. Data from 27,214 subjects aged ≥20 years in the 1999-2010 National Health and Nutrition Examination Survey were analyzed. After adjustment for age, sex, race/ethnicity, body mass index (weight (kg)/height (m)(2)), and medications for lowering blood pressure, glucose, and lipids, the prevalence of elevated CRP decreased significantly from 36.7% in 1999-2002 to 32.0% in 2007-2010, corresponding to a decrease in mean CRP level from 1.92 to 1.66 mg/L (both P < 0.001). The trend remained significant after additional adjustment for several traditional cardiovascular risk factors and use of different medications, including statins. However, the decreasing trends were attenuated after additional adjustment for total bilirubin (P = 0.08 and 0.02), which increased from 0.62 to 0.73 mg/dL over 12 years (P < 0.001). The decreasing trend of CRP levels is encouraging and may be related to the increase in total bilirubin levels. Such trends may be explained in part by the increasing use of medications such as statins, which can increase bilirubin levels and decrease CRP levels.

Abstrak: In this study, we examined the relationship between exposure to siblings and 1) the risk of age-related macular degeneration (AMD) and 2) C-reactive protein levels. We retrospectively analyzed pooled cross-sectional data from 2 studies: the Cardiovascular Health and Age-Related Maculopathy Study (2001-2002) and the Age-Related Maculopathy Statin Study (2004-2006). Associations between number of siblings and AMD were assessed by using multinomial logistic regression. Associations between number of siblings and C-reactive protein levels were examined by using a generalized linear model for γ distribution. A higher number of younger siblings was associated with significantly lower odds of early AMD in those with a family history of AMD (odds ratio = 0.2, 95% confidence interval: 0.1, 0.8) (P = 0.022) but was unrelated to AMD for those who had no family history of the disease (odds ratio = 1.0, 95% confidence interval: 0.9, 1.2) (P = 0.874). A higher number of younger siblings correlated with lower C-reactive protein levels (β = -0.19, 95% confidence interval: -0.38, -0.01) (P = 0.036). This supports the theory that immune modulation contributes to AMD pathogenesis and suggests that exposure to younger siblings might be protective when there is a family history of AMD.