The relation between C reactive protein and age related macular degeneration in the Cardiovascular Health Study.

AIM: To test the hypothesis that individuals with age related macular degeneration (AMD) have increased C reactive protein (CRP) levels.
METHODS: A cross sectional study design using data from the Cardiovascular Health Study (CHS), a longitudinal study that enrolled older adults from four communities in the United States from 1989 to 1990, was employed to investigate the existence of an association between AMD and CRP levels in this population. Fundus photographs from 1997 and 1998 were used to identify individuals with (n=390) and without AMD (n=2365). The association between AMD and CRP levels (measured at baseline) was compared, adjusting for the potentially confounding effect of demographic, lifestyle, and health related characteristics.
RESULTS: Among the 2755 CHS participants with gradable fundus photographs, 390 were identified as having AMD. Overall, median CRP levels among those with AMD (1.76 mg/l) were similar to those without AMD (1.77 mg/l). CRP levels were categorised into quartiles and compared between those with and without AMD. Relative to those in the lowest quartile (0.07-0.93 mg/l), the odds ratios (OR) in the higher quartiles, adjusted for demographic, lifestyle, and health related characteristics were increased but not statistically significant (0.94-1.77 mg/l: OR=1.14, 95% CI 0.82 to 1.60; 1.78-3.04 mg/l: OR=1.24, 95% CI 0.88 to 1.75; >3.04 mg/l: OR=1.24, 95% CI 0.87 to 1.78).
CONCLUSIONS: In the CHS, there is no evidence that CRP levels are associated with AMD. These data do not support the theory alleging non-specific systemic inflammation in the aetiology and natural history of this disease.