Environmental cadmium and lead exposures and age-related macular degeneration in US adults: the National Health and Nutrition Exam Survey, 2005 to 2008

摘要

Background: Age-related macular degeneration (AMD) is the leading cause of blindness in the US. It is a complex disease resulting from the interplay of genetic predisposition and environmental exposures, and has been linked to oxidative stress and inflammatory mechanisms. Lead and cadmium can accumulate in human retinal tissues and may damage the retina through oxidative stress, and may thereby play a role in the development of AMD. Aim: To examine the associations of cadmium and lead with AMD in US adults. Methods: We analyzed data from 5,390 participants aged 40 years and older from two cycles of the National Health and Nutrition Examination Survey from 2005 to 2008. Retinal photographs were graded with a modification of the Wisconsin Age-Related Maculopathy Grading System to identify signs of any AMD including both early and late AMD. Results: The weighted prevalence of AMD was 6.6% (n=426) and the geometric mean blood lead, blood cadmium, and urinary cadmium levels were 1.65 (95% confidence interval (CI), 1.60-1.71) μg/dL, 0.41 (0.39-0.42) μg/L, and 0.29 (0.27-0.31) μg/L, respectively. After controlling for age (linear and quadratic), gender, race/ethnicity, education and body mass index (＜25, 25-29.9, 30+ kg/m2), those in the highest blood cadmium quartile had a higher odds of AMD compared to the lowest quartile (odds ratio (OR)=1.56, 95% confidence interval (CI): 1.02, 2.40), with a significant trend across quartiles (p for trend=0.02). After further adjustment for pack-years of cigarette smoking, these estimates were somewhat attenuated (OR=1.43; 95% CI: 0.91, 2.27; p for trend=0.08). There was a suggestive association between urinary cadmium and AMD (OR comparing the highest with the lowest quartiles of urinary cadmium=2.18; 95% CI: 0.70, 6.83; P for trend=0.09). We found no association between blood lead and AMD. Conclusion: Higher cadmium body burden may increase risk of AMD. Additional studies are needed to confirm the association between cadmium and AMD.