Association between late age-related macular degeneration and dietary intake of copper, iron, zinc and selenium: a 2005-2008 NHANES cross-sectional observational study.

BACKGROUND

Age-related macular degeneration (AMD) is a significant global cause of visual impairment. Our study seeks to explore the relationship between the intake of copper, iron, zinc, selenium in diet and late AMD.

METHOD

In this cross-sectional study, we utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted during 2005-2008. We employed three logistic regression models with or without adjustments to examine the association between dietary copper, iron, zinc, selenium and late AMD.

RESULT

Our study involved 4996 individuals aged 40 years and above with graded fundus pictures and dietary trace element intake data from a representative sample. The levels of copper intake were linked to a reduced risk of late AMD, resulting in odds ratios (OR) of 0.24 (95% confidence interval [CI] = 0.13-0.46), 0.38 (95% CI = 0.16-0.90), and 0.37 (95% CI = 0.17-0.82) for crude model 1, adjusted model 2, and adjusted model 3 respectively. The intake levels of dietary iron, zinc and selenium showed an inverse correlation with the prevalence of late AMD in the crude model; ORs (95% CI) were as follows: Iron - 0.92 (0.86, 0.97); Zinc- 0.88 (0.81, 0.96); Selenium- 0.98 (0.97, 0.99). However, in model 2 and 3, no significant association was observed between these three elements and late AMD. In subgroup analysis divided by age, there was only a significant inverse correlation observed between late AMD and copper intake in 70-85 years of age group.

CONCLUSION

Our findings suggest a higher dietary copper intake may be associated with a reduced risk of late AMD, with the protective effect remaining significant among individuals aged 70-85 years. While no significant association was identified between dietary intake of iron, zinc, selenium and AMD after adjusting for confounding factors. Further research is warranted to elucidate the mechanism underlying the relationship.