Cigarette Smoking, Fish Consumption, Omega-3 Fatty Acid Intake, and Associations With Age-Related Macular Degeneration

Abstract

To evaluate modifiable risk and protective factors for age-related macular degeneration (AMD) among elderly twins. Methods:The US Twin Study of Age-Related Macular Degeneration comprises elderly male twins from the National Academy of Sciences-National Research Council World War II Veteran Twin Registry. To determine genetic and environmental risk factors for AMD, twins were surveyed for a prior diagnosis of AMD and underwent an eye examination, fundus photography, and food frequency and risk factor questionnaires. This environmental component of the study includes 681 twins: 222 twins with AMD (intermediate or late stages) and 459 twins with no maculopathy or early signs. Risk for AMD according to cigarette smoking and dietary fat intake was estimated using logistic regression analyses.Results: Current smokers had a 1.9-fold increased risk (95% confidence interval, 0.99-3.68, P=.06) of AMD while past smokers had about a 1.7-fold increased risk (95% confidence interval, 1.2-2.6, P =.009). Increased intake of fish reduced risk of AMD, particularly for 2 or more servings per week (P trend=.04). Dietary omega-3 fatty intake was inversely associated with AMD (odds ratio, 0.55; 95% confidence interval, 0.32-0.95) comparing the highest vs lowest quartile. Reduction in risk of AMD with higher intake of omega-3 fatty acids was seen primarily among subjects with low levels (below median) of linoleic acid intake, an omega-6 fatty acid (P trendϽ.001). The attributable risk percentage was 32% for smoking and the preventive fraction was 22% for higher omega-3 intake.Conclusions: This study of twins provides further evidence that cigarette smoking increases risk while fish consumption and omega-3 fatty acid intake reduce risk of AMD.

Reconsidering the connection between vitamin D levels and age-related macular degeneration

“…8,9,49,50 This cross-sectional study found that higher vitamin D levels are not associated with decreased prevalence of AMD, as expected by the above evidence.…”

The marine n-3 PUFA DHA evokes cytoprotection against oxidative stress and protein misfolding by inducing autophagy and NFE2L2 in human retinal pigment epithelial cells

“…13 The AREDS study demonstrated that daily supplementation with antioxidant reduced the risk of developing advanced AMD by 25% at 5 y. Epidemiological studies have suggested a protective role of n-3 PUFAs for developing AMD. [37][38][39][40][41][42][95][96][97] Also, subgroup analysis from the Nutritional AMD Treatment 2 Study from 2013, revealed that high levels of n-3 PUFAs in red blood cells can prevent AMD progression. 98 To assess if antioxidants and n-3 PUFAs could induce additive effects, a second AREDS2 study was designed to evaluate if inclusion of n-3 PUFAs to the AREDS formulation further reduced the risk of progression to advanced AMD.…”

“…35,36 Epidemiological studies indicate an inverse correlation between dietary intake of fish and the risk of developing AMD. [37][38][39][40][41][42] The disease preventive effects of increased fish intake have been associated with the content of marine omega-3 polyunsaturated fatty acids (n-3 PUFAs). 43 Deficiency of n-3 PUFAs in photoreceptors is associated with the development of AMD.…”

Vascular endothelial growth factor in eye disease

“…18D). In addition to inflammatory stressors, smoking, an environmental factor shown to greatly increase risk of AMD (Seddon et al, 2006a;Seddon et al, 1996), has been reported to increase serum levels of activated complement factors C3 and B (Robbins et al, 1991;Chao et al, 1982). Thus, stimuli that cause complement accumulation and activation conceivably may stress a system that is not regulated efficiently or effectively and increase the risk of neovascular AMD formation through upregulation of VEGF.…”