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Eric H. Souied, Cécile Delcourt, Nathalie Puche, Giuseppe Querques, Alain Zourdani, Pascale Benlian, NAT2 study group; The NAT-2 Study: genetic analysis. Invest. Ophthalmol. Vis. Sci. 2012;53(14):2934.
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The NAT-2 (Nutritional AMD treatment-2) study was a randomized, placebo-controlled, double-blind, parallel, comparative study. The purpose of NAT-2 was to evaluate the efficacy of oral docosahexaenoic acid (DHA) supplementation for preventing exudative age-related macular degeneration (AMD). The purpose of this ancillary study was to correlate the effects of DHA supplementation with genetic background.
263 patients (Full Analysis Set) aged ≥55 and <85 years with early lesions of age-related maculopathy and visual acuity ≥+0.4 LogMAR units in the study eye and neovascular AMD in the fellow-eye. Patients were randomly assigned to receive either 840 mg/day DHA from fish oil capsules or the placebo (olive oil capsules) for 3 years. The primary outcome measure was time to occurrence of choroidal neovascularization (CNV) in the study eye. Secondary outcome measures in the study eye were: percentage of patients developing CNV and changes in visual acuity, occurrence and progression of drusen, and EPA+DHA concentration changes in red blood cell membrane (RBCM). The rs1061170 polymorphism of CFH gene and the rs10490924 polymorphism of the ARMS2 gene were analyzed.
Time to occurrence and incidence of CNV in the study eye were not significantly different between the DHA (19.5 ± 10.9 months, 28.4%, respectively) and placebo groups (18.7 ± 10.6 months, 25.6%, respectively). EPA+DHA concentration significantly increased in RBCM in the DHA group (+70%; p<0.001), suggesting a good ability of DHA to penetrate cells, but unexpectedly in the placebo group also (+9%; p=0.007). In the DHA treated group, high DHA responders (third tertile for EPA+DHA concentrations in RBCM) had a significantly lower risk (-70%; p=0.047) for developing CNV over 3 years. A significant effect of DHA was observed in patients without CFH at-risk allele. In this population without CFH at-risk allele, CNV occurred in 4/24 (16.7%) patients in the DHA group versus 13/34 (38.2%) in the placebo group (OR= 0.2, 95 % confidence interval [0.1-0.9]; p=0.034). No differences were found with the ARMS2 polymorphism.
Oral DHA had the same effect on 3-year CNV incidence as placebo. However, CNV incidence appeared markedly reduced in DHA supplemented patients with the highest EPA+DHA index. A significant effect of DHA was observed in patients without CFH at risk allele.
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