Association of Dietary Nitrate and a Mediterranean Diet With Age-Related Macular Degeneration Among US Adults

ImportanceLow dietary nitrate intake has previously been suggested to be a risk factor for age-related macular degeneration (AMD) progression; however, this finding has not been replicated in other cohorts or adjusted for dietary patterns.ObjectiveTo determine whether there is an association between dietary nitrate intake and AMD progression.Design, Setting, and ParticipantsThis cohort study analyzed data from the prospective Age-Related Eye Disease Study (AREDS) and AREDS2 randomized clinical trial cohorts and their extended follow-up studies, which were conducted in multicenter outpatient retinal practices. Participants in both trials had non–late AMD in at least 1 eye. Data were analyzed from March 1, 2020, to September 30, 2022.ExposureDietary nitrate intake.Main Outcomes and MeasuresAssociation between dietary nitrate intake and development of late AMD (neovascular AMD [nAMD] or geographic atrophy [GA]) or large drusen. The interactions of dietary patterns, with common at-risk single-nucleotide polymorphisms, were also assessed.ResultsIn the combined AREDS/AREDS2 cohort of 7788 participants (4288 AREDS participants and 3610 AREDS2 participants [110 of whom participated in both studies]), there were 13 511 eligible eyes. The combined cohort comprised 4396 women (56%) and 3392 men (44%), and the combined mean (SD) age was 71.1 (6.6) years. Dietary nitrate intake was associated with a decreased risk of progression to late AMD in the combined AREDS/AREDS2 cohort (hazard ratio [HR], 0.77 [95% CI, 0.69-0.86] for quartile 4 vs quartile 1 of intake) and a decreased risk of GA (HR, 0.71 [95% CI, 0.61-0.83]) and nAMD (HR, 0.85 [95% CI, 0.73-0.99]). In AREDS, increased nitrate intake (quartile 4 vs quartile 1) was associated with a decreased risk of late AMD (HR, 0.77 [95% CI, 0.65-0.91]) and GA (HR, 0.80 [95% CI, 0.65-0.97]) but not nAMD; in AREDS2, there was no association between nitrate intake (quartile 4 vs quartile 1) and late AMD (HR, 0.90 [95% CI, 0.80-1.02]) or nAMD (HR, 0.93 [95% CI, 0.78-1.11]). There was a correlation between Mediterranean dietary patterns and dietary nitrate intake (r = 0.52, P &amp;amp;lt; .001).Conclusions and RelevanceThe findings of this cohort study suggest that dietary nitrate intake was associated with lower AMD risk. However, this association disappeared after adjusting for Mediterranean dietary patterns. These results are subject to potential bias and are hypothesis-generating in nature; therefore, they are insufficient to support new clinical recommendations. Previously described associations between dietary nitrate intake and AMD may in fact represent overall dietary patterns. Further research is needed before dietary nitrate intake can be recommended as a therapy for AMD.</jats:sec

Variant Interpretation for Dilated Cardiomyopathy

Background: The hypothesis of the Dilated Cardiomyopathy Precision Medicine Study is that most dilated cardiomyopathy has a genetic basis. The study returns results to probands and, when indicated, to relatives. While both the American College of Medical Genetics and Genomics/Association for Molecular Pathology and ClinGen’s MYH7 -cardiomyopathy specifications provide relevant guidance for variant interpretation, further gene- and disease-specific considerations were required for dilated cardiomyopathy. To this end, we tailored the ClinGen MYH7 -cardiomyopathy variant interpretation framework; the specifications implemented for the study are presented here. Methods: Modifications were created and approved by an external Variant Adjudication Oversight Committee. After a pilot using 81 probands, further adjustments were made, resulting in 27 criteria (9 modifications of the ClinGen MYH7 framework and reintroduction of 2 American College of Medical Genetics and Genomics/Association of Molecular Pathology criteria that were deemed not applicable by the ClinGen MYH7 working group). Results: These criteria were applied to 2059 variants in a test set of 97 probands. Variants were classified as benign (n=1702), likely benign (n=33), uncertain significance (n=71), likely pathogenic (likely pathogenic; n=12), and pathogenic (P; n=3). Only 2/15 likely pathogenic/P variants were identified in Non-Hispanic African ancestry probands. Conclusions: We tailored the ClinGen MYH7 criteria for our study. Our preliminary data show that 15/97 (15.5%) probands have likely pathogenic/P variants, most of which were identified in probands of Non-Hispanic European ancestry. We anticipate continued evolution of our approach, one that will be informed by new insights on variant interpretation and a greater understanding of the genetic architecture of dilated cardiomyopathy. Clinical Trial Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03037632 </jats:sec