Association of Dietary Fatty Acid Intake With Glaucoma in the United States

Abstract

Importance: Identifying whether an association exists between daily dietary polyunsaturated fatty acid (PUFA) consumption and the prevalence of glaucoma in the United States may provide modifiable dietary risk factors for the development of glaucoma.

Objective: To analyze the association between glaucoma and daily dietary intake of PUFAs, including ω-3 fatty acids, in the US population.

Design, setting, and participants: Data from 3865 participants in the National Health and Nutrition Examination Survey (NHANES) 2005-2008 database who were 40 years or older, had participated in the vision health and dietary intake questionnaires, and had available results from laboratory tests and eye examinations that included frequency-doubling technology visual field loss detection tests and optic disc photographs were included. Data collection was performed by NHANES from 2005 to 2006. Data for the present study were downloaded from their database May 1 to 30, 2017. Data analyses were performed from June 1 to October 1, 2017.

Exposures: Daily dietary intake of PUFAs, including ω-3 fatty acids.

Main outcomes and measures: Prevalence of glaucoma in the United States as defined using the Rotterdam criteria, which included a combination of optic cupping or asymmetry and visual field defect results.

Results: Of the 83 643 392 weighted survey participants included in this cross-sectional study, 43 660 327 (52.2%) were women and 3 076 410 (3.7%) met our criteria for having glaucoma. Compared with participants without glaucoma, those with glaucoma were older (mean [SE] age, 61.4 [0.8] vs 53.7 [0.4] years; P < .001). Increased levels of daily dietary intake of eicosapentaenoic acid (odds ratio [OR], 0.06; 95% CI, 0.00-0.73) and docosahexaenoic acid (OR, 0.06; 95% CI, 0.01-0.87) were associated with significantly lower odds of having glaucoma. However, participants with daily total dietary PUFA intake levels in the second (OR, 2.84; 95% CI, 1.39-5.79) and third (OR, 2.97; 95% CI, 1.08-8.15) quartiles showed significantly increased odds of meeting our criteria for a diagnosis of glaucoma.

Conclusions and relevance: Increased daily dietary consumption levels of eicosapentaenoic acid and docosahexaenoic acid were associated with lower likelihood of glaucomatous optic neuropathy. However, consumption levels of total PUFAs in the higher quartiles were associated with a higher risk of glaucoma, which may have resulted from the relative intakes of ω-6 and ω-3 fatty acids and other confounding comorbidities. This study also hypothesizes that increasing the proportion of dietary ω-3 consumption levels while controlling overall daily PUFA intake may be protective against glaucoma. However, longitudinal studies or randomized clinical trials are needed to assess these hypotheses.

Figure.. Chemical Structures of ω-3 Fatty Acids α-Linolenic Acid, Eicosapentaenoic Acid, and Docosahexaenoic Acid

A, α-Linolenic acid (18:3 ω-3) is a carboxylic acid with an 18-carbon (indicated as numbers below the structure) chain and 3 cis double bonds. B, Eicosapentaenoic acid (20:5 ω-3) is a carboxylic acid with a 20-carbon chain and 5 cis double bonds. C, Docosahexaenoic acid (22:6 ω-3) is a carboxylic acid with a 22-carbon chain and 6 cis double bonds. For all 3 structures, the first double bond is located at the third carbon (indicated by the numbers above the structures) from the ω end of the fatty acid chain.