A higher dietary inflammatory index is associated with increased risk of age-related eye diseases

Abstract

Purpose : Inflammation is involved in the pathogenesis of cataract, age-related macular degeneration (AMD), and possibly open-angle glaucoma (OAG). We aimed to replicate the previously found adverse association between the dietary inflammatory index (DII) and cataract. Moreover, we assessed whether the DII was also associated with AMD and OAG. Serum inflammation markers were investigated as possible mediators.

Methods : Participants aged >45 years were derived from the prospective, population-based Rotterdam Study. From 1991 onwards, every 4-5 years, participants underwent extensive eye examinations. At baseline, serum samples and dietary data were collected. A total of 7436 participants were included in the analyses; 4036 developed incident eye diseases (cataract=2895, early-intermediate AMD=891, late AMD=81, OAG=169). Additionally, 3084 participants showed preliminary signs of AMD. We used multivariable logistic regression, adjusting for age, sex, body mass index, energy intake, follow-up time, lifestyle, and comorbidities. Mediation analyses were performed using mediation package in R.

Results : A higher DII was significantly associated with increased inflammation. A higher neutrophil-lymphocyte ratio (NLR) was associated with an increased risk of cataract and AMD. Additionally, complement component 3c (C3c) and systemic immune-inflammation index (SII) were associated with increased risks of cataract and late AMD, respectively. Every point increase in the DII was associated with a 9% increased risk of cataract (Odds ratio [95% confidence interval]: 1.09 [1.04-1.14]). The NLR and C3c mediated 7.5% and 4.8% of this association. We also identified associations of the DII with risks of AMD (preliminary AMD, OR [95% CI]: 1.02 [0.97-1.07]; early-intermediate AMD, OR [95% CI]: 1.11 [1.03-1.19]; late AMD, OR [95% CI]: 1.24 [1.02-1.53]). The NLR and SII mediated 10.2% and 7.7% of the association between the DII and late AMD. The DII was not associated with OAG.

Conclusions : In this study, we confirmed the unfavorable association between the DII and cataract. More importantly, we found an association between the DII and risk of AMD. Especially markers that mirror the balance between acute- and chronic inflammation and the adaptive immune system seem to be involved. These findings are relevant for patients with AMD and substantiate the current recommendations to strive for a healthy lifestyle to prevent blindness.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.