Association of insulin resistance with visual decline in older individuals without diabetes: a cross-sectional mediation analysis

TL;DR

This study found that visual decline in older women without diabetes is linked to insulin resistance, partly explained by body fat.

Contribution

The novel finding is the mediation of visual decline and insulin resistance through body fat in non-diabetic older women.

Findings

Visual decline correlated with insulin resistance in women without diabetes after adjusting for covariates.

Body fat mass and body fat percentage partially mediated the relationship between visual decline and insulin resistance.

Abstract

It remains unknown how visual decline affects insulin resistance in individuals without diabetes. Therefore, we investigated the association between visual impairment and insulin resistance in older individuals without diabetes.

Data from the Kyotango Longevity Cohort Study, a prospective investigation encompassing adults aged 65 years and above, were included. The study protocol was approved by the Ethics Committee of the Kyoto Prefectural University of Medicine (ERB-C-885). Visual acuity and insulin resistance were assessed using logarithmic minimum angle of resolution (logMAR) and homeostasis model assessment ratio (HOMA-R), respectively. The correlation between logMAR and HOMA-R was examined using Spearman’s rank correlation coefficient and multiple regression analysis. Causal mediation analysis was performed with body composition as a mediating factor.

In total, 797 participants were enrolled. Mean age was 74.8 ± 6.6 years in men and 73.4 ± 5.6 in women. logMAR and HOMA-R were correlated in women without diabetes after adjustment for covariates (β = 0.166, P = 0.0002). Causal mediation analysis revealed that body fat mass (proportion mediated: 0.567, 95% CI: 0.058–0.938) and body fat percentage (proportion mediated: 0.685, 95% CI: 0.250–1.027) significantly mediated the relationship between logMAR and HOMA-R in women.

Vision decline was associated with insulin resistance, with body fat statistically accounting for part of this association.

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