Association of central obesity with retinal neurodegeneration: Cross-sectional and longitudinal evidence from two countries

Objective: This study aimed to evaluate the association of central obesity with retinal neurodegeneration. Methods: Databases from the UK Biobank study and the Chinese Ocular Imaging Project (COIP) were included for cross-sectional and longitudinal analyses, respectively. Retinal ganglion cell-inner plexiform layer thickness (GCIPLT) measured by optical coherence tomography (OCT) was used as a retinal indicator of neurodegeneration. All subjects were divided into six obesity phenotypes according to BMI (normal, overweight, obesity) and waist to hip ratio (WHR; normal, high). Multivariable linear regression models were fitted to investigate the association of obesity phenotypes with GCIPLT. Results: A total of 22,827 and 2082 individuals from UK Biobank (mean age: 55.06 [SD 8.27] years, women: 53.2%) and COIP (mean age: 63.02 [SD 8.35 years], women: 61.9%) were included, respectively. Cross-sectional analysis showed GCIPLT was significantly thinner in normal BMI/high WHR individuals compared with normal BMI/normal WHR individuals (β = −0.33 μm, 95% CI = −0.61, −0.04, p = 0.045). But thinner GCIPLT was not observed in individuals with obesity/normal WHR. After 2-year follow-up in COIP, normal BMI/high WHR was associated with accelerated GCIPLT thinning (β = −0.28 μm/y, 95% CI = −0.45, −0.10, p = 0.02), whereas obesity/normal WHR was not. Conclusions: Even with normal weight, central obesity was associated with accelerated GCIPLT thinning cross-sectionally and longitudinally.