Weighing in on link between BMI and retinal structural changes

A group of Chinese investigators, led by lead authors Qiong Ding, MD, and Huimin Wu, MD, found that obesity affects retinal structures in different ways depending on whether the obesity is generalized or abdominal.¹

Dr. Ding is from the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China, and Dr. Wu is affiliated with the Shenzhen Children’s Hospital, Shenzhen, Guangdong, China.

In this cross-sectional study, the authors used optical coherence tomography angiography (OCTA) to identify possible associations between body mass index (BMI) and the waist-to-hip ratio (WHR) with macular vessel density and foveal avascular zone in healthy Chinese adults.

A total of 1,555 Chinese adults age 50 years or older were recruited for the study from communities in Guangzhou, China. The participants had no history of ocular disease. All underwent OCTA performed with a 6-x-6-mm macular angiography model.

The investigators used the images to calculate the foveal avascular zone of the superficial capillary plexus and the vessel density of the superficial capillary plexus and deep capillary plexus. The analyses determined the effect of the BMI and WHR on the vessel density and foveal avascular zone.

Effects of obesity

The investigators reported that the vessel density of the superficial capillary plexus increased with increases in the BMI; the average measurements were 39.30±2.14 for normal weight, 39.52±2.07 for overweight, and 39.76±2.03 for obesity (p = 0.001). Likewise, the vessel density of the deep capillary plexus also increased with increases in the BMI (p = 0.009).

A positive association was found between generalized obesity and the superficial vessel density in the entire image (β = 0.350, p = 0.008), the inner circle (β=0.431, p=0.032), and the outer circle (β = 0.368, p = 0.005).

After adjusting for confounders, tertile 3 of the WHR level was positively associated with the superficial vessel density (β = 0.472, p = 0.033) and deep vessel density (β = 0.422, p = 0.034) in the inner circle, they reported.

The study concluded that generalized obesity and increased superficial vessel density are associated, and abdominal obesity and increased superficial and deep vessel density are associated only in the inner circle. This indicates that different manifestations of the retinal microvasculature may reflect distinct roles of body composition on macular vessel changes and disease occurrence.

Reference

Ding Q, Wu H, Wang W, et al. Association of body mass index and waist-to-hip ratio with retinal microvasculature in healthy Chinese Adults: An OCTA Study. Am J Ophthalmol. Published online October 11, 2022; DOI: https://doi.org/10.1016/j.ajo.2022.09.012