Retinal Microvasculature Changes With Patient Body Mass Index, Waist-to-Hip Ratio

General obesity can increase superficial macular vessel density, and abdominal obesity in particular can increase superficial and deep vessel density in the inner circle.

Generalized obesity is associated with increased superficial vessel density (VD), while abdominal obesity specifically is associated with increased superficial and deep VD, but only in the inner circle, according to findings of an optical coherence tomography angiography (OCT-A)-based study published in the American Journal of Ophthalmology.

Researchers conducted a cross-sectional study to investigate the association of body mass index (BMI) and waist to hip ratio (WHR) with macular VD and foveal avascular zone (FAZ) in healthy Chinese adults using OCT-A. 

The study included 1555 Chinese adults aged 50 years of older who had no history of ocular disease. Investigative methods included performance of OCT-A with 6×6 mm macular angiography model, and a calculation of FAZ of the superficial capillary plexus (SCP), and VD of SCP and deep capillary plexus (DCP). The researchers used univariable and multivariable linear regression analyses to evaluate the effect of BMI and WHR on VD and FAZ.

The researchers found that VD of the SCP increases along with increases in BMI, with average measurements of 39.30±2.14 for normal, 39.52±2.07 for overweight, and 39.76±2.03 for obesity (P =.001). There was also an increase observed in the VD of the DCP as BMI increased (P =.009). A positive association between generalized obesity and superficial VD in the whole image (β=0.350, P =.008), the inner circle (β=0.431, P =.032), and the outer circle (β=0.368, P =.005) was identified by multiple regression models. Tertile 3 of the WHR level was positively associated with superficial VD (β=0.472, P =.033) and deep VD (β=0.422, P =.034) only in the inner circle, after adjusting for confounders.

Studies on the effects of generalized and abdominal obesity on retinal microcirculation may help reveal the potential mechanism behind the effects of obesity on the occurrence of systemic and ocular vascular diseases.

The researchers explain that this study identified a stronger BMI/VD association in the SCP than in the DCP, and that overall, new information was identified by the study regarding these relationships.

“Our findings confirmed the close association between obesity and retinal microcirculation,” the study authors explain. “Studies on the effects of generalized and abdominal obesity on retinal microcirculation may help reveal the potential mechanism behind the effects of obesity on the occurrence of systemic and ocular vascular diseases.”

Study limitations include possible confounding of the causal relationship between the OCT-A index and obesity due to the cross sectional design; possible confounding of VD accuracy measurements due to the OCT-A device’s system resolution; and limited generalizability of the results to populations outside of China.

References:

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:10.1016/j.ajo.2022.09.012