Retinal Vessel Abnormalities as a Possible Biomarker of Brain Volume Loss in Obese Adolescents

OBJECTIVE: Endothelial dysfunction in childhood obesity may precede cerebrovascular damage and cognitive impairment in adulthood. Identifying risk for microvascular damage in obese children requires a non-invasive proxy of microvascular health. DESIGN AND METHODS: We assessed the associations of hippocampal volumes and global cerebral atrophy with retinal vessel caliber in 40 normal BMI controls and 62 obese age-matched non-diabetic adolescents and evaluated the contribution of inflammation, obesity and insulin resistance to retinal vessel caliber. RESULTS: Compared to controls, obese adolescents had smaller retinal arterioles (8.3% decrease, p<.05) and wider venules (5.4% increase, p<.01). Larger retinal arteriole diameters were associated with less global cerebral atrophy (B=−.24(95% CI:−.48,−.002) and larger hippocampal volumes (B=.01(95% CI:0,.02). Inflammation (fibrinogen) predicted venule diameters (B=84.2(95% CI:30.3, 138.1). Insulin resistance, indicated by logHOMA values (B=−17.03(95% CI:−28.25,−5.81) and body mass index (BMI) (B=−.67(95% CI:−1.09,−.24), predicted arteriolar diameters. All analyses were adjusted for mean arterial pressure, sleep apnea, and vessel diameter. CONCLUSION: Measures of brain health, BMI, and insulin resistance are associated with retinal vessel caliber. If confirmed in larger studies, retinal arteriolar caliber may serve as a possible non-invasive proxy for brain atrophy in obese adolescents, and the identification of elevated risk for cerebral microvascular disease in adulthood.