Abstract
Purpose:
Retinal vascular parameters are markers of arteriosclerosis and predict the onset of retinopathy and systemic vascular diseases. This study aims to examine the relationship between serum carotenoids (lutein and zeaxanthin) and quantitative retinal vascular parameters in elderly Singaporean Chinese population.
Methods:
In this cross-sectional study, 45 degrees digital color fundus photographs from 67 healthy Singaporean Chinese subjects aged 40 years and above were analyzed. A range of retinal vascular parameters (arteriolar and venular caliber, branching angle, vascular tortuosity, and fractal dimension) were measured quantitatively using computer software (Singapore “I” Vessel Assessment, SIVA). Serum levels of lutein (L) and zeaxanthin (Z) were estimated using high performance liquid chromatography. The association between serum carotenoids and retinal vascular parameters were evaluated using multivariable linear regression models after adjusting for confounding factors, such as gender, smoking and body mass index.
Results:
The mean (± SD) age of the study population was 54.54 ± 7.22 years, with a range of 40 to 81 years. There was preponderance of female participants (females = 61%; males = 39%). A positive history of smoking (current and past) was present in 28% of the participants. The mean (±SD) serum levels of L and Z in our population were 0.23 (±0.13) and 0.08 (±0.14) µg/ml, respectively. Serum Z demonstrated a positive correlation with retinal venular caliber (r = 0.223) and length diameter ratio arteriole (LDRa, r = 0.349) but only the latter relationship remained statistically significant in multivariable linear regression models after adjusting for other confounding factors (β = 3.25, p = 0.004). Similarly, serum L was inversely related with asymmetry ratio venule (AFv or asymmetry factor, r = -0.383) and this relationship remained statistically significant in multivariable linear regression models after adjusting for confounding factors (β = 0.65, p = 0.002).
Conclusions:
Serum levels of L and Z were significantly associated with decrease in AFv and an increase in LDRa, respectively. These observations suggest that antioxidant carotenoids L and Z may influence early retinal arteriosclerosis and may contribute to the pathogenesis of retinal diseases.
Keywords: 424 antioxidants •
688 retina