Serum and Macular Carotenoids in Relation to Retinal Vessel Caliber Fifteen Years Later, in the Second Carotenoids in Age-Related Eye Disease Study

PURPOSE. We investigated whether dietary carotenoids lutein and zeaxanthin (L/Z) in the serum and macula were associated with central retinal arteriole and venule calibers in a follow-up ancillary study among older women in the Women's Health Initiative. METHODS. Among 390 women who participated in Carotenoids in Age-Related Eye Disease Study 2 (CAREDS2) (2016-2019), we investigated associations between serum L/Z at Women's Health Initiative baseline (1994-1998), and macular pigment optical density (MPOD) at CAREDS baseline (2001-2004), with central retinal vessel caliber in CAREDS2. MPOD was measured using heterochromatic flicker photometry (0.5 degrees from the foveal center) in CAREDS baseline and CAREDS2. Vessel calibers were measured from fundus photographs (CAREDS2). We also explored associations in women with stable MPOD (+/- 0.10 optical density units) over 15 years (n = 106), given the long-term increases in MPOD related to diet patterns and supplement use. Associations were investigated using linear modeling. RESULTS. In the full sample (n = 390), higher serum L/Z (tertile 3 vs. 1) was positively associated with arteriole caliber (mean +/- SE, 145.0 +/- 1.4 mu m vs. 140.8 +/- 1.4 mu m; P = 0.05) and venule caliber (214.6 +/- 2.2 mu m vs. 207.5 +/- 2.2 mu m; P = 0.03). MPOD was also associated with wider vessel calibers (tertile 3 vs. 1), but the trend was only statistically significant for venules (144.4 +/- 1.4 mu m vs. 141.1 +/- 1.4 mu m [P = 0.121 and 213.3 +/- 2.1 mu m vs. 206.0 +/- 2.1 mu m [P = 0.02], respectively.) Most associations were strengthened in women with stable MPOD over 15 years, including between MPOD and arteriole caliber (149.8 +/- 2.6 mu m vs.135.8 +/- 3.0 mu m; P = 0.001). CONCLUSIONS. Higher L/Z status in serum and retina was associated with larger central retinal vessel calibers. Prospective studies and clinical trials are needed to elucidate whether L/Z supplementation prevents vision loss through increasing blood flow.

Automated summary

The study found that higher levels of L/Z in serum and retina were associated with larger central retinal vessel calibers, and MPOD levels were also related to vessel calibers, especially in women with stable MPOD over 15 years.