Importance: After the Age-Related Eye Disease Study 2 (AREDS2) study, the beta carotene component was replaced by lutein/zeaxanthin for the development of the revised AREDS supplement. However, it is unknown if the increased risk of lung cancer observed in those assigned beta carotene persists beyond the conclusion of the AREDS2 trial and if there is a benefit of adding lutein/zeaxanthin to the original AREDS supplement that can be observed with long-term follow-up.
Objective: To assess 10-year risk of developing lung cancer and late age-related macular degeneration (AMD).
Design, setting, and participants: This was a multicenter epidemiologic follow-up study of the AREDS2 clinical trial, conducted from December 1, 2012, to December 31, 2018. Included in the analysis were participants with bilateral or unilateral intermediate AMD for an additional 5 years after clinical trial. Eyes/participants were censored at the time of late AMD development, death, or loss to follow-up. Data were analyzed from November 2019 to March 2022.
Interventions: During the clinical trial, participants were randomly assigned primarily to lutein/zeaxanthin and/or ω-3 fatty acids or placebo and secondarily to no beta carotene vs beta carotene and low vs high doses of zinc. In the epidemiologic follow-up study, all participants received AREDS2 supplements with lutein/zeaxanthin, vitamins C and E, and zinc plus copper. Outcomes were assessed at 6-month telephone calls. Analyses of AMD progression and lung cancer development were conducted using proportional hazards regression and logistic regression, respectively.
Main outcomes and measures: Self-reported lung cancer and late AMD validated with medical records.
Results: This study included 3882 participants (mean [SD] baseline age, 72.0 [7.7] years; 2240 women [57.7%]) and 6351 eyes. At 10 years, the odds ratio (OR) of having lung cancer was 1.82 (95% CI, 1.06-3.12; P = .02) for those randomly assigned to beta carotene and 1.15 (95% CI, 0.79-1.66; P = .46) for lutein/zeaxanthin. The hazard ratio (HR) for progression to late AMD comparing lutein/zeaxanthin with no lutein/zeaxanthin was 0.91 (95% CI, 0.84-0.99; P = .02) and comparing ω-3 fatty acids with no ω-3 fatty acids was 1.01 (95% CI, 0.93-1.09; P = .91). When the lutein/zeaxanthin main effects analysis was restricted to those randomly assigned to beta carotene, the HR was 0.80 (95% CI, 0.68-0.92; P = .002). A direct analysis of lutein/zeaxanthin vs beta carotene showed the HR for late AMD was 0.85 (95% CI, 0.73-0.98; P = .02). The HR for low vs high zinc was 1.04 (95% CI, 0.94-1.14; P = .49), and the HR for no beta carotene vs beta carotene was 1.04 (95% CI, 0.94-1.15; P = .48).
Conclusions and relevance: Results of this long-term epidemiologic follow-up study of the AREDS2 cohort suggest that lutein/zeaxanthin was an appropriate replacement for beta carotene in AREDS2 supplements. Beta carotene usage nearly doubled the risk of lung cancer, whereas there was no statistically significant increased risk with lutein/zeaxanthin. When compared with beta carotene, lutein/zeaxanthin had a potential beneficial association with late AMD progression.