More than 25 years after the start of the original Age-Related Eye Disease Studies (AREDS and AREDS2), new analysis of the data confirms targeted dietary supplementation can slow progression of age-related macular degeneration (AMD), the most common cause of blindness in older adults. Results show the AREDS2 formula, which substituted lutein and zeaxanthin for beta-carotene, not only reduced the risk of lung cancer due to beta-carotene, but was more effective at reducing risk of AMD, compared to the original formula. The new results were published in JAMA Ophthalmology (DOI:10.1001/jamaophthalmol.2022.1640).
Supported by the US National Institutes of Health (NIH), the original AREDS study showed that a formulation of 500mg vitamin C, 400IU vitamin E, 2mg copper, 80mg zinc, and 15mg beta-carotene could significantly slow the progression of AMD—a degenerative disease of the retina—from moderate to late disease. However, two concurrent studies showed smokers who took beta-carotene had a significantly higher risk of lung cancer.
In a statement on the new findings, Emily Chew, MD, director of the Division of Epidemiology and Clinical Application at the National Eye Institute (NEI), and lead author of the study report, commented: “Because beta-carotene increased the risk of lung cancer for current smokers in two NIH-supported studies, our goal with AREDS2 was to create an equally effective supplement formula that could be used by anyone, whether or not they smoke. This 10-year data confirms that not only is the new formula safer, it’s actually better at slowing AMD progression.”
At the start of AREDS2 in 2006, participants who had never smoked or had quit smoking received the beta-carotene formulation, while others received a supplement with 10mg lutein and 2mg zeaxanthin instead. After five years, researchers concluded lutein/zeaxanthin did not increase lung cancer risk, and the new formulation could reduce the risk of AMD progression by 26%. All study participants were then offered the updated formulation.
For the current study report, researchers followed up with 3,882 of the original 4,302 AREDS2 participants, assessing AMD progression and lung cancer incidence. At 10 years after intervention, the odds ratio of having lung cancer was 1.82 for those randomly assigned to beta-carotene and 1.15 for lutein/zeaxanthin. In addition, the group originally assigned to receive lutein/zeaxanthin had a 20% reduction in risk of progression to late AMD compared to those originally assigned to beta-carotene.