There was also less lung cancer incidence even among non-smokers among those on the lutein/zeaxanthin blend, found the researchers behind the ‘AREDS2’ cohort extension, led by Emily Chew, MD, from the National Institutes of Health in Bethesda, Maryland.
Dr Chew and colleagues found the progression of ADM was significantly curtailed among some 2,900 participants featured in the final cohort taking lutein/zeaxanthin blends, in comparison to variations containing omega-3s, beta-carotene and zinc.
“These findings suggest that the AREDS2 supplement with lutein/zeaxanthin instead of beta-carotene was safe, with no association with developing lung cancer and a potential beneficial association with further reduction in progression to late AMD,” wrote the researchers.
AMD is the most common cause of elderly blindness in the US and most western nations. It is estimated 288 million people will be affected by AMD by 2040.
In the original 2006 AREDS2 cohort, AMD-suffering participants were randomly assigned to take lutein/zeaxanthin and/or omega-3s or placebo, with the secondary introduction of low or high doses of zinc, plus analysis against the earlier beta-carotene featuring data.
Roughly equal numbers of participants were divided into four primary groups:
- just the AREDS2 supplement (lutein/zeaxanthin, vitamins C and E, zinc, copper)
- just omega-3s
- the AREDS2 supplement plus omega-3s
For the second AREDS2 five-year study period, all remaining participants were offered the lutein/zeaxanthin AREDS2 blend because the earlier study period had determined no late-AMD effect for the DHA/EPA omega-3 blend. 90% are estimated to have taken the AREDS2 formulation mailed to them, affirmed by phone interviews.
“…essentially all participants, regardless of their randomised assignment, were taking lutein/zeaxanthin and not beta carotene during the follow-up study,” the researchers wrote.
Using an event probability model called Kaplan-Meier, it was estimated 47.9% of the lutein/zeaxanthin group would progress to late AMD by 10 years compared to 49% for those not taking lutein/zeaxanthin. The number increased to 52.2% for those who had taken beta-carotene.
Although almost all individuals had ceased taking the beta-carotene formulation, lung cancer rates remained significantly higher in the group that had originally been using beta-carotene, even among non-smokers.
There was no increase among the lutein/zeaxanthin group.
The present five-year cohort analysis is a follow-up to the National Eye Institute-sponsored AREDS/AREDS2 clinical trials that date back to 1996 and 2006 respectively.
The 1996 AREDS intervention of 500mg of vitamin C, 400 international units (IU) of vitamin E, 2mg of copper, 80mg of zinc and 15mg of beta-carotene significantly slowed the rate of progression in those with moderate or late forms of AMD.
But other studies at the time found rates of lung cancer were elevated among smokers who also took beta-carotene.
In 2006 AREDS2 commenced where Dr Chew’s team drew data from 3882 participants with an average age of 72 years, who were given the same blend but beta-carotene substituted for a lutein (10mg) and zeaxanthin (2mg) formulation provided by Kemin.
That five-year cohort found lung cancer risk did not increase while this lutein/zeaxanthin formulation. It reduced AMD progression risk by a quarter in those with intermediate AMD in one eye.
The current cohort investigated an additional five years and found the lutein/zeaxanthin blend reduced AMD progression by an additional 10-20%, again with no increase in lung cancer risk.
Published Online: doi:10.1001/jamaophthalmol.2022.1640
‘Long-term outcomes of adding Lutein/Zeaxanthin and Omega-3 Fatty Acids to the AREDS Supplements on Age-Related Macular Degeneration Progression: AREDS2 Report #28’
Authors: Chew EY et al.