Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Wednesday, December 16, 2015

Tempest In An Eyeball

"I think the whole thing needs to be taken extremely seriously. We believe there is a group of individuals, about 15% of all of those who take vitamins for AMD [age-related macular degeneration], who are actually experiencing a doubling of their risk ... doubled risk of going blind, or of having the condition associated with blindness."
Dr. Brent Zanke, medical oncologist, geneticist, chair, Arctic DX

"If they're right and we are harming people, that's a concern for me, because I don't want to be harming patients."
But we could not replicate anything that they did [in research findings]."
Dr. Emily Chew, deputy director, National Eye Institute, Washington

Two quite different medical entities are at odds over a supplement that one insists is useful to prevent or minimize AMD, and the other declared, as a result of their research, may in fact hasten AMD for some genetically predisposed people. Vitamin-zinc pills are being used to protect against the onset of AMD, a serious eye affliction leading to blindness which hits the elderly disproportionately as all bodily functions experience fatigue and changes as we age.

One of the entities is a small Canadian company, the other a large American government research agency, with a commercial interest in the ongoing use of the supplement hailed for its anti-blindness properties. Arctic DX, located in Toronto, claims their own DNA research indicates that the supplement increases the risk of vision loss for North Americans with a certain genetic profile, affecting hundreds of thousands of people.

This is a company that has made its name as an expert genetic-testing company. Their warning about the continued use of the zinc supplement has been largely set aside by doctors because of the opposition from the National Eye Institute in Washington which itself was responsible for a study leading to the widespread use of the vitamin-zinc pill.

Despite what the scientists at Arctic DX claim in their warning about the use of the supplement and its deleterious effects for a sizeable demographic, the Washington-based institute insists it has done its due diligence which confirms their confidence in the ongoing use of the vitamins, their brand names Preservision and Vitalux, as being perfectly safe for patients with AMD.

The product, manufactured by the Bausch and Lomb division of Valeant Pharmaceuticals out of Quebec, is reliable, claims Dr. Chew, and the decision to continue its use, she stresses owes nothing whatever to the fact that self-interested commercial interests are involved. And nor is Dr. James Whelan, president of the Canadian Retina Society impressed with the arguments put forward by Arctic DX.

Dr. Whelen remains unconvinced that patients with any genetic profile could be at risk with the use of the supplement. "It's been a very hot topic at all the national and international meetings", he commented. The National Eye Institute's study released in 2001 suggested that a high-dose anti-oxidant vitamins E and C, Zinc and copper supplement would cut risks of AMD advancement.

Arctic DX has developed a genetic test to identify the AMD patients most potentially at risk through DNA samples they obtained of almost one thousand of the people in the NEI's Age-related Eye Disease Study, with the intention of discovering more useful data relating to the effects of the supplement. Their analysis concluded that 13% of those people increased their risks taking vitamins.

Since 2013, the Arctic DX researchers published two studies giving details of their work leading to the conclusion of doubling the risks for vulnerable patients with the use of the supplement.  A Nashville, Tennessee ophthalmologist who does consulting work for the Toronto company, and who co-authored the studies, points out that the NEI scientist uses all opportunities to debunk the Arctic DX research.

What is most telling is the discovery of the Actic DX team that Dr. Frederick Ferris [Dr. Chew's superior] of the NEI has himself earned $1.8-million from the Bausch and Lomb patent.

Rafal Nustra a biostatistician at the University of Toronto scrutinized an editorial in the journal Ophthalmology written by two scientists who worked with Dr. Chew, leading him to conclude that the raw data in the NEI's study supported the contention by Arctic DX that 19% of patients had the genotypes that auger they will not fare well given the supplement.

Moreover, Dr. Nustra charged, the institute's article was replete with statistical inconsistencies. Harvard University biostatistician Bernard Rosner, hired by Arctic DX, confirmed Dr. Nustra's conclusion. And just to round out the accusations and denials, the American Academy of Ophthalmology reached their own conclusion that genetic testing for macular degeneration patients was not justified.

Hitting Arctic DX squarely where it would draw their fixed attention; the anticipation that their genetic testing firm would see an uptick in demand for genetic testing with the final acceptance of their findings that mitigate against the continued use of the vitamin-zinc supplement.

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