The public discussion of the draft consensus statement from the NIH’s State-of-the-Science Conference on Prevention of Alzheimer’s Disease and Cognitive Decline was one of the more interesting and lively sessions of the conference. Although many commenters commended the panel for their enormous efforts, as with all things Alzheimer’s, there was a lot of disagreement. Here are some of the highlights:
Still Wrangling with Terminology
Several comments from National Institute on Aging staff highlighted the fact that the report seemed to use “mild cognitive impairment” and “cognitive decline” interchangeably, perhaps confusing professionals and the general public. Decline in cognition associated with age has a much broader range than the concept of mild cognitive impairment, they said, and can mean a more modest decline that doesn’t necessarily cause impairment.
Arnold Potosky of Georgetown University, a panelist, said the panel had struggled with this distinction. “As a measurements person,” he said, “this bothers me. It’s vital.” He talked about some of their considerations: how to define and measure cognition, the differences between measuring it in a memory clinic and in the community, whether measures are sensitive enough to differences in individuals, and what is the real impact of cognitive impairment on quality of life and daily functioning.
It seems to me that this terminology problem reflects the continued lack of agreement on where to draw the line (if anywhere) between normal aging and difficulties with memory and thinking that are caused by an illness. The problem was also reflected in the continued arguing about prevalence numbers and statistics on “progression.” It’s unrealistic to expect one event’s panel, however expert, to sort this out.
Questions on Weight Given to Food and Nutrient Studies
Martha Clare Morris of Rush University questioned the emphasis on data from one study on the Mediterranean diet as opposed to what she considers to be equally good data from multiple studies on the effectiveness of Vitamin E in people with very low food intake and on beta-carotene over a ten year period. She felt this data should be moved from the “no evidence” section of the report to the “limited evidence” section. Carl Cotman of UCLA Irvine agreed.
Dr. Morris’s concern is that by publishing this report with an emphasis on the Mediterranean diet [whether or not the science for that study is good], the panel may effectively close the door to further research on Vitamin E and other promising nutrients. Panelists replied that they relied on the review of the analysis that Duke University prepared for the conference, and that the concern was with consistency of the data. Someone in the audience commented that you really can’t come to any conclusions based on only one study – replication is needed. So, even though Vitamin E has more than one positive study, there are also some negative ones, and this counted against it in this type of review. Clearly some in the audience disagreed with the analysis used in this case.
A panelist, Dr. Granieri, said she didn’t believe publishing this report would close the door to future investigations. However, in response to Dr. Theis’s comments below, another panelist said the panel hoped that their report will arm researchers to work with the NIH to get funds for their work. See below for more concerns about how the report will be interpreted.
Bill Theis from the Alzheimer’s Association pointed out that there is no funding for the research recommendations in the report. “If we don’t find a way to prevent Alzheimer’s,” he said, “the reality is that in most cities in the world, we will see demented people wandering the streets because there will be no place to put them all.”
Negative Tone of the Report
Perhaps the biggest concern for those speaking during the comment session was the effect the negative tone of the report would have on both individual and prevention efforts.
First off, Zoe Wong of the National Library of Medicine questioned the entire introduction and problem statement. “Alzheimer’s is a disease you’re lucky to have,” she says. “Why? Because the person with Late Onset Alzheimer’s disease has survived…you are past all the things that can kill you.”
Other commenters may not have shared her concerns about the introduction, but worried about the effect of issuing the report. Although the report is based on a strict standard of scientific evidence, one commenter said, it does a disservice by not saying that things like exercise and cognitive activity are good to do even if evidence is still insufficient. One of the panelists replied that the report is an overarching wide policy statement, not necessarily recommendations for what to do in the clinic. The panel can’t go out on a limb and say these things [with insufficient evidence] work, he said.
Others in the audience said they thought there was more reason for optimism on cognitive reserve, estrogen, and lifestyle measures for “brain health” than the report reflects. “It would be unfortunate if [the report] were interpreted as a call to end brain health activities because they are not fruitful and not supported,” said Bill Theis.
A family medicine doctor in the audience disagreed. “I find the conclusions helpful for the kinds of patients I see – the worried well and family members,” he said. “This gives me the opportunity to say here’s what we know, here’s what we don’t know.… People spend thousands of dollars…but at this time, there is no evidence for prevention.” He noted he will continue to “throw everything I’ve got” at treating patients with dementia.
For a copy of the final statement, and details on presentations and discussions, go to http://consensus.nih.gov/2010/alz.htm.