Friday, April 17, 2015

Steve: Good News about Memory Lapses

Spring in State College 2014

This morning, lying in bed waiting for the alarm to go off, I was thinking about a movie I saw awhile ago and couldn’t remember the name of an actor who was in the movie.  This is something that happens from time to time, and it seems to happen more often than in the past.  There are even a couple of actors, Richard Dreyfuss and Julia Roberts (imagine that!), whose names I routinely have trouble retrieving.  Sound familiar?  Is this a sign of the dreaded “A” disease?

All the attention in the media and the research community about Alzheimer’s disease has sensitized us to wonder if each new lapse of memory is a sign of illness.  A new report released this week by the Institute of Medicine on Cognitive Aging reminds us of something that has actually been known for a long time: occasional and mild cognitive problems—what everyone experiences from time to time—is a process related to normal changes associated with aging, but not to disease.  The report also reminds us of something else that is important—there are gains in cognitive abilities with aging.  We gain expertise and maybe grow wise, and many of us learn to manage our emotions and personal relationships better than we did in the past.

Judy and I did some work many years ago where we conducted memory training classes for older people.  We actually did parallel studies: two studies involved training of people who we felt only had problems associated with normal aging, and a third study was specifically for persons who had obvious signs of dementia.  We’ll come back to that group in a later posting, but let’s look at training for healthy older people.  In those studies, classes that involved actual cognitive training were compared to classes that created the expectation that participants were doing something to improve memory, for example, examining current events or focusing on attention and personal effectiveness.  Cognitive training had small positive effects on memory, but all participants reported fewer memory problems after the classes, whether they received actual cognitive training or were in the faux training class.  A lot of what we emphasized in the classes was reassurance—that everyday lapses did not indicate a more serious problem and that people could do something about memory loss, if they wanted.  They wanted the reassurance and in the end were less interested in using strategies to remember names or shopping lists or other things they had occasional problems with.
The Institute of Medicine report suggests practical strategies to help promote “cognitive health.”  These make a lot of sense and include:

·       Stay physically active
·       Manage risk factors for cardiovascular disease, including high blood pressure and diabetes.
·       Review medications regularly.  Avoid the piling up of too many medications that is all too common with older people.
·       Be socially engaged
·       Get adequate sleep and treatment if you have a sleep problem.

Staying cognitively active can be helpful, too.

But perhaps the main message is that the stereotype that forgetting means we are hopelessly slipping into senility is wrong.  Stereotypes have a way of becoming self-fulfilling prophesies.  There is work by the social psychologist Becca Levy that shows that these negative expectations decrease performance, including of memory.  She has even found that calling something a memory test leads to poorer performance than if the test has a different name.

Here is a link to the Institute of Medicine Report.  The full report has not been uploaded yet, but you can find summaries of the committee’s findings and recommendations:

For everything good about the Cognitive Aging report, a New York Times article reported on two studies that purported tell us just how much exercise we should get to extend our lives.  Both studies looked at how much exercise people reported and their risk of death over a 14-year period in one study and an 8 year period in the other study. 
The article states that “the takeaway message seems straightforward.”  But is it?  Exercise is probably good for all of us, but think about it—is the difference in mortality due to how much exercise people engage in?  Or is something else different about people who exercise and people who do not that might cause a difference in mortality?  Think about it.   Send us your suggestions.  Our answer will appear next week.

Here is a link to the article, which also includes links to the two scientific papers.

Friday, April 10, 2015

Steve: More Food and Dementia Zaniness

I had thought my previous entry on the craziness in nutrition research would allow me to put that topic away for a while.  But then Andrew and Allison Heid send me a link from the Washington Post with the eye-popping headline:  “Being fat in middle age reduces risk of developing dementia, researchers say.”  I had to check it out.  Unfortunately, I have only been able to download the abstract of the article.  Without the whole article, it’s hard to make sense of what might really be behind the findings, but like the media, I’m going to jump in without all the facts.

Just to make things clear, I do have to talk about the Body Mass Index (BMI), which you probably know about.  It’s the ratio of one’s weight divided by one’s height squared.  If you want to compute your BMI, you divide your weight in kilograms by your height in meters squared.  A “healthy” BMI is considered 18.5 to 25.  I can’t help  the fact that the USA alone in the world maintains the old English measurements, but since you found this blog, you can probably find a simple conversion on the web to translate pounds and inches to kilograms and meters.

So what does the article say:
·       It was a study of nearly 2 million people in Britain aged 40 and older, with information obtained from medical records.  The people in the study were followed on average for 9.1 years.

·       Compared to individuals with a healthy weight, people who were underweight (BMI less than 20 kg/m2) were reported to have a 34% increased risk of dementia.

·       As weight increased, risk of dementia fell, and the very obese (BMI greater than 40 kg/m2) had a 29% lower risk of dementia that people with a healthy weight.

In the Post article, the head of the study, Dr. Nawab Qizilbash, acknowledges that prior research found that having a big belly in your 40s increased your risk of dementia in your 70s.  There is fairly extensive work that shows similar findings.  Dr. Qizilbash argues, however, that his study “overshadows” prior work because of the size of the sample.

So is it time to run out to buy some ice cream and cookies? 
It’s hard to say.  Here are the problems:

·       A big sample is an advantage in some ways and a disadvantage in other ways.  The bigger and more diverse the sample, the less the findings can say anything about any given individual.  In other words, the bigger the sample, the less likely the findings will apply to YOU. 

·       A big sample is a problem in another way, because the standard in research is to accept findings that are statistically significant.  Significance is highly dependent on sample size and with nearly 2 million people, this study would find nearly everything statistically significant.

·       I could carp about the accuracy of the diagnosis of dementia in medical records, but the more important issue is what is encompassed by “dementia.”  It includes Alzheimer’s disease but also several other conditions, such as Fronto-temporal dementias, Lewy Body dementia, vascular dementias.  These various disorders differ in type of brain pathology and so they likely differ in the cause. Each of these categories has sub-types that may differ from each other in important ways.If risk factors or causes of the disease differ across the different types of dementia, as everyone suspects they do, then findings from studies that combine different disease groups together will not give a clear answer.  The findings of this study or any other study like it might depend in part on how many people with each type of dementia are included in the sample, as well as how many cases are there of mixed dementia (two or more types, which is common) .   It could be that too much weight predisposes people to one type of dementia and protects them from another type.  Most of the studies you read about group together people with diverse diagnoses and so it is not at all clear what their findings show.

·       What about the magnitude of the differences reported by this study?  The amount of increased and decreased risk sounds impressive, but as my colleague Eric Loken and his collaborator Andrew Gelman have argued, a large effect in a study does not assure that findings are not due to chance or quirks associated with the sample or how the data were handled.  One of the examples they cite is work that claimed that women at peak fertility in their menstrual cycles were more likely to wear red or pink, presumably to attract a male.  The study reported a large difference, yet it could not be replicated.  In other words, it was a chance finding.  We can begin to trust a finding when it has been found across studies.

So what to do?

Resist the hysteria.  The conflicting findings show that the issue of weight and dementia is still very much up in the air.  Too much and too little weight have lots of known health risks, so a reasonably healthy weight is a good thing, but the findings are too muddled at this point to say that it matters for dementia.

Quell the understandable worry we all have about Alzheimer’s.  I’d recommend as the perfect treatment that you go to Judy’s other blog ( and bake something delicious, like the orange danish shown at the top of this entry.  After all, a little extra weight may not be a big deal.

Here’s the link to the Washington Post story:

Here’s the link to the abstract for the article:

Wednesday, April 1, 2015

It’s Nuts: The Confusing Findings from Nutrition Research

Is your head spinning with all the confusing and contradictory news reports on diets that prolong life and prevent disease?   Just this week in the New York Times, there were reports that red meat was really not bad for us, that fish oil probably doesn’t do anything to prevent stroke or heart disease and that eating nuts increases our lifespan and prevents Alzheimer’s disease. These articles come in the wake of other reports that suggest that dietary fat, at least from some sources, is not the enemy.  Butter even made a starring appearance on the cover of Time magazine.

Why is there so much contradictory evidence on food?  And what should we believe? The gist of the argument goes this way.  Nutritional research on humans is difficult to do, and much of it has been flawed and of poor quality.  A 2013 paper written by two researchers, Jonathan Schoenfeld and John Ionnidis, evocatively titled, “Is everything we eat associated with cancer? A systematic cookbook review,” found that there were claims that 40 ingredients frequently mentioned in cookbooks were associated either with increased or decreased cancer risk.  In their detailed statistical analysis of the research behind these claims, Schoenfeld and Ionnidis found that most of the evidence was weak.  In fact, the more studies done on an ingredient, the more likely the average effects found trended toward zero. 

How do we make sense of the information presented in the media?  Unfortunately, many health reporters appear more concerned with headlines than understanding science.  An exception is Aaron Carroll, who wrote the “Red Meat Is Not the Enemy,” article and has authored other thoughtful pieces on nutritional research.

There are some criteria you can apply next time you read or hear a story about the nutritional benefits of a food or diet.

1.  Is the evidence from a descriptive study?  What I mean by that is a study that gathered information on large numbers of people and looked for associations between dietary or other factors and a particular disease.  There are two major problems with these kinds of studies.  First, the findings may be due to chance.  If researchers test the association of 100 different foods with a disease such as Alzheimer’s, we know that at least five of those comparisons will be statistically significant by chance.  In other words, these will be false positive findings. Some statisticians argue that the false positive rate may be as high as 13 out of 100 comparisons.  Many descriptive studies have probably done this kind of fishing in their data, looking for the comparisons that are significant and ignoring the ones that are not.

The second problem is these associations are not the same thing as causation.  The association of nuts and health may be due to the fact that some other factor might lead people to eat nuts and also contribute to health.  Maybe nut eaters among us are wealthier, or more health conscious to start with so they exercise more and avoid processed foods like potato chips and French fries.  It may not be the nuts at all that make a difference.

2. In contrast to descriptive studies, researchers sometimes conduct experiments in which people are randomly assigned to the experimental diet or to a control group.  This is potentially a stronger research approach, which can establish that it is the specific diet, and not other things people might be doing, that contributes to a positive outcome.  This approach is the main way that medications are tested, and it works well in the short run.  But there are two problems that plague research on diets.  First, people comply with the diet in varying degrees. Second, we need long time periods to be able to see the effects of diet.  As the study goes on, people are less likely to be compliant and some will begin to drop out.  In the end, the people who stay in the study and stick with a diet will be highly conscientious and so they are probably doing other things to assure good health.

3.  Whatever type of research is used, a single food is not likely to make a difference. As much as we would wish to find foods that have magical abilities to prevent illness or delay aging, there are no superfoods. This is the point of the cancer paper and it’s the point that Aaron Carroll makes in the red meat article.  Carroll states that one food is not “the culprit,” but rather that too many of us eat too much.  In other words, it’s obesity that increases the likelihood of many different diseases and an early death, and not any one specific food that we eat.

What to do?  In truth, we all know what a healthy diet looks like.  A variety of whole, natural foods in reasonable quantities.  Really, it's that simple.  There is a large body of research on diets, whether it's Weight Watchers, Atkins, the Mediterranean diet, or any other diet "prescription." That research tells us that people lose weight while they are on any of these diets, but the majority of people will gain back the weight when they stop adhering closely to the diet.  In fact, the implication of a diet plan is that we "go on" the diet, and eventually "go off."  And that's the problem.  Most of these very rigid and restrictive diets are not sustainable because people feel deprived of many foods they love.  And they find it difficult to eat in restaurants or with friends.  

What makes more sense is to decide to focus on healthy foods and perhaps to make one change at a time.  For instance, deciding to eliminate soft drinks and substitute flavored sparkling water will subtract calories (or subtract artificial sweeteners in the case of diet soft drinks) without decreasing the amount of liquids that you drink.  Eating a piece of fruit at the end of a meal instead of a cookie is another possibility. Having an open-faced sandwich halves the amount of bread used.  Only eating half of your entree in a restaurant and taking the rest home will give you a more reasonable portion in most cases.  It takes several weeks to establish a new habit, so pick one thing (we usually recommend the easiest one first), and continue until you no longer have to think about it.  Then make one more change.  There's no real end point, just a series of changes moving you towards a healthier diet.  And because you aren't "on a diet," if situations arise where you splurge on a treat, it's okay.  Just go back to the good habits you're developing the next day.  One of the advantages of making your own decisions about what you eat rather than following a prescription is that you don't have to feel guilty if you "go off the diet," nor ashamed because you couldn't stay on it.  

After all, enjoying good food is one of life’s pleasures. 

Links to the articles cited here:

Fish Oil Claims Not Supported by Research

Red Meat Is Not the Enemy

Nuts Are a Nutritional Powerhouse

Is Everything We Eat Associated with Cancer? A Systematic Cookbook Review