The Most Important Principles for Staying Young: Intention and Prevention

12 Nov

Our basic premise is that your body is amazing.  You get a do over. It doesn’t take that long, and it isn’t that hard if you know what to do.  In these notes, we give you a short course in what to do so it becomes easy for you and for you to teach others. We want you to know how much control you have over both the quality and length of your life.

This month, let’s talk about intention and prevention, starting with findings from two recent studies that led to the following dogma-contradicting headline: Data from nearly 20,000 older adults showed that taking aspirin as a preventative measure had no effect on survival rates of healthy, elderly individuals. That conclusion raised eyebrows in the medical community because taking aspirin has been associated with positive health outcomes—fewer heart attacks and strokes, as well as a lower risk for nine cancers. But the “no-benefit” conclusion also raised our eyebrows for another reason: The method used—an “intention-to-treat analysis” in both studies—may be misleading if it’s the only way used to report outcomes of various preventive behaviors such as exercise, smoking cessation, and lowering stress.

Here’s how it works, in simple terms. In an intention-to-treat analysis, you can divide study subjects into various groups. Say you want to measure the effect of exercise on bodyweight. One group is assigned to exercise (the investigators “intend” them to exercise) and one group is asked not to exercise (is “intended” not to exercise). And then researchers would measure bodyweight at the end of the allotted time period and draw conclusions about the effect of exercise on bodyweight.

See the problem? The methodology doesn’t even look at if the study subjects actually even exercised.

So, what happens to the data if many of those who intended to exercise never did and some of those who didn’t intend to exercise decided at some point to sweat their tail off five days a week?

Exactly. The data becomes more mixed up than a vat of jambalaya. And there’s no way to draw any conclusions about what effect actual exercise did or didn’t have on a person’s bodyweight. What’s really measured is how well participants in the study were motivated to follow the behaviors assigned to their group.

This is what happened in these two studies. In the first study, an intention-to-treat analysis involving almost 7,000 people in each group, the researchers concluded that taking a low-dose aspirin provided no benefit in reducing cardiovascular deaths, strokes, or heart attacks. That was the headline.  But the research team also separately examined the data of almost 4,000 people in each group who followed the protocol at least 60 percent of the time. The researchers observed a very significant 47 percent reduction in heart attacks. That was never mentioned in the mainstream news coverage I saw.  (Disclosure:  I have no commercial or equity interest in any company known to produce aspirin.)

The same issue came up in the other study. In the group that intended to take the aspirin, 38 percent of the group intending to take aspirin didn’t do it 80 percent of the time. And in the group that didn’t intend to take it, some—it looks like 8 percent; it is unclear—in the placebo group did take it. This means it’s a jumbled-up batch of data and where, in my opinion, the editors of the New England Journal of Medicine could have insisted the authors analyze the data of those who followed the protocols, as no place in the three articles about that study is there analysis of actual takers or non-takers.

Using only intention-to-treat analysis looks at this question: Did people assigned to preventive measures like exercise, smoking cessation, or taking a daily low-dose aspirin actually do so? However, it may be more useful to ask a question like, “Is exercise or smoking cessation or aspirin effective when done as prescribed?”

It should be noted that the study authors and others maintain that an intention-to-treat analysis is a good way to do studies about preventive medicine, because they say it’s a “real-life scenario” of how well patients follow protocol—sometimes they do, something they don’t do what they’re supposed to do. However, I maintain that—while it may simulate how people follow preventative guidelines—it doesn’t show whether a treatment is effective or not. Preventative lifestyle behaviors only work when you actually carry them out, not if you merely intend to do so.

 Thanks for reading. Feel free to send questions to:

Dr. Mike Roizen

PS: Please continue to order the new book by Jean Chatzky and myself, AgeProof: Living Longer Without Running Out of Money or Breaking a Hip. 



NOTE: You should NOT take this as medical advice.

This article is of the opinion of its author.

Before you do anything, please consult with your doctor.

You can follow Dr Roizen on twitter @YoungDrMike (and get updates on the latest and most important medical stories of the week).  The YOU docs have two newly revised books: The patron saint “book” of this column YOU Staying Young—revised and YOU: The Owner’s Manual…revised —yes a revision of the book that started Dr Oz to being Dr OzThese makes great gifts—so do YOU: ON a Diet and YOU: The Owner’s Manual for teens.  


Michael F. Roizen, M.D., is chief wellness officer and chair of the Wellness Institute at the Cleveland Clinic. His radio show streams live on Saturdays from 5-7 p.m. He is the co-author of 4 #1 NY Times Best Sellers including: YOU Staying Young.

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