Tag Archive for: BMI

Life Expectancy Is More Than Living Longer

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What’s more important to you: living longer or living better with the years you have? Think about it as you read this Memo and I’ll come back to that later.

The Upside of the Study

There were three important lifestyle variables that clearly stood out (1). The more exercise you get, the better off you are. Of those who got perfect 5s, they averaged over an hour per day of exercise. Second, the lower the BMI, the better; researchers didn’t track who might have lost weight over the years to get in the lowest BMI category, but it’s clear that carrying fewer pounds helps.

Finally, the Alternate Healthy Eating Index (AHEI) is a score of the quality of the diet, not the quantity. The highest quintile was below 60 out of 100 possible points. That means you don’t have to eat perfectly; just eat your vegetables and fruit and fewer refined carbohydrates and sugars, and you’ll see benefits.

The Downside of the Study

The subjects were overwhelmingly white and they were nurses and doctors for the most part. Whether that translates to other races and professions, we just don’t know.

The biggest issue for me is the Food Frequency Questionnaire used in the original studies as well as the AHEI scores. Trying to remember what you’ve eaten in so many categories over a year never made sense to me; there’s just too much potential for error. There were also differences in AHEI scores between the Nurses Study (all women) and the Health Professionals Follow-Up Study (all men). The men had an AHEI of 59 while the women in the nurses study had an AHEI of 37.5 in the groups assigned a 5. That makes no sense to me. I know the FFQ were slightly different, but the way the data are extracted to arrive at the AHEI score should have accounted for that. Are men so much better with the quality of their diet? Not buying it.

Supplements

Here’s something I found interesting. The use of a baby aspirin went up as the overall scores went up. In contrast, multivitamin use went up as the overall scores went down. To me, that means that healthcare professionals in all professions know that taking a baby aspirin is good for you. It also means that the poorer the diet, the more people try to compensate with supplements. The goal should be to complement a good diet with a multi, not try to make up for a poor one.

Amount of Time Living with Disease

I asked you a question at the beginning of this memo: what’s more important to you: living longer or living better? Right now, the average number of years spent living with some form of disease is almost 12 years (2). Not every condition is as debilitating as others, but would you rather live longer no matter what your health is or would you rather live well right up to the day you check out? Only you can answer that one. The study didn’t examine quality of life so we don’t know how the subjects did.

Here’s my guess: I would wager that the more healthy lifestyle variables you can add to your life, the longer and better you will live. Eat less. Eat better. Move more. It all starts with those six words.

What are you prepared to do today?

Dr. Chet

 

References:
1. https://doi.org/10.1161/CIRCULATIONAHA.117.032047.
2. https://ourworldindata.org/life-expectancy.

 

The Truth Behind the Obesity Paradox

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In my opinion, the short answer to the obesity paradox is that it doesn’t really exist. But what fun would that be? That doesn’t teach you anything. Let’s take a look at the problems with the research that contributed to this paradox.
 

Study One: Dialysis, BMI, and Mortality

A study of dialysis patients led to the first observation that people with higher BMIs lived longer (1). After tracking over 1,300 subjects on dialysis for a year, researchers found that those who were overweight had a decreased risk of dying and had fewer hospital stays when compared to those who were underweight. This may have been the study that yielded the name The Obesity Paradox. The problem? The study lasted only one year. Trying to generalize what will happen to all overweight and obese people on dialysis from a study that lasted only one year and at only a single location isn’t realistic. It raises an intriguing question, but we’ll need a much more extensive study to really make a solid prediction.
 

Study Two: The Rotterdam Study

I described this study on Thursday (2). While the study appeared to show a protective benefit from being overweight or obese, the subjects were elderly with an average age of 77 at the study’s beginning. One risk factor that you cannot change is age: the older you are, the more likely you are to die. But that’s not the whole story. We can probably say that older people may live longer with a little extra weight, but to extend that prediction to all age groups isn’t valid.
 

Study Three: BMI and Mortality

While this study claimed to analyze the data on over two million people, it was still a meta-analysis (3), which doesn’t yield cause and effect, just a statistical association. Further, they used studies of varying lengths without necessarily knowing exact causes of deaths. They also did not have precise BMIs on everyone; some studies included metrics such as BMI under 27.5 and over 27.5. They tried to include the highest number of subjects, but the quality of data varied and that made it a mess. Researchers chose too many different types of studies in the meta-analysis, and it just doesn’t work. I wouldn’t bet my life on it.
 

Study Four: A Broader Look

The real problem with every approach is the lack of acknowledgement that people with advanced disease may have lost weight before they were included in the study; diseases such as heart failure, diabetes, or renal disease will often lead to weight loss. Those who were heavier when disease hit had the benefit of extra energy stored as fat to deal with the disease, and that could explain the outcomes of those studies. It had nothing to do with being obese; it was a matter of timing.

A study published last month appears to confirm that (4). Researchers in the Cardiovascular Disease Lifetime Risk Pooling Project obtained data from 10 different longitudinal studies, including individual-level data and accurate mortality data. They found that as BMI increased, the death rate from all forms of CVD increased. For those who carried extra weight while younger, CVD occurred earlier, making it more likely they would die before their time.
 

The Bottom Line

As I said, there really is no obesity paradox. Being overweight or obese carries with it risks of degenerative disease. Some people may have better genes and may gain protection for a few years. But in the end, being overweight or obese carries a higher risk of various diseases than the limited protection from an advanced disease you may gain by carrying extra weight. So my advice is the same as it always was: if you’re overweight, your best bet for a long, healthy life is to lose it.

What are you prepared to do today?

Dr. Chet

 

References:
1. Kidney International, Vol. 55 (1999), pp. 1560–1567.
2. European Heart Journal (2001) 22, 1318–1327.
3. JAMA. 2013; 309(1): 71–82.
4. JAMA Cardiol. doi:10.1001/jamacardio.2018.0022.

 

Does a Little Extra Weight Keep You Alive?

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The Rotterdam Study was begun in 1991 to investigate the risk factors of cardiovascular, neurological, ophthalmological, and endocrine diseases in people 55 and older (1). The study is still ongoing, but periodically subsets of subjects are examined to find out which characteristics are associated with these diseases. In a study published in 2001, researchers reported on a group of subjects who were diagnosed with heart failure at the beginning of the study and followed for an average of six years—181 out of over 5,000 subjects. By the end of five years, 85 subjects had died. One of the observations that researchers noted was that a higher BMI was associated with reduced mortality; in plain terms, the heavier people were more likely to stay alive.

It didn’t stop there. In 2013, a study was published that directly examined the relationship between BMI and mortality (2). This meta-analysis included 97 studies and examined more than 2.88 million participants and more than 270,000 deaths. They reported that while grades 2 and 3 obesity (grade 2: BMI of 35-39.9; grade 3: BMI more than 40) were associated with increased mortality, grade 1 (BMI of 30-34.9) was not, and the overweight category (BMI of 25-29.9) actually showed a reduced risk of dying. (How do you rate? Check your BMI here.)

Is this true? Is body weight not associated with an increased risk of death? Have we been trying to lose weight for no reason? I’ll finish this on Saturday.

What are you prepared to do today?

Dr. Chet

 

References:
1. European Heart Journal (2001) 22, 1318–1327.
2. JAMA. 2013 January 2; 309(1): 71–82.

 

What Is the Obesity Paradox?

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Did you ever hear something that didn’t seem to make sense? That seemed to go against everything you thought to be true? One example of this is something called “The Obesity Paradox.” I’ve seen a few headlines this week that have talked about it, so it’s time to address it in the Memo.

One of the variables that we would think is related to the development of cardiovascular disease would be body weight. It seems logical: as weight increases, so does the strain on pumping the blood through the additional blood vessels required to feed the extra fat and muscle. People who are overweight may eat the wrong foods, consume too much food, and move too little.

But since the early 2000s, several studies have been published seeming to show that body weight wasn’t necessarily a risk factor for CVD or an early death. They showed that those who were overweight, a BMI between 25.0 and 29.9, had lower mortality rates than those who were normal weight. Some showed that stage-one obesity, a BMI between 30.0 and 34.9, was also not related to mortality. Thus the term “The Obesity Paradox” was coined. But is it true? We’ll take a look at the research the rest of the week.

What are you prepared to do today?

Dr. Chet

 

Essential Tests: Bones and Body Fat

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After Saturday’s Memo, the logical question is: “How do I really know if I’m overfat?” This weeks Memos are going to be about tests. No, you don’t have to study for these tests. I’m talking about medical tests to talk about with your healthcare provider.

At this point, the best way to test for body fatness is using dual-energy X-ray absorptiometry (DEXA). This process uses low-beam radiation and can identify the three main tissues that make up our body: bone mass, lean mass, and fat mass. Yes, DEXA is the same technology that’s used to determine your bone mass to test for osteopenia and osteoporosis. Instead of just doing the wrist and pelvis, the entire body is scanned to determine body composition.

If you want to know your bone health and your body composition, check out the medical services in your area. There’s one hospital that offers DEXA for both purposes in Grand Rapids. If you’re over 40, it’s a great idea to do both tests. The bone scan will most likely be covered by insurance while you may have to pay for the body composition. The cost is about $100 in this area. If you want the most accurate method for bone mass and body composition, check out the DEXA availability in your area.

The goal is to use this information to improve your health. Reducing body fat and increasing bone mass both end up using a similar strategy: Eat less. Eat better. Move more. On Thursday another simple test that’s too often ignored.

What are you prepared to do today?

Dr. Chet-

 

Normal BMI but Still Too Fat

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Last week the health headlines shouted “Study Shows Over 90% of All Americans Are Overfat!” The rate of overweight as assessed by Body Mass Index (BMI) is already 70%; now scientists want to say even more people are too fat? What’s going on? I’ll explain what overfat means first and then tell you about the study behind it.

For the most part, the greater the BMI, the greater the risk for cardiovascular disease, prediabetes, and hypertension. For those of you who aren’t sure of your BMI, check out your BMI in the Health Info section of our website. And if you think you’re just big boned, we show you how to prove it.

But there are people who have a normal BMI under 25.0 but still may be overfat. Considering Waist Circumference in addition to BMI may help but that could still miss some people. How? They may have lost muscle mass; the subtle loss of lean muscle with a gain of fat could lead to overfatness. That increases their risk for the diseases I mentioned earlier.

Here’s the most common example of someone who has a normal BMI but is overfat: a very sedentary elderly person who looks slim, but has very little muscle. As the saying goes “use it or lose it” and they’ve lost it.

A clinician from Arizona has taken it upon himself to redefine the terminology associated with excess body fat. He claims that overfatness gets missed in too many people. The problem he sees is that people who could begin treatment with diet, exercise, and medication if necessary are being missed. He outlined his arguments in a paper published in January 2017 (1), but it was his paper published in July that lead to headlines (2).

He and his co-authors examined the BMIs of people in countries all over the world. Using prior studies that estimated the number of normal-weight people who are overfat, ranging from 9.7% to 20%, he then applied that to the normal-weight populations (as assessed by BMI) in the top 30 developed countries in the world. That’s how they derived the headlines of over 90% overfat—not just in the U.S. but also New Zealand, Iceland, and Greece as well. To be fair, this applied only to males. Don’t rest on your laurels, ladies. All the same countries were greater than 80% for females.

 

The Problems

There are three with his approach in my opinion. First, adding another definition to replace BMI doesn’t really help people or their physicians as he implies. Confirming a person with normal BMI is overfat would require a more advanced exam or assessment of body fat. I’m not sure that’s practical.

Second, I looked at his work from every direction and couldn’t get the numbers to work. If 70% of Americans are overweight or obese and you add 20% of the remaining 30%, it adds up to 76% not 90%. Even if the numbers worked, the statistic would apply to a physician’s total number of patients. There would be no way to identify who is overfat without additional testing.

Third, there’s another group that needs to be addressed, and that would be those who are overweight according to their BMI but are metabolically healthy. In fact, that’s a significant problem today. Even after losing over 30 pounds, my BMI is still in the overweight category. By every test of metabolic fitness—blood pressure, cholesterol, HbA1c, or insulin—I’m at no additional risk of heart disease, yet I’m still classified as “at risk” due to my BMI. I think that’s a greater issue and will be more so as healthcare gets debated. Is your BMI over 25? You’ll pay more, even if your test results are stellar.

 

The Bottom Line

I agree with the concept that the author put forth: there are people with normal BMIs that are overfat, and they’re at greater risk for CVD and metabolic diseases. But new definitions aren’t necessary. What is necessary is identifying who is at risk. That will only occur when doctor and patient meet face to face. When was your last doctor’s appointment?

What are you prepared to do today?

Dr. Chet

 

References:
1. Front. Public Health 4:279. doi: 10.3389/fpubh.2016.00279.
2. Front. Public Health 5:190. doi: 10.3389/fpubh.2017.00190.

 

The Data Must Make Sense

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The data has to make sense before you do any type of statistical analysis; that’s why I always look at the mean and standard deviations. Let me explain what I found that seemed a little off in the Fried Potato Study.

The authors divided the data into quintiles based on potato consumption from less then once per month to greater than three days per week. The researchers reported 19 variables from age to calorie intake to the percentages of various diagnosed diseases in each quintile of potato intake.

I focused on the caloric intake and the Body Mass Index in each category of potato intake. As potato intake increased, the caloric intake increased 600 calories per day—from 1,150 calories per day to 1,750 calories per day. Keep in mind there are 3,600 calories in a pound, so that’s over a pound a week. In every quintile, as the potato intake increased, so did the caloric intake. That could make sense although we don’t know if the additional calories all came from potatoes.

What didn’t make sense was that the BMI for each quintile was about the same: 28.5. That makes no sense at all. If the calories increased, the BMI had to increase for each quintile. It did not. Physical activity could not explain it because those in the highest caloric intake were less active than those with the lowest potato intake. It would be wonderful if calories didn’t add up and we could eat all we want without gaining a pound. I’m sad to say it doesn’t work that way.

While the study leaves that question unanswered and many more, it still isn’t the single biggest question of all. Can you guess what it is—even without reading the study?

What are you prepared to do today?

Dr. Chet

 

Reference: Am J Clin Nutr doi: 10.3945/ajcn.117.154872

 

BMI, WHR, and Lifestyle

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The study we’ve been examining is interesting on so many levels: large numbers of subjects; new statistical techniques due in large part to progress in computing capabilities; genetic analysis that allows for rapid analysis and identification of polymorphisms. It’s all very exciting. You’re probably anticipating a “but” coming and you’d be correct.

This study demonstrated that when using genetic information, WHR is a risk for CVD and type 2 diabetes even with a normal BMI. But there’s still at least two factors to consider that are dependent on each other.

First, just because someone has a mutated gene or genes, it doesn’t mean it will ever express itself, i.e., turn on. More than likely, the second factor has a role to play and that’s the lifestyle of the individual. Some studies refer to it as environment, but they’re intertwined. Where you live may limit or provide you with easy access to healthier foods. It may be easier to exercise in the suburbs than in a large city, or just the opposite given the park systems in different areas of the countries.

Then there’s the home environment: what foods you ate growing up and what your diet is now. All these can impact whether some genes may be expressed. Others may express themselves only when you get to a specific weight or fat intake. The variables are too numerous to consider.

I’m not attempting to confuse the issue. I just want you to know that while this study provides insight that we didn’t have before, you don’t have to be overly concerned. If you keep to a normal BMI and WHR, less than 0.9 for men and less than 0.8 for women, your risk for CVD and type 2 diabetes will not be high.

When all is said and done, it still comes down to three things. Eat less. Eat better. Move more.

What are you prepared to do today?

Dr. Chet

 

Reference: JAMA. 2017;317(6):626-634.

 

Waist-Hip Ratio vs. BMI

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In Tuesday’s message, I said researchers used a unique approach to answering the question of whether waist-hip ratio (WHR) is associated with cardiovascular disease and type 2 diabetes regardless of BMI. They found 48 genes which were associated WHR, a unique approach using the genetic information with Mendelian randomization of epidemiological data. If that isn’t a brain-full, I don’t know what is. Let me see if I can break it down for you.

As I’ve said many times before, epidemiological data cannot show cause and effect; they’re just observations. By using the genetic information related to WHR, researchers can analyze the data by statistically removing the effect of BMI. Because the genetic traits follow some randomization based on Mendel’s genetic work, if the WHR is still associated with the increased risks of disease, that means that where you carry your body fat is important, whether your BMI says you’re overweight or not.

They found that WHR is an independent risk factor for CVD and type 2 diabetes, confirming that the location of your body fat is important regardless of your BMI. That may be why people with a high BMI but low WHR have normal blood pressure and cholesterol levels while others with a normal BMI but a high WHR may have high numbers.

What are you prepared to do today?

Dr. Chet

 

Reference: JAMA. 2017;317(6):626-634.

 

Redefining the Risks of Extra Weight

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Studies show that 70% of the population is overweight; by definition, that means that their body mass index (BMI) is greater than 25 or more. But are all overweight people at the same risk? Just because you’re overweight, are you automatically at greater risk for cardiovascular disease and type 2 diabetes?

That’s what a group of researchers in the U.S. attempted to find out. They had the benefit of access to the U.K. Biobank, an independently funded databank that has collected biometric data on over 500,000 subjects in the U.K. and contains accurate measures of BMI as well as the waist-hip ratio (WHR) on all subjects. They also had one more thing: the genetic information on a large sub-group of subjects. They identified 48 genes that seemed to be associated with WHR and used a unique approach to tease out the effects of WHR from BMI. I’ll cover that the rest of the week.

In the meantime, check out your BMI and measure your waist and hip to calculate your WHR. Measure your waist about an inch below your belly-button and your hips at the widest point; divide waist by hips and you have your ratio.

What are you prepared to do today?

Dr. Chet

 

Reference: JAMA. 2017;317(6):626-634.