Tag Archive for: WHR

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.