The Nation's Health + [Metabolic syndrome]

Can skinny be fat?

You're going to hate this.

Dr. Romero-Corral and colleagues from the Mayo Clinic presented an analysis of the National Institutes of Health-funded National Health and Nutrition Examination Survey (NHANES-3) at the recent American College of Cardiology meetings. (Science Daily also has some coverage on this report.)

Their analysis identified 2127 adults from the NHANES database who had normal body-mass indexes (BMI) between 18.5 and 24.9 units), average age 41 years old. When broken down by percent body fat (measured with bioimpedance, meaning a small electrical current is passed through the body, much like what the store-bought Tanita devices do), with normal-weight obesity defined as >20% body fat in males , >30% body fat in females , 55% of participants met criteria for designation as normal-weight obesity .

Compared to people with similar BMI's but who fell below these body fat percentage cut-offs, the normal-weight obese men had increased ratios of Apo B to Apo A1; were much more likely to have increased blood sugars or be diabetic; have higher C-reactive protein (CRP); were several-fold more likely to meet other criteria for diagnosis of metabolic syndrome; had lower HDL cholesterols; and had higher blood pressure. Women with normal-weight obesity were four-fold more likely to have coronary disease.

While preliminary, this suggests that a substantial number of people with apparently favorable body weights and BMIs are, in actuality, overweight when judged by metabolic parameters. This then probably leads to increased risk for heart disease. We can then fairly readily extrapolate the argument that a reduction in weight to even lower BMIs likely reduces or corrects these patterns.

This argument is similar to that proposed by several others, arguing that BMI is a flawed measure, since it does not incorporate muscle mass or skeletal factors ("big- or small-boned"). Instead, they have argued that waist circumference is preferable.

The normal-weight obesity syndrome was originally identified by Dr. Antonio de Lorenzo and colleagues at the University of Tor Vergata, Rome, Italy, and reported in Normal weight obese (NWO) women: an evaluation of a candidate new syndrome. Their studies of women with this "syndrome" have suggested that heightened measures of inflammation are present despite apparently normal body weight and BMIs. One such report, Normal-weight obese syndrome: early inflammation?, is available in full-text.

Is there a lesson to be learned for the Track Your Plaque program? I believe there is. I believe it means that, if you have any weight-sensitive parameter, such as low HDL, small LDL, high triglycerides, high CRP, high blood sugar, high blood pressure, etc., then further weight loss might be considered, even if BMI is around 25. Obviously, there is a rational limit to how far you can push this concept. (Anorexia is not good for you either.)

I find this a useful concept. It provides yet another potential strategy to pursue when the above patterns are encountered. Perhaps it's also a way to cap reliance on niacin, whose effects closely mimic that of weight loss.

Now that's a lot more preferable to more and more statin drug, isn't it?

Copyright 2008 House, MD