Wednesday, September 5, 2007

Waist to Hip - Thank you Erin!

Okay because I can't put it better, I'm just going to quote exactly what super med student Erin has told me about the Waist to Hip ratio I mentioned 2 posts down.

Erin Says:

Okay, so here's some information that I adapted from a textbook I have called "Evidence Based Physical Diagnosis" by Steven McGee (2007). Just ask me if you have any questions about what's in there. All this information is based on scientific and medical studies. This means that when the word "significant" is used, it doesn't just mean "notable"; it usually means that, statistically, if the study were to be repeated, there would be a 19 out of 20 chance that they would get the same results. If you need any of the specific references for what I've given you here (journal articles, etc.) let me know. I included info on waist-to-hip ratio, waist circumference, and BMI:

The waist-to-hip ratio (WHR) is the circumference of the waist divided by that of the hips. It is based on the premise that the most important characteristic of obesity is its distribution, not its quantity. "Abdominal" obesity (aka apple-shaped) has a much worse prognosis than "gluteal-femoral" obesity (aka pear-shaped).

Most authorities measure the waist circumference at the midpoint between the lower costal margin (your last rib, on the side of your body) and the iliac crest (your hip bone, on the side of your body) and the hip circumference at the widest part of the gluteal (buttock) region. Divide the measurement of the waist by that of the hips. Adverse health outcomes increase significantly when the WHR exceeds 1.0 in men and 0.85 in women.

WHR predicts health outcomes better than any other measure of the body. Even after accounting for the effects of BMI, the WHR correlates significantly with blood pressure, cholesterol level, incidence of diabetes mellitus, stroke, coronary events, and overall mortality.

The main contributor to abdominal obesity is fat that surrounds the intestines, stomach, and other organs behind the abdominal wall (called visceral fat), not fat that is just beneath the skin (subcutaneous fat). Visceral fat is very active metabolically, meaning that it readily releases fat that contributes to high cholesterol, plaque build up in the arteries, and problems with insulin which may lead to diabetes. Fat that is around the hips and thighs, on the other hand, is metabolically inactive, except during and shortly after pregnancy.

Waist circumference is simply the waist measurement taken for the WHR calculation. Although this measurement is simpler to do, it is not as good a measure as WHR. Recommended cutoffs for increased health risk are a waist circumference greater than 102 cm (40 inches) in men and 88 cm (35 inches) in women.

The BMI correlates well with precise measurements of total body fat, much better than other formulas of weight and height. The BMI also correlates significantly with the patient's cholesterol level, blood pressure, incidence of coronary events, and overal mortality.

The arbitrary cutoff of 25 kg/m^2 was chosen in part because it reflects the level at which there is a significant increase in mortality, although increased rates of complications such as diabetes appear at lower cutoffs

Wholey! I just learned a lot! And also learned that an alcohol soaked mind distorts conversations.. wait no I knew that already!

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