Thursday, February 09, 2006

Obesity and the heart

It is common knowledge that the Chinese like their food. In fact, the usual greetings when Hokkien Chinese meet is, "chiap pah ba?" (Literally "have you eaten"). To the Chinese a big tummy is a tummy of prosperity. Unfortunately, the potbelly is a danger to all of us.

As demonstrated again recently in subgroup analysis of the "INTERHEART" study and presented at the Nov. 2005 AHA annual scientific meeting. The original INTERHEART study (which involved 27,000 subjects in 52 countries) was first presented at the European congress of cardiology in 2004 and published in the Lancet in 2004.

The subgroup analysis of the INTERHEART study, showed that the waist to hip (WTH) ratio was a better indicator of cardiovascular risk then the conventional BMI, in any country and across any culture. In fact although we set a WTH ratio of 0.9 quite arbitrarily as ideal, the lower the WTH ratio, the less the CVS risk.

This finding is in line with pathogenetic study which showed that the abdominal fat is an active hormonal organ which secrete adiponectin and also the pro-inflammatory interleukin-6 (IL6). The adiponectin acts to produce insulin resistance, hypertension and also increase CVS risk, and the IL6 acts on the liver to produce CRP, serum amyloid and fibrinogen.

This is in line with our understanding that coronary artery disease is an inflammatory disease and that the metabolic syndrome may also be an inflammatory disease. It is interesting to note that if visceral fat is remove by surgery, the IL6 levels goes down and so also the risk of cardiovascular disease and metabolic syndrome.

In summary, we learn from INTERHEART study, that obesity is a general term, and maybe better defined by measurement of waist to hip ratio then "body mass index". Let us all strive to keep our waist thinner then our hip. Besides lowering our CVS risk, it may allow us to wear hipster jeans.

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