Is Obesity a Cardiovascular Risk Factor?

sharma-obesity-cardiac-rehabThis morning I am presenting a plenary talk for the Canadian Association of Cardiac Rehabilitation at the Vascular 2013 conference in Montreal.

This topic is certainly relevant to this organisation, as, in a paper published in the Journal of Cardiopulmonary Rehabilitation back in 2004, we showed that about 35% of patients seen in cardiac rehab programs have a BMI greater than 30 kg/m2.

Thus, it was not surprising that the topic I was asked to speak on, is whether or not obesity is a cardiovascular risk factor.

As I hopefully made clear in my presentation, this is not as straightforward a question as many may think.

No doubt, excess body fat is associated with well-known risk factors for cardiovascular disease including hypertension, dyslipidemia and diabetes mellitus.

However, we have also learnt that much depends on the molecular and cellular composition as well as the anatomical location of this excess fat.

While intra-abdominal or visceral fat as well as other ectopic fat depots (e.g. heart, muscle, liver) are strongly associated with cardiovascular risk factors, excess fat deposition limited to subcutaneous depots (particularly hips and thighs) may even be deemed protective.

Thus, whether or not excess body fat is a risk factor for cardiovascular problems really depends on the exact nature of that fat.

That said, there are other aspects of excess weight that warrant medical attention.

Although, diabetes may be the most important predictor of mortality in obese individuals (see yesterday’s post), there are other significant health problems associated with excess weight (arthritis, sleep apnea, reflux disease, urinary incontinence, etc.) that may exist even in the otherwise metabolically healthy obese individuals.

As we showed in our 2004 paper, substantial benefits on cardiovascular risk factors can be derived from exercise-based cardiac rehab programs even with minimal or no weight loss.

Whether or not weight loss significantly adds to reducing cardiovascular risk in the long-term, interestingly enough, still needs to be demonstrated.

Montreal, QC