Exactly How Important is Obesity in Heart Attack and Stroke Risk?

It is well known that the risk of developing diabetes, high blood pressure, and high cholesterol is increased with overweight or obesity.  However, it's been long debated as to whether obesity itself increases the risk of heart attack and stroke (and if so, how important is this effect), or whether the risk conferred by excess body weight is strictly mediated by these risk factors.

A new study in the Lancet puts some numbers on these answers for us.  The study pooled data from 1.8 million people from almost 100 different studies globally, and they looked at what percentage of heart attack and stroke risk was attributable to blood sugar, blood pressure, cholesterol, vs overweight and obesity themselves.

They found that for every 5 kg/m2 increase in body mass index (you can calculate your own BMI here in the right hand column), the risk of heart disease went up by 27%, and the risk of stroke increased by 18%.  They found that only about half of the excess risk of heart disease with higher BMI was mediated by blood sugar, blood pressure and cholesterol, and about three quarters for the risk of stroke.

In other words, about half of the risk of heart disease, and about a quarter of the risk of stroke, appears to be mediated by excess body weight itself (and/or possibly unknown risk factors), independent of these other risk factors.

The take home messages here, as I see it, is that it is not enough to treat the blood sugar/pressure/cholesterol abnormalities in a person who carries excess body weight, nor is it enough to target weight management alone - all too often, we see these risk factors go untreated for years as individuals continue to try the lifestyle approach, unfortunately most often without success. These risk factors need to be proactively treated, in addition to a sound approach to permanent lifestyle changes that will facilitate weight management and improvement in these risk factors.

Follow me on twitter: @drsuepedersen

www.drsue.ca © 2014

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Obesity and Hearing Loss in Women

Excuse me?  Didn't quite catch that.  Yes - it's correct that obesity and hearing loss are together in the title of this post, as it seems that obesity is an emerging risk factor for hearing impairment.

A recent study looked at over 68,000 women enrolled in the Nurses' Health Study between 1989 and 2009, and found that just over 11,000 cases of hearing impairment were reported.  They found that for women with a Body Mass Index of 40 or higher, there was a 25% increased risk of developing hearing impairment, compared to women with a BMI under 25.  A larger waist was also associated with a higher risk of hearing loss.

Interestingly, higher physical activity was associated with a lower risk of hearing impairment.

How can this be?  It is possible that in states of obesity or poorer metabolic health, some of the 'bad' or 'inflammatory' chemicals that are produced by the unhealthy metabolic fat that collects around our organs may damage the nerve cells in the ear.  In medical terms, this includes oxidative stress and the formation of reactive species.  Hardening of the arteries probably also plays a role - just like atherosclerosis manifests as narrowing of the arteries in the heart and brain, the small arterioles become hardened as well and can compromise blood supply to our hearing apparatus.

One more health concern to add to the list of possible concerns associated with carrying excess body weight.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2014

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