Although excess weight is well known to substantially increase the risk for heart disease, we and others have consistently reported that obese patients with heart failure actually live longer than those who are normal weight or skinny.

This obesity “paradox” obviously begs the question of whether or not weight loss is something that you would actually recommend to someone who is obese and has heart failure - if being obese when you have heart failure, wouldn’t losing weight make things worse?

Believe or not, there are almost no studies addressing the impact of intentional weight loss on heart function. The few available studies are largely limited to small series of patients who underwent bariatric surgery, where weight loss does show marked improvements in heart function.

But can similar effects be achieved with dietary weight loss?

This is exactly the question that will be addressed by a study to be performed in collaboration with researchers at the Mazankowski Alberta Heart Institute. The study will include twenty severely obese individuals with heart failure, who will undergo intentional weight loss using a standardized low calorie diet (OPTIFAST 900). Their cardiac function and other parameters will be carefully measured and will hopefully show significant improvements in hemodynamic function and exercise capacity.

The study is funded with a $250,000 grant provided by the Alberta University Hospital Foundation and is due to be completed within three years (if not sooner).

To watch a video on this study as reported on CTV News click here or to read more about the background on CBC News click here.

AMS
Edmonton, Alberta

A few hours ago I arrived in Hong Kong to speak on the relationship between obesity and hypertension at the 1st International Conference on Abdominal Obesity. While excess weight is probably one of the most important risk factors for high blood pressure, weight loss is certainly one of the most effective treatments.

This relationship between excess weight and blood pressure and how this relationship is affected by a prudent diet, exercise and weight loss is the topic of a paper by James Blumenthal (Duke University, Durham, NC) and colleagues published in this week’s issue of the Archives of Internal Medicine.

The aim of this study was to compare the so-called Dietary Approaches to Stop Hypertension (DASH) diet alone or combined with a weight management program with usual diet controls in 144 overweight or obese participants with prehypertension or stage 1 hypertension (130-159/85-99 mm Hg).

Participants were randomised to four months of their usual diet, DASH diet alone, or DASH diet plus weight management. The DASH diet is reduced in total fat (27%), saturated fat (6%), and cholesterol and contains about 3 times as much dietary fiber, potassium, magnesium, and calcium as the usual diet.

Participants in the weight loss arm were asked to reduce caloric intake by 500 kcal/day and attended weekly 30- to 45-minute small group sessions that also included a weekly cognitive-behavioral intervention as well as supervised exercise sessions 3 times per week at a level of 70% to 85% of their initial heart rate reserve consisting of 10 minutes of warm-up exercises, 30 minutes of biking and/or walking or jogging, and 5 minutes of cool-down exercises.

Participants in the weight management group lost 8.7 kg compared to virtually no weight changes in the other two groups.

The greatest reduction in blood pressure (16.1/9.9 mm Hg) was seen in the DASH plus weight management group compared to only (11.2/7.5 mm) on the DASH diet alone) or 3.4/3.8 mm on the usual diet.

While the study clearly shows that the DASH diet combined with weight loss and exercise can lead to a far greater reduction in blood pressure than the DASH diet alone, there are two important caveats:

1) This is a relatively short term study (4 months) and can therefore not be considered much more than a “proof of principle”.

2) The study was performed at a tertiary care medical center and may therefore have limited applicability to weight or blood pressure management in primary practice.

Nevertheless, the study does remind us of the importance that both diet and weight loss can play in the management of overweight and obese patients with high blood pressure.

AMS
Hong Kong

Yesterday, the Heart and Stroke Foundation of Canada released a report titled “A Perfect Storm” in which they present an alarming increase in hypertension and other cardiovascular risk factors in young adults.

According to this report, currently over 160,000 Canadians aged 20-30 and over 340,000 Canadians aged 35-44 are hypertensive.

This should really not come as a surprise, as the same report states that currently 40.5% or 2,5 million 20-30 year olds and 51.5% or another 2.4 million 35-44 year olds are overweight or obese.

Why, given these obesity numbers, does this increase in hypertension not surprise me in the least?

Because, as someone who has extensively worked on the relationship between excess weight and blood pressure, I am only all too familiar with the profound effect that overweight and obesity can have on blood pressure - especially in the young!

Thus, as we reported in a paper that was published back in 2004 in the American Journal of Hypertension, overweight and obesity are indeed the primary drivers of hypertension in the young.

In this cross-sectional study of 45,125 unselected consecutive primary care attendees in a representative nationwide sample of 1912 primary care physicians in Germany, we not only found that blood pressure levels were consistently higher in obese patients (increasing from 34.3% in normal weight to 60.6% in overweight, and well over 70% in obese individuals), but that this increase was also associated with markedly poorer blood pressure control rates (odds-ratio for good blood pressure control in diagnosed and treated patients was 0.8 in overweight and as low as 0.5 in obese patients).

However, even more relevant to yesterday’s report, was the clear finding that the younger the patients, the greater the impact of excess weight on their blood pressure.

As seen in the figure (click figure to enlarge), while in patients older than 60 years, there was little impact of BMI class on hypertension prevalence, in younger patients, there was a steep and consistent increase in hypertension rates with increasing BMI.

This is not surprising, when we look at the pathophysiology of hypertension, which in older individuals is driven almost entirely by stiffening of arteries and an increase in peripheral resistance (or in other words “aging”), while in younger individuals hypertension is driven mainly by the increased sympathetic activity, volume expansion, and increased cardiac output typically associated with excess weight.

Let us not forget that the prevalence of diabetes in the young (over 66,000 in 20-30 year olds and over 130,000 in 35-44 year olds according to the report) is also virtually entirely driven by overweight and obesity.

If all of this is not enough to get us to focus all our efforts on preventing and treating overweight and obesity, I don’t know what is.

If we want to prevent hypertension and diabetes in the young, we need to prevent overweight and obesity.

If we want to treat hypertension and diabetes in the young, we need to treat overweight and obesity.

It is that simple!

AMS
Edmonton, Alberta.

With all the talk about obesity as a risk factor for diabetes and heart disease, we may often forget that excess weight affects all organ systems.

One set of organs that appears particularly sensitive to the ill-effects of excess weight are the kidneys.

This is nicely illustrated in a study just published in the American Journal of Kidney Disease by John Munkhaugen and colleagues from the Norwegian University of Science and Technology, Trondheim, Norway.

The researchers examined the combined effect of blood pressure (BP) and body weight on the risk for end-stage renal disease or chronic kidney disease (CKD)-related death.

Participants included data from 74,986 adults of the first Health Study in Nord-Trøndelag (88% participation rate), which were linked to the Norwegian Renal Registry and Cause of Death Registry.

During a median follow-up of 21 years (1,345,882 person-years), 507 men (1.4%) and 319 women (0.8%) initiated renal replacement therapy (n = 157) or died of CKD (n = 669).

The risk associated with body weight started to increase from a BMI of 25.0, but this increased risk was not seen in participants with BP less than 120/80 mm Hg.

In contrast, in participants with even moderately increased BP (pre-hypertension or hypertension), there was a progressive increase in the risk for kidney disease with increasing BMI suggesting an almost 6-fold increased risk in participants with a BMI greater than 35.

The study strongly suggests that individuals with a BMI greater than 30 are increasingly vulnerable to kidney disease even with a modest increase in blood pressure.

This finding has several important clinical implications:

1) Blood pressure should be carefully monitored in all individuals with BMI greater than 30.

2) Even moderately elevated blood pressure (pre-hypertension) should be addressed with lifestyle and, if necessary, pharmacological treatment in obese individuals.

3) Blood pressure treatment targets in obese patients may need to be similar to targets in patients with diabetes (i.e. below 130/80 mm Hg).

AMS
Edmonton, Alberta

Regular readers are certainly familiar with my many posts on the limitations of BMI and on the idea that not all fat is bad and that different fat depots may have quite different effects on cardiometabolic risk.

You can now find much more on this topic in a comprehensive review article by Konstantinos Manolopoulos and colleagues at Oxford University, UK, published in this month’s issue of the International Journal of Obesity.

The review not only concludes that there is now ample evidence to support the notion that not just the amount of body fat, but rather its distribution is an important determinant of the metabolic and cardiovascular risk associated with obesity. In fact there is now increasing evidence that being too skinny may well be bad for you and that carrying a few extra pounds of fat on your hips and thighs may actually be protective.

Thus, studies show that increased hip and thigh fat is independently associated with protective lipid and glucose profiles. This protective effect may be in part due to the fact that gluteofemoral fat can absorb and store excess fatty-acids, thereby removing them from the circulation. In addition, leptin and adiponectin levels tend to be positively associated with gluteofemoral fat while the level of inflammatory cytokines is negatively associated.

As the authors point out, the loss of gluteofemoral fat, as observed in Cushing’s syndrome and lipodystrophy is in fact associated with an increased metabolic and cardiovascular risk.

This may not be good news for people seeking medical help to reduce the size of their hips and thighs - I would probably have to advise them against it - definitely not a message many of my patients want to hear.

On the other hand, if the excess fat is largely located around your midsection, then, this excess “belly” fat is probably the biggest driver of your risk for type 2 diabetes and heart disease.

So really, not much new for regular readers of my blog, but certainly a noteworthy article that nicely summarizes what is currently known about this issue.

Wonder what it’ll take to make large butts and thighs more socially acceptable?

AMS
Edmonton, Alberta