My 2 Cents

Saturday, September 29, 2012

Friday, September 28, 2012

Testosterone vs HDL & Heart Disease

In case you hadn't noticed the pattern, I typically spend the week reviewing a handful of recent articles. Over the weekends, I answer questions posted online at www.avvo.com and more recently at www.healthtap.com. I've gravitated towards these two mainly because they limit the folks who answer questions to licensed providers.

Anyway, one of the topics that I answer quite frequently is in regard to testosterone and its replacement. Obviously, there's quite a bit of controversy about this hormone, especially when it comes to prostate cancer. But there's also a need for clarity regarding its impact on HDL & cardiovascular disease.

That's why I wanted to point out a short editorial published recently in Clinical Lipidology. It turns out the published data is rather confusing & contradictory. Part of this is due to the difference between abuse and normal replacement as well as methodology employed. Taken in excess, all sort of side effects are possible, one of which is heart disease and other thrombotic events. This excess is commonly achieved via injections. But this doesn't mean that injections can't be used safely. It just requires close monitoring and a willingness to adjust both dose & frequency of injections. It's clear that transdermal products are less likely to lead to large peak:trough ratios while oral anabolic/androgenic steroids are rife with concern due to first-pass metabolism.

For my patients, I always counsel, prior to prescribing anything, that excess testosterone, however achieve, can lead to an increase in blood pressure, decrease in HDL (good cholesterol), and increase in blood viscosity (polycythemia), all of which increase the risk for clot formation, eg heart attack and/or stroke. Adjusting the dosing regimen or switching methodology is the key, I believe, to safely replacing testosterone in hypogonadal men.

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Thursday, September 27, 2012

Nature vs Nurture: Genetic Risk of Obesity vs Exercise

It's been an interesting week looking at the effect of sugar-sweetened beverages on children, adolescents & adults. More specifically, in 3 adult populations, there appears to be a link between sugar-sweetened beverages and genetic-predisposition towards obesity. So while I typically wait for peer-reviewed publication before commenting, I couldn't resist a segue based upon an abstract presented at last week's Obesity Society conference linking exercise to decrease in genetic risk of obesity.

Specifically, the presenter noted that moderate-to-vigorous physical activity tempered one's genetic risk of obesity from up to 42 loci associated with weight in a study of 8,113 adolescents. If you're like me, you probably had a Duh! moment. After all, regular exercise and proper nutrition are key to obtaining & maintaining a healthy weight. So, as I've noted previously in a series of posts, don't just sit there, do something!

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Wednesday, September 26, 2012

Sugar-Sweetened Beverages vs Weight Gain Part 3

Just 2 days ago, we looked at the link between consumption of sugar-sweetened beverages & weight gain in children. Yesterday, we looked at the impact of sugar-sweetened beverages & weight gain in adolescents. So it seems a propos that we look at how sugar-sweetened beverages affect adults in the 3rd of 3 studies published early online last Friday in the New England Journal of Medicine. In fact, the authors concluded that sugar-sweetened beverage consumption was linked to greater genetic predisposition to obesity. So perhaps nurture is impacting nature? While it may appear intuitive that drinking calories devoid of nutritional value would lead to weight gain, this study only proves an association but not cause & effect.

Thanks to modern technology, scientists have located at least 32 areas of our genome associated with body mass index (obesity). The authors developed a genetic-predisposition score based upon said loci and compared this to consumption of sugar-sweetened beverages in 6,934 women (Nurses' Health Study) and 4,423 men (Health Professionals Follow-up Study). They then took it one step further and compared this genetic predisposition score to sugar-sweetened beverage consumption in 21,740 women (Women's Genome Health Study). The findings were similar in each case: greater consumption of sugar-sweetened beverages was associated with greater genetic predisposition towards obesity.

Nature vs nurture. Genes vs environment/experience. We've always questioned which matters more. This study supports a link between the two. I'm not convinced we should throw up our hands & blame our eating habits on our genes but it would certainly appear that our eating habits do have some association with our genes. Chicken or egg, anyone?

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Tuesday, September 25, 2012

Sugar-Sweetened Beverages vs Weight Gain Part 2

In yesterday's post, I pointed out that those children 5-12yo randomized to diet, sugar-free beverages gained less weight over 18 months compared to those who drank sugar-sweetened beverages. In the second study in a series examining the impact of sugar-sweetened beverages, the authors randomized 224 overweight & obese adolescent consumers of sugar sweetened beverage to either intensive intervention to decrease the likelihood of consumption of sugar-sweetened beverages vs no intervention at all.

Over the 1st year of intervention, those adolescents who received continued intervention to decrease sugar-sweetened beverage consumption noted significantly less weight gain. However, when left to their own devices for the 2nd year w/o supervision, the difference in weight between the two groups was negligible. In truth, this shouldn't be a surprise to any parents of teenagers who need constant supervision & reminders to do what they're supposed to do since they appear to be more externally driven as opposed to internally motivated. Hopefully, they'll see the light and make better nutrition choices before their body mass index clears 30kg/m2.

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Monday, September 24, 2012

Sugar-Sweetened Beverages vs Weight Gain

This past Friday, a series of studies & editorials was made available early online prior to print publication in the New England Journal of Medicine, all of which concluded that sugar-sweetened beverages have an impact on weight (gain).

In the first study, the authors followed for 18 months 641 normal-weight children ranging from just under 5yo to just under 12yo who were randomized to 8oz of either a diet, sugar-free beverage or a similar non-diet, sugar-sweetened beverage. The caloric difference was only 104 kcal/drink. The drinks were distributed at school to be sure the participants had access.

Granted, 1 out of 4 children dropped out of the study. But using an intention-to-treat analysis, the authors noted that body mass index z-score increased to a lesser extent in those randomized to diet, sugar-free beverages compared to those who drank an extra 104 kcal/day.

So as much as I don't like artificially sweetened beverages (high fructose corn syrup tastes better), I better start to like drinking water (even though I'm way beyond 12yo).

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