What does it mean to be metabolically healthy obese?

     Over the past weekend, I read a summary statement for a research study by Camhi and Katzmarzyk, 2013.  I was intrigued because the exercise and health scientists explored the differences in body composition (e.g., % lean mass, fat mass, bone density, central fat tissue) between two groups of obese people. The people in the study were classified as metabolically healthy obese or abnormal obese. The summary statement did not indicate if obesity was determined by BMI, waist to hip ratio, waist circumference or some other measure.  It did say how the determination of healthy vs unhealthy (metabolically speaking) was made, and I thought this a teaching point.  (FYI: Simply put, metabolic refers to under the skin - cellular processes. So the researchers were not looking at whether or not there were mental health issues, or physical conditions like arthritis, in this group of obese persons.)  I also do not know why the researchers chose the criteria listed below to determine metabolic health, but each has been independently associated with poor health outcomes, like heart disease, in other studies.  Of the following measures, an obese person in the study who had 1 or less of them was considered metabolically healthy, and an obese person in the study who had 2 or more was considered metabolically abnormal.  

The measures were:

1. a blood pressure reading higher than 130/85 mm/Hg
2. a fasting glucose level greater than 100 mg/dl
3. a waist circumference greater than 102 cm men, 88 cm women (click here to convert to inches) 
4. triglyceride level (blood fats) higher than 150 mg/dl
5. hdl (good) cholesterol less than 40 mg/dl men, 50 mg/dl women

     I noticed that they did not use total cholesterol levels or LDL levels. 

     The aim of the study was to see if something about body composition was different between the two groups (could this difference explain the accumulating risk factors).  The researchers did find differences, which were specific to gender.  For most of the body composition measures they assessed(not described here), the metabolically healthy obese had lower values.  For example, both metabolically healthy men and women had lower fat mass and less stomach or trunk fat.  Most every measure was related to a type of adipose(fat) tissue, such that the more fat one had on their body, and in specific places, the more likely they were to have more than 2 of the risk factors and thus be metabolically unhealthy.
     Take home point.  Your absolute weight is not as important as your body composition and the 5 measures listed here are numbers you might want to pay attention to at your doctor's visits.
 

Breast Cancer Rise and Significance

   Last week it was reported in the popular press that a new study had found a rise in the number of younger women (ages 25-39) who were being diagnosed with advanced breast cancer.  I did not seek out the actual research, but what I did hear on the news (likely NBC Nightly News) is important to clarify.  We were told that in the last 30 years, the rate of diagnoses per 100,000 women went from 1.5 to just about 3.  That means for every 100,000 women in that age group, almost 3 were found to have advanced breast cancer in 2009.  The news reporters and scientists have noted that this is a small but significant increase in cases. (the significance statement is being questioned by some researchers, but lets say it is not).
   When you read a study and see that it is significant what that means is that it is 'real'.  It does not mean it is big or even important. You need both the effect size and whether or not it was 'real' to make your assessment.  Is 1.5 more cases a big deal?  That is for you to decide. In the statistics world, the significance means that the finding (here more cases of breast cancer) is very likely due to something other than chance. 
    When comparing two values (here at two time points) the assumption is that there is no difference.  The p value tells you the percent of times you could expect to find a real difference if there  wasn't one.  How many times you'd be making a mistake.
  The study researchers think that the finding in this case is real.  It could be that more women are obese and that obesity somehow increases the risk, or that as women are starting puberty earlier this could be upsetting hormone levels and increasing the risk.  The scientists who published this current study do not KNOW the reason.  They are only saying that the cases increased and something is behind it.  (Usually scientists or statisticians set a level of .05 or .01 at the start of a study and only accept 'significance' if they have a p < .05).   I am thinking you wish I had stopped talking about a paragraph ago!
Just eat right and exercise, ok!?  ( and of course, don't expose yourself to cigarette smoke, first hand or otherwise)

Circumsicing Babies

   The focus of this blog has included the application of research to real life and evaluating headlines that are in response to research.  In other words, the "truthiness" of those headlines.
   The American Academy of Pediatrics confirmed its stance and recommendation for male infant circumcision today.  The rationale behind the recommendation is that there are lower rates of certain infections amongst males who have had the procedure.  The outcome that shows a greater difference between circumcised and uncircumcised boys is urinary tract infections.  UTI rate also seems to have the most evidence behind it- it has been studied the longest. Other outcomes that researchers associate with lack of circumcision are HIV, HPV, cancer, and sexually transmitted infections in general.  (associated  meaning the outcomes are higher in one group than the other)
   If I had a male child I would have him circumcised, but not because I believe that it prevents sexually transmitted diseases.  I believe that it may reduce infections in general and to tell you the honest truth - my decision is also aesthetic.
   This morning I heard someone make an argument for circumcision as an HIV prevention strategy using the results of the change in HIV rates in African men, living in African countries who are circumcised as adults.  The person who was using this evidence to support circumcision in infant American boys was challenged.  Can you see why?  How are these two groups similar?  They are not.  The results from the adult study in another country does not translate to these boys.  Even if it makes biological sense, you can't extrapolate to such a different context.
   Another point made in the discussion was that the rate of circumcision in the UK is much lower than that in the USA and UK men HIV is lower in the UK.  This was countered by another who said that the number of new cases was much higher in the UK - or the rate vs the prevalence (chronically ill vs newly ill).  Again - the two groups are not the same and a comparison is suspect. (what else protects against HIV?  Maybe UK men have less sex?  Maybe many are HIV and undiagnosed?  Who knows, but you can't show cause and effect either way.)
  My biggest issue however, is when any of them try to say that circumcision prevents the "disease in question" or that not being circumcised causes it.  The only way to claim that direct link is to have some boys circumsized and others not and then make sure that they are exposed to the same conditions and risks throughout their lives and see if one groups gets more diseases than the others.  That has not been done and it will not be done.
   I imagine that instead, most of these studies are looking at the characteristics of men with a disease.  To determine what those characteristics are, they have to ask questions - either of the men, their physicians or their partners. Or some combination. Whether or not they have been circumcised is observable but the number of sexual partners, the use of condoms with partners, consistent or occasional use of condoms, the risk behaviors of the people the men have sex with... all of those things have to be considered and all of those things have certain biases.  For example, a person might not remember, might not know, or might not want to say.  But, what if boys who are not circumcised have different kinds of sexual partners/experiences on average than the circumcised boys/men do? With all of these things impacting the risk of getting sick, how can one say that circumcision is the determinant?  Maybe a question to ask is whether or not condoms are more or less protective based on circumcision status.
    I am not at all speaking out against the procedure - just the use of studies to make a link between the penis status and the diseases.  I am especially suspect of the circumcision - HPV link.  
   Today I heard someone say that HPV causes penile cancer (they were claiming that circumcision prevents HPV and thus can prevent penile cancer).   That got a reaction from me! I feel certain that if HPV caused a cancer in men Merck (drug company with the HPV vaccine) would be all over it.  Unless of course,  the association is real but the actual cancer incidence is extremely low. 
   I have not reviewed any of the studies, my main point is that there is a great deal to consider and just because someone says it on the radio, doesn't make it true.
   Here is a link to the actual statement from the pediatric organization as published in their leading journal.

Medicine

My plan for tonight's blog does not seem to be materializing. I could use some of my ideas that I have for later in the week, or expand one of the Odds and Ends I have put aside, but I am pretty stubborn that way- and don't want to do that.

So I will explain where I was going to go with today's post first, then I will mention the article I was going to blog about before I had that "brilliant" idea that didn't pan out.. And THEN I will just call it a day.

I came across a term teaching a class last night and the meaning escaped me - which bothered me. The word was anxiolytic. It got me thinking about analgesics, antibiotics, anti inflammatories, diuretics,psychotropics, anesthetics, antiemetics etc . I know analgesics reduce pain but I couldn't for the life of me recall what an anxiolytic did. It is an anti anxiety medication or chemical - duh, but we always call them that -anti anxiety drugs- not anxiolytics. I was hoping to find a list of drugs by their scientific names and then to describe them all, but that list doesn't really exist. Surely there is a fancy name for a fever reducing drug, but I couldn't find it. Just to be thorough, since I did mention a few- I will explain them. The first is a pain reliever, the second fights bacterial infections, the next, inflammation, diuretics are fluid pills, psychotropics are drugs that can affect ones mood, anesthetics reduce consciousness and antiemetics are anti vomit medications.

So that's all I have for that thought.

Yesterday I was intrigued by a brief story regarding Medco which is a pharmacy benefits management company. In other words, a health insurance company might use Medco to review and determine what medications are on the formulary and what copayments apply to them. Medco was the company that first reported a drug interaction between a proton pump inhibitor and plavix. The company CEO has stated that they are going to spend more resources - staff and money - on independent research in the coming year. I know a lot of people get upset about benefits managers telling us which drugs we should take, especially because all those commercials we see make the newest drugs appear to be the best, but I for one am GRATEFUL for comparative research, and if it saves money that is all the much better because the country's insurance premiums seem to rise in unison.

Are YOU at risk for VTE?

True to the nature of this blog, I am reporting beyond the headlines. Only yesterday a study on Venous Thromboembolism was reported in the peer reviewed journal, The Annals of Internal Medicine. After seeing the Reuters story I sought the actual research article and a few other sources in order to address the issue of travel related blood clots. A venous thromboembolism is a clot in the vein. The fear with VTE is that it can lead to a clot moving through the vein to the lung. This is often referred to as PE, which is pulmonary embolism and it can cause death. It is a very serious condition. (clots can interrupt blood flow or cause an artery or vessel or vein to burst)

You may have heard at least one story about flying and the risk of getting blood clots in the last few years. What the scientists from Harvard sought to find was evidence for or against the increased risk and explanation for why some studies show an increased risk and others do not.

Much is explained in the actual research article that leads me to believe that their conclusion that traveling, by plane or car, (in other words, being immobilized) does increase the risk of VTE as compared to not being stationary for those two plus hours. They found a 3 fold increase.

There was a lot for me to sort through and a few good points to make to you. First of all, what is a 3fold risk. To the best of my understanding it is 3 times the risk. That being said, 3 times WHAT? If the risk for getting a clot or VTE is 1 percent in general and now it is 3 percent, well there is a 97% chance I won't get one, so not so bad. The best I could come up with was in reading another article about deep vein thrombosis where people were put into categories of low/no risk and moderate and high etc. It said that the low/no group had a rate of 4 per 10(4) which I interpreted to mean 4 per 100,000 people. So that many people might randomly be expected to get a blood clot. This new study would then be saying that 12 people out of 100,000 would get one from traveling. Not to0 high, but I don't like that number so much.

I learned a lot in my research today. Firstly, there is a triad of things that could lead to a blood clot, this triad is named after the clinician who described them. It is the Virchow triad. The scientists found that travel can lead to 2 of the 3 conditions of Virchow's Triad. The conditions pertain to:

the vessel wall, blood flow and blood composition

The vessel wall is lined with special flat blood cells called endothelial cells and they exists to keep blood from clotting inside the blood vessel. (coagulation is a good thing when you have a cut, but it is called thrombosis when it occurs inside the blood vessel, and a thrombosis is bad)

Endothelial cells can be damaged from smoking.
The vessel wall changes do not occur because one is traveling or immobilized. The other two conditions can. They are stasis, or sluggish blood flow and a change in blood composition. The change in blood composition means that the blood platelets are more likely to come together and form a mass or clot. Some reasons this may occur are dehydration, being on birth control pills and having a history of blood clots, as they can scar the vessel walls. Further, being obese and having high blood fats will increase thrombosis risk. Another risk factor is varicose veins. They interrupt blood flow because they are often kinked, crooked and bulging. Normal blood vessels are straight and narrow.
So what can you change and not change and what is specific to traveling. You know that you can work on weight and hyperlipidemia and stop smoking. That is a given for any disease risk.
For flying, at this time there is concern about hydration and ambulation. After two hours the risk of VTE is up 18% and so rises every two hours. Right now you can choose to stop often and walk if you are traveling by car and do drink adequate amounts of water. When I travel by plane, I sit in the aisle seat and always go to the bathroom (to stretch my legs).
The studies that were reviewed by these scientists were not experiments, so the results are not the strongest. They do call for more research and I think they make a good argument. They call the issue a public health one, as world travel has increased. They pondered measures such as having people wear TED hose to having people take medication before travel, blood thinners. They did NOT disclose any pharmaceutical ties or funding!
They noted that older persons, pregnant women and women on birth control or HRT might be in the high risk category.



My ending though is this. If this issue gains weight through additional replicable research and dehydration is a big risk factor.. will airlines, for fear of lawsuit, limit or ban caffeinated and or alcoholic beverages in flight?



Here is the published study:
http://www.annals.org/cgi/content/full/0000605-200908040-00129v1