Contributed by Guest Blogger: S. Bekele ’14
Obesity is an extremely serious problem, especially in the United States. Excessive weight gain can lead to many health problems, such as diabetes, heart failure, and cancer. Most people think that this is due to overeating and living a sedentary life, but new research suggests that a virus, specifically adenovirus-36, could be one of the causes of obesity. Perhaps obesity is not an overweight person’s fault, it could be simply due to an infection by a virus.
In order to find an association between adenovirus-36 and obesity, researchers in a recent study took blood samples of obese and non-obese subjects. They examined the blood serum to see if it contained antibodies for the adenovirus-36. Their BMI, cholesterol, triglyceride levels and percent body fat were also noted. After all the obese subjects’ data were gathered together, it was found that 30% had adenovirus-36 antibodies, while among the non-obese subjects, 11% had these antibodies. Also what was interesting to note was that obese and non-obese subjects with Ad-36 had lower levels of cholesterol and triglycerides, which were higher for those without the antibodies. Other types of adenovirus antibodies were viewed such as Ad-2, Ad-31 and Ad-37. There were no differences in BMI among obese and non-obese subjects; it appears that Ad-36 is the only strain of adenovirus that is associated with obesity.
From the data, it was shown that obese patients were three times higher to have Ad-36 antibodies. The researchers explained this by suggesting that those that are obese are more likely to be infected with adenovirus-36, since they may have have impaired immune function. Ad-36’s role in obesity is unknown, but researchers came up with a few ideas. For example, Ad-36 may affect fat cells which would in turn lead to an increase in the number and size of those fat cells, thus causing obesity.
The association found between this virus and obesity sparks many interesting questions. Is it truly possible that we can blame a virus (at least partially) for obesity? If we were all vaccinated for adenovirus-36, would there be a great reduction in the number of obese people, especially in the United States? If we begin to understand the effects of this virus, perhaps we can examine how big a role it plays in obesity.
It is the most alarming rise in obesity ever. According to CDC over 63% of the population are overweight and obese meaning over 180 million. Also based on CDC, obesity has tripled in men and women in the last 2 decades. According to the American Heart Association over 110 million are walking with partially blocked arteries. Over 160 million have blood pressure and pre-blood pressure and over 76 million have diabetes and pre-diabetes. There are currently over 50 million smokers. The majority of people have a combination of the above if not ALL of the above. I witness this very fact at the pharmacy EVERY DAY. Mortality statistics are even more startling.
Do we have to have just one cause for a disease like obesity? We know there are many factors that contribute to obesity. Alone or in combination, any of these factors may be contributing to obesity in any given individual. Certainly, 30% isnt enough to say that this is THE cause of obesity for everyone, but it sure is a lot of people where it may be a significant contributing factor. As for the causal relationship vs correlation, there is past data to support causation. If you infect animals with Ad-36 they gain weight, but any other adenovirus tested does not have that effect.
Very interesting topic. Yet I am also not persuaded that obesity, in large, can be attributed to an infection by virus that causes fat cells to grow in both size and number. The difference between 11% and 30% is just too small for a causal relationship to be drawn from what we see in obese people and the adenovirus-36. But once again it is interesting because I would never have thought that a virus could possibly be involved in why obese people “cant help themselves.”
The possibility of fat cells growing in size and numbers due to infection by a virus is a very interesting thought. Were this hypothesis proven to be true, it would make the battle against obesity much more feasible. However, I have to agree with Dip. I don’t think there is a big enough difference between 11% and 30% for us to conclude that obesity is caused, at least in part, by this virus. The immune systems of the obese subjects were weaker than those of their healthier counterparts, making them more susceptible to being infected by the Ad-36 virus. Let’s hope more research is done on Adenovirus-36 so that we can gain a clearer understanding of its relation to obesity.
If obesity is really caused by the virus, then it may explain that when some people say they cannot help their obesity and that it is hereditary, then possibly the virus is genetic and passed from mother to child. This could be similar to HIV. Some children contract HIV from the mother during pregnancy and “cannot help” the fact that they are HIV positive. This could potentially explain a similar situation for obesity in many people. I would be interested in learning more about this topic.
I loved this post! With all due respect, I find this research very amusing. I think this post highlights the two types of scientists or researchers we have – the kind sleeplessly looking for a cure of threats such as HIV and the other kind that engage in simply interesting research and try to prove that obesity is caused by a virus. Excuse my disbelief but I simply do not think that there is enough evidence to seriously consider the claim being made by these researchers. I say this because I do not believe that 30% is a significant enough number. Furthermore, in my opinion, the difference between 11% and 30% is really small (in the grand scheme of things).
Yes, I do wish that obesity may be caused by a virus but realistically speaking, I doubt that. Infact, the largely significant amounts of data linking something like fast food in the U.S. to obesity (compared to other parts of the world), is probably way more believable than a mere 30%.
Then again… thats just what I think.
Good luck for finals and have an awesome holiday people!
I find this post very interesting. I never thought that obesity could be caused by a virus. I, like Sarah and Michael, assumed that it was due to lifestyle choices and to a certain extent genetics. I’m curious though, how exactly are the researchers sure that the relationship between obesity and the adenovirus is causation, instead of correlation? Isn’t it very possible that there are more adenovirus antibodies in the obese subjects because their obesity makes them weaker and more susceptible?
This post was very surprising to me. I always assumed that obesity was due to lifestyle choices or even genetics. This study raises many possibilities. If obesity is associated with a certain virus, maybe other disorders/diseases are related to other viruses. This association with viruses can help researchers develop antivirals to reduce obesity.
In my view, the Adenovirus-36 doesn’t cause obesity. The effects of obesity- a weaker immune system- lead to more susceptibility to certain viruses. I’m interested in if any more relationships between viruses and disorders will be discovered- and which ones they are.
From what I gathered, the researchers were interested in seeing who among the groups possessed the antibodies in order to see who had already been infected with the adenovirus-36, and then make inferences about that. For example, if there was a large percentage of obese people possessing antibodies for Ad-36, then researchers could conclude there is an association between the virus and obesity.
This post was really interesting to me- we frequently hear that obese people are not always able to control their obesity, but I have never heard it at least partially attributed to a virus. I have a questions though: it sounds like the group of obese subjects possessed the antibodies. If so, wouldn’t we expect them to be more protected from adenovirus-36? Or is it possible that the antibodies’ response to the virus can lead to obesity?
You also brought up an interesting point about the causal relationship. It sounds like obesity leads to compromised immune systems, which can allow infection more easily, which leads to more infection- a vicious cycle!