Are Obesity and Birth Control Pills Raising Your Odds of MS?

Scientists are learning more about the role that hormones play in multiple sclerosis (MS).

Two studies released today suggest that both obesity and taking birth control pills can raise your odds of being diagnosed with the disease. The results of these studies will be presented at the American Academy of Neurology’s 66th Annual Meeting in Philadelphia, April 26 to May 3.

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Fat Cells and Hormones

For the obesity study, researchers measured the body mass index (BMI) of 210 MS patients. They compared those results with 210 people of the same age and sex who did not have MS at age 20 or at the time of the study.

Researchers discovered that people who were obese at age 20 were twice as likely to develop MS as people who were not obese. The study found that as a person's BMI rose, so did their levels of leptin, a hormone produced by fat cells that regulates hunger and and weight.

Leptin also reacts negatively with a person's immune system, causing an increase in inflammation. This “could potentially explain the link between obesity and MS,” study author Dr. Jorge Correale of the Raúl Carrea Institute for Neurological Research in Buenos Aires said in a press release.

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Contraception and Hormones

A separate study found that women who took birth control pills were at higher risk of developing MS.

Researchers looked at the history of 305 women who had been members of Kaiser Permanente Southern California for at least 3 years and had been diagnosed with MS. These women were either taking birth control pills or had stopped taking them within 3 months prior to the start of the study. Most had been taking a combination of progestin and estrogen.

Their records were compared to those of 3,050 women who did not have a diagnosis of MS. The results revealed that women who had taken hormonal contraceptives were 35 percent more likely to develop MS than those who didn't.

“These findings suggest that using hormonal contraceptives may be contributing at least in part to the rise in the rate of MS among women,” lead study author Dr. Kerstin Hellwig, a post-doctoral research fellow with Kaiser Permanente, said.

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Pregnancy and MS

For many years, it has been the general consensus that women with MS who are pregnant tend to experience fewer relapses. This was thought to be, in part, due to the hormones that a woman’s body produces during pregnancy.

According to the National Multiple Sclerosis Society (NMSS), many studies examining hundreds of pregnant women with MS have all reached the same conclusion: pregnancy reduces the number of MS relapses, especially during the second and third trimesters.

“Relapse rates tend to rise in the first three to six months postpartum, and the risk of a relapse in the postpartum period is estimated to be 20-40 percent," NMSS says on its website. "Pregnancy is known to be associated with an increase in a number of circulating proteins and other factors that are natural immunosuppressants. Additionally, levels of natural corticosteroids are higher in pregnant than nonpregnant women. These may be some of the reasons why women with MS tend to do well during pregnancy.”

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The Connection

While these were two separate studies, both focused on the role that hormones play in MS. More studies are needed before we know the whole story.

The purpose of birth control pills is to raise hormone levels in order to dupe a woman’s body into believing she's pregnant. So the study regarding birth control pills appears to contradict previous studies that show pregnancy reduces MS relapses.

Furthermore, since these are two separate studies, the question of whether obese women on birth control pills are at even greater odds of developing MS than either of the study groups will need further investigation.

In the meantime, if you are concerned about your risk for developing MS based on these studies, talk to your doctor. Perhaps starting a weight loss program and switching your method of contraception could reduce your odds.

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