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Research Links Month of Birth to Disease
February 03, 2004
- Marc Lallanilla
ABCNews.com
You may dismiss astrology as a harmless pseudo-science, but your birthday could have more importance than you think. Some scientists now believe the month in which you were born may predispose you to certain illnesses.
Medical experts worldwide have found specific illnesses and behavioral disorders are more prevalent among people born during certain months or seasons of the year. The list includes asthma, epilepsy, multiple sclerosis, leukemia, dyslexia, diabetes and others.
Schizophrenia, for example, has been shown to be more common among people born in January, February and March. Narcolepsy, a sleep disorder, is more frequent among people born in March and less common among those born in September.
Click here to discover what diseases are more common among people born in your birth month.
But don't worry this means you're destined to come down with a particular disorder. Experts agree their findings can't predict what will happen to individuals. They also agree more study is needed to understand the ways your birth month or season influences your health.
The Winter of our Discontent
So what causes the link between disease and birth month or season? Most scientists suspect environmental factors are the culprit.
For instance, fetal exposure to seasonal viruses like the flu virus, or to a symptom of viral exposure like fever, might be a possible cause.
"Some infectious diseases have a seasonal variation," says Dr. Marvin J. Bittner, epidemiologist with the Veterans Affairs Medical Center in Omaha, Neb. "The reason for these variations is not entirely understood. In other cases, seasonal variation leads to insights. For example, mosquito-borne diseases vary with mosquito populations and factors such as weather."
Researchers also believe neurological and behavioral disorders like schizophrenia might be linked to viral exposure during the second trimester of pregnancy, when fetal neurodevelopment begins.
Other factors occurring during pregnancy have been considered, including seasonal dietary deficiencies, prenatal or newborn exposure to seasonal allergens like pollen, and vitamin D deficiencies over the dark months of winter (vitamin D is synthesized by your body during exposure to sunlight).
No study, however, has been able to prove a definite cause-and-effect relationship.
"Environmental factors are very difficult to study and are very speculative," says Dr. Emmanuel Mignot, professor of psychiatry at Stanford University, whose research discovered the increase in narcolepsy among people born in March. "It's nearly impossible to find out what could be involved, like finding a needle in a haystack."
Using Common Sense
Because it's hard to establish a clear link between disease and birth month, most experts advise a common-sense approach to understanding these studies.
Pregnant women, for example, should consider getting a flu shot, in addition to making healthy lifestyle choices like eating a sensible diet, exercising, getting plenty of rest and practicing proper hygiene.
"Just like any other research, you have to take the results with a lot of caution," says Dr. Steven C. Capps, neuropsychologist and director of the Learning Diagnostic Clinic at Southwest Missouri State University in Springfield, Mo. "You've got to do research multiple times with a variety of sample populations. You always need to remember that caveat, 'more research needs to be done.' "
Capps' own research has found learning disabilities are 8 percent more likely to occur among those born April through July. Like many other scientists, Capps has stated there is clear link between schizophrenia and those born January through March.
"The evidence is stronger for schizophrenia than for any other disease," says Dr. E. Fuller Torrey, psychiatrist with the Stanley Medical Research Institute in Bethesda, Md. "But even with schizophrenia, we're looking at a statistical increase of 6 to 8 percent. The research really doesn't have any predictive value. It's not like half the people born in March develop schizophrenia and nobody born in September develops the disease."
Some researchers see limited meaning in all of this. "The value of these studies can range from zero to extraordinarily beneficial," says Bittner. "Some links make biological sense since some infectious diseases, like respiratory syncytical virus, have known seasonal variation. Other apparent links may be mere coincidence."
But while many of these studies are preliminary, Mignot believes the findings have real value. "The importance of this research is that in general it points out that there are risks that may occur during pregnancy." To researchers like Mignot, the real interest in understanding the link between birth month and certain diseases lies in how it can help us discover the underlying causes of these diseases.
Original article is here
