It's not just astrologers who'd say yes! Scientists have made a surprising connection between the season you're born in and certain medical conditions
Your birth month may reveal more about you than whether you’re a stubborn Taurus or loyal Capricorn. You may be at an increased risk for certain diseases based on the month in which you were born, according to a team of researchers at Columbia University Medical Center. (Birth month also affects your outlook on life. Check out 4 Weird Ways When You're Born Affects Your Personality.)
In a new study published in the Journal of the American Medical Informatics Association, researchers combed through a medical database containing information on nearly two million individuals over 14 years. What they found: 55 different diseases were associated with birth month. Overall, people born in May had the lowest risk of disease while October and November babies had the highest, researchers found. People born in early spring were most at risk for developing cardiovascular disease later in life whereas those born in early fall were more likely to be diagnosed with a respiratory illness. Winter babies had the highest risk of reproductive diseases, and neurological diseases were most closely associated with November birthdays.
What could be behind this relationship (other than the new moon syncing with Mars the night you were born)? Researchers have two (scientific!) theories: The first is prenatal exposure—things that might affect a developing fetus during pregnancy. For example, some research shows that babies born to mothers who had the flu while pregnant have an increased risk of heart disease, though more research is needed to understand why, says Mary Boland, a Ph.D. student in the Department of Biomedical Informatics at Columbia. The second is perinatal exposure, such as coming into contact with allergens or viruses shortly after birth that could impact a baby’s developing immune system.
“Asthma has been tied to birth month in our study and a previous study from Denmark,” Boland says. “It seems that children born in months where the dust mite prevalence is high have an increased likelihood of developing dust mites allergies and this increases their risk of asthma later in life.” Specifically, people born in July and October had the greatest risk for developing asthma, their study found.
Sunlight may also play a role. “Vitamin D has been shown to be a critical hormone necessary for the developing fetus,” Boland says. In the winter months, especially in the north, research has shown that women are often underexposed to sunlight. Since vitamin D is so critical in fetal developmental processes, Boland thinks this could be behind some birth month-disease risk relationships (although more research is still needed). (5 Weird Health Risks of Low Vitamin D Levels.)
So should you treat your health like a horoscope, preparing for what your birth month has in store for your future? Not so fast, say researchers. “It’s important to understand that birth month only increases risk a small amount, and that other factors such as diet and exercise remain more important in mitigating disease risk,” Boland says. Still, as researchers gather more information on how birth month and disease rates may be linked, they could uncover other environmental mechanisms that may be driving disease risk. We might, then, be able to better prevent disease some day….if the stars all align, that is!