Researchers at Columbia University, using computers to look for a link between disease risk and birth month, report finding 55 illnesses associated with the season of a person's birth.
Using an algorithm to analyze medical databases in New York City, they found people born in May faced the lowest disease risk while those born in October had the highest.
"This data could help scientists uncover new disease risk factors," says biomedical informatics Professor Nicholas Tatonetti, senior author of the study published in the Journal of American Medical Informatics Association.
Until such risk factors become clear, however, it is not possible to determine whether the link between birth month and health is anything more than a coincidental correlation.
The researchers say they have plans to use the same algorithm on data from a number of locations around the United States and in other countries to see if results vary by location or environmental factors.
There have been no large-scale studies of connections between birth season and disease incidence, although previous research on specific diseases such as asthma and ADHD has suggested such a link.
July and October babies have the greatest risk of developing asthma, one earlier study found, while researchers in Denmark found the greatest risk for it there in people born in May and August -- months when sunlight levels in Denmark closely match what New York experiences in July and October.
The Columbia study found one in 675 occurrences of ADHD correlated to being born in November, which matches the findings of a Swedish study also yielding peak rates for the condition in November.
For their wider study, the Columbia researchers compared more than 1,600 diseases against birth months and medical histories recorded for 1.7 million patients at New York-Presbyterian Hospital/CUMC from 1985 to 2013.
In addition to confirming 39 links already described in scientific literature, they found 16 new associations, including nine kinds of heart disease.
People born in March displayed the highest risk for congestive heart failure, atrial fibrillation and mitral valve problems, the researchers say.
Despite the increase in links found between birth season and disease, the researchers say there is no reason to take the results as an occasion for worry.
There are more important factors to keep in mind, they emphasize.
"It's important not to get overly nervous about these results because even though we found significant associations, the overall disease risk is not that great," says Tatonetti. "The risk related to birth month is relatively minor when compared to more influential variables like diet and exercise."
Still, the researchers say, the study is important for revealing the wealth of medical information that Big Data can yield.
"Faster computers and electronic health records are accelerating the pace of discovery," says lead author and Columbia graduate student Mary Regina Boland. "We are working to help doctors solve important clinical problems using this new wealth of data."
