People born in May have the lowest disease risk and those born in October the highest, an American study based on New York medical databases indicates.

Columbia University scientists used a computational algorithm they developed to correlate diseases with season of birth and applied it to New York City medical databases. They found 55 diseases correlated with the season of birth.

However, the scientists assure that there is no need to be unduly influenced or alarmed by the results as the birth month related risk is minor compared to diet and exercise associations.

More important, the study has been done only with New York data and will have to be validated with more global studies.

"This data could help scientists uncover new disease risk factors," said study senior author Nicholas Tatonetti, an assistant professor of biomedical informatics at Columbia University Medical Center (CUMC) and Columbia's Data Science Institute.

The researchers plan to replicate their study with data from several other locations in the US and abroad. By identifying the reason for the association, they hope to figure out how to close the gap.

The study was published in the Journal of American Medical Informatics Association.

The study compared 1,688 diseases against the birth dates and medical histories of 1.7 million patients treated at New York-Presbyterian Hospital/CUMC between 1985 and 2013.

The Columbia study, which is a large-scale one compared to earlier research, matched earlier findings on the link between the birth month and diseases like asthma, ADHD and heart disorders.

It found that asthma risk is the greatest for July and October babies. An earlier Danish study too had found that the peak risk was in the months (May and August) when Denmark's sunlight levels are similar to New York's in the July and October period.

For ADHD, the Columbia data matched a Swedish study showing peak rates in November babies.

Weak March hearts
A relationship between birth month and nine types of heart disease showed people born in March facing the highest risk for atrial fibrillation, congestive heart failure and mitral valve disorder.

A previous study using Austrian and Danish patient records found that those born in months with higher heart disease rates --March through June -- had shorter life spans.

The study ruled out more than 1,600 associations and confirmed 39 links previously while uncovering 16 new associations.

The researchers performed statistical tests to check that the 55 diseases for which they found associations did not arise by chance.