Hippocrates, who lived in ancient Greece, first described a connection between seasonality and disease almost 2,500 years ago, and the study of the seasonality of birth and its relationship to health and disease has been the focus of many research projects in recent years.
This March, University of Southampton researchers discovered epigenetic DNA markers that link birth season to an increased risk of allergic diseases and eczema. Epigenetic markers are attached to DNA and are known to influence gene expression for years and perhaps even to carry on to the next generation.
“It might sound like a horoscope by the seasons, but now we have scientific evidence for how that horoscope could work,” Gabrielle Lockett, lead author of the study, which was published in Allergy, said in a press release. “The epigenetic markers discovered in this study could also potentially be the mechanism for other seasonally influenced diseases and traits too, not just allergy.”
This was not the first study to link the prevalence of certain health conditions to birth months.
Last year, researchers from Columbia University evaluated the medical histories of 1.7 million babies born between 1900 and 2000 at the New York-Presbyterian Hospital/Columbia University Medical Center and discovered that the time of year in which babies are born could have a profound effect on the likelihood of them developing particular diseases.
In order to determine this effect, the researchers used a high-throughput algorithm called SeaWAS. They found 55 diseases that were significantly dependent on the birth month of their subjects and concluded that lifetime disease risk is affected by birth month. Their results were published in the June 2, 2015 issue of The Journal of the American Medical Informatics Association.
Previous research has revealed that people born in winter months have a higher risk of neurological disorders, including schizophrenia, seasonal affective disorder and bipolar depression, as described by researchers at Vanderbilt University and published in Nature Neuroscience in 2010.
“Our biological clocks measure the day length and change our behavior according to the seasons,” Douglas McMahon, Professor of Biological Sciences at Vanderbilt University, said in a press review. “We were curious to see if light signals could shape the development of our biological clock.”
The researchers in that study explained that our biological clock regulates our moods, and they found that it could have an effect on behavioral disorders and perhaps on overall personality.
On a positive note, another study once showed that female babies who are born in the summer months are more likely to become healthy adults. The authors of this report, which was conducted at the University of Cambridge in the United Kingdom, and published in the October 2015 issue of Heliyon, studied almost 500,000 subjects and concluded that mothers’ increased exposure to sunlight, which helps them produce more vitamin D during pregnancy, could be the reason for the effect that they observed.
“We think that vitamin D exposure is important and our findings will hopefully encourage other research on the long-term effects of early life vitamin D on health,” John Perry, the lead author of this study, said in a press release.
Even the length of our lives has been linked to the month in which we are born. According to studies conducted by researchers in Austria and Denmark, individuals born in the fall tend to live longer than those born in the spring.
While many may consider the findings of these researchers interesting, other scientists insist that much more work is needed to confirm and clarify their results and conclusions.
