A new study found that our immune systems react to the changing seasons. The finding provided insight on why some diseases are worse in winter than other seasons.
Researchers at the University of Cambridge monitored the activity of 25 percent, or 5,136 genes, as the seasons change in a year. The genetic samples, from blood and fat, were collected from 16,000 participants from the northern and southern hemisphere.
Researchers wanted to find out why certain diseases, such as heart disease and rheumatoid arthritis, are worse in winter compared to summer.
The study is the first to link seasonal changes to how the immune system works.
The analysis showed that some genes are really more active during winter, while others are active in the summer.
One particular gene - the ARNTL - helps regulate the circadian rhythm of the body, and is more active during summertime. The researchers also observed variations in blood and fat samples depending on the time of the year when the samples were collected.
"It helps explain why so many diseases, from heart disease to mental illness, are much worse in the winter months - but no one had appreciated the extent to which this actually occurred. The implications for how we treat disease like type 1 diabetes, and even how we plan our research studies, could be profound," Professor John Todd, Director of the JDRF/Wellcome Trust Diabetes and Inflammation Laboratory, said in a press release.
The researchers said that further study is needed because the study didn't pinpoint the actual cause of the changes in the immune systems. However, the study is still beneficial, as it provided a possible explanation of why vaccines are better administered during the summer when the immune systems are stronger.
"This is an excellent study which provides real evidence supporting the popular belief that we tend to be healthier in the summer. Seasonal variation to this extent is a fascinating find - the activity of many of our genes, as well as the composition of our blood and fat tissue, varies depending on the seasons. Although we are still unclear of the mechanism that governs this variation, one possible outcome is that treatment for certain diseases could be more effective if tailored to the seasons," said professor Mike Turner, Head of Infection and Immunobiology at the Wellcome Trust.
The study was published in the May12 issue of Nature Communications.
