In 2017, a group of researchers underwent an epic cancer study, looking into a whopping four million diagnoses in 11 states. To be as precise in their analytics as possible, they examined socioeconomic status, which county subjects were from, and even the latitudes they lived at. Surprisingly, it was the latter that revealed something truly odd. People who lived in the western portion of each time zone had the biggest chance of getting cancer -- by as much as 12 percent for some types. Turns out your fourth-grade teacher was right; knowing your time zones is important.
Why exactly is this happening? It's down to your circadian rhythm and the electric light. While we pretend that hundreds of miles of territory are all hit by sunlight at exactly the same time, it can actually differ by, well, slightly under one hour (or up to five if you live in China). This means people on the west side of a time zone technically get up earlier than those on the east, which means they wake up to a lot more darkness outside. This messes with your body's clock, which thinks you should still be sleeping, and researchers are starting to fear this small but constant circadian disruption could cause the body to be more vulnerable to cancer.
And this isn't some weird American statistical anomaly, either. Another study looked at time zones in Russia and found almost the same thing. The more westerly people lived in the time zone, the more likely they were to get breast cancer. That's another weird thing -- only certain cancers adhere to this strange rule, and men and women are affected differently. While both are more likely to get leukemia, women are at greater risk of esophageal, colorectal, lung, breast, and uterine cancer. Meanwhile, men have an increased risk of non-Hodgkin lymphoma, liver, stomach, and prostate cancer. So on top of everything else, cancer discriminates along both geographical and gender lines.