Do You Know How the Sun is Truly Affecting Your Body?
You likely already know that sunbathing is bad for your skin and can eventually cause lethal skin cancers like melanoma, but did you know sunbathing could cause infertility and increased child mortality as well? New research from the Norwegian University of Science and Technology shows that increased exposure to ultraviolet radiation (UVR) may have a marked effect on infertility and mortality across multiple generations. Your summer tan could impact your future grandchildren.
"Several long-term studies on a wide variety of species, including humans, have revealed that the environment an organism is exposed to early in life may influence adult life-history traits, such as survival, fertility and lifetime reproductive success," write the authors.
The researchers took church records from 1750-1900 involving 9,062 people. They examined several variables including the age at which women had their children, how many children survived after birth and how many of them went on to marry and have children themselves.
The researchers then compared this information with environmental data for the time periods in question. They discovered that children born in years with high levels of solar activity had a greater risk of mortality compared with children born in years with less solar activity.
Solar activity varies within an eleven-year cycle; eight years of low activity followed by three years of high activity. The more solar activity that occurs, the more UVR is present on Earth.
The researchers found that the lifespan of children born during years with high solar activity was an average of 5.2 years shorter than other children. The authors also found that children born in years with high solar activity tended to have fewer children, who in turn would reproduce less themselves. "In addition, fertility and lifetime reproductive success were reduced among women born in years with high solar activity," they said.
UVR exposure before and after birth could not be distinguished by the authors using the available data. However, as the gestation period is the most vulnerable developmental stage for children, the authors believe that their findings are due to the effects of UVR during pregnancy as opposed to after.
“There are probably many factors that come into play, but we have measured the long-term effect over generations,” says the study’s lead author. “The conclusion of our study is that you should not sunbathe if you are pregnant and want to have a lot of grandchildren.”