New research suggests that too much sunlight is detrimental to our reproductive health
When we consider the risks associated with too much sun exposure it’s common to instantly think of skin cancers. However, new research undertaken at the Norwegian University of Science and Technology’s Department of Biology suggests that female fertility may also be negatively affected by over exposure to sunlight. Furthermore, our lifespan may also be cut short.
What the researchers examined
In a recent paper published in the journal Proceedings of the Royal Society B, Norwegian researchers investigated the relationship between life history and solar activity. Analysing church records maintained from 1750 to 1900, Skjærvø and colleagues assessed over 9,000 people.
They focused on the age of women when they had the first and last child and how many years were between the birth of each child. They also investigated the number of children that survived and then when on to marry and have children of their own.
This data was then compared to environmental factors, specifically solar activity. This is measured by observing the number the sunspots present on the sun surface. Over an 11 year period, the sun waxes and wanes, with approximately eight years of low activity and three years of high activity.
Based on this information, Skjærvø calculated the amount of UV radiation exposure for any given year over the study period. The more solar activity, the higher UV radiation is present on the planet.
The study found that:
- Children born during years of high solar activity had a higher risk of dying compared with those born during years with reduced solar activity.
- Babies born in years with lots of solar activity and lived, were less likely to have children. Those that did have children were less likely to become grandparents, suggesting that high UV exposure may negatively impact future generations.
- Researchers went on to state that “In addition, fertility and lifetime reproductive success were reduced among low-status women born in years with high solar activity.”
Figure 1: Probability (mean ± s.e.) of survival to adulthood in relation to solar activity for boys and girls. **p < 0.1 and *p < 0.05. Dark grey bars denote periods of high solar radiation, light grey bars denote periods of low solar radiation.
What does all this mean?
The researchers said “There are probably many factors that come into play, but we have measured a long-term effect over generations. The conclusion of our study is that you should not sunbathe if you are pregnant and want to have a lot of grandchildren.”
Although this is only a preliminary study, it does highlight the potential fertility risks linked to excess UV radiation exposure. People with fair skin should be particularly cautious if they live in warmer climates, especially women trying to conceive or already pregnant. Hopefully with more research, the relationship between UV radiation exposure and fertility will be better understood.
You may also be interested in these fertility news articles