Gine Roll Skjaervoe at the Norwegian University of Science and Technology's (NTNU) ( http://www.ntnu.edu ) Department of Biology has studied church records from the period 1750-1900 and looked at life history variables: how old were women when they had their first child, and their last? How many years passed between the birth of each child, and how many of these children survived? How many of these children were in turn married and had children?
On average, the lifespan of children born in years that had a great deal of solar activity was 5.2 years shorter than other children. The largest difference was in the probability of dying during the first two years of life.
Children who were born in years with lots of sunshine and who survived were also more likely to have fewer children, who in turn gave birth to fewer children than others. This finding shows that increased UV radiation during years of high solar activity had an effect across generations.
Skjaervoe used information on the number of sunspots as an indication of the amount of UV radiation in a given year. The number of sunspots reaches a maximum every 11 years on average, which results in more UV radiation on Earth during years with high sunspot and solar activity.
UV radiation can have positive effects on human vitamin D levels, but it can also result in a reduction of vitamin B9 (folate). It is known that low folate levels during pregnancy are linked to higher child mortality.
http://www.eurekalert.org/pub_releases/2015-01/nuos-msm010915.php
Also covered by: http://www.sciencedaily.com/releases/2015/01/150109045540.htm
[Paper]: http://rspb.royalsocietypublishing.org/content/282/1801/20142032
(Score: 2) by frojack on Sunday January 11 2015, @09:26PM
This is a really good study correlating sun/UV activity to human longevity (and long term fertility).
Agreed, and it also kind of depends on just how good the sun activity records were back in 1750. Or any time thereafter till people stated keeping records. Even weather reports for those times are sketchy and local at best.
There are far too many other, and more influential factors, from wars, diseases, volcanos, crop failures, pestilence, etc. Even local economy variations are ignored. Birth rates usually drop significantly [time.com] during economic down turns.
Finding correlations is fun, but have't we learned the folly of this over the years?
No, you are mistaken. I've always had this sig.