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Study links lifespan, solar activity

Jan. 9, 2015
Courtesy of the Royal Society
and World Science staff

Talk about a rough start in life. Be­ing born when the sun is stormy might cut around five years off of it, if a new study of Nor­we­gians is any guide.

The study re­ports that his­tor­ic­ally, peo­ple born when there was low so­lar ac­ti­vity lived long­er on av­er­age than those born in times of high­er so­lar ac­ti­vity, which comes in 11-year cy­cles.

A mid-level solar flare last Dec. 4 (Image credit: NASA Goddard Space Flight Center licensed under CCBY2.0)


The re­search­ers be­hind the study say the find­ings might have some­thing to do with harm­ful ul­tra­vi­o­let, or UV, radia­t­ion gen­er­at­ed from so­lar ac­ti­vity. 

For this rea­son, they spec­u­lat­ed that peo­ple with darker skin, who tend to have more nat­u­ral UV pro­tec­tion, might be less sus­cep­ti­ble to the so­lar ac­ti­vity ef­fect.

The find­ings were pub­lished in the journal Pro­ceed­ings of the Roy­al So­ci­e­ty Jan. 8. 

Al­though the re­port did­n’t dis­cuss ways that new par­ents might try to avoid the so­lar ac­ti­vity ef­fect, the Amer­i­can Can­cer So­ci­e­ty has some long­stand­ing gen­er­al ad­vice for lim­it­ing harm­ful UV ex­po­sure, the most straight­for­ward piece be­ing just to avoid much di­rect sun­light.

The au­thors of the new study an­a­lyzed births and deaths in two parts of Nor­way be­tween 1676 and 1878. They com­pared people’s life­span to the amount of so­lar ac­ti­vity in the year of birth. Their re­sults found that peo­ple born in times when the sun was at its least ac­tive lived on av­er­age five years long­er than those born when the sun was most ac­tive.

The sun goes through 11-year cy­cles, with eight years of low ac­ti­vity fol­lowed by three years of high ac­ti­vity. Dur­ing peak times when the sun is most ac­tive, people’s UV ex­posure can go up. The so­lar cy­cle last peak­ed in 2013, but rel­a­tively weakly in that case.

UV “can sup­press es­sen­tial mo­lec­u­lar and cel­lu­lar mech­a­nisms dur­ing early de­vel­op­ment,” the re­search­ers wrote, so “varia­t­ions in so­lar ac­ti­vity dur­ing early de­vel­op­ment” may af­fect health and re­pro­duc­tion.

The in­ves­ti­ga­tors say UV’s det­ri­men­tal ef­fects dur­ing de­vel­op­ment are un­clear but that high lev­els of the radia­t­ion might degrade vit­a­min B which is needed for healthy gesta­t­ion, and cause DNA and mem­brane dam­age in fe­tus­es.

The team an­a­lyzed da­ta from church records of more than 8,500 peo­ple born in Nor­way be­tween 1676 and 1878. Of all the chil­dren, around 20 per­cent died be­fore they reached 20. Those born in years with high so­lar ac­ti­vity had a low­er prob­a­bil­ity of sur­viv­ing to adult­hood than those born in years with low so­lar ac­ti­vity.


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Talk about a rough start in life. Being born when the sun is too stormy might cut around years off your existence, if a new study of Norwegians is any guide. The study reports that historically, people born when there was low solar activity lived longer on average than those born in times of higher solar activity, which comes in 11-year cycles. The researchers behind the study say the findings might have something to do with harmful ultraviolet, or UV, radiation generated from solar activity. For this reason, they speculated that people with darker skin, who tend to have more natural UV protection, might be less susceptible to the solar activity effect. The findings were published in Proceedings of the Royal Society Jan. 8. Although the report didn’t discuss ways that new parents might try to avoid the solar activity effect, the American Cancer Society has some longstanding general advice for limiting harmful UV exposure, the most straightforward piece being just to avoid much direct sunlight. The authors of the new study analyzed births and deaths in two parts of Norway between 1676 and 1878. They compared the lifespan of individuals to the amount of solar activity in the year of the person’s birth. Their results found that people born in times when the sun was at its least active lived on average five years longer than those born when the sun was most active. The sun goes through 11-year cycles, with eight years of low activity followed by three years of high activity. During peak times when the sun is most active the amount of ultraviolet radiation people are exposed to can rise. This could have damaging effects, the scientists said. The solar cycle last peaked in 2013, but relatively weakly in that case. UV “can suppress essential molecular and cellular mechanisms during early development,” the researchers wrote, so “variations in solar activity during early development” may affect health and reproduction. The investigators say UV’s detrimental effects during development are unclear but that high levels of ultraviolet radiation might cause degradation of vitamin B which is needed for healthy gestation, DNA damage and membrane damage in developing fetuses. The team analyzed data from church records of more than 8,500 people born in Norway between 1676 and 1878. Of all the children, around 20% died before they reached 20. Those born in years with high solar activity had a lower probability of surviving to adulthood than those born in years with low solar activity.