Moles, the spin of the earth, and the kids

We all know about UV and ‘Australia has the worst skin cancer rate in the world’ has become a cliché after forty years of sun-safe campaigns. 

It’s all in the spin. Our summer sun is 7-10% stronger than similar northern latitudes during the same season, as Earth’s elliptical orbit brings the Southern Hemisphere closer to the sun than it does the Northern. 

Our relatively pollution-free skies add to the effect, meaning that Australia gets close to 15% more UV radiation than equivalent northern latitudes. And the tropical north is worst hit as there is less ozone at the equator than at the poles. Finally, the Antarctic ozone ‘hole’, created by chlorofluorocarbon (CFC) use last century, sometimes drifts over Australia — letting in yet more UV.  And then there is climate change.

Moles, surf and sunburn 

Our legendary sun-drenched Australian childhoods, and moles and melanoma are intimately linked.

“The number of pigmented moles is one of the most important risk factors for skin cancer development later in life” says Dr Simone Harrison, Director and Principal Research Fellow of James Cook University’s Skin Cancer Research Unit in Townsville, North Queensland.

“And a single childhood sunburn can almost double the chances of developing melanoma in the future”, she says.

Harrison and colleagues, Drs Petra Buettner and Madelaine Nowak, of James Cook University, are now calling for mandatory sun-protective clothing standards at preschools after their multi-year study comparing mole counts on kids at Townsville day-care centres.

Kids in the sun

Five hundred kids and their parents were involved in the research, published in the journal, Cancers. Children, initially under 3 years old, and with two or more grandparents of European origin, were examined at twenty-five Townsville childcare centres. 

Day care centres were matched for socioeconomic status and shade provision. Children at 13 centres wore supplied UPF 32 – 50 (Ultraviolet Protection Factor) sun-protective clothes, and were also given sun-protective swimwear and hats for home use. 

A single childhood sunburn can almost double the chances of developing melanoma in the future

Dr Simone Harrison

Kids at 12 control centres wore their own clothing, which included hats, and sunscreen. 

All children were examined for the number and size of moles at the beginning of the study (1999–2002), then annually for up to 4 years. Parents contributed information on their child’s ethnicity, demographic characteristics, sensitivity to sunlight, use of protective clothing and sunscreen use and sunburn history.

“While almost all preschool centres mandate sun-safe hats (such as bucket, broad-brimmed and legionnaire style hats) and sunscreen, we wanted to see what effect sun-protective clothing had on the risk of developing pigmented moles,” says Harrison.

Moles to melanomas

Moles are usually harmless, raised clusters of the melanin-producing cells (melanoctyes) that give the skin its colour. Let’s not confuse them with freckles — also clusters of melanocytes but lying flat on the skin.

Too much sun, especially in early childhood, can increase the risk of these moles turning cancerous. 

About 1% of infants have moles at birth (called ‘congenital melanocytic naevi’), with more developing during childhood and early teenage years. Tropical kids develop more moles earlier than those further south, says Harrison, although differences may disappear by 15 years old.  

Australians may also have many more moles than those of similar backgrounds in the Northern Hemisphere. 

Melanoma develops in those moles’ melanocytes, and ranks third in Australia after prostate and breast cancers —  17,756 Australians were diagnosed with melanoma in 2022, the worst in the world, thanks to our predominantly light-skinned population. Queensland has the highest rate in Australia, with about 64.3 melanoma cases per 100,000, 25% higher than the national average (48.7 per 100,000).

It’ll never happen to me

In 2018, 54% of Queensland adults and 46% of children reported being sunburnt over the previous 12 months, with about 33,000 of the children having five or more sunburns. Tropical North Queensland’s UV is high to extreme all year-round.  

“Townsville gets 8 times more UV than Melbourne in winter”, says Harrison, “never averaging below high UV (i.e. 5.5 – 7.5)”.  Contrast that with Melbourne, where winter UV levels are mostly low ‑ and those in Sydney, Adelaide and Perth are similar, with a little movement into moderate.

Townsville gets 8 times more UV than Melbourne in winter

Covering the kids

Back to the study — after 3.5 years of follow-up, children wearing sun protective clothing, at the intervention centres, had 24.3% fewer new moles overall and 31.6% fewer new moles on clothing-protected skin compared to control children. 

That’s 24.3% fewer moles that might otherwise catch the attention of a dermatologist down the track.

The study is the first to show that pigmented mole development can be prevented in young Caucasian children by dressing them each day in UPF 30-50+ clothing that covers at least half their body, says Harrison.

This is a significant finding, as moles are very important risk factor for melanoma, says Professor Ann Cust, Chair of the Cancer Council National Skin Cancer Committee.

Covering kids has long-term benefits. A melanoma diagnosis, particularly if it’s repeated, may also indicate genetic susceptibility to other cancers, possibly reflecting how your DNA repairs itself when damaged, and similar genetic pathways, says Cust.  

Melanoma survivors are 9 times more likely to develop more melanomas than the general population for at least 20 years after their first melanoma diagnosis and are at increased risk for breast and prostate cancers and non-Hodgkin lymphoma.

Roles for government, childcare centres, the community, and parents

“I believe schools have a responsibility to ensure the safety of their children in their care”, says Cust. “It’s important that schools have sun smart policies in place and that they model good behaviours.”

“One of our staff has a two-year-old toddler, and she’s recently switched childcare centres for him because he was getting multiple sunburns — he was in pain. Talking with the centre had no effect as he kept getting sunburned. So, I think there’s potential for improvement, and it probably depends on the leadership at the centre,” she says.

Prof Cust continues: “I think regulations are important, but so is not scheduling play in the middle of the day. And community pressure and expectations, as well as sun safety education, particularly for children, to make sure people do the right thing.” 

Sun protection should be about coverage, not just a garment’s UPF, says Harrison.

UPF is an important standard, maintained by ARPANSA, the Australian Radiation Protection and Nuclear Safety Agency, but this just considers UV penetration through the fabric. Harrison and colleagues have proposed a ‘Garment Protection Factor (GPF)’ which considers both body coverage and the fabric’s UPF.  

Regulations are important, but so is not scheduling play in the middle of the day. 

Professor Ann Cust

The Australian UPF standard has been copied in other countries and has had a huge global impact, but sometimes the briefest of swimwear is marketed as sun protective.

“It’s misleading to tell people that their tiny nipple covers, that are made from high UPF fabric, are sun protective. I just think it sends the wrong message”, says Harrison.

The GPF approach would reward manufacturers for garments that cover more skin, and help consumers make a more informed choices when buying sun-protective clothing. The battle continues to get this standard accepted. 

We’ve all heard this stuff a million times, but think it will never happen to us … until it does.