This document summarizes evidence on the harmful effects of ultraviolet radiation (UVR) exposure in childhood and epidemiological studies on childhood melanoma. Key points include: 1) Australian children receive 8 times more UV exposure than Danish children and 50% of lifetime UV exposure by age 20; 2) UVR exposure in childhood is linked to increased moles and signs of photoaging; 3) While rare under 20, melanoma incidence is higher in Australia than England for those under 25; and 4) Successful public education campaigns in Australia in the 1980s-90s coincided with decreased melanoma rates in children aged 10-14.

1. Harmful effects of UVR exposure in childhood:
epidemiological evidence
Adele Green
Queensland Institute of Medical
Research, Australia
&
University of Manchester, UK

2. Outline
1. Levels of UVR exposure in childhood
2. Childhood skin effects: Benign to cancer
3. Risk factors – genetic, solar UVR
4. Is childhood a susceptible window?
5. Primary prevention

3. Levels of UVR exposure in childhood
• Estimated mean summer sun exposure
2-4 hours/day: similar across studies
-summer in Europe/Canada; year round in
Australia
• Estimated average UV exposure
- 8 times greater in Australia than Denmark
• Estimated % of life-UVR (up to 60 y) received
by children <20 y
- 50%: Australia 25%: Denmark

4. Benign skin effects of UVR in childhood
• Photoaging- prevalence in 13-15 yr olds (assessed
by skin surface microtopography)
-in Scotland: 33% with mild skin damage
-in Australia: 40-70% (Fritschi et al 1995)
• Melanocytic naevi (moles)- median counts
Germany Tropical Queensland
(Bauer et al 2005) (Harrison et al 2005)
Age 2: 3 20
Age 5: 7 60
Age 6-7: 17 70

5. Skin cancer incidence in childhood
• Melanoma – rare < 20 years: accounts
for 2% of all melanomas
• BCC, SCC – negligible sporadic

6. Melanoma in Females by Age in England
CUTANEOUS MELANOMA INCIDENCE IN FEMALES BY AGE GROUP
IN ENGLAND (1979-2006)
400
INCIDENCE RATE (PER 10^6 PERSO
350
300
YEARS AT RISK)
250 <25
25-44
200
45-64
150 65-89
100
50
0
1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005
YEAR OF DIAGNOSIS

7. Melanoma in Females <25 Years by site

8. Melanoma at ages 10-24 years:
England vs Australia
Annual incidence rates per million in 2006
England Australia
Males 15 43
Females 24 51

9. Causal pathways to melanoma
Genes Environment

10. Genetic susceptibility
• Mutations in “direct effect” genes eg CDKN2A - rare
•**Multiple genes controlling pigmentation in skin, hair, eyes
•**Tendency to multiple naevi (moles)

11. Youth Melanoma -pigmentary risk factors
OR 95% CI
Brown 1.0
Eye Hazel 3.7 1.0-13.5
Colour Green 3.8 0.9-16.5
Blue 4.5 1.5-13.6
Brown/Black 1.0
Hair
Blonde 1.7 0.8-3.7
Colour
Red 5.4 1.0-28.4
Dark 1.0
Tanning Medium 3.4 0.7-16.5
Ability Mild 3.9 1.0-16.0
No Tan 4.7 0.9-24.6

12. Youth Melanoma -
freckling and family history
OR 95% CI
None 1.0
Facial Few 0.6 0.2-1.7
Freckling Some 1.0 0.4-2.9
Many 3.2 0.9-12.3
Relative No 1.0
with
melanoma Yes 4.0 0.8-18.9
Youl et al, Int J Cancer 2002

13. UVR causes melanoma
Sun exposure
Artificial tanning devices
Class 1 carcinogens (IARC
2009)

14. Latitude gradient for
(childhood)melanoma
60
50
40
30
20
10
0
y
A
LD
K
Z
an
S
N
U
Q
U
m
er
G

15. Cohort study of melanocytic nevi
in adolescents
Methods N= 110, aged 12-14 yr, followed 4 yrs
All melanocytic nevi on body mapped photographed
Results Amount of
school lunch Naevi: Face & Neck Shoulder & Back
time in sun
OR 95%CI OR 95%CI
Very little 1.0 1.0
Some 1.8 1.2-2.6 1.7 1.1-2.5
All 1.7 1.2-2.6 1.8 1.2-2.8
Darlington et al, Arch Dermatol, 2002

16. Childhood a susceptible window?

17. Migration studies
Relative Risk
native-born
high exposure 1.0
0.9
“forward”
migration 0.4
0.3
Relative Risk
4.0
“reverse”
2.5
migration
1.5
native-born
low exposure 1.0
birth death

18. UVR Protection campaigns in high-risk
populations
Underlying trends in Melanoma awareness
Australia
• 1960s – Melanoma public and
professional education
• 1980s – Prevention campaign
“Slip, slop, slap”
• 1990s – “SunSmart” Campaign
Emphasis on sun protection in
children

20. Melanoma incidence trends among children aged 0-14 yrs
in Australia, 1983-2006, by sex
Queensland

21. Melanoma incidence trends for children 10-14 yrs
in Australia, 1983-2006
Source: Australian Paediatric Cancer Registry
Queensland

22. Trends in melanoma incidence
among children in Australia (and Sweden)
Possible influence of sun protection programs
Since late 1980s/early 1990s:
• community education programs on sun protection (shirts,
hats, sunscreen) I G I N A L R E P O R T
OR
• policy emphasis eg accreditation programs for pre- ,
primary schools
From mid-1990s:
• melanoma incidence rates among children aged 10-14
years have decreased significantly by 8.5% per year
Baade et al 2011

23. ng p eople
in you
mela noma
vention of
Pre Increase
Awareness-
Personal; Professional; Policymakers..
•Avoidance of intense sun, including sunbeds
•Use of clothes &
Sunscreen in summer
…in childhood