Transcript EXPOSURE TO ULTRAVIOLET (UV) LIGHT

EXPOSURE TO
ULTRAVIOLET (UV) LIGHT
Sophie J. Balk, M.D.
Professor of Clinical Pediatrics
Albert Einstein College of Medicine
NEETF
Children’s Environmental Health
Faculty Champions Initiative
www.charlie.org
GOALS: TO DISCUSS..
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Background on UV radiation
(UVR)
Health effects
• Focus on skin cancer
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Prevention messages
What to ask in the history
Resources
SUNLIGHT
UVR MODIFIED BY PASSAGE
THROUGH ATMOSPHERE….
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Stratosphere (10 - 50 Km above
sea level)
• Absorption by ozone
• Scattering by molecules
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Troposphere (0 -10 Km above
sea level)
• Absorption by pollutants
• Scattering by particulates
• Clouds
INCREASED UV
INTENSITY...
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At midday
In summer
Closer to the equator
At higher altitudes
Reflected from ground
surfaces, sand, snow, water
HEALTH EFFECTS OF UVR
Skin
 Eyes
 Immune system
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AAP Pediatric Environmental Health, November 2003.
EFFECTS ON THE SKIN
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Vitamin D Production
Erythema and sunburn
Tanning
Skin aging
Photosensitivity
Non-melanoma skin cancer
• Basal cell carcinoma
• Squamous cell carcinoma
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Melanoma
AAP Pediatric Environmental Health, November 2003.
American Cancer Society 2006 ( www.cancer.org)
Gilchrest et al. NEJM April 1999.
ERYTHEMA & SUNBURN
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Minimal erythemal dose
(MED) depends on
• Skin type and thickness
• Amount of melanin and ability
to produce melanin after
exposure
• Intensity of the radiation
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Six sun-reactive skin types
SKIN TYPES
TANNING
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Protective response to sun
exposure
Immediate tanning: Induced
by UV-A, no new melanin
Delayed tanning: Induced by
UV-B, begins at 2-3 days,
peaks at 7-10 days, new
melanin formed
NON-MELANOMA
SKIN CANCER (NMSC)
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Basal cell carcinoma (BCC) and
squamous cell carcinoma (SCC)
Most common malignancies in
adults: > 1,000,000/year
Found on maximally-exposed areas
Usually not fatal unless untreated
Related to cumulative sun exposure
American Cancer Society 2006 ( www.cancer.org). Accessed 6-28-06.
MELANOMA
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Most common fatal skin cancer
2006: 62,190 new cases with
7,910 deaths1
Occurs in teens, young adults
Metastatic melanoma has a grave
prognosis
Prevention, early detection are
key
1 – American Cancer Society 2006 (www.cancer.org). Accessed 6-28-06.
MELANOMA IN YOUNG ADULTS
AND CHILDREN
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A common malignancy in whites1
• 2nd most common, women 20 – 29
• 3rd most common, men 20 - 29
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Melanoma in children2
• Incidence rising
• 33 patients < 14; 25 yr experience
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Presentation often atypical: most
lesions raised, well-defined borders
Lesions unlike any other on child
1 - Wu et al. Cancer Causes and Control 2005; 2 - Ferrari et al, Pediatrics 2005
MELANOMA
A - Asymmetry
B - Border
C - Color
D - Diameter
E - Evolving
MELANOMA
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Lifetime risk
• 1930:
• 1987:
• 2002:
• 2010:
1
1
1
1
in
in
in
in
1500
120
681
501
1- Rigel DS. Dermatol Clin 2002; 20
WHY IS THE INCIDENCE OF
MELANOMA RISING?
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Thought to be related to sun
exposure
• Depletion of the ozone layer
• Changing patterns of dress
• More leisure time
• “Sun culture”
Pediatric Environmental Health. AAP 2003
SUNLIGHT AND MELANOMA
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Epidemiologic and biological
evidence implicate sunlight in
the pathogenesis of
melanoma
Pediatric Environmental Health. AAP 2003
SUNLIGHT AND MELANOMA
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Latitude
Race and pigmentation
Childhood exposure
Nevi
Pediatric Environmental Health. AAP 2003
CHILDHOOD EXPOSURE
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~25% of lifetime sun exposure
occurs during childhood and
adolescence1
Episodic high exposures
sufficient to cause sunburn,
particularly in childhood and
adolescence, increase the risk of
melanoma2
1- Godar et al. Photochem Photobiol 2003
2 -Elwood, Jopson. Int J Cancer 1997;73
CHILDHOOD EXPOSURE
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Migration studies: High sun
exposure during childhood is
important in the pathogenesis of
melanoma1
1 - Khlat et al. Am J Epidemiol. 1992;135
NEVI
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Acute sun exposure is implicated
in the development of nevi in
children1
There is a relationship between
the number and type of nevi and
the development of melanoma1
Dysplastic nevi: precursor lesions
that increase risk2
1 – Gallagher et al. Arch Dermatol. 1990; 126
2 - Clark. Arch Dermatol. 1988;124
BIOLOGIC EVIDENCE
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UVB exposure  DNA lesions
(pyrimidine dimers) whose
incomplete repair leads to
mutations1
UVA causes oxidative damage to
DNA  mutations1
UVR contributes to immune
suppression2
1 - Gilchrest et al. N Engl J Med. 1999;340
2 – Strickland, Kripke. Clin Plast Surg. 1997;24
BIOLOGIC EVIDENCE: XP
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Xeroderma pigmentosum (XP):
Grossly deficient repair of DNA
damaged by UVR1
SCC, BCC and melanoma seen
beginning at young ages1
1 - Photosensitivity. In Behrman, Kliegman, Jenson, eds. Nelson Textbook
of Pediatrics. 16th ed. Philadelphia, PA: WB Saunders Co; 2000:1998-2001
SUN PROTECTION
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Sun protection is recommended
to prevent skin cancer, including
melanoma
Sun protection is recommended
beginning early in life
Pediatric clinicians may play an
important role in delivering
messages
Pediatric Environmental Health. AAP 2003
PREVENTION AT ALL
DEVELOPMENTAL STAGES
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Infants
• Lack mobility
• Skin has less melanin than at any
other time
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Children
• New patterns of exposure
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Adolescents
• Susceptible to society’s ideas about
beauty and health
UV LIGHT –
PREVENTION MESSAGES
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Do not burn; avoid sun tanning and
tanning beds
Generously apply sunscreen
Wear protective clothing
Seek shade
Use extra caution near water, snow
and sand
www.skincancerprevention.org/Tips/
tabid/54/ Default.aspx
DO NOT BURN; AVOID SUN
TANNING AND TANNING BEDS
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Burning raises melanoma risk
Avoid/limit exposure during
peak hours (10AM – 4PM)
Avoid intentional tanning
GENEROUSLY APPLY SUNSCREEN
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Sunscreen is the sun protection
method most commonly used1
Apply to all exposed skin using
SPF > 15
Broad protection (UVA & UVB)
Reapply often
1 - Olson et al. Pediatrics 1997;99
WEAR PROTECTIVE CLOTHING
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Simple, practical protection
The structure (weave) of the
fabric is most important
Light-weight long pants and
sleeves suggested
Hats with a bill or brim
Sunglasses
SEEK SHADE
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Shade is useful but…
Shade offers insufficient
protection because UV light is
scattered and reflected
• A fair-skinned person sitting
under a tree can burn in an
hour
SUNSCREENS
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Came into use in 1950’s
Promoted tanning without
burning
First true sunscreen (PABA)
became available in 1970’s
High-intensity sunscreens within
last 15 years
Rigel DS. Dermatol Clin 2002; 20.
OPAQUE SUNSCREENS
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Scatter, reflect, block UV light
Zinc oxide, titanium dioxide, red
vetenary petrolatum, talc
Effective for diseases related to
light exposure (SLE, XP, solar
urticaria)
Useful for those spending
extensive periods outside
Rigel DS. Dermatol Clin 2002; 20.
CHEMICAL SUNSCREENS
Protection Range
PABA
260 – 313
Octyl methoxycinnamate
Oxybenzone
280 – 310
Parsol
310 – 400
Rigel DS. Dermatol Clin 2002; 20.
270 – 350
UVB: 290 – 320 nm
UVA: 320 – 400 nm
SUN PROTECTION FACTOR SPF
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Ratio of amount of time to sunburn
with sunscreen compared to time to
sunburn without sunscreen
1970’s: SPF’s 2 – 4:
50 – 75% protection
High-potency sunscreens:
SPF’s 15 – 50, 93 – 98% protection
Rigel DS. Dermatol Clin 2002; 20.
LIMITATIONS OF SPF SYSTEM
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Applies to UVB protection only
Measured under ideal conditions
Concerns about:
• Using adequate amounts
• Applying before needed
• Need for frequent reapplication
SUNSCREEN AND MELANOMA
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Sunscreen
• Reduces sunburn
• Can prevent actinic keratoses1
• Can prevent SCC2
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No conclusive data in humans to
demonstrate that sunscreen
prevents melanoma or BCC
1 - Thompson, Jolley, Marks. NEJM 1993; 329
2 – Green et al. Lancet 1999; 354
IS SUNSCREEN USE A RISK
FACTOR FOR MELANOMA?
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Swedish case-control study
found increased risk1
Several studies found increased
risk with sunscreen use; some
studies found decreased risk;
others found no change2
1 – Westerdal et al. Melanoma Res 1995; 5:59-65.
2 - Cooper, Lim. J Amer Acad Dermatol 1999; 40.
IS SUNSCREEN USE A RISK
FACTOR FOR MELANOMA?
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No studies demonstrate that
sunscreens are carcinogenic1
Sunscreen users may extend
their time out in the sun2
There may be greater exposure
to UVA1
1-Cooper, Lim. J Amer Acad Dermatol 1999; 40
2-Autier et al. J Natl Cancer Inst. 1999;91:1304-1309
SUNSCREEN MAKERS SUED
FOR MISLEADING CLAIMS
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April 2006: 9 suits involving
popular brands charged that
manufacturers inflated claims
about sunscreens’ protection
Sunscreen called the “snake oil
of the 21st century“
Focus on labels claiming equal
UVA/UVB protection; “all day”;
“waterproof”;
www.consumeraffairs.com/news04/2006/03/sunscreen.html. Accessed 7-29-06
RECOMMENDATIONS
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AAP, ACS, AAD, EPA, CDC, others
recommend multi-component
message
Sunscreen is one part of a sun
protection program
Sunscreen should not be used to
extend time spent in the sun
SUNSCREEN AND VITAMIN D
METABOLISM
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Vitamin D produced in the skin
by action of UVB
Inadequate sunlight is an
important risk factor for rickets
Concerns that sunscreen use may
affect levels of Vitamin D
SUNSCREEN AND VITAMIN D
METABOLISM
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AAP policy - April 2003
Infants need 200 IU Vit D/day
Human milk: < 25 IU/L Vit D
Infant formula: 400 IU/L Vit D
Supplementation: all breast-fed
infants, formula-fed infants
taking <500 ml/day, children
with inadequate intake/sun
AAP Section on Breastfeeding and Committee on Nutrition. Pediatrics 2003; 111.
VITAMIN D
AND CANCER PREVENTION
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Recent studies suggest a role for
vitamin D in cancer prevention
• Colon, breast, prostate, lung
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High prevalence of vitamin D
deficiency/insufficiency
Insufficient evidence to make
recommendations about sun
exposure
http://msnbc.msn.com/id/7875140/print/1/displaymode/1098. Accessed 7-04-06
People Magazine May 05
INDOOR TANNING1
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Salon use in <25 year olds
• 1996 - 8%; 2003 - 26%
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College students: 32% – 55%
usage rates
High school students
• Males 6 - 44%
• Females 20 – 70%
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2001: Indoor tanning industry
generated $4 billion in revenues
1 - Scientific and regulatory issues related to indoor tanning. JAAD 2004.
INDOOR TANNING AND
MELANOMA
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Epidemiologic evidence suggests
that indoor tanning causes
melanoma and SCC; perhaps
BCC1
NIEHS recommends that UV light
from artificial sources such as
tanning booths and tanning beds
be listed as a known human
carcinogen2
1 - Scientific and regulatory issues related to indoor tanning. JAAD 2004
2 - http://www.nih.gov/news/pr/oct97/niehs-30.htm. Accessed 7-04-06
INDOOR TANNING LEGISLATION
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Federal regulation of
manufacturers
States regulate operation of
equipment
26 states regulate salon
operators
• Legislation varies
• Limited enforcement
http://news.findlaw.com/prnewswire/20050317/17mar2005164738.html
ARE SUN PROTECTION
MESSAGES EFFECTIVE?
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Melanoma rates rising quickly
Geller et al: Nationwide survey of
> 10,000 teens 12 - 18
• 83%: >1 sunburns in previous
summer
• 36%: >3 sunburns
• Sunscreen use in 34%
• ~ 10% reported tanning bed use in
previous year
Geller et al. Pediatrics 2002.
UV LIGHT - HISTORY
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Family history of melanoma?
Are you (your child) protected
from excess sun exposure?
Do you visit tanning parlors?
Target children at high risk
• Family history of melanoma
• Skin Types I & II
• Nevi, freckling
• Sunburns
UV LIGHT –
PREVENTION MESSAGES
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Do not burn; avoid sun tanning and
tanning beds
Generously apply sunscreen
Wear protective clothing
Seek shade
Use extra caution near water, snow
and sand
Early detection is also recommended
www.skincancerprevention.org/Tips/tabid/54/ Default.aspx
RESOURCES
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Ultraviolet Index
EPA SunWise Program:
www.epa.gov/sunwise
CDC “Choose Your Cover”
campaign:
www.cdc.gov/ChooseYourCover
National Council on Skin Cancer
Prevention:
www.skincancerprevention.org
RESOURCES
Pediatric Environmental
Health, November 2003
THANK YOU!
Contact Information
Leyla Erk McCurdy
Senior Director, Health & Environment
National Environmental Education & Training
Foundation (NEETF)
Email: [email protected]
Phone: 202.261.6488
NEETF is tracking pediatric environmental health
education activities for health care providers and
requests your feedback
http://www.neetf.org/health