Update on Sun Protection 2009

8/14/2019 Update on Sun Protection 2009

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Skin cancer and sunlightSkin cancer and sunlight

Exposure to UVR causes > 90% of skin cancersExposure to UVR causes > 90% of skin cancers

Skin cancer is commonest cancer in NZSkin cancer is commonest cancer in NZ >50,000 new cases per year>50,000 new cases per year

~300 deaths per year~300 deaths per year ~$33.4 NZ million per year~$33.4 NZ million per year

International Agency for Research on Cancer. IARC Monographs on the evaluation ofInternational Agency for Research on Cancer. IARC Monographs on the evaluation of

carcinogenic risks to humans. Solar ultraviolet radiation. Lyon: International Agencycarcinogenic risks to humans. Solar ultraviolet radiation. Lyon: International Agency

for Research on Cancer, 1992.for Research on Cancer, 1992.

Armstrong BK. How sun exposure causes skin cancer. In: Hill D, Elwood JM, EnglishArmstrong BK. How sun exposure causes skin cancer. In: Hill D, Elwood JM, EnglishDR, Eds. Prevention of Skin Cancer. Dordrecht: Kluwer Academic Publishers, 2004.DR, Eds. Prevention of Skin Cancer. Dordrecht: Kluwer Academic Publishers, 2004.

ODea D. The Costs of Skin Cancer to New Zealand. Wellington: Cancer Society ofODea D. The Costs of Skin Cancer to New Zealand. Wellington: Cancer Society of

New Zealand, 2000.New Zealand, 2000.

New Zealand Health Information Service. Cancer, New Registrations and Deaths.New Zealand Health Information Service. Cancer, New Registrations and Deaths.

Wellington: New Zealand Health Information Service, 2004.Wellington: New Zealand Health Information Service, 2004.


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MelanomaMelanoma

1842 new cases in 20021842 new cases in 2002

328328 directly attributable to severe sunburndirectly attributable to severe sunburn (Sneyd and Cox 2006)(Sneyd and Cox 2006)

Authors recommended, Authors recommended, to reduceto reduceburden of melanoma in NZ, need toburden of melanoma in NZ, need to

prevent excessive sun exposure andprevent excessive sun exposure and

(facilitate) early diagnosis(facilitate) early diagnosis

Whilst cancer overall is rare inWhilst cancer overall is rare in

adolescence, melanoma was commonestadolescence, melanoma was commonest

cancercancer


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MelanomaMelanoma

NZ incidence and death rate among worldNZ incidence and death rate among world

highesthighest

56.2/100,000 in European population of56.2/100,000 in European population of

Auckland highest reported worldwideAuckland highest reported worldwide men >50yrs present with more advancedmen >50yrs present with more advanced

melanoma and have higher mortality ratemelanoma and have higher mortality rate

incidence in


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Sun protectionSun protection

Avoid sunAvoid sun

Broad rim hatBroad rim hat

Wrap-round sunglassesWrap-round sunglasses Large area of skin coveredLarge area of skin covered

Densely woven clothingDensely woven clothing

SunscreenSunscreen


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Avoid the sun?Avoid the sun?

When?When?


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How Ultraviolet Radiation (UVR)How Ultraviolet Radiation (UVR)

Behaves During a DayBehaves During a DayNZ Cancer SocietyNZ Cancer Society


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,,circularcircular

Earth - sun distance varies through theEarth - sun distance varies through the

yearyear

Solar radiation received by earth variesSolar radiation received by earth varies


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NZ latitudeNZ latitude ~~Southern hotSouthern hot

EuropeEurope

but without the heat!but without the heat!


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UV issues for NZUV issues for NZ

Peak UV intensities in NZPeak UV intensities in NZ exceed those at comparable latitudes andexceed those at comparable latitudes and

altitudes in Northern hemisphere by 41 5%,altitudes in Northern hemisphere by 41 5%, Comparable toComparable to 1 km higher, 5 degrees closer to1 km higher, 5 degrees closer to

the equatorthe equator Anomalously extreme high UVI valuesAnomalously extreme high UVI values

lower ozone amounts + the closer Earthlower ozone amounts + the closer EarthSun separation in summer all contribute toSun separation in summer all contribute to

the relatively high UV intensities at the NZthe relatively high UV intensities at the NZ UVI in NZ winter lowerUVI in NZ winter lower large summer/winter contrast in NZ UVIlarge summer/winter contrast in NZ UVI


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UV index (UVI)UV index (UVI) NIWANIWA standardmeasurement of erythemal (sun-burncausing) tendencystandardmeasurement of erythemal (sun-burncausing) tendency

more objective measure c.f. oldtime to burnmore objective measure c.f. oldtime to burn

Open-endedscale :UVIOpen-endedscale :UVI 10>10 is extremeis extreme

depends ondepends on

sunelevationanglesunelevationangle

ozone amount,ozone amount,

cloudcover,cloudcover,

sun-earthseparation,sun-earthseparation,

altitude,altitude,

pollution,pollution,

surface reflections (e.g., snowcover)surface reflections (e.g., snowcover)

InNZwinter UVI rarelyInNZwinter UVI rarely >> 33 ..

NIWAwebsite provides Daily Predictions andMeasurementsNIWAwebsite provides Daily Predictions andMeasurements


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UVI issues for NZUVI issues for NZ

NZ UVI anomalouslyNZ UVI anomalously High in summerHigh in summer

Low in winterLow in winter

Greater contrast too betweenGreater contrast too between

Northland and SouthlandNorthland and Southland


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Avoid sunAvoid sun


Wrap-round sunglassesWrap-round sunglassesLarge area of skin coveredLarge area of skin covered

Densely woven clothingDensely woven clothing

SunscreenSunscreen


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variable sun protection for the head,variable sun protection for the head,

face and neckface and neck Depending on fabric, design, way they areDepending on fabric, design, way they are

worn,worn, brim widthbrim width

wide (>7.5cm) provide SPF 7 for nose, 3wide (>7.5cm) provide SPF 7 for nose, 3for cheek, 5 for neck and 2 for chin.for cheek, 5 for neck and 2 for chin. Medium (2.5cm-7.5cm) provide SPF 3 forMedium (2.5cm-7.5cm) provide SPF 3 for

nose, 2 for cheek and neck and none fornose, 2 for cheek and neck and none for

chin.chin. Narrow (


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SunglassesSunglasses

Cataracts and eye cancer arise from chronicCataracts and eye cancer arise from chronic

sun exposure to the lenssun exposure to the lens

single or several additive exposuressingle or several additive exposures

relevantrelevant sunglasses which absorb 99-100% ofsunglasses which absorb 99-100% of

the full UV spectrum (up to 400nm)the full UV spectrum (up to 400nm)

should be wornshould be worn

Additional retinal protection can beAdditional retinal protection can be

provided by lenses that reduce violet/blueprovided by lenses that reduce violet/blue

light transmissionlight transmission


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UPFUPF == UV protection factorUV protection factorfromfrom clothingclothing

transmission of UVA and UVB through fabricstransmission of UVA and UVB through fabrics

measured by spectrophotometrymeasured by spectrophotometry

UPF should be > 30UPF should be > 30

clothing design should cover the upper andclothing design should cover the upper andlower bodylower body (base of neck down to hip and across shoulders(base of neck down to hip and across shoulders

down to of upper arm, and lower body coveragedown to of upper arm, and lower body coverage

should be from waist to knee)should be from waist to knee)


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clothing UPFclothing UPF byby tighter woven fabricstighter woven fabrics

darker coloursdarker colours

optical brightenersoptical brighteners

laundering with UV absorber Tinosorb FDlaundering with UV absorber Tinosorb FD distance of fabric from the skin i.e. not too tightdistance of fabric from the skin i.e. not too tight

hydrationhydration viscose or silk UPF but cotton UPFviscose or silk UPF but cotton UPF

For adequate photoprotection, denier count needs to beFor adequate photoprotection, denier count needs to be>>

40 but popular40 but popular

pantyhose 15 denier provides less than 2 UPF.pantyhose 15 denier provides less than 2 UPF.


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Avoid sunAvoid sun


Wrap-roundWrap-round

sunglassessunglassesLarge area of skinLarge area of skin

coveredcovered

Densely wovenDensely woven

clothingclothingSunscreenSunscreen


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SunscreenSunscreen

SPFSPF == sunsun

protection factorprotection factor

Burn time withBurn time with

sunscreensunscreencompared to nocompared to no

sunscreensunscreen

UVB protectionUVB protection

factorfactor

No universallyNo universally

agreed measure ofagreed measure of

UVA protectionUVA protection


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SunscreensSunscreens

Physical /non-chemical / inorganicPhysical /non-chemical / inorganic

Organic / chemicalOrganic / chemical


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Inorganic sunscreenInorganic sunscreen

Titanium dioxide and zinc oxideTitanium dioxide and zinc oxide photostablephotostable not absorbed systemicallynot absorbed systemically

not been reported to sensitisenot been reported to sensitise reflect and diffuse UVRreflect and diffuse UVR


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Micro-ionised sunscreensMicro-ionised sunscreens

particle size to (10-50nm) c.f.particle size to (10-50nm) c.f. 200-500nm of200-500nm ofnon-microionised formnon-microionised form

better cosmesisbetter cosmesis but shifts protection towards shorterbut shifts protection towards shorter

wavelengths, unless particles coated withwavelengths, unless particles coated withdimethicone or silicadimethicone or silica

No systemic absorptionNo systemic absorption through intact normal skinthrough intact normal skin SafeSafe

A review of the scientific literature on the safety of nanoparticulate titaniumA review of the scientific literature on the safety of nanoparticulate titaniumdioxide or zinc oxide in sunscreens.dioxide or zinc oxide in sunscreens. Australian Therapeutic GoodsAustralian Therapeutic Goods

Administration 2006,Administration 2006, Nanotechnology, Cosmetics and the Skin: Is there a Health Risk?Nanotechnology, Cosmetics and the Skin: Is there a Health Risk? SkinSkin

Pharmacol PhysiolPharmacol Physiol 2008:21:136-1492008:21:136-149


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Organic / chemicalOrganic / chemical

sunscreenssunscreens absorb UVR energyabsorb UVR energy converted to unnoticeable heatconverted to unnoticeable heat

variable UVL spectrum covervariable UVL spectrum cover Classified as UVB or UVA filtersClassified as UVB or UVA filters

variable duration of effectvariable duration of effect photostablephotostable : able to absorb UVR photons repetitively: able to absorb UVR photons repetitively

pphotounstablehotounstable: filter rapidly loses its absorption capacity: filter rapidly loses its absorption capacity

and protective potencyand protective potency

Photoreactive:Photoreactive: if absorbed UV photons createif absorbed UV photons createphotoexcited molecules reacting with skin biomolecules,photoexcited molecules reacting with skin biomolecules,

ambient Oambient O22 or other sunscreen componentor other sunscreen component


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Examples ofExamples offiltersfilters

UVAUVA filtersfilters titanium dioxide and zinctitanium dioxide and zinc

oxideoxide benzophenonesbenzophenones

(oxybenzone,(oxybenzone,sulisobenzone,sulisobenzone,dioxybenzone),dioxybenzone),

butyl methoydibenzoylbutyl methoydibenzoylmethane (avobenzone,methane (avobenzone,Parsol 1789)Parsol 1789)

menthyl anthranilatementhyl anthranilate Bemotrizinol (methylene-Bemotrizinol (methylene-

bis-benzotriazolyl-phenol)bis-benzotriazolyl-phenol)

UVBUVB filtersfilters para-aminobenzoic acidpara-aminobenzoic acid

(PABA) derivatives (e.g. Octyl(PABA) derivatives (e.g. Octyldimethyl para-aminobenzoicdimethyl para-aminobenzoicacid)acid)

Cinnamates (octylCinnamates (octylmethoxycinnamate,methoxycinnamate, Parsol MCX, cinoxate)Parsol MCX, cinoxate) salicylates (octyl salicylate,salicylates (octyl salicylate,

homosalate, trolaminehomosalate, trolaminesalicylate),salicylate),

OctocryleneOctocrylene phenylbenzimidazole sulfonicphenylbenzimidazole sulfonic

acidacid Bemotrizinol (methylene-bis-Bemotrizinol (methylene-bis-

benzotriazolyl-phenol)benzotriazolyl-phenol)


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Broad spectrumBroad spectrum

sunscreenssunscreenshigh level of absorption in both thehigh level of absorption in both the

UVB and UVA rangesUVB and UVA ranges


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Sunscreen stabilitySunscreen stability

variable, sovariable, so Sunscreens need frequent re-applicationSunscreens need frequent re-application

keep sunscreens away from heat andkeep sunscreens away from heat and

sunlight when not in usesunlight when not in use

discard sunscreens after best-before-datediscard sunscreens after best-before-date


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Other aspects ofOther aspects of

sunscreensunscreen Sun sensitivitySun sensitivityre SPF number (fair vs. pigmented skin)re SPF number (fair vs. pigmented skin) Sensitivity / intoleranceSensitivity / intolerance

non-perfumed hypoallergenic / low irritant sunscreens e.g.non-perfumed hypoallergenic / low irritant sunscreens e.g. Ego LowEgo LowIrritantIrritant

Microionised sunscreensMicroionised sunscreens cosmetically better toleratedcosmetically better tolerated

DrynessDryness

sunscreen with a moisturising base e.g. sunscreen creams or ointments.sunscreen with a moisturising base e.g. sunscreen creams or ointments.E.g. Ego Ultra, Ego Daily Face Matt Formula, Neutrogena Age Shield.E.g. Ego Ultra, Ego Daily Face Matt Formula, Neutrogena Age Shield. Nicotinamide (improves intercellular lipidsNicotinamide (improves intercellular lipids hydration and sensitivity)hydration and sensitivity)

oily / acne-prone / hairy skinoily / acne-prone / hairy skin lighter base, e.g. lotion or gel. elighter base, e.g. lotion or gel. e.g. Neutrogena Dry Touch. Ego Sports.g. Neutrogena Dry Touch. Ego Sports

Milk, Ego Sports GelMilk, Ego Sports Gel..

Nicotinamide may reduce sebum excretionNicotinamide may reduce sebum excretion Ego productsEgo products ActivityActivity

wet / sweaty choose water resistant, longer lasting or rub resistantwet / sweaty choose water resistant, longer lasting or rub resistantsunscreen esunscreen e.g. Day Long SPF 30+, Ego Sports Milk or gel..g. Day Long SPF 30+, Ego Sports Milk or gel.


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Amount of sunscreen &Amount of sunscreen &

SPFSPF The declared sun protection factor (SPF) isThe declared sun protection factor (SPF) is

based on the use of a sunscreen layer of 2 mgbased on the use of a sunscreen layer of 2 mgcmcm22..

Only around 25% (0.5 mg/ cmOnly around 25% (0.5 mg/ cm2)2) of this amountof this amount

is applied by sunbathers.is applied by sunbathers. at the usual application rate of 0.5 mg/cmat the usual application rate of 0.5 mg/cm22,,

thethe true SPF is a 4th root of the claimed SPFtrue SPF is a 4th root of the claimed SPF @ 2 mg/cm@ 2 mg/cm22 SPF 30;SPF 30;

@ 1.0 mg/cm@ 1.0 mg/cm22

SPF 5.5; SPF 5.5; @ 0.5 mg/cm@ 0.5 mg/cm22 real SPF 2.3real SPF 2.3

Faurschou A, Wulf HC. The relation between sun protection factor and amount ofFaurschou A, Wulf HC. The relation between sun protection factor and amount ofsuncreen applied in vivo. Br J Dermatol. 2007 Apr;156(4): 716-9.suncreen applied in vivo. Br J Dermatol. 2007 Apr;156(4): 716-9.


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sunscreenssunscreens

- how much to use?- how much to use? AverageAverageadult sizeadult size

1/2 teaspoon1/2 teaspoon faceface neck (frontneck (front

&back)&back) earsears

1 teaspoon1 teaspoon each arm and leg,each arm and leg, on the backon the back and on the torsoand on the torso

*Sunscreen should be*Sunscreen should bereapplied frequentlyreapplied frequentlye.g. every two hourse.g. every two hours


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Do sunscreensDo sunscreens

make a difference?make a difference?


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Regular use ofRegular use of

SunscreenSunscreen reduces the rate of development of newreduces the rate of development of new

actinic keratosesactinic keratoses Regular use of sunscreen SPF > 7.5 canRegular use of sunscreen SPF > 7.5 can

lifetime incidence of non-melanoma skinlifetime incidence of non-melanoma skin

cancer by ~80%cancer by ~80% Daily use of high SPF (>17) developmentDaily use of high SPF (>17) development

of new solar keratoses (SCC precursor) andof new solar keratoses (SCC precursor) and remission of existing lesions remission of existing lesions AJD 2007;48:67-76AJD 2007;48:67-76

significantly reduce UV-induced skinsignificantly reduce UV-induced skindamage, BCC and SCC skin cancersdamage, BCC and SCC skin cancers in early life, might reduce naevus countsin early life, might reduce naevus counts

and subsequent melanoma risk.and subsequent melanoma risk.


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References re benefit ofReferences re benefit of

regular sunscreen useregular sunscreen use Seite S, Fourtanier A. The benefits of daily photoprotection. J Am Acad of Dermatol 2003Seite S, Fourtanier A. The benefits of daily photoprotection. J Am Acad of Dermatol 2003 Marks R. Epidemiology of melanoma. Clin Exp Dermatol 2000;25:459-63.Marks R. Epidemiology of melanoma. Clin Exp Dermatol 2000;25:459-63. Green A, Williams G, Neale R et al. Daily sunscreen application and betacaroteneGreen A, Williams G, Neale R et al. Daily sunscreen application and betacarotene

supplementation in prevention of basal-cell and squamous cell carcinomas of the skin: asupplementation in prevention of basal-cell and squamous cell carcinomas of the skin: arandomised controlled trial. Lancet 1999;16:31-7.randomised controlled trial. Lancet 1999;16:31-7.

Naylor M, Boyd A, Smith D et al. High sun-protection factor sunscreens in the suppression ofNaylor M, Boyd A, Smith D et al. High sun-protection factor sunscreens in the suppression ofactinic neoplasia. Arch Dermatol 1995;131:170-5.actinic neoplasia. Arch Dermatol 1995;131:170-5.

MacLennan R, Kelly J, Rivers J et al.MacLennan R, Kelly J, Rivers J et al. The Eastern Australian childhood nevus study: siteThe Eastern Australian childhood nevus study: sitedifferences in density and size of melanocytic nevi in relation to latitude and phenotype. Jdifferences in density and size of melanocytic nevi in relation to latitude and phenotype. J

Am Acad Dermatol 2003;48:367-75.Am Acad Dermatol 2003;48:367-75. Vainio H, Miller A, Bianchini F.Vainio H, Miller A, Bianchini F. An international evaluation of the cancer-preventativeAn international evaluation of the cancer-preventative

potential of sunscreens. Int J Cancer 2000;88:838-42.potential of sunscreens. Int J Cancer 2000;88:838-42. Huncharek M, Kupelnick B. Use of topical sunscreens and the risk of malignant melanoma: aHuncharek M, Kupelnick B. Use of topical sunscreens and the risk of malignant melanoma: a

meta-analysis of 9067 patients from 11 case-control studies. Am J Public Healthmeta-analysis of 9067 patients from 11 case-control studies. Am J Public Health2002;92:1173-7.2002;92:1173-7.

Rigel D. The effect of sunscreen on melanoma risk. Dermatol Clin 2002;20:601-6Rigel D. The effect of sunscreen on melanoma risk. Dermatol Clin 2002;20:601-6 Risk reduction for nonmelanoma skin cancer with childhood sunscreen use. Arch DermatolRisk reduction for nonmelanoma skin cancer with childhood sunscreen use. Arch Dermatol

1986;122:537-451986;122:537-45

Reduction of solar keratoses by regular sunscreen use. N Engl J Med 1993;1147-51Reduction of solar keratoses by regular sunscreen use. N Engl J Med 1993;1147-51


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Effects of UVREffects of UVR

ImmunosuppressionImmunosuppressionNon-melanoma skin cancer is proportional to the level andNon-melanoma skin cancer is proportional to the level and

duration of immunosuppressionduration of immunosuppression AJD 2007AJD 2007

Oxidative mitochondrial DNA damageOxidative mitochondrial DNA damage

DNA photoproducts e.g. cyclobutane pyrimidine dimerDNA photoproducts e.g. cyclobutane pyrimidine dimerformationformation skin cancer & photoageing skin cancer & photoageing

Increased skin pigmentationIncreased skin pigmentation Vit D productionVit D production

Thickening of epidermal layerThickening of epidermal layerVit D productionVit D production


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Other UVR effects onOther UVR effects on

skinskin DNA signature mutation, (cytosine changed toDNA signature mutation, (cytosine changed to

thymine) inthymine) in p53p53 tumour suppression genetumour suppression gene

defective DNA repair & apoptosis of damaged cellsdefective DNA repair & apoptosis of damaged cells

thus propagation of mutated keratinocytes skinthus propagation of mutated keratinocytes skincancerscancers

AJD 2007;48:67-76.AJD 2007;48:67-76.


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Skin cancer developmentSkin cancer development

UVL UVL UVL UVL UVLUVL UVL UVL UVL UVL

initiationinitiation promotion promotion cancer cancer


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SunscreensSunscreens

Reduce UV-inducedReduce UV-inducedp53p53 mutationsmutations Decrease immunosuppressive effects ofDecrease immunosuppressive effects of

sunlightsunlight

Immune protective factor correlated withImmune protective factor correlated withUVA protection factor of sunscreens (notUVA protection factor of sunscreens (notSPF)SPF)

SPF (sun protection factor) onlySPF (sun protection factor) onlyinternationally recognised end-point for theinternationally recognised end-point for theevaluation of sunscreen effectivenessevaluation of sunscreen effectiveness


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UVBUVB UVAUVA

280-315nm280-315nm


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What about Vitamin D?What about Vitamin D?

Vit D production from UVB part of UVVit D production from UVB part of UV

spectrumspectrum

High SPF sunscreen better protectionHigh SPF sunscreen better protection

from UVBfrom UVB Regular sunscreen usage and sunRegular sunscreen usage and sun

protective behaviour does not impairprotective behaviour does not impair

Vit D levelsVit D levels (Marks,95)(Marks,95)


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Vitamin D benefitsVitamin D benefits

helps bone, joint, muscle and neurologicalhelps bone, joint, muscle and neurological

function, calcium regulation, TSH production,function, calcium regulation, TSH production,

hair growth and developmenthair growth and development

link between sunlight exposure, vitamin D levelslink between sunlight exposure, vitamin D levelsand osteoporosis, well established.and osteoporosis, well established. Working Group of the Australian and New Zealand Bone and Mineral Society, Endocrine Society of Australia,Working Group of the Australian and New Zealand Bone and Mineral Society, Endocrine Society of Australia,

Osteoporosis Australia. Vitamin D and Adult Bone Health in Australia and New Zealand: a position statement.Osteoporosis Australia. Vitamin D and Adult Bone Health in Australia and New Zealand: a position statement.

Med J Aust 2005;182(6):281-5.Med J Aust 2005;182(6):281-5.


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Vitamin DVitamin D

maymayhelp prevent or improve thehelp prevent or improve the

outcome ofoutcome of breast, prostate and colorectal cancer,breast, prostate and colorectal cancer,

non-Hodgkin lymphoma,non-Hodgkin lymphoma, cardiovascular disease,cardiovascular disease,

diabetes anddiabetes and

autoimmune diseases (e.g. Multipleautoimmune diseases (e.g. MultipleSclerosis)Sclerosis)


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Vitamin D benefitsVitamin D benefits

mechanism been linked to themechanism been linked to the

regulatory role of 25-hydroxyvitaminregulatory role of 25-hydroxyvitamin

D on cellular growth both in normalD on cellular growth both in normal

and cancer cells.and cancer cells.

7-dehydrocholesterol (abundant in


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7 dehydrocholesterol (abundant inskin)

UVB (290-320nm)

Previtamin D skin temperature dependent

conversion

Vitamin D3 (cholecalciferol) liver hydroxylation

Hydroxycholecalciferol

kidney (& paracrine in other organs)hydroxylation

1,25-dihydroxycholecalciferol

Eff f MED Vi i DEff t f MED Vit i D


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Effect of MED on Vitamin DEffect of MED on Vitamin D

productionproduction

Vit D deplete and 1 MEDVit D deplete and 1 MED 3 x serum Vit D3 x serum Vit D 2X 25OH D2X 25OH D 8X 1,25(OH)2 D (4 x upper limit of normal)8X 1,25(OH)2 D (4 x upper limit of normal)

Vit D replete and 3 MEDVit D replete and 3 MED 7-10 x serum Vit D in 2/77-10 x serum Vit D in 2/7 Returned to baseline in 1/52Returned to baseline in 1/52 2 x 25OH D by 2-3/522 x 25OH D by 2-3/52 1,25(OH)2 D remains in normal range1,25(OH)2 D remains in normal range

MED = minimal erythema doseMED = minimal erythema dose

Vit i D d tiVit i D d ti


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Vitamin D productionVitamin D production

regulationregulation

Maximal at suberythemal UVB doseMaximal at suberythemal UVB dose

Further UV exposure results inFurther UV exposure results in

production of biologically inertproduction of biologically inertlumisterol & tachysterollumisterol & tachysterol

If synthesised Vit D > amount leachedIf synthesised Vit D > amount leached

into circulation, remaining Vit D3 in theinto circulation, remaining Vit D3 in theskin is further degraded by sunskin is further degraded by sun

exposureexposure

Optimal Vit D withoutOptimal Vit D without


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Optimal Vit D withoutOptimal Vit D without

burning / tanningburning / tanning Diagram from SolaracDiagram from SolaracLampsLamps

At lower UVBAt lower UVB

wavelengths morewavelengths more

burning, less Vit Dburning, less Vit D

productionproduction

Optimal Vit DOptimal Vit D

~308nm~308nm

(therapeutic nbUVB)(therapeutic nbUVB)

No vitamin D fromNo vitamin D fromTanning lampsTanning lamps

Vi i D i ffi iVit i D i ffi i t


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Vitamin D insufficiency atVitamin D insufficiency at

risk groupsrisk groups ElderlyElderly

Darkly pigmentedDarkly pigmented

Covered-up (religious or cultural,Covered-up (religious or cultural,extreme sun protection)extreme sun protection)

ObeseObese

Babies of vitamin D deficient mothersBabies of vitamin D deficient mothers Housebound or in institutional careHousebound or in institutional care

May require extra oral vitamin DMay require extra oral vitamin D


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Vitamin DVitamin D33 vs. Vitamin Dvs. Vitamin D22

Vitamin D3 from sunlight or animalVitamin D3 from sunlight or animalsourcessources

Vitamin D2 is synthesised fromVitamin D2 is synthesised from

ergosterol (in plants) also by the actionergosterol (in plants) also by the actionof UVRof UVR Vitamin D2 follows the sameVitamin D2 follows the same

hydroxylation pathway and ishydroxylation pathway and is

equipotent to Vitamin D3equipotent to Vitamin D3 So dietary vitamin D = skin/ liver /So dietary vitamin D = skin/ liver /

kidney vitamin Dkidney vitamin D


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Oral Vitamin DOral Vitamin D

DietaryDietary Oily fish, liver, kidneys, lamb, sun-treatedOily fish, liver, kidneys, lamb, sun-treated

shittake mushroomsshittake mushrooms

Eggs, milkEggs, milk Fortified food, e.g. margarine, soy milk,Fortified food, e.g. margarine, soy milk,

Anchor (Fonterra) milkAnchor (Fonterra) milk

Cholecalciferol 1.25mg = 50,000IU on RCholecalciferol 1.25mg = 50,000IU on Rxx


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Vitamin D toxicityVitamin D toxicity

Difficult to achieve!Difficult to achieve!

Possible after long-term intake of > 100Possible after long-term intake of > 100

000 i.u. daily000 i.u. daily

Anorexia, vomiting, diarrhoea,Anorexia, vomiting, diarrhoea,

Hypercalcemia, hypercalciuriaHypercalcemia, hypercalciuria

OsteoporosisOsteoporosis Rx withdraw Vit D, low calcium diet,Rx withdraw Vit D, low calcium diet,

systemic corticosteroidssystemic corticosteroids


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Sunlight and vitaminsSunlight and vitamins

UV destroys folates in the bodyUV destroys folates in the body

Folate deficiencyFolate deficiency Impaired spermatogenesisImpaired spermatogenesis

Pregnancy complicationsPregnancy complications

Birth (CNS) defectsBirth (CNS) defects

Optimal Vitamin D production withOptimal Vitamin D production with

minimal sunlightminimal sunlight


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FutureFuture

Better protectionBetter protection Improved sunscreenImproved sunscreen Photoprotectant clothing / glassesPhotoprotectant clothing / glasses

FashionsFashions Window glass (tint etc)Window glass (tint etc) AntioxidantAntioxidant

Better detection?Better detection? Better treatment for skin cancersBetter treatment for skin cancers

further immune modulatorsfurther immune modulators


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Summary 1Summary 1

Skin cancersSkin cancers areare a big problem in NZa big problem in NZ Morbidity / $cost/ mortalityMorbidity / $cost/ mortality Sun protectionSun protection doesdoes help reduce skinhelp reduce skin

cancers (and photoageing)cancers (and photoageing) Avoid sun when UVI >3Avoid sun when UVI >3 Broad rim hatBroad rim hat Wrap-round sunglassesWrap-round sunglasses Cover large area (3/4) of skinCover large area (3/4) of skin UPF clothing >30UPF clothing >30 SunscreenSunscreen (especially UVA coverage / broad spectrum)(especially UVA coverage / broad spectrum) Healthy dietHealthy diet


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Summary 2Summary 2

Adequate Vitamin D levels important forAdequate Vitamin D levels important for

optimal healthoptimal health currentcurrent optimal leveloptimal level80nmol/l?80nmol/l?

Efficient Vitamin D productionEfficient Vitamin D productionbyby Keeping pale (non pigmented /non sunKeeping pale (non pigmented /non sun

damaged skin)damaged skin)

Minimal sun exposureMinimal sun exposure (sub MED)(sub MED)

But regular outdoor exerciseBut regular outdoor exercise Healthy dietHealthy diet

Documents

Update on Sun Protection 2009