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ULTRAVIOLET LIGHT Man’s best friend Dr. D. Czarnecki MD MBBS.

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Presentation on theme: "ULTRAVIOLET LIGHT Man’s best friend Dr. D. Czarnecki MD MBBS."— Presentation transcript:

1 ULTRAVIOLET LIGHT Man’s best friend Dr. D. Czarnecki MD MBBS

2 Ultraviolet light Sunlight has many beneficial effects on men and it has been known for a long time that sunlight is good for you – even though exactly what sunlight did was unknown until recentlySunlight has many beneficial effects on men and it has been known for a long time that sunlight is good for you – even though exactly what sunlight did was unknown until recently 1385 BC - Echnaton (Egypt) praised sunlight1385 BC - Echnaton (Egypt) praised sunlight Hippocrates noted that sunlight leads to faster healing of fracturesHippocrates noted that sunlight leads to faster healing of fractures 135 AD - Anthyllos (Greece) stated that exposure to sunlight made bodies stronger and activated brain function135 AD - Anthyllos (Greece) stated that exposure to sunlight made bodies stronger and activated brain function 20 th century - it was found that the sun prevents rickets20 th century - it was found that the sun prevents rickets Ultraviolet light (UVL) is the part that of the sun’s spectrum that causes the most benefitUltraviolet light (UVL) is the part that of the sun’s spectrum that causes the most benefit

3 Ultraviolet light Ultraviolet light (UVL) is the part of the sun’s spectrum lying between 200 and 400 nmUltraviolet light (UVL) is the part of the sun’s spectrum lying between 200 and 400 nm It is divided into three components based on certain propertiesIt is divided into three components based on certain properties UVC does not penetrate through ozoneUVC does not penetrate through ozone UVB does not penetrate through glass or sunscreens. It is attenuated by ozoneUVB does not penetrate through glass or sunscreens. It is attenuated by ozone UVA does not penetrate through opaque materialsUVA does not penetrate through opaque materials

4 Ultraviolet light 200nm nm UVCUVBUVA ozone Glass sunscreen opaque material

5 Ultraviolet light UVC is the strongest component – most likely to burnUVC is the strongest component – most likely to burn UVB is strong and causes sunburnUVB is strong and causes sunburn It produces a tanIt produces a tan It damages DNAIt damages DNA It causes the skin to produce chemicalsIt causes the skin to produce chemicals UVA is weakUVA is weak It darkens existing pigment but does not produce new pigmentIt darkens existing pigment but does not produce new pigment It penetrates deeply into the skin – may cause wrinklesIt penetrates deeply into the skin – may cause wrinkles

6 Ultraviolet light keratinocyte CYTOKINES GROWTH FACTORS VITAMIN D HORMONES The epidermal cells (Keratinocytes) are chemical power houses are chemical power houses

7 Vitamin D Vitamin D is one of the most important chemicals produced by the skinVitamin D is one of the most important chemicals produced by the skin 7 dehydrocholesterol is converted into previtamin D by UVL7 dehydrocholesterol is converted into previtamin D by UVL Previtamin D moves into the circulation, to the liver where it is converted into 25 hydroxy vitamin D (25 OHD)Previtamin D moves into the circulation, to the liver where it is converted into 25 hydroxy vitamin D (25 OHD) 25 OHD is transported into the kidneys where it is converted into 1 25 dihydroxy vitamin D (1 25OHD) – the active form25 OHD is transported into the kidneys where it is converted into 1 25 dihydroxy vitamin D (1 25OHD) – the active form

8 7 dehydrocholesterol previtamin D LIVER 25OHD3 1.25OHD3 KIDNEYS UVB Ultraviolet light is the most important source of vitamin D Epidermis 1.25OHD3Blood

9 Vitamin D Dietary precursors enter the liver to be converted into 25OHDDietary precursors enter the liver to be converted into 25OHD People cannot obtain enough vitamin D via their dietsPeople cannot obtain enough vitamin D via their diets People cannot produce too much vitamin D from the sunPeople cannot produce too much vitamin D from the sun UVL UVL UVL UVL 7 dehydrocholesterol previtamin D inert substance 7 dehydrocholesterol previtamin D inert substance

10 Vitamin D It was only recently discovered that he skin also produces the active form of vitamin D (1 25 OHD)It was only recently discovered that he skin also produces the active form of vitamin D (1 25 OHD) UVL UVL 7 dehydrocholesterol previtamin D 1 25 OHD 7 dehydrocholesterol previtamin D 1 25 OHD Many other organs, apart from the kidneys, also produce 1 25 OHDMany other organs, apart from the kidneys, also produce 1 25 OHD

11 Vitamin D The current recommendations – vitamin D intakeThe current recommendations – vitamin D intake <13 yrs – 200 IU (international units)<13 yrs – 200 IU (international units) 51 – 70 yrs – 400 IU51 – 70 yrs – 400 IU >70 yrs – 600 IU>70 yrs – 600 IU Studies of people who are covered in clothing when outside, and studies of submariners, suggest that 1000 IU a day are needed if people do not get some sun on their skinsStudies of people who are covered in clothing when outside, and studies of submariners, suggest that 1000 IU a day are needed if people do not get some sun on their skins

12 Vitamin D Dietary sources of vitamin DDietary sources of vitamin D 1 teaspoon of cod liver oil – 1360 IU1 teaspoon of cod liver oil – 1360 IU 100 g of salmon – 360 IU100 g of salmon – 360 IU 1 egg – 20 IU1 egg – 20 IU 1 cup of fortified milk – 98 IU1 cup of fortified milk – 98 IU There is little in breast milkThere is little in breast milk People cannot obtain enough vitamin D from their ordinary dietsPeople cannot obtain enough vitamin D from their ordinary diets

13 Vitamin D It is needed to maintain normal body calcium levelsIt is needed to maintain normal body calcium levels It promotes calcium absorption from the small intestineIt promotes calcium absorption from the small intestine It promotes re-absorption from the kidneysIt promotes re-absorption from the kidneys A fall in serum calcium triggers the parathyroid gland to produce parathyroid hormoneA fall in serum calcium triggers the parathyroid gland to produce parathyroid hormone The kidneys produce more 1,25 vitamin DThe kidneys produce more 1,25 vitamin D Bone is resorbedBone is resorbed

14 Vitamin D Needed for healthy bonesNeeded for healthy bones Needed for healthy musclesNeeded for healthy muscles Prevents osteoporosis?Prevents osteoporosis? Prevents cancersPrevents cancers Reduces the incidence of auto-immune diseasesReduces the incidence of auto-immune diseases Reduces the incidence of multiple sclerosisReduces the incidence of multiple sclerosis Reduces hypertension and myocardial infarctionReduces hypertension and myocardial infarction Alleviates depression?Alleviates depression? Deficiency – causes poor spermatogenesis?Deficiency – causes poor spermatogenesis?

15 Vitamin D musculoskeletal system Vitamin D deficiency is associated with osteomalacia and increased bone turnover – a risk for fracturesVitamin D deficiency is associated with osteomalacia and increased bone turnover – a risk for fractures Deficiency might be associated with osteoporosisDeficiency might be associated with osteoporosis Deficiency – poor muscle co-ordination might be presentDeficiency – poor muscle co-ordination might be present Deficiency – muscle pain might be present. Deficiency might be the cause of “fibromyalgia” in older patientsDeficiency – muscle pain might be present. Deficiency might be the cause of “fibromyalgia” in older patients

16 Hip fractures Thin bones, and poor muscle co-ordination – a risk for fracturesThin bones, and poor muscle co-ordination – a risk for fractures About 20,000 hip fractures a year in AustraliaAbout 20,000 hip fractures a year in Australia 87% are older than 55 years87% are older than 55 years 6% die – inpatients6% die – inpatients 15 – 20% die within 12 months15 – 20% die within 12 months 50% have some disability50% have some disability Double blind, placebo controlled studies have found that vitamin D and calcium reduce falls and reduce the number of fractures when falls occurDouble blind, placebo controlled studies have found that vitamin D and calcium reduce falls and reduce the number of fractures when falls occur

17 Vitamin D Cancer The closer to the equator people live, the less risk of internal cancers and dying of cancerThe closer to the equator people live, the less risk of internal cancers and dying of cancer Women given vitamin D in Nebraska developed fewer cancers over 4 years compared to controls – a prospective studyWomen given vitamin D in Nebraska developed fewer cancers over 4 years compared to controls – a prospective study Double blind, placebo controlled studies of calcium and vitamin DDouble blind, placebo controlled studies of calcium and vitamin D Reduced the risk of colonic adenomas Reduced the risk of colonic adenomas Rats given vitamin D then carcinogens developed fewer cancers of the colon Rats given vitamin D then carcinogens developed fewer cancers of the colon

18 Calcium and vitamin D reduce the incidence of bowel polyps Fewer bowel polyps – fewer cancers

19 Vitamin D Cancer In tissue culture – vitamin D kills cancer cells (prostate cancer, melanoma)In tissue culture – vitamin D kills cancer cells (prostate cancer, melanoma) It has anti-proliferative effectsIt has anti-proliferative effects Blocks the cell cycleBlocks the cell cycle Promotes the differentiation of cellsPromotes the differentiation of cells Induces apoptosisInduces apoptosis Boosts the immune responseBoosts the immune response Reduces angiogenesisReduces angiogenesis

20 Vitamin D Cancer Improves the response to chemotherapyImproves the response to chemotherapy Improves the response to radiotherapyImproves the response to radiotherapy Causes hypercalaemiaCauses hypercalaemia Analogues are being developedAnalogues are being developed These will have some of the benefits without the hypercalaemia side effectThese will have some of the benefits without the hypercalaemia side effect

21 Vitamin D – death prevention Norway – surgery for CA in winter is more likely to kill you than if it is undertaken in the summerNorway – surgery for CA in winter is more likely to kill you than if it is undertaken in the summer Boston – lung CA surgery in the winter is more likely to result in death than if it is in the summerBoston – lung CA surgery in the winter is more likely to result in death than if it is in the summer Similar findings with cardiac surgery in the UK – higher death rate in winterSimilar findings with cardiac surgery in the UK – higher death rate in winter It may be more than the surgeon’s winter depressionIt may be more than the surgeon’s winter depression

22 Vitamin D – melanoma The role of sunlight in the genesis of melanoma is still being debated. Sunburn is the common finding in studies through out the worldThe role of sunlight in the genesis of melanoma is still being debated. Sunburn is the common finding in studies through out the world Indoor workers have a higher incidence than outdoor workers – through out the worldIndoor workers have a higher incidence than outdoor workers – through out the world Melanoma excised in the summer in Australia - live longer (adjusted for age, sex, thickness, site, type) than if a melanoma is excised in the winterMelanoma excised in the summer in Australia - live longer (adjusted for age, sex, thickness, site, type) than if a melanoma is excised in the winter Melanoma survival is better in regions closer to the equatorMelanoma survival is better in regions closer to the equator

23 CR of incidence for common cancers Men, Australia 2010 CancerQueenslandTasmania Lung Breast Colon Prostate Melanoma

24 ACR of incidence for common cancers Women, Australia 2010 CancerQueenslandTasmania Lung Breast Colon Prostate Melanoma

25 ACR of mortality for common cancers Men, Australia 2010 CancerQueenslandTasmania Lung Breast Colon Prostate Melanoma

26 CR of mortality for common cancers Women, Australia 2010 CancerQueenslandTasmania Lung Breast Colon Prostate Melanoma

27 Vitamin D Diabetes UK children given 2000IU of vitamin D – 80% less diabetes than their control groupUK children given 2000IU of vitamin D – 80% less diabetes than their control group Diabetes-prone mice given 25 OHD – 80% less diabetesDiabetes-prone mice given 25 OHD – 80% less diabetes Obesity is associated with lower vitamin D – it is a risk factor for diabetesObesity is associated with lower vitamin D – it is a risk factor for diabetes Insulin resistance is more common in vitamin D deficient people – can be corrected with supplementsInsulin resistance is more common in vitamin D deficient people – can be corrected with supplements

28 Sun Exposure The sun is good for you in small dosesThe sun is good for you in small doses Too much sun exposure damages the skin. It causes thinning, wrinkles, brown macules, burst blood vessels – an aged appearanceToo much sun exposure damages the skin. It causes thinning, wrinkles, brown macules, burst blood vessels – an aged appearance People have to be educated about safe sunbathingPeople have to be educated about safe sunbathing The aim is not to get sun burnt. Wear appropriate clothes and put sunscreen on exposed skin after a certain period of exposureThe aim is not to get sun burnt. Wear appropriate clothes and put sunscreen on exposed skin after a certain period of exposure

29 Too much UVL damages the skin – thin wrinkled, bruised The skin of his stomach is what his skin should look like. Note the difference

30 The demarcation line is visible. The skin looks aged. Note the normal skin in the unexposed sites – this is his age

31 How many minutes it takes for untanned skin to burn at noon, on a clear day. CityJanuaryJuly Darwin Brisbane Sydney Melbourne Hobart

32 Sun Exposure The average white Australian’s tan has an SPF of 3 – he can stay outside three times as long as someone with out a tanThe average white Australian’s tan has an SPF of 3 – he can stay outside three times as long as someone with out a tan The average Indian has an SPF of 15 – he will burn every day in Darwin if he stays outside all dayThe average Indian has an SPF of 15 – he will burn every day in Darwin if he stays outside all day 4 months of the year in Melbourne 4 months of the year in Melbourne Even Blacks burn – Viv Richards will tell you that sunburn is just as painful in blacks as whitesEven Blacks burn – Viv Richards will tell you that sunburn is just as painful in blacks as whites Some Asians have pale skin - 14% of Koreans have light skin– they easily burnSome Asians have pale skin - 14% of Koreans have light skin– they easily burn

33 How many minutes it takes for untanned and (an average tanned skin) to burn CityJanuaryJuly Darwin 9 (27) 9 (27) 19 (57) 19 (57) Brisbane 10 (30) 59 (177) 59 (177) Sydney 11.5 (31.5) 120 (360) Melbourne 12.5 (37.5) 210 (630) Hobart 14.3 (42.9) 450

34 Sunscreens Slow down sun damageSlow down sun damage Prevent new solar keratoses (SKs) – Australia, USA, EuropePrevent new solar keratoses (SKs) – Australia, USA, Europe Prevent new SKs even in renal transplant recipients – if they are applied every dayPrevent new SKs even in renal transplant recipients – if they are applied every day Prevent SCCs – a Queensland prospective studyPrevent SCCs – a Queensland prospective study Prevent skin cancer in renal transplant recipients (German study)Prevent skin cancer in renal transplant recipients (German study) Sunscreens prevent vitamin D formationSunscreens prevent vitamin D formation

35 Sunscreens Some studies suggest that sunscreen use is associated with an increased risk of melanomaSome studies suggest that sunscreen use is associated with an increased risk of melanoma These were not always well designed studies.These were not always well designed studies. Some facts that need to be addressed in future studiesSome facts that need to be addressed in future studies People who sunburn easily – more likely to use a sunscreen (also more likely to get a melanoma)People who sunburn easily – more likely to use a sunscreen (also more likely to get a melanoma) People may apply a sunscreen when at the beach, but what about the rest of the time? A lot of exposure occurs during activity e.g. walking aroundPeople may apply a sunscreen when at the beach, but what about the rest of the time? A lot of exposure occurs during activity e.g. walking around Some studies were retrospective therefore biased – people are more likely to use a sunscreen after a melanoma was diagnosedSome studies were retrospective therefore biased – people are more likely to use a sunscreen after a melanoma was diagnosed

36 Vitamin D deficiency is largely a cultural problem. Moslem women Women who work in offices Nursing home patients African immigrants Dermatologists Expose the head and forearms to the sun for 15 minutes, five times a week at noon

37 Vitamin D For adequate levels of vitamin DFor adequate levels of vitamin D People need to expose 20% of the body, at noon, forPeople need to expose 20% of the body, at noon, for 10 minutes if they do not tan 10 minutes if they do not tan for 15 minutes if they tan for 15 minutes if they tan Three days a week (no sunscreen)Three days a week (no sunscreen) After this exposure, cover up or put a sunscreen onAfter this exposure, cover up or put a sunscreen on

38 Vitamin D Why not take vitamin D and avoid the sun?Why not take vitamin D and avoid the sun? UVL induces the skin to produce many other chemicals including hormonesUVL induces the skin to produce many other chemicals including hormones These hormones have many properties such as:These hormones have many properties such as: producing a tan producing a tan anti-inflammatory properties anti-inflammatory properties appetite suppression appetite suppression influence lipid metabolism influence lipid metabolism influence mood influence mood

39 Hormones Keratinocytes produce a large hormone calledKeratinocytes produce a large hormone called pro-opiomelanocortin pro-opiomelanocortin This enters the circulation and is cleaved into other hormones in different tissuesThis enters the circulation and is cleaved into other hormones in different tissues These hormones have many beneficial effects. The endorphins make people feel better and is possibly why sunbathing is addictive to someThese hormones have many beneficial effects. The endorphins make people feel better and is possibly why sunbathing is addictive to some

40 Keratinocyte UVL Pro-opiomelanocortin αMSH endorphinsACTH

41 Ultraviolet Light Damages the epidermis and dermis (in big doses)Damages the epidermis and dermis (in big doses) Suppresses the immune system Causes the epidermal cells to produce many chemicalsCauses the epidermal cells to produce many chemicals Produces a tanProduces a tan Causes skin cancerCauses skin cancer

42 Langerhans cells inactive Melanocyte - DNA damage Keratinocyte - DNA damage, p53 damaged ULTRAVIOLET LIGHT UVL damages DNA, DNA repair enzymes, and causes cutaneous immunosuppression (it damages Langerhans cells)


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