Sunlight skin cancer and bones:

Making sense of “mixed” messages

Seeta Durvasula Centre for Developmental Disability Studies

University of Sydneyseetad@med.usyd.edu.au

CDDSCentre for Developmental Disability Studies

Sun exposure and skin cancer

1920s – attitudes to sunlight exposure seen as health promoting “tanned is beautiful”

In Australia, sun exposure causes 99% of non-melanoma skin cancers 95% of melanomas (Armstrong, 2004)

So, strong public health campaigns for sun protective measures

Sun Protection Measures

Minimise time in the sun between 11am and 3pm (daylight saving time);

Use shade wherever you can including trees, shelters and umbrellas;

Slip! on a shirt made from tightly woven fabric, with sleeves and a high neck or collar and other clothing that covers the skin;

Slop! on a broad spectrum water resistant sunscreen with an SPF rating of 30+; and

Slap! on a wide brimmed hat or legionnaire's cap, that shades the face, neck and ears.

NSW Health, 1999

““Slip, Slop, Slap”Slip, Slop, Slap”

Slip, Slop, Slap!It sounds like a breeze when you say it like thatSlip, Slop, Slap!In the sun we always say "Slip Slop Slap!“

Slip, Slop, Slap!Slip on a shirt, slop on sunscreen and slap on a hat,Slip, Slop, Slap!You can stop skin cancer - say: "Slip, Slop, Slap!" The Cancer Council

Australia

Vitamin D and Bones

Hormone Necessary bone health

helps absorb calcium from gut Beneficial effect on muscle

strength and balance Prevention of fractures in elderly May also have beneficial effects on

some types of cancer

Where do you get it? (Vitamin D)

In Australia, 90% from sunlight - UVB Food - minor source of Vitamin D in

Australia milk, cheese margarine liver oily fish –sardines, mackerel, salmon

classical

non classical

Pancreatic cells

What is Vitamin D Deficiency?(Position statement, 2005)

Defined by serum Vitamin D level

Mild Vitamin D deficiency – 25 (OH) vitamin D level - 25 – 50 nmol/L

= Insufficiency raised parathyroid hormone level

Moderate Vitamin D deficiency 12.5-25 nmol/L

Severe Vitamin D deficiency < 12.5 nmol/L

Vitamin D deficiency

Increase in parathyroid hormone release of calcium from bones

Reduced bone density osteomalacia in adults rickets in children

Increased fracture risk in older people Muscle pains, muscle weakness Linked to falls in older people Associated with Type 1 diabetes,

some cancers

Causes of Vitamin D deficiency

Inadequate sunlight exposure elderly – especially in aged care facilities immobility skin covering

Sunlight less effective ageing skin pigmented skin

Diet – low consumption Malabsorption and abnormal gut

function

How common is vitamin D deficiency?

General population 43% in young women - Geelong (Pasco et

al. 2001) 23% in adult population - SE QLD

(McGrath et. Al, 2001) Specific groups at risk

elderly in high level care – 55% (Flicker et al. 2003)

dark skin pigmentation, especially if also covered/veiled 80% in one study (Grover & Morley, 2001)

People with developmental disability

Studies mainly in institutionalised populations on anticonvulsant therapy 47% of people with developmental disability

living in institution in NSW (Beange et al. 1994)

57% of those in a residential facility in SA– those with poor mobility, difficulty in taking solids (Valint & Nugent, 2006)

Community living adults - 36% men and 40% women (Centre et al. 1998)

43% of a clinic population in Sydney – older people, people with Down syndrome, overweight (Durvasula et al. 2005 - unpublished)

Prevention of Vitamin D deficiency in general

population Diet

200IU if < 50yrs; 400IU if 51-70 yrs; 600 IU if >70yrs (US Food &Nutrition Board)

Most Australians get <100 IU/day<100 IU/day Sun exposure = 1/3 Minimal

Erythema Dose (MED) To Reduce fracture risk in elderly –

1000IU day

Recommended sun exposure

1 minimal erythema dose (MED) is amount of sun exposure which produces faint skin redness

=Whole body exposure to 10-15mins of midday sun in summer

= 15,000U of vitamin D Recommend 1/3 MED

= exposing hands, face and arms to of sunlight on most days

Recommended sun exposure times (mins) for 1/3MED for moderate

fair skinRegion Dec-Jan July-Aug

at 10 am or 2pm

Auckland 6-8 30-47Christchurch 6-9 49-97Cairns 6-7 9-12Brisbane 6-7 5-19Adelaide 5-7 25-38Perth 5-6 20-28Sydney 6-8 26-28Melbourne 6-8 32-52Hobart 7-9 40-47

Sun exposure in people with developmental

disability Paucity of reliable data except for

those physical disability, or those in institutional care

Possible other at risk groups e.g those with challenging behaviour,

autism

Note: Reliance on carers/ support staff

Mixed messages?

Sun protection – prevent skin cancer

Sun exposure – prevent vitamin D deficiency

Not so “mixed”

Risks and Benefits of Sun Risks and Benefits of Sun Exposure (2005)Exposure (2005)

Aust. and NZ Bone Society, Osteoporosis Australia, Australasian College of Dermatologists, The Cancer Council of Australia http://www.cancer.org.au/content.cfm?randid=299825

Recommendations Sun protection required when UV index is

moderate or higher (≥3) Most people achieve adequate Vitamin D

levels through typical day to day activities, without deliberately seeking additional sun exposuresummer – expose face, arms and hands to

average of 5 minutes most days of the week outside peak UV levels

winter, in Southern States – exposure of hands, face, arms for 2-3 hours over a week

Use of solaria not recommended due to level of UV exposure

Recommendations

Those at increased risk of skin cancer need more vigorous sun protection practices and should discuss their vitamin D requirements with their doctor

Those at increased risk of Vitamin D deficiency should discuss their vitamin D status with their doctor

Recommendations – special groups

Older adults – if not at high risk of skin cancer, ensure incidental exposure

Skin type – dark skin pigmentation, especially if covered – may need vitamin D supplementation

What about sunscreen?

Necessary to prevent skin damage if prolonged exposure (long enough to cause erythema) is planned

For incidental exposure, of less than 10 minutes, may be able to omit sunscreen short exposures better for vitamin D

synthesis(Nowson et al, 2004)

What about people with developmental disability?

Recommendations as for general population for prevention of vitamin D deficiency i.e. safe sun exposure

But, need to take into account skin type/pigmentation, latitude, season, medication use (anticonvulsants), mobility

What about people with developmental

disability? However, many are at increased

risk of Vitamin D deficiency e.g. Medications Limited sun exposure

poor mobilitystaffing limitationschallenging behaviour

Therefore, incidental sun exposure may not be enough

Recommendations

Vitamin D insufficiency is common in people with developmental disability and can only be confirmed by measuring 25OH D

Either monitor yearly at end of winter (lowest values) and treat those < 50nmol/L with vitamin D supplements

Optimal calcium intake also needed – diet or supplements

Message not so “mixed”

Incidental safe sun exposure where possible

Check Vitamin D levels and treat if required

Need further research Identify those with developmental

disability who are especially at risk Determine levels of sun exposure in those

living in the community

Management Vitamin D Deficiency

3000 – 5000 IU/day ergocalciferol for 6-12 weeks

50 000 IU cholecalciferol. One tablet monthly for 3-6 months (NZ only)

Reassess after 3-4 months of treatment

1000 IU/day of ongoing treatment required for most patients

Contraindicated in hypercalcaemia