Download Sunlight, Skin Cancer and Bones: Making Sense of “Mixed” Messages

CDDS
Centre for
Developmental
Disability
Studies
Sunlight skin cancer and bones:
Making sense of “mixed”
messages
Seeta Durvasula
Centre for Developmental Disability Studies
University of Sydney
[email protected]
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!
It sounds like a breeze
when you say it like that
Slip, 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
Pancreatic 
cells
non classical
classical
What is Vitamin D Deficiency?
(Position statement, 2005)
 Defined
 Mild
by serum Vitamin D level
Vitamin D deficiency –
 25 (OH) vitamin D level - 25 – 50 nmol/L
= Insufficiency
 raised parathyroid hormone level
 Moderate
 Severe
Vitamin D deficiency 12.5-25 nmol/L
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
 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 skin
Region
Auckland
Christchurch
Cairns
Brisbane
Adelaide
Perth
Sydney
Melbourne
Hobart
Dec-Jan
6-8
6-9
6-7
6-7
5-7
5-6
6-8
6-8
7-9
at 10 am or 2pm
July-Aug
30-47
49-97
9-12
5-19
25-38
20-28
26-28
32-52
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
 Sun
protection – prevent skin cancer
exposure – prevent vitamin D
deficiency
Not so “mixed”
Risks and Benefits of Sun
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
exposure
 summer – 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 mobility
staffing limitations
challenging 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