Sun exposure

Health and Social Behaviour: The Effects on Health of Sun Exposure and Combating the Issue

Definition

The sun is the main source of Ultraviolet Radiation (UVR), but some individuals expose themselves to artificial sources including sunbeds (cosmetic tanning), industrial lights, and medical UVR therapies. UVR is radiation in the range of
wavelengths 100-400nm. It is divided by wavelength into 3 types of radiation: UVA 315-400nm, UVB 280-315nm and UVC 100-280nm. There are a number of health effects and hazards associated with exposure to UVR, skin cancer being the most well-known.

Epidemiology

• Sun exposure is the main cause of melanoma and non-melanoma skin cancers. 
• Approximately 80% of melanomas are caused by exposure to sunlight.
• More than 75,000 cases of non-melanoma skin cancer are reported/registered each year but The British Association of Dermatologists estimates that the actual number is at least 100,000 cases in the UK each year*.
• Approximately 9,000 cases of melanoma skin cancer are diagnosed each year in the UK.
• Non-melanoma skin cancer is extremely common.  However it is usually detected early and is not life-threatening.
• Although malignant melanoma makes up only 11% of skin cancer cases, it is responsible for around 80% of skin cancer deaths.
• Over the last 25 years the incidence of malignant melanoma has increased more than for any other major cancer in the UK.
• Around 2,300 people die from skin cancer every year in the UK.
• Melanoma is the third most common cancer amongst 15 to 39 year olds.
• Skin cancer is more common with increasing age, but melanoma is disproportionately high in younger people. Although melanoma is more than twice as common in young women as in young men, more men die from it.
• Melanoma rates are higher in people living in more affluent areas.

*NOTE: The incidence of skin cancer cases in the UK is difficult to predict as the registration data of non-melanoma skin cancer is known to be incomplete.

Effects on Health of Sun Exposure

The National Radiological Protection Board (NRPB) has a statutory responsibility to provide advice and information on the health effects associated with exposure to UVR. It is believed that any UVR exposure is associated with an increased
individual risk of a number of negative health effects. The main tissues of the body that are affected are the skin and eyes and there are also effects on the immune system. UVR exposure is, however, involved with the production of vitamin D in the
skin which is needed for bone growth and maintenance. But only relatively low levels of UVR exposure are required.

Skin

• UVR is strongly linked to the induction of skin cancers.
• There are two main types of skin cancer: non-melanoma skin cancer (very common) and melanoma (less common but more serious).
• UVR is a recognised risk factor for both non-melanoma and melanoma skin cancers.
• The risks are greater for people with light skin, red or blond hair, and blue eyes.
• People with a previous non-melanoma skin cancer have a much higher risk of developing a second one.
• People with a close relative diagnosed with skin cancer have a higher risk of developing it themselves.
• Treatment with immunosuppressants and radiotherapy can increase the risk of non-melanoma skin cancer.
• Excessive short-term exposure of the skin causes sunburn: skin reddening (erythema) and swelling (oedema). Sun exposure is often followed by increased production of melanin which is recognised as a suntan – this offers some protection against
  further exposure but is not an indication of good health.
• Chronic exposure of the skin cause photoageing: leathery, wrinkled and loss of elasticity.
• ‘Photosensitivity’ arises when certain individuals have abnormal skin responses to UVR exposure. This is due to genetic, metabolic or other abnormalities or because of intake of certain drugs. 
• Sunscreens protect against sunburn but there is limited evidence to demonstrate that they protect against skin cancers.

Eye

• UVR is probably linked to some eye disorders
• Excessive URV exposure leads to photokeratitis and photoconjunctivitis (inflammation of the cornea and conjunctiva).
• Chronic exposure of the eye to intense levels of UVR contributes to the development of cortical cataract. It is unclear whether UVR exposure contributes to eye melanoma or macular degeneration.
• Intentionally gazing at very bright light sources for prolonged periods causes retinal damage.

Immune responses

• UVR is probably linked to suppression of the body’s immune system
• Some evidence suggests that UVR can suppress the immune system (the normal antigen-specific immune response to some skin tumours and pathogens).
• Sun exposure increases the reappearance of symptoms of herpes simplex virus (cold sores) in latently infected individuals.

Combating Health Effects of Sun Exposure Using a Wide Range of Approaches (including health service interventions and broader cultural interventions)

We live in an environment where UVR is usually present because the main source of exposure comes from the sun. Scientific studies cannot demonstrate that there is a completely safe level of UVR exposure and therefore the general population must
implement protective measures.

Public health advice on limiting sun/UVR exposure

The provision of information to the general public on protective measures to limit sun/UVR exposure is outlined below:

• Take sensible precautions to avoid sunburn (e.g. wear hats, wrap-around sunglasses and clothing, seek shade particularly around the four hours around midday).
• Apply sunscreens (but this should not be used to intentionally prolong exposure).
• Take particular care with children.
• Limit exposure to UVR at work, both indoors and outdoors. The Health and Safety Executive has issued advice to outdoor workers and their employers (HSE, 2001).
• Discourage use of sunbeds and sunlamps for cosmetic tanning.
• Health professionals and manufacturers to warn patients and the general public about the interactions between UVR and some prescribed medicines, drugs, foods and cosmetics that can cause sensitisation of the skin and eyes i.e. make an
  individual more sensitive to sunlight.

SunSmart, the UK’s national skin cancer prevention campaign is run by Cancer Research UK. The SunSmart’s key messages are listed below:

SunSmart provide materials and information for health professionals working with the general public, for example, Sunbeds poster, Skin cancer kills flyer and poster, Warning! SunSmart information card and poster, Kids Cook Quick poster, and Skin
cancer identification poster.

Public health advice to increase the awareness of sun exposure/UVR risks

Education programmes and awareness raising campaigns aim to increase the awareness of the health effects of UVR exposure in order to improve knowledge, influence attitudes and change behaviour. Programmes should be targeted at parents, school
teachers, and others responsible for the care of children. Resources have been produced by a number of organisations:

• The 2008 SunSmart campaign focused on young people. It includes advice and resources for schools and parents on how they can become more SunSmart. Specific advice for schools includes:
  • developing their own school sun protection policy
  • incorporating sun protection into the school curriculum
  • making sure they provide sufficient shade in the school grounds
  • warning parents about the dangers of too much sun
  • organising a SunSmart sports day.
• The World Health Organisation has produced a Global Solar UV Index: a simple measure of the UV radiation level at the Earth’s surface, designed to indicate the potential for adverse health effects and to encourage people to protect
  themselves. The index ranges from zero upward and the higher the value, the greater the potential for damage to the skin and eye, and the less time it takes for harm to occur.
• The World Health Organisation’s Global UV project, INTERSUN, has developed and introduced an internationally agreed communication concept to ensure uniformity of sun protection messages and to facilitate the delivery of a simple and relevant
  message. The concept is published in a WHO booklet Global Solar UV Index: a Practical Guide. The following exposure categories and colours are associated with various values of the UVI:
  
   

  Category	UVI range	Colour
  Low Moderate High Very high Extreme	0 to 2 3 to 5 6 to 7 8 to 10 ≥ 11	Green Yellow Orange Red Purple

   
  
  A standard graphical presentation of the UVI promotes consistency in reporting and improves people's understanding of the problem.

Information relating to early diagnosis of skin cancer is readily available to the public

• Cancer Research UK has produced a range of health awareness leaflets, including detailed leaflets on skin cancer. 
• The Royal College of Physicians has produced guidelines for the prevention, diagnosis, referral and management of melanoma.

References

• Cancer Research UK http://info.cancerresearchuk.org [accessed 01.08.08]
• National Radiological Protection Board (1995) Health Effects from Ultraviolet Radiation. Report of an Advisory Group on Non-Ionising Radiation, 6: 7-190
• World Health Organisation  http://www.who.int [accessed 01.09.08]

© Hannah Pheasant 2008