2 Supporting information for practitioners

2 Supporting information for practitioners

The following information is based on authoritative UK sources and the Consensus vitamin D position statement (British Association of Dermatologists et al.). The evidence base underpinning this information has not been systematically reviewed for this guideline. For more detail on how it was compiled see overview of sunlight exposure messages.

Risks and benefits of sunlight exposure

Environmental, biological and behavioural factors

  • The intensity of sunlight varies according to:

    • Geographical location: solar UV levels increase nearer to the equator and at higher altitudes.

    • Time of year: from March to October UVB rays help people produce vitamin D, but excessive exposure can also cause sunburn. Solar UV levels are highest during the summer (and most intense in late June).

    • Time of day: solar UV levels are highest around the middle of the day when the sun is highest in the sky.

    • Weather conditions: solar UV levels are reduced by cloud cover but they can still be intense enough to cause sunburn (even if it is not warm).

    • Reflection: sunlight reflects off surfaces such as snow, sand, concrete and water. This can increase the risk of sunburn and eye damage, even in shaded areas.

  • UVA penetrates glass (although more weakly than direct exposure) and over long periods of exposure will cause skin damage. However, the vitamin D‑inducing UVB does not penetrate glass.

  • Skin type affects the potential risks and benefits from sunlight exposure.

  • Increased frequency and time spent in the sun increases the potential risks of sunlight exposure.

How to minimise the risks and maximise the benefits of sunlight exposure

People need to be aware of the following:

  • How daily exposure to sunlight can affect their skin and why it is important to protect it.

  • Unless someone has a very dark skin type, they should protect their skin when out in strong sunlight for more than a short period of time, both in the UK and abroad. The UV index provides an indicator of the sun's strength for a given location, date and time. This information, combined with skin type and behaviour, can be used to assess someone's risk of sunburn. The Met Office provides daily information on UV levels in the UK.

  • When possible, only a limited amount of time should be spent in strong sunlight. It is preferable to spend more time in the shade.

  • People who choose to expose their skin to strong sunlight to increase their vitamin D status should be aware that prolonged exposure (for example, leading to burning or tanning) is unlikely to provide additional benefit.

  • Exposing commonly uncovered areas of skin such as forearms and hands, for short periods when in strong sunlight provides vitamin D. (Longer periods of exposure may be needed for those with darker skin.)

  • Protection from the sun can be achieved by covering up with suitable clothing, seeking shade and applying sunscreen. Suitable clothing includes: a broad‑brimmed hat that shades the face, neck and ears, a long‑sleeved top, and trousers or long skirts in close‑weave fabrics that do not allow sunlight through. It also includes sunglasses with wraparound lenses or wide arms (to provide side protection) that have the CE Mark (an indication that they meet the relevant European Standard – at the time of publication this was EN 1836:2005).

  • Because many young people and adults will have experienced sunburn, they can use this experience to:

    • know what their skin looks like normally and how it reacts to sunlight

    • know how long they can be exposed without risking sunburn and how to protect their skin accordingly.

  • Skin that is not usually exposed to sunlight (for example, the back, abdomen and shoulders) is particularly likely to burn, so extra care is needed.

The strength of sunlight at different times of day

In the UK, sunlight is strongest between 11am and 3pm between March and October.

  • Between 11am and 3pm:

    • Sunburn is most likely.

    • Most people can make sufficient vitamin D by going out for short periods and leaving only areas of skin that are often exposed uncovered (such as forearms, hands or lower legs). Longer periods may be needed for those with darker skin.

  • Before 11am and after 3pm:

    • it takes longer to synthesise sufficient vitamin D

    • the risk of sunburn is less.

Advice for children and young people

  • Children under 6 months of age should be kept out of direct strong sunlight.

  • Between March and October in the UK, children and young people need their skin protecting. They should cover up with suitable clothing, be encouraged to spend time in the shade (particularly between 11am and 3pm) and wear sunscreen.

  • The parents and carers of children younger than 5 should be given advice on vitamin D supplements (see NICE's guideline on vitamin D: increasing supplement use among at-risk groups).

Advice according to people's skin type

  • People with genetically darker skin (skin types V and VI) are at relatively lower risk of burning and, therefore, skin cancer. But they are at higher risk of vitamin D deficiency in the UK. This means:

    • they may need more time in sunlight to produce the same amount of vitamin D as people with lighter skin

    • generally they can be exposed for longer before risking sunburn and skin cancer, but should not get to the point where their skin is likely to burn

    • they need advice on vitamin D supplements (see NICE's guideline on vitamin D: increasing supplement use among at-risk groups).

  • People with naturally very light skin or fair or red hair or freckles (skin types I and II):

    • do not need much time in the sun (less than the time it takes them to burn) to produce vitamin D

    • are at greater risk of sunburn and skin cancer – including after shorter periods of exposure – than people with darker skins.

Approaches to protecting skin

  • Skin should be protected from strong sunlight by covering up with suitable clothing, seeking shade and applying sunscreen.

  • Sunscreen is not an alternative to covering up with suitable clothing and seeking shade, but it does offer additional protection. It can also be useful when other methods of protection are not available, but only if used liberally, carefully and repeatedly on all exposed skin.

  • Sunscreen should:

    • Meet minimum standards for UVA protection (the label should have the letters 'UVA' in a circle logo). Preferably, the label should state that it provides good UVA protection (for example, at least '4‑star UVA protection').

    • Provide at least sun protection factor (SPF)15 to protect against UVB.

  • Because most people do not apply enough sunscreen it is probably helpful to make them aware that:

    • The amount of sunscreen needed for the body of an average adult to achieve the stated SPF is around 35 ml or 6 to 8 teaspoons of lotion.

    • If sunscreen is applied too thinly, the amount of protection it gives is reduced (for example, someone using too little SPF15 may only be achieving around SPF5 level of protection or less).

    • Using SPF30 sunscreen or higher may partially overcome problems with inadequate application. But it does not necessarily mean people can spend more time in the sun without the risk of burning.

    • Sunscreen needs to be reapplied liberally, frequently and according to the manufacturer's instructions. This includes straight after being in water (even if it is 'water‑resistant') and after towel drying, sweating or when it may have rubbed off.

    • If someone plans to be out in the sun long enough to risk burning, sunscreen needs to be applied twice to exposed areas of skin: half an hour before, and again around the time they go out in the sun. This includes the face, neck and ears (and head if someone has thinning or no hair), but a wide‑brimmed hat is better.

    • Water‑resistant sunscreen is needed if sweating or contact with water is likely.

Checking for possible signs of skin cancer

All adults should be encouraged to check their skin for any possible signs of cancer. Changes to check for include: a new mole, growth or lump, or any moles, freckles or patches of skin that change in size, shape or colour (people should tell their doctor if they notice any unusual or persistent changes). See section 1.7 in NICE's guideline on suspected cancer.

Clarifying common misconceptions about sunlight exposure

It is important to note that:

  • Even if it is cool or cloudy, it is possible to burn in the middle of the day in summer. It is also possible to burn at other times of the day and year.

  • There is no safe or healthy way to get a tan from sunlight.

  • Getting a tan provides little protection against later exposure to sunlight and the resulting skin damage outweighs any later protective effect.

  • It is not possible to get enough vitamin D by sitting next to a closed sunny window.

  • It is not possible to get enough vitamin D from sunlight between October and March in the UK.

  • National Institute for Health and Care Excellence (NICE)