Abstract
Due to its latitude, topography and cloudless skies, South Africa receives high solar ultraviolet radiation (UVR). This country has a multi-ethnic population classified into black, colored, Asian and white groups, who have varying degrees of response to sun exposure. In this review, information relating to the effects of solar UVR on skin cancer development, oculocutaneous albinism, melasma, the immune system and vitamin D production are discussed in the context of the peoples of South Africa. Methods of personal photoprotection are included. Effective sun safety messages for the public need to be developed, particularly aimed at the most susceptible groups, while recognizing the issues associated with variations in skin color in the South African population.
Financial & competing interests disclosure
CY Wright acknowledges Parliamentary Grant funding from the Council for Scientific and Industrial Research, and LM Davids for funding from the National Research Foundation. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.
Key issues
• The population of South Africa may be exposed to high solar ultraviolet radiation (UVR) due to the country’s latitude, topography and cloudless skies with mild ambient temperatures all year round. Such irradiation can lead to both positive and negative effects on health.
• The population of South Africa is divided into four groups: black, colored, Asian/Indian and white, with about 80% being black. Each group has different responses to solar UVR depending largely on skin color.
• Although recent data are sparse, figures from 2000 to 2004 indicate significant numbers of cases of the common skin cancers (basal cell carcinoma [BCC], squamous cell carcinoma [SCC] and cutaneous melanoma [CM]) in the population groups of South Africa. The annual incidence was highest in whites and lowest in blacks. In 2009, it was estimated that there were 69 cases of CM per 100,000 whites living in the Cape region, making this one of the highest rate in the world.
• Oculocutaneous albinism (OCA) leading to reduced melanin in the hair, skin and eyes occurs to varying degrees in different tribes in South Africa; the incidence can be as high as 1 in 832. Such people have an increased risk of developing skin cancers, particularly SCCs on the head, and should take robust photoprotection measures.
• Melasma, a hypermelanosis of the face, occurs predominantly in women with pigmented skin living in areas of high solar UVR. Sun exposure is a common exacerbating factor and the disease can affect the quality of life. Its prevalence in South Africa is not known but is predicted to be relatively high.
• Immunosuppression follows solar UVR. Such a change may have consequences for the immune control of infections such as tuberculosis which present major health issues in South Africa, and for the effectiveness of vaccination.
• Much of the vitamin D in the majority of people is produced following solar UVR. Although no large-scale surveys have been undertaken to date in South Africa, limited information indicates a satisfactory vitamin D status in most population groups, and therefore the health benefits ascribed to this molecule should follow. However, a poor vitamin D status was associated with active tuberculosis in a study of black subjects in Cape Town, and increasing urbanization may lead to lower vitamin D levels, particularly in those with pigmented skins.
• Knowledge about personal photoprotection is not widespread in South Africa and awareness campaigns are required to inform the public about the dangers of excessive sun exposure, what the UV Index (UVI) signifies and how best to avoid sunburn. Such information requires to be tailored appropriately for the different population groups and for different ages.