High Risk Groups
Two extremes of life are more prone (Children and the aged). The little children and the senior citizens are affected more by the UV rays than those falling in the inner range. They need more protection.
Eg. Albinism. These persons have practically no melanin in their skin and therefore need intensive protection.
Eg. Porphyria. Persons suffering with such disorders get sun damage much faster.
Race & Ethnicity:
Caucasians (Europeans and Americans) or the white skinned population on the earth needs more protection. Their body has poor natural defense against the UV than the dark skinned.
Smokers and those on high fat diet will get more damage by UVR than others. Avoid smoking and take a low fat diet.
There are still people for whom the best routine sunscreen is still insufficient to protect them against sun induced skin problems. These may include those with lupus, rosacea, transplant patients, post radiation patients, skin cancer patients, chemotherapy patients, or those who have recently undergone skin procedures such as laser resurfacing etc. For some other individuals who may also experience sensitivities to other forms of light, a sunscreen which totally blocks light is best used.
Additionally, the antibiotics tetracycline and minocycline - as well as vitamin A derivative prescription drugs such as Accutane and topical acne preparations made from retinoin (Retin-A) necessitate taking additional sun care precautions. These medications make skin highly susceptible to burning from sunlight and ultraviolet radiation.