Some Thoughts on Sun Protection

Children in the 1950s and 1960s didn’t worry too much about exposure to the sun. Older people in sunny climes like Australia are now paying the price with most people having skin cancers removed. The vast majority of these cancers are basal cell carcinomas, which are rarely lethal.

From the 1970s there was more awareness of the dangers of sun exposure and people were encouraged to limit this exposure, especially in the middle of the day. Many schools adopted policies where students had to wear hats any time they were outside, so as to avoid any exposure to the sun.

There are, however, downsides to such policies, as explained below.

Vitamin D Deficiency

It is not possible to get adequate vitamin D from the food we eat. People who do not take vitamin D supplements (that is the majority of people) rely on sunshine for their vitamin D. Vitamin D is formed in the skin on exposure to UVB radiation. UVB radiation levels are negligible when the sun is lower than 45 above the horizon. (See the article ‘Vitamin D and Covid’ linked from the ‘Miscellaneous Rantings’ section of the davidilsley.com home page for further explanation.) As people are commonly advised to avoid going out in the sun in the middle of the day, many people end up receiving very little vitamin D.

In recent decades, vitamin D deficiency has become significantly more widespread in western societies. It seems that a major proportion of the Australian population is at least somewhat deficient in vitamin D, especially in winter.

Vitamin D is important for maintaining a healthy immune system, particularly immunity to respiratory infections. This became obvious during the Covid pandemic when a strong correlation was found between hospitalisation for Covid and vitamin D deficiency. Adequate levels of vitamin D are necessary to prevent the cytokine storm that kills a lot of people with Covid, the flu and other respiratory infections.

Vitamin D is also important for calcium absorption from the intestine, and deficiency can lead to increased risk of bone problems including osteoporosis. Of course, this will not be obvious until later in life. Just as we currently have a lot of people with skin cancers, it is possible that, in coming years, osteoporosis will become a major problem. A basal cell carcinoma can be removed in a few minutes. Osteoporosis is much more difficult to deal with and generally cannot be significantly reversed.

Other results of vitamin D deficiency appear to include increased risk of diabetes and certain cancers.

Cardio-vascular health

It was discovered fairly recently that sunlight (UVA specifically) causes the production of nitric oxide in the skin. This then circulates through the blood stream and causes dilation of the blood vessels. It seems that regular limited sun exposure is related to healthier, more flexible blood vessels with less arterial plaque.

Studies have shown outdoor workers to be less likely to suffer cardio-vascular disease than indoor workers. People who develop non-lethal skin cancers in older age are significantly less likely to die from heart attacks, strokes and other cardio-vascular diseases than those who do not.

Skin cancer

It is sunburn rather than short periods of sun exposure that is the main cause of skin cancer. In fact, regular exposure to sunshine in moderation protects the skin from cancer by encouraging the production of melanin (tanning). Studies have suggested that people who work outdoors are less likely to develop fatal skin cancer than people who work indoors. This may be related to indoor workers exposing untanned skin to long periods of sunshine during their holidays.

The face is one of the most common sites for skin cancer. Allowing students in schools to expose their faces to regular short periods of sunshine (like the duration of school breaks) could be a protection against fatal skin cancer rather than a cause of it.

Conclusion

In light of these observations, it could be in our long-term interests to get regular short periods of sun exposure. Not wearing a hat when walking around a school during recesses could actually be better for students in the long term.

My understanding is that sun protection policies in schools serve two purposes: one is to protect the students’ health; the other is to protect the school from litigation down the track. As evidence exists for the adverse health effects of too little regular sun exposure, it could be prudent to review schools’ sun protection policies, both from the point of view of student health and possible future litigation.