Friday, October 10, 2008

Benefits vs. risks of sunlight exposure: 2000:1?

Note: The comments on this blog are for information only. Do not make any changes in sunlight exposure, tanning-bed exposure or nutritional habits without first consulting a medical professional.

In 2007 at the Smart Tan International Conference in Nashville, I presented data on the risks and benefits of UV exposure. I looked at the number of deaths caused by heart disease, cancer, MS, osteoporosis, influenza, etc. and estimated the proportion of those deaths that might be prevented by achieving higher vitamin D levels through UV exposure. I concluded that for every death caused by UV, there were 275 lives lost by underexposure to UV. That seemed to be a very conservative estimate. However, it may have been far too conservative. I may have grossly underestimated the benefits of sunlight. Dr. Oliver Gillie from the UK, through his new book, alerted me to the following research which was published this year.

Dr. Robyn Lucas and colleagues from Australian National University recently performed an analysis on benefits and risk based on the number of lives that would be saved and disabilities prevented by regular sunlight exposure vs. deaths and disabilities caused by following the United Kingdom’s “sun protection” recommendations exactly as written; basically that people apply sunscreen every time they venture outdoors, and that they always stay covered with clothing and wear a hat. In other words, avoid nearly all sunlight exposure. (Lucas, R. et al. Int J Epidemiol 2008;37(3):654-67.) They assessed the burden of disease and death by “disability adjusted life years” (DALYs). They concluded that total abstinence from UV exposure would cause about 3.3 billion DALYs, whereas normal sunlight exposure would cause 1.6 million DALYs. This is a ratio of 2,000:1. In other words, 2,000 cases of death and disability are created by total sunlight avoidance for every case of death or disability caused by sunlight. That might have been impressive enough, but the research done by Dr. Lucas considered only musculoskeletal diseases that would result from total avoidance of sunlight—diseases such as rickets, osteoporosis, osteomalacia, fractures, muscle weakness, tendency to fall, etc.—no assessment of cancer, heart disease, MS, diabetes or some of the other 105 disease, mentioned in my book as being due in part to vitamin D deficiency, were considered in this analysis.

It is safe to say, based on the profound cancer-reducing influences of vitamin D, along with the other disorders that have been shown to correlate so closely to deficiency of that marvelous hormone, that at least 4,000 DALYs would occur with total sun avoidance, compared to one DALY from sunlight exposure. Dr. Gillie states in his book, Scotland’s Health Deficit: an Explanation and a Plan, that many people in the UK accepted the advice to stay out of the sunlight, “did what was advised and as a result obtained no effective sun exposure, obtained virtually no vitamin D other than the very small amount available from food, and put themselves at great risk of serious illness or death.”One wonders at what point the advice to avoid the sunlight moves out of the realm of stubbornness and stupidity and into the realm of criminality.

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