Sunscreen and MS

So there’s a really bizarre article in the Economist about multiple sclerosis (MS) that’s hard to believe.

First, it’s been known for a long time that the incidence of MS is much higher in higher latitudes, and lower near the equator. In the US, the highest rates are in Washington State and Minnesota. So there has long been speculation – even an assumption – that a lack of sunlight (or vitamin D) is harmful for those susceptible to MS. Some MS books even advise those with MS not to slather on sunscreen, because the progression of MS is a greater risk for those individuals than the risk of skin cancer.

So not surprisingly, a scientist at the University of Wisconsin, Madison, was studying the effects of UV light on mice with MS.  He set up the experiment with a variety of types of conditions: UV, no UV, UV with sunscreen, sunscreen but no UV, no UV and no sunscreen, etc. The hypothesis would be that the mice exposed to UV with no sunscreen would improve, and the others with no UV, or UV with sunscreen, would not.

What he got was…improvements in the health of the mice who got sunscreen – regardless of whether they were even exposed to UV light or not! What? Sunscreen helps MS, independently of whether there’s even sunlight?

So he changed his study, and started testing out different types of sunscreen on mice with MS. And it appears that something in the sunscreen might actually be suppressing MS. In particular, it looks like “homosalate” and “octisalate” were effective in suppressing MS.

I don’t have MS, but that’s enough to make you want to run out and buy some Coppertone!

And kudos to those scientists who stuck with it, even when their initial results must surely have seemed in error.

Here’s the full article, https://www.economist.com/news/science-and-technology/21725497-neat-example-role-serendipity-science-chance-finding-may-lead