Colorful sunscreen from here

In class, Andrew talked about how no one knew smoking was dangerous because the results weren’t prevalent until 20 years later, and this made me wonder what I have been doing that could create health problems for me in the future. I am a redhead, which means that my entire life has consisted of smearing sunscreen on my entire body whenever leaving the house to prevent a nasty burn. For the past 18 years, I have pretty much always been covered in sunscreen, and now I am curious to see if sunscreen could be dangerous. What if the chemicals in our sunscreens actually caused cancer?

Photo from here

I first visited the American Academy of Dermatology’s website, where I learned that on average, 5.4 million people will be diagnosed with skin cancer each year, making it the most common cancer diagnosed. Melanoma is considered the most fatal skin cancer and will perhaps affect up to 76,380 people world wide this year. The ACD recommends daily sunscreen application.

squamous-cell carcinoma from here

I wanted to see the data, so I used google scholar to find this journal, The Null Hypothesis was that wearing sunscreen did not effect levels of BBCs, and the Alternative Hypothesis was that wearing sunscreen did effect levels of BBCs. This paper, focusing on the effect of sunscreen,  was first published in November, 2006.  This study was a randomized experiment, and the participants were 1,621  members of Nambour, an Australian community. These scientists has conducted a previous study where they discovered that there was a reduction of a type of cell called a squamous cell carcinomas (referred to as a SCC) in individuals that wore sunscreen daily and regularly over the course of four years. The Null Hypothesis was that wearing sunscreen did not effect levels of BBCs, and the Alternative Hypothesis was that wearing sunscreen did effect levels of BBCs. There was not the same type of decrease in the basal cell carcinoma cells (called BBC), but it was identified that BBCs could be delayed when compared to the results from the control group (no application of sunscreen). 92% of the participants followed the study until its completion in 2004. The remaining subjects were exposed to follow ups in their randomized groups.

Researchers discovered that those with fair skin (like me) had slightly lowered BBC rates then the participants who did not wear any sunscreen. For this conclusion, the researchers have included the p value, stating that P=0.03. With a low p-value below the usual alpha level of 0.05, the researchers were able to reject the null hypothesis and conclude that wearing sunscreen, especially for people with fair skin did indeed lower rates of BBCs.

After reading this paper, I googled, “Is Sunscreen bad for you?” Of course, many biased holistic sites popped up, but I was able to find a TIME Magazine article titled, Is Sunscreen Safe, and Do I Need It Every Day?  that addressed the subject.  Most sunscreens have nanoparticles, which reflect the sun’s UV lights, preventing skin exposure.  According to the EWG, nanoparticles definitely provide great sun protection.  Now, scientists worry that nanoparticles are small enough to be actually absorbed by our skin, and easily enter our blood streams.   Researchers are more concerned than ever after unsettling results from lab tests on rats. Rats injected with these nanoparticles showed signs of cell distress, which is correlated with cancer. Although there is room for worry, these rats were inhaling and being injected with these particles, and tests have not been done where the particles were topically applied to the rat’s skin.

Although we should be concerned with the results on this rat study, more studies have to be conducted before scientists can make any claims. There is evidence that sun screen prevents the development of skin cancer and there is a pretty slim chance that these findings are all a fluke. Although it is impossible to rule out chance completely, it seems very unlikely that sunscreen does not have any effect on the reduction or delay of the development of BBCs. There is just developing research that sun screen could potentially cause other kind of cancers. For now, I will still keep wearing my sunscreen, but I will definitely change my skin care habits if more research emerges.