On this week's episode, we look into one of the key benefits of clinical trials: that they tend to isolate against confounding variables. We look at what confounding variables are and look at the long-term example of reported links between sunscreen use and increased skin cancer rates. We look at why excessive sun exposure is dangerous, how sunscreen works, why rates of skin cancer appeared to increase as sunscreen was introduced.

References:

• Lapides R, Saravi B, Mueller A, Wang-Evers M, Maul LV, Németh I, Navarini A, Manstein D, Roider E. Possible explanations for rising melanoma rates despite increased sunscreen use over the past several decades. Cancers. 2023 Dec 16;15(24):5868. https://doi.org/10.3390/cancers15245868
• Garland CF, Garland FC, Gorham ED. Rising trends in melanoma an hypothesis concerning sunscreen effectiveness. Annals of epidemiology. 1993 Jan 1;3(1):103-10. https://doi.org/10.1016/1047-2797(93)90017-x
• Stern RS. Prevalence of a history of skin cancer in 2007: results of an incidence-based model. Archives of dermatology. 2010 Mar 1;146(3):279-82. https://doi.org/10.1001/archdermatol.2010.4
• Olsen CM, Wilson LF, Green AC, Bain CJ, Fritschi L, Neale RE, Whiteman DC. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Australian and New Zealand journal of public health. 2015 Oct 1;39(5):471-6. https://doi.org/10.1111/1753-6405.12470
• Neale R, Janda M. Sun Exposure Summit Position Statement. 2023. http://assc.org.au/wp-content/uploads/2023/01/Sun-Exposure-Summit-PositionStatement_V1.9.pdf
• Cadet J, Douki T. Formation of UV-induced DNA damage contributing to skin cancer development. Photochemical & Photobiological Sciences. 2018;17(12):1816-41. https://doi.org/10.1039/C7PP00395A
• Suh S, Pham C, Smith J, Mesinkovska NA. The banned sunscreen ingredients and their impact on human health: a systematic review. International journal of dermatology. 2020 Sep;59(9):1033-42. https://doi.org/10.1111/ijd.14824
• Kaden DA, Gentry R, Ledger BM. Comparative Health Risks from Benzene in Sunscreens. Brief. 2024 Jul 1;53(4). 
• Chang MS, Moore KJ, Trepanowski N, Koru-Sengul T, Hartman RI. Sunscreen use is not associated with increased blood concentrations of benzene among adults in the United States: data from the National Health and Nutrition Examination Survey 2003-2006 and 2009-2018. Journal of the American Academy of Dermatology. 2022 Aug 1;87(2):440-3. https://doi.org/10.1016/j.jaad.2021.09.003
• DiNardo JC, Downs CA. Dermatological and environmental toxicological impact of the sunscreen ingredient oxybenzone/benzophenone‐3. Journal of cosmetic dermatology. 2018 Feb;17(1):15-9. https://doi.org/10.1111/jocd.12449

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