This episode may offer the most important advice you will get regarding skin health.  It’s about the #1 most effective skin health product: sunscreen.

I went right to the expert, Suzan Obagi MD a board-certified dermatologist who is widely known as a cosmetic skin care guru.

In our conversation we cover the following:

• Does sun exposure increase the risk of skin cancers?
• Does UV radiation lead to premature facial aging?
• Which type of sunscreen is best, physical or chemical?
• What about vitamin D deficiency and sunscreen use?
• What should I know about SPF?
• Does sunscreen disrupt our hormones?
• and more…

PUBLICATIONS MENTIONED IN THIS PODCAST

J Clin Oncol. 2016 Nov 20;34(33):3976-3983. doi: 10.1200/JCO.2016.67.5934. Epub 2016 Sep 30. Sunscreen Use and Subsequent Melanoma Risk: A Population-Based Cohort Study. Ghiasvand R¹, Weiderpass E¹, Green AC¹, Lund E¹, Veierød MB¹. Abstract Purpose To assess melanoma risk in relation to sunscreen use and to compare high- with low-sun protection factor (SPF) sunscreens in relation to sunbathing habits in a large cohort study. Materials and Methods We used data from the Norwegian Women and Cancer Study, a prospective population-based study of 143,844 women age 40 to 75 years at inclusion with 1,532,247 person-years of follow-up and 722 cases of melanoma. Multivariable Cox proportional hazards regression was used to estimate the association between sunscreen use (never, SPF < 15, SPF ≥ 15) and melanoma risk by calculating hazard ratios and 95% CIs. The population attributable fraction associated with sunscreen use was estimated. Results Sunscreen users reported significantly more sunburns and sunbathing vacations and were more likely to use indoor tanning devices. SPF ≥ 15 sunscreen use was associated with significantly decreased melanoma risk compared with SPF < 15 use (hazard ratio, 0.67; 95% CI, 0.53 to 0.83). The estimated decrease in melanoma (population attributable fraction) with general use of SPF ≥ 15 sunscreens by women age 40 to 75 years was 18% (95% CI, 4% to 30%). Conclusion Use of SPF ≥ 15 rather than SPF < 15 sunscreens reduces melanoma risk. Moreover, use of SPF ≥ 15 sunscreen by all women age 40 to 75 years could potentially reduce their melanoma incidence by 18%.

Br J Dermatol. 2019 Apr 4. doi: 10.1111/bjd.17980. [Epub ahead of print]The effect of sunscreen on vitamin D: a review. Neale RE¹, Khan SR¹, Lucas RM², Waterhouse M¹, Whiteman DC¹, Olsen CM¹. Abstract BACKGROUND:Sunscreen use can prevent skin cancer, but there are concerns that it may increase the risk of vitamin D deficiency. OBJECTIVES: We aimed to review the literature to investigate associations between sunscreen use and vitamin D₃ or 25 hydroxyvitamin D [25(OH)D] concentration. METHODS:We systematically reviewed the literature following the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We identified manuscripts published in English between 1970 and 21 November 2017. Eligible studies were experimental [using an artificial ultraviolet radiation (UVR) source], field trials or observational studies. The results of each of the experimental studies and field trials are described in detail. Two authors extracted information from observational studies, and applied quality scoring criteria that were developed specifically for this question. These have been synthesized qualitatively. RESULTS: We included four experimental studies, three field trials (two were randomized controlled trials) and 69 observational studies. In the experimental studies sunscreen use considerably abrogated the vitamin D₃ or 25(OH)D production induced by exposure to artificially generated UVR. The randomized controlled field trials found no effect of daily sunscreen application, but the sunscreens used had moderate protection [sun protection factor SPF) ~16]. The observational studies mostly found no association or that self-reported sunscreen use was associated with higher 25(OH)D concentration. CONCLUSIONS: There is little evidence that sunscreen decreases 25(OH)D concentration when used in real-life settings, suggesting that concerns about vitamin D should not negate skin cancer prevention advice. However, there have been no trials of the high-SPF sunscreens that are now widely recommended.

Am J Prev Med. 2019 May;56(5):742-746. doi: 10.1016/j.amepre.2018.11.025. Epub 2019 Mar 16. Regular Sunscreen Use and Risk of Mortality: Long-Term Follow-up of a Skin Cancer Prevention Trial.Lindstrom AR¹, von Schuckmann LA¹, Hughes MCB¹, Williams GM², Green AC³, van der Pols JC⁴. Abstract INTRODUCTION: Sunscreen is widely used to protect the skin from harmful effects of sun exposure. However, there are concerns that sunscreens may negatively affect overall health. Evidence of the general safety of long-term regular sunscreen use is therefore needed. METHODS: The effect of long-term sunscreen use on mortality was assessed over a 21-year period (1993-2014) among 1,621 Australian adults who had participated in a randomized skin cancer prevention trial of regular versus discretionary sunscreen use (1992-1996). In 2018, an intention-to-treat analysis was conducted using Cox proportional hazards regression to compare death rates in people who were randomized to apply sunscreen daily for 4.5years, versus randomized to use sunscreen at their usual, discretionary level. All-cause mortality and deaths resulting from cardiovascular disease, cancer, and other causes were considered. RESULTS: In total, 160 deaths occurred in the daily sunscreen group compared with 170 deaths in the discretionary sunscreen group (hazard ratio=0.94, 95% CI=0.76, 1.17); 59vs 76 cardiovascular disease deaths (hazard ratio=0.77, 95% CI=0.55, 1.08), 63vs 58 cancer deaths (hazard ratio=1.09, 95% CI=0.76, 1.57), and 45vs 44 deaths resulting from other causes (hazard ratio=1.02, 95% CI=0.67, 1.54) occurred respectively. CONCLUSIONS: Regular use of a sun protection factor 16 sunscreen on head, neck, arms, and hands for 4.5years did not increase mortality.

Int Arch Occup Environ Health. 2009 Feb;82(3):357-63. doi: 10.1007/s00420-008-0342-0. Epub 2008 Jul 23. Outdoor work and skin cancer incidence: a registry-based study in Bavaria. Radespiel-Tröger M¹, Meyer M, Pfahlberg A, Lausen B, Uter W, Gefeller O. Abstract OBJECTIVE: To analyse the association between occupational ultraviolet (UV) light exposure and skin cancer (basal cell carcinoma, BCC; squamous cell carcinoma, SCC; cutaneous malignant melanoma, CMM) based on data from the Bavarian population-based cancer registry. METHODS: The population-based cancer registry of Bavaria (Germany) provided data on incident cases of BCC, SCC, and CMM, respectively, during the period 2001 until 2005. Eleven Bavarian districts with complete skin cancer registration were included in this analysis based on 2,156,336 person years. Cases were assigned to “indoor”, “mixed indoor/outdoor”, and “outdoor” exposure categories according to their job title. We computed age-specific and age-adjusted incidence rates of BCC (n = 1,641), SCC (n = 499), and CMM (n = 454) by work type, and the relative risk (RR) of skin cancer occurrence for “outdoor” and “mixed indoor/outdoor” workers, respectively, compared to “indoor” workers. RESULTS: The risk of BCC was substantially elevated in male (RR, 2.9; 95% CI, 2.2-3.9) and female (RR, 2.7; 95% CI, 1.8-4.1) outdoor workers compared to male and female indoor workers, respectively. We also found an elevated risk of similar magnitude for SCC in male (RR, 2.5; 95% CI, 1.4-4.7) and female (RR, 3.6; 95% CI, 1.6-8.1) outdoor workers compared to male and female indoor workers, respectively. CMM risk was not significantly associated with outdoor work. CONCLUSION: Our study confirms previous reports on the increased risk of BCC and SCC in outdoor workers compared to indoor workers.

Dermatol Surg. 2018 Nov;44(11):1373-1378. doi: 10.1097/DSS.0000000000001541. Risk Factors for Basal Cell Carcinoma in Men Younger Than 40 Years: A Case-Control Study. Nemer KM¹, Bauman TM¹, Boyd AS². Abstract BACKGROUND:  Basal cell carcinoma (BCC) is the most common malignancy in the United States and is more prevalent in older populations. OBJECTIVE: The aim of this study was to investigate BCC risk factors in male patients younger than 40 years. MATERIALS AND METHODS: A consecutive series of male patients with pathology-proven BCC and younger than 40 years at time of diagnosis were retrospectively identified along with matched controls. Phone interviews were conducted using a structured questionnaire, and differences between patients with and without BCC were investigated. RESULTS: A total of 50 patients with BCC and 27 controls were included in this study. Compared with controls, patients with BCC worked outdoor jobs for longer lengths of time (43.2 vs 15.6 months; p = .04), were more likely to have a family history of skin cancer (66% vs 44%; p = .02), and were more likely to use sunscreen heavily after biopsy (p = .02). Patients with multiple BCCs (n = 20) were more likely to have a history of substantial recreational sun exposure (p = .01) than patients with solitary lesions (n = 30). CONCLUSION: The authors conclude that outdoor sun exposure in patients with underlying genetic susceptibility is the most likely mechanism of BCC formation in young male patients.

Plast Reconstr Surg. 2009 Apr;123(4):1321-31. doi: 10.1097/PRS.0b013e31819c4d42. Factors contributing to the facial aging of identical twins. Guyuron B¹, Rowe DJ, Weinfeld AB, Eshraghi Y, Fathi A, Iamphongsai S. Abstract BACKGROUND: The purpose of this study was to identify the environmental factors that contribute to facial aging in identical twins. METHODS: During the Twins Day Festival in Twinsburg, Ohio, 186 pairs of identical twins completed a comprehensive questionnaire, and digital images were obtained. A panel reviewed the images independently and recorded the differences in the perceived twins’ ages and their facial features. The perceived age differences were then correlated with multiple factors. RESULTS: Four-point higher body mass index was associated with an older appearance in twins younger than age 40 but resulted in a younger appearance after age 40 (p = 0.0001). Eight-point higher body mass index was associated with an older appearance in twinsyounger than age 55 but was associated with a younger appearance after age 55 (p = 0.0001). The longer the twins smoked, the older they appeared (p < 0.0001). Increased sun exposure was associated with an older appearance and accelerated with age (p = 0.015), as was a history of outdoor activities and lack of sunscreen use. Twins who used hormone replacement had a younger appearance (p = 0.002). Facial rhytids were more evident in twins with a history of skin cancer (p = 0.05) and in those who smoked (p = 0.005). Dark and patchy skin discoloration was less prevalent in twins with a higher body mass index (p = 0.01) and more common in twins with a history of smoking (p = 0.005) and those with sun exposure (p = 0.005). Hair quantity was better with a higher body mass index (p = 0.01) although worse with a history of skin cancer (p = 0.005) and better with the use of hormones (p = 0.05). CONCLUSION: This study offers strong statistical evidence to support the role of some of the known factors that govern facial aging.

Twins and facial aging: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4174174/