News, Views, and Reviews. Carrots Before Sticks: Appealing to Vanity Promotes Sun Protection

August 2013 | Volume 12 | Issue 8 | Features | 952 | Copyright © August 2013


Kendra Gail Bergstrom MD FAAD

Abstract
Daily broad-spectrum sunscreen use is an important intervention to prevent squamous cell carcinoma and invasive melanoma. Now dermatologists can feel confident confirming that it prevents photoaging in middle aged adults as well. A new randomized trial from Australia confirms that consistent use of broad-spectrum sunscreen can slow photoaging in adults in as little as four years in middle-aged adults. Because young adults respond better to anti-aging messages than anti-cancer messages regarding sun exposure, this data may help motivate younger patients to avoid indoor tanning and pursue consistent sun protection. Visual examples of aging over time are particularly effective for teens and young adults.

J Drugs Dermatol. 2013;12(8):952-953.
Daily broad-spectrum sunscreen use is an important intervention to prevent squamous cell carcinoma and invasive melanoma. Now dermatologists can feel confident confirming that it prevents photoaging in middle aged adults as well. A new randomized trial from Australia confirms that consistent use of broad-spectrum sunscreen can slow photoaging in adults in as little as four years in middle-aged adults. Because young adults respond better to anti-aging messages than anti-cancer messages regarding sun exposure, this data may help motivate younger patients to avoid indoor tanning and pursue consistent sun protection. Visual examples of aging over time are particularly effective for teens and young adults.

Never Too Late: Daily Sunscreen Use Prevents Photoaging

Dermatologists promote sun safety, including daily sunscreen and avoiding indoor tanning, to almost all patients. While warnings about preventing future skin cancer can be powerful, these warnings may seem too abstract to teens or 'too little too late' for older adults. Fortunately, avoiding ultraviolet light can both prevent cancer and help people look younger. New data about the efficacy of daily sunscreen to prevent photoaging can be an important educational tool. Combined with data from psychology literature, interventions that highlight the risk of premature aging appear to be more effective in changing behavior in teens and young adults than warning about future cancer risks.
The role of consistent sunscreen use in preventing actinic keratoses, squamous cell carcinoma, and invasive melanoma has been established, particularly for high-risk populations such as those with immunosuppression or history of previous skin cancer.1,2 The extent to which sunscreen prevents photoaging has been studied in mice and porcine models, but only to a limited extent in humans. Limitations to human studies on photoaging have been the relatively long observation period that would be required to see differences, and the need until now for pre- and post-study skin biopsies, which are unappealing to potential study patients.
A new study published in June 2013 in the Annals of Internal Medicine is the first to formally follow adult volunteers and evaluate the impact of daily sunscreen use3. It was conducted in Nambour, Australia near Brisbane at latitude 26 degrees south, comparable in latitude to Johannesburg, South Africa, and north of the ozone hole that covers Antarctica. This location is at the same latitude as southern Texas and Florida in the northern hemisphere.
Six hundred white adults, mainly skin types I or II, age 25-55 were randomized to daily or discretionary sunscreen use. For the group assigned to daily use, compliance was intermittently monitored by weighing sunscreen tubes. For the group assigned to discretionary use, by report all were using sunscreen 'frequently' and two-thirds reported regularly wearing hats while outside before study onset. Each patient was assigned to use the same broad-spectrum SPF 15 sunscreen with containing octinoxate (Eusolex, or 8% ethylhexyl-p-methoxycinnamate) that protects against ultraviolet B and 2% avobenzone (Parsol 1789, or 4-tert-butyl-4' methoxy-4-dibenzoylmethane) that protects against a broad spectrum of ultraviolet A.
Photoaging was measured by analysis of skin texture and fine wrinkling, so-called microtopography, of a silicone cast of the skin at the beginning and end of the study period. This model has shown to parallel elastin changes seen on skin biopsy and avoids the more invasive skin biopsies that would otherwise be needed.
Among the 600 patients, those using daily sunscreen were 24% less likely to show any photoaging. A majority showed no detectable increase in skin aging after 4.5 years, and some actually showed an improvement in skin texture over baseline.
The protection from photoaging in the daily use group compared to the discretionary group is even more striking because the control group also used sunscreen and hats. These individuals were instructed to continue to use sunscreen whenever they thought it would be needed. This tells us that even in monitored conditions, invidividuals may be poor judges of, or poor planners for, conditions with excess UV radiation.
This study highlights that good news for patients seeing to prevent photoaging:
  • Daily sunscreen use is much more effective than discretionary use
  • Broad-spectrum SPF 15 is adequate to prevent photoaging
  • Discretionary sunscreen use is not enough to protect against UV radiation
  • Interventions starting in middle age still have an impact
  • This impact can be seen in as little as 4 years
  • This study was also powered to evaluate the efficacy of oral beta carotene supplementation, at 30 mg daily, on photoaging, and did not measure any significant difference from placebo.