Sunscreen. Antioxidants. Much is touted about their ability to prevent skin aging. Well, in the sunny environs of Australia and New Zealand (at latitude 26o S – about the same distance from the equator as Corpus Christi, Texas), a clever study may shed some shade on the matter. Investigators followed 903 adults, younger than age 55, from 1992 to 1996, randomized to one of four skin care regimens consisting of:
- Daily use of a broad spectrum sunscreen and 30 mg of beta-carotene
- Daily use of a broad spectrum sunscreen and placebo
- Discretionary use of a broad spectrum sunscreen and 30 mg of beta-carotene
- Discretionary use of a broad spectrum sunscreen and placebo
Comparisons in skin changes based on microtopography (sounds like small maps or something) were graded by assessors blinded to treatment allocation.
The daily sunscreen groups showed no detectable increase in skin aging after 4.5 years. Skin aging from baseline to the end of the trial was 24% less in the daily sunscreen group than in the discretionary sunscreen group (OR 0.76 [95% CI, 0.59 to .98]).
Beta-carotene supplementation had no overall effect on skin aging.
Fine wrinkles in the study were that it was limited by some missing data and had only a moderate power to detect moderate treatment effects and further study was stated to be required.
What with summer coming – all you middle-aged doctors and other clinicians – what are you going to do?
Marshall Kubota, MD
Maria Celia B. Hughes, MMedSci; Gail M. Williams, PhD; Peter Baker, PhD; and Adèle C. Green, MBBS, PhD, “Sunscreen and Prevention of Skin Aging: A Randomized Trial,” Ann Intern Med. 2013;158(11):781-790. doi:10.7326/0003-4819-158-11-201306040-00002