Sunscreen and Prevention of Skin Aging: A Randomized Trial

Ann Intern Med. 2013 Jun 4;158(11):781-90. doi: 10.7326/0003-4819-158-11-201306040-00002.

Abstract

Background: Sunscreen use and dietary antioxidants are advocated as preventives of skin aging, but supporting evidence is lacking.

Objective: To determine whether regular use of sunscreen compared with discretionary use or β-carotene supplements compared with placebo retard skin aging, measured by degree of photoaging.

Design: Randomized, controlled, community-based intervention. (Australian New Zealand Clinical Trials Registry: ACTRN12610000086066).

Setting: Nambour, Australia (latitude 26° S).

Patients: 903 adults younger than 55 years out of 1621 adults randomly selected from a community register.

Intervention: Random assignment into 4 groups: daily use of broad-spectrum sunscreen and 30 mg of β-carotene, daily use of sunscreen and placebo, discretionary use of sunscreen and 30 mg of β-carotene, and discretionary use of sunscreen and placebo.

Measurements: Change in microtopography between 1992 and 1996 in the sunscreen and β-carotene groups compared with controls, graded by assessors blinded to treatment allocation.

Results: The daily sunscreen group 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 (relative odds, 0.76 [95% CI, 0.59 to 0.98]). β-Carotene supplementation had no overall effect on skin aging, although contrasting associations were seen in subgroups with different severity of aging at baseline.

Limitation: Some outcome data were missing, and power to detect moderate treatment effects was modest.

Conclusion: Regular sunscreen use retards skin aging in healthy, middle-aged men and women. No overall effect of β-carotene on skin aging was identified, and further study is required to definitively exclude potential benefit or potential harm.

Primary funding source: National Health and Medical Research Council of Australia.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antioxidants / therapeutic use*
  • Dietary Supplements*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Skin Aging / drug effects*
  • Sunscreening Agents / therapeutic use*
  • beta Carotene / therapeutic use*

Substances

  • Antioxidants
  • Sunscreening Agents
  • beta Carotene