Long-term Maintenance of a Successful Occupational Sun Safety Intervention FREE

Skin cancer prevention specialists should attempt to reduce UV radiation (UVR) exposure among outdoor workers, as pointed out in a recent review.¹ To address this need, Project SUNWISE,^{2 - 3} a randomized controlled sun safety intervention trial with Southern Californian US Postal Service letter carriers, was conducted from 2001 through 2004.

The intervention consisted of providing free sunscreen, free wide-brim hats, a series of 6 brief on-site educational sessions, and sun safety prompts. The primary outcome measures were validated questionnaire items that asked participants how often they had used specific sun protection strategies over the past 5 workdays while delivering mail.^{2 - 3} The questionnaires were administered at baseline and 3, 12, 24, and 36 months after baseline. The 5 response options ranged from “never” to “always”; we considered “always” as “consistent use” in analyses.

At the 2-year follow-up evaluation, participants at the intervention postal stations had significantly higher rates of consistent sunscreen and wide-brim hat use than those at control stations.² Details about the study procedures and sample characteristics have been published previously.² Immediately following the 2-year evaluation, control station participants received the free items and 3 of the educational sessions (ie, introduction and protection strategies, sun safety for eyes, and review and encouragement to maintain sun safety practices). At the intervention stations, we continued to provide free sunscreen during that year. Herein, we describe the behavioral outcomes at the 3-year follow-up evaluation.

Evaluation cohort retention rates (of those completing questionnaires) from the 2- to 3-year follow-up periods were 93.2% (927 of 994) for the intervention group and 94.4% (1130 of 1196) for the control group. The trends over 3 years in 2 key outcomes—consistent use of sunscreen and wide-brim hats—were analyzed using generalized linear mixed models treating 3 months, 1 year, 2 years, and 3 years as a set of repeated measures on each postal worker. In addition, we adjusted for postal workers clustered within post offices within a multilevel model. The intraclass correlation coefficients for sunscreen and hats were 0.015 and 0.067, respectively. All analyses were adjusted for the baseline level of the corresponding outcome variable. For each analysis, we tested (1) the time × condition interaction to determine if the intervention effect remained constant over time and (2) the condition main effect. Consistent sunscreen use rates for intervention participants at the 2- and 3-year follow-up periods were 39.2% and 38.3%, respectively, and for control participants, the rates were 26.3% and 34.3%, respectively. Wide-brim hat use rates for intervention participants during these periods were 40.0% and 43.8%, respectively, and for control participants, the rates were 22.3% and 33.0%, respectively. Results of the analyses for each of these outcomes showed significant time × condition interaction effects (P<.001 for all), indicating that the differences between the conditions were changing over time. The Table lists these findings. For both behaviors, the change in the odds ratios from year 2 to year 3 was not due to a lowered use rate among intervention participants but rather to an increased rate among control group participants.

We are encouraged that intervention effects were maintained at least 1 year after the program ended and that once the control participants received the intervention, their consistent use of sun protection increased substantially.

Correspondence: Dr Mayer, 9245 Sky Park Court, Ste 220, San Diego, CA 92123 (jmayer@mail.sdsu.edu).

Author Contributions:Study concept and design: Mayer, Slymen, Clapp, Elder, Sallis, Eichenfield, and Weinstock. Acquisition of data: Mayer and Pichon. Analysis and interpretation of data: Mayer and Slymen. Drafting of the manuscript: Mayer, Slymen, Clapp, Pichon, Elder, Sallis, Eichenfield, and Weinstock. Critical revision of the manuscript for important intellectual content: Mayer. Statistical analysis: Slymen. Obtained funding: Mayer, Elder, and Sallis. Administrative, technical, and material support: Clapp. Study supervision: Clapp and Pichon.

Financial Disclosure: None reported.

Funding/Support: This study was supported by grants R01CA085980, R01CA085980S1, R01CA085980S2, and K05100051 from the National Institutes of Health, National Cancer Institute, Bethesda, Maryland.

Role of the Sponsors: The sponsors had no role in the design and conduct of the study; in the collection, analysis, and interpretation of data; or in the preparation, review, or approval of the manuscript.

Additional Contributions: Dr Eichenfield served as a dermatologist expert consultant, and Dr Weinstock provided dermatoepidermal expertise. Laura Eckhardt, MPH, Sam Oh, MPH, Gabriel Galindo, MPH, Cynthia Balderrama, BA, and April Achter provided scientific contributions to this study. Our contacts at the US Postal Service (USPS) in Southern California and the National Association of Letter Carriers provided valuable contributions, and the USPS letter carriers participated in the evaluation. Debra Rubio, BA, provided assistance in manuscript preparation.