Very few unhealthy behaviors have healthy desirable alternatives. Sunless tanning is a risk-free alternative to suntanning, but has not been well-studied in the context of skin cancer prevention. Results revealed that an intervention that promoted sunless tanning led to both short- and long-term behavior change. Sunbathers exposed to the intervention in the middle of summer reported declines in sunbathing and sunburns, as well as increased use of protective clothing during the rest of the summer, compared to their counterparts who only completed questionnaires. One-year following the intervention, effects were maintained for sunbathing.. Use of sunless tanning during the year following the intervention increased significantly more in the intervention group compared to the control group.
Nearly half of the intervention participants (48%) had used sunless tanning at least once prior to the study. Another 9% of intervention participants newly adopted sunless tanning at 2-months and about 6% at 1-year. Of the intervention participants who tried sunless tanning for the first time at 2-months and 1-year following the intervention, the majority (64% and 75%, respectively) used it more than once, suggesting that many who tried sunless tanning as a result of the study adopted it as a habit. In spite of the small increase in sunless tanning, intervention participants reduced their sunbathing. Further investigation is merited to determine what aspect or aspects of the intervention generated the observed effects. Sunless tanning was promoted within an intervention that provided skin cancer education and UV imaging. While education and UV imaging affect knowledge and intentions,28
neither has reduced sunbathing behavior (e.g.,29, 23, 30–32
), which was the reason sunless tanning was added to this intervention. In a previous study of beach visitors, we tested an intervention that included all aspects of the present intervention (i.e., skin cancer education, free sunscreen, UV imaging) except
the sunless tanning content. 29
Instead of sunless tanning, that study focused on sunscreen and other sun protection (e.g., clothing). Using the same measures, the previous study did not impact sunbathing, but did decrease sunscreen use. The focus of the present study on tanning alternatives may have better reinforced an abstinence message as opposed to a harm reduction message (i.e., using sun protection during exposure) as in the previous study. A message focused on sunscreen and other forms of sun protection might inadvertently reinforce the misconception that people can tan “safely.” Future research should examine which prevention messages reduce sunbathing, and which increase sun protection.
Results from the present study suggest that sun safety recommendations have the greatest impact during the season they are received. At 1-year, the intervention effect on sunbathing remained significant, but effects on secondary outcomes did not. Participants in all groups significantly reduced their sunburns and increased their use of protective clothing at 1-year, which could suggest either a social desirability bias in survey responses, an intervention effect of surveys, or that people in this region are exhibiting a trend toward healthier habits over time. Regardless, recurrent sun safety messages may be necessary to reinforce the impact on behavior. The present study also suggests that health messages received in the environments in which people sunbathe can deter future sunbathing.
Physicians might be reluctant to recommend sunless tanning due to concerns that it might inadvertently reinforce the patient’s desire to be tan. The literature is limited but does not seem to support this contention. Although one cross-sectional study found that people who use sunless tanning report more indoor tanning and sunburns than non-users, 21
this is probably because first adopters of sunless tanning are users of other forms of tanning. Several studies in the US and Australia have found that sunless users have higher rates of sunscreen use, which suggests that sunless tanning may cluster with other sun safety behaviors.17–20
The extent to which use of sunless tanning offsets
a previously existing tanning habit has only been explored in one study. Almost three quarters (73%) of people receiving a sunless spray tan reported that they had decreased their indoor tanning since they began sunless tanning, while only 7% reported having increased their indoor tanning.22
These data suggest that sunless tanning might be associated with declining UVR tanning, which is a promising trend to capitalize on in skin cancer prevention efforts. The only other trial to test a sunless tanning intervention found promising effects on self-efficacy and intentions to use sunscreen, but no actual behavior change.23
As our study demonstrated, messages promoting sunless tanning might be of greater interest to people who are frequent tanners, such as beach visitors.
The present study had some limitations. The refusal rate was 46% which could have contributed to selection bias. Because sunless tanning was not specifically mentioned when participants were invited to participate, refusal would not have been related to attitudes about sunless tanning. Also possibly contributing to selection bias is that randomization occurred by beach instead of individual. Individual randomization is not feasible in this setting given multiple entrances and the transient nature of beach patrons. Because of the possibility of selection bias, we explored baseline differences on demographic variables. Age was significantly different between groups and was consequently entered as a covariate in all analyses. Another limitation is that all measures were self-report which may be subject to underreporting due to social desirability bias. Self-report measures are typically used in studies of sun-related behavior27
because very few practical, objective measures exist for large samples, and follow-up could not be done in person. Items used in the present study have recently been put forth as the standard in sun exposure and sun protection measurement.27
Effect sizes were fairly small. The intervention was a brief, one-shot, inexpensive approach to behavior change in the very setting in which high-risk behavior occurs. Results of the present study suggest that future studies that increase the intensity and length of the intervention are merited. Further investigation is merited to determine what aspect or aspects of the intervention generated the observed effects. Sunless tanning was promoted within an intervention that provided skin cancer education and UV imaging. While education and UV imaging affect knowledge and intentions,28
neither has reduced sunbathing behavior, (e.g.,29, 23, 30–32
) which was our reason for adding sunless tanning to this standard intervention.
Loss to follow-up occurred and differed by group. The follow-up rate at 1-year was 66%, but is comparable to the 70% follow-up rate reported in the only other beach-based intervention study to follow participants for 1-year or longer.32
A systematic review revealed that two-thirds of skin cancer prevention studies follow participants for 6 weeks or less and over half follow participants for less than 3 months.28
The present study extends the literature by examining maintenance of intervention effects over the following summer. A marginally significant difference between study groups was apparent for missing data on the primary outcome at the 2 month follow-up [χ2
(1) = 3.75, p=.05], such that more control participants had missing data (28.8%) than intervention participants (18.4%), but not at the 1 year follow-up [χ2
(1) = 1.77, p=.18]. This transient difference in missing data between groups perhaps resulted from intervention participants receiving more personalized attention than control participants, which may have increased their sense of obligation to follow-up. Finally, even though DHA, the active ingredient in sunless tanning products has been FDA approved for cosmetic use since 1973 and has only received reports of rashes,33
studies of the safety of long-term use are lacking. One study in 2004 revealed that DHA lead to DNA damage in cultured keratinocytes, but it remains unknown if DHA induces the same effect in the human epidermis.34
Sunless tanning is the only safe means of tanning. Encouraging sunbathers to switch to sunless tanning could have an important health impact, but sunless tanning has been considered a cosmetic more so than a health care tool. Findings have implications for both public health and clinical efforts to prevent skin cancer. Promoting sunless tanning to sunbathers within the context of a skin cancer prevention public health message may be helpful in reducing sunbathing and sunburns, as well as promoting use of protective clothing. Future research should determine how to further convince tanners to switch to sunless tanning. Physicians should encourage patients who sunbathe to consider safe alternatives like sunless tanning. Finally, reinforcing sun safety messages every season is likely to be necessary to maximize the impact of the message.