Characteristics Associated With Use or Intention to Use Indoor Tanning Among Adolescents

Background  Indoor tanning is a popular behavior that may increase skin cancer risk.

Objective  To examine characteristics associated with use or intention to use indoor tanning among adolescents.

Methods  A telephone interview was conducted with 1273 adolescents, aged 14 to 17 years, in the Minneapolis– St Paul, Minn, and Boston, Mass, metropolitan areas. Questions included demographic and phenotypic characteristics, knowledge, attitudes, social factors, use of indoor tanning, and intention to tan indoors.

Results  Twelve percent of boys and 42% of girls had tanned indoors. Among nontanners, 22.4% planned to start, and 77.2% of tanners planned to continue tanning indoors. Nontanners and tanners at risk for future indoor tanning use were each significantly more likely to be female, less likely to use sun protection, less knowledgeable about skin cancer risks, more likely to agree that tans were attractive, and more strongly influenced by social factors compared with their low-risk counterparts.

Conclusions  Our data suggest that intention to tan indoors may identify a group of adolescents at risk for adopting the behavior; prospective studies are needed for confirmation.

The incidence of squamous cell, basal cell, and melanoma skin cancers has risen dramatically since the mid 1950s.^1-4 Solar UV radiation is an established risk factor for these cancers, with the magnitude of the risk depending on patterns of sun exposure, intermittent or cumulative, and frequency of sunburn.⁵ Despite recommendations to avoid all sources of UV radiation,^6-9 the desire for a tan and the availability of artificial sources of UV radiation from tanning beds and booths has given rise to the indoor tanning industry, estimated to be a $5 billion enterprise.¹⁰ The tanning industry estimates that 28 million Americans have used indoor tanning facilities, with about 1 million visits each day.¹¹

Typical indoor tanners in the United States today (20 sessions per year) could add anywhere from 0.20% to 24% more UV-B radiation (S. A. Miller, written communication, March 2003) but as much as 30% to 300% more UV-A radiation¹² to their annual solar exposures by tanning indoors, depending on the tanning device. While UV-B has generally been viewed as the component of UV radiation responsible for skin cancer development, laboratory studies, experiments in animals, case reports of skin cancer following tanning bed exposure, and increased incidence of skin cancer among patients with psoriasis treated with UV-A and psoralen strongly suggest that UV-A may also be carcinogenic.^13-27 The majority of epidemiologic studies of indoor tanning and skin cancer predate the current availability of low UV-B–, high UV-A–emitting tanning devices or have insufficient information on indoor tanning use to draw conclusions.^28-33 However, a recent study from Sweden²⁹ among individuals primarily exposed to tanning devices in use today reported a strong positive association for melanoma, thus providing preliminary epidemiologic evidence that currently available tanning devices could increase the risk of melanoma.

Given the carcinogenic potential and the popularity of indoor tanning, we conducted a comprehensive assessment of indoor tanning–related practices among public health agencies and tanning businesses and among adolescents and their parents in the metropolitan regions of Minnesota and Massachusetts. Herein, we report our findings for characteristics associated with indoor tanning use among adolescents, as others have recently done,^34-36 and then we examine whether these characteristics are also related to intention to either initiate indoor tanning use among nontanners or to continue use among tanners. The model for this approach was developed by Pierce et al,^37,38 who defined adolescents' "susceptibility" to tobacco use according to their intention to smoke in the near or long term or their ability to refuse a cigarette from friends. Adolescent nonsmokers who met the definition of susceptibility shared characteristics with current smokers in cross-sectional analyses,³⁷ and a prospective assessment confirmed that the probability of subsequent smoking increased according to susceptibility and past smoking experience.^38,39 This concept is now used to describe stages of smoking acquisition among adolescents⁴⁰ but has not been routinely applied to other adolescent behaviors. Second, we examine practices and attitudes specific to indoor tanning use among adolescents who had tanned indoors.

We identified adolescents aged 14-17 years in fall 2000 from a targeted age list purchased from Survey Sampling, Inc, Fairfield, Conn, for the Boston, Mass, and Minneapolis–St Paul, Minn, metropolitan statistical areas. Randomly selected households were called to determine if a teenager resided at that number, selecting 1 at random if more than 1 adolescent in the age range was in the household. We oversampled girls relative to boys in a 2:1 ratio. In the Boston area, 33.0% of households (n = 2699) were found to have an adolescent in the desired age range; in the Minneapolis–St Paul area, 44.7% of 1650 households had an adolescent in the desired age range (37.4% overall). Among eligible households, 651 adolescents (73.1%) in Boston and 647 adolescents (87.8%) in Minneapolis–St Paul completed a telephone interview with their parents' consent. Because we were interested in the use of commercial tanning facilities, we excluded 23 adolescents (1.8%) who reported home use only and 2 adolescents who did not provide information about intention to tan, for a total of 1273 participants. The study was approved by the institutional review boards at the University of Minnesota, Minneapolis–St Paul, and Harvard University School of Public Health, Boston.

We collected information about personal characteristics including age, sex, smoking history, use of sun protection, skin cancer risk factors (eg, color of hair, eyes, skin, propensity to sunburn, and history of severe sunburns), body satisfaction (eg, how often are you happy with the way you look), and depression (eg, how often have you been bothered by feeling unhappy, sad, and depressed⁴¹). From the risk factors for skin cancer, we created a skin cancer risk summary score (range, 4-17; the higher the score, the higher the risk). A knowledge summary score was created by giving 1 point for each correct answer (0-5 points possible) to questions about tans being a marker of skin damage, indoor tanning being a possible cause of skin cancer, whether indoor tanning is safer than the sun or protects one from sunburn, and that medications could make one more sensitive to the effects of UV radiation. Positive attitudes toward tans were measured by the percentage of teens who agreed or strongly agreed that people with tans looked more attractive or healthier than those without a tan. Social influences were assessed by agreement with the statements that most of their friends liked to be tan or that their parents allowed them to tan indoors, and perceived norms were based on adolescents' estimates of the proportion of their friends or adults who tan indoors (dichotomized at the median value, specific to each measure).

Age at tanning initiation and recency of indoor tanning use was asked of adolescents who had ever tanned. Those who had tanned in the past year were asked detailed questions about tanning frequency, parental consent (required by law in each state, depending on age), perceived difficulty to stop tanning indoors, indoor tanning practices (eg, wearing goggles), and adverse effects experienced from tanning (from a list including itching, red/painful skin, eye problems, warts, medication reaction, other). We also asked these teens to indicate their level of agreement with 3 positive (compliments about indoor tan, indoor tanning helps lift spirits, or is relaxing) and 5 negative (feeling claustrophobic in a tanning bed, getting hot and sweaty from indoor tanning, and indoor tans look fake, are expensive, or make skin smell) attitudes about indoor tanning. Items were reordered so that a high value indicated positive attitudes toward indoor tanning, and a summary score was created by taking the mean of values across items (Cronbach α = .55).

For outcome measures, we first classified all adolescents according to whether they had ever tanned indoors. We defined our second outcome according to adolescents' self-reported intention to use indoor tanning. Intention was asked slightly differently depending on an adolescent's previous indoor tanning experience. Adolescents who had tanned indoors and reported being very or somewhat likely to do so again in the next year (298 tanners [77.2%]) were classified as being at risk to continue the behavior relative to tanners who responded not very or not at all likely to tan in the next year. Nontanners who answered yes to a question about plans to tan indoors sometime in the future (198 nontanners [22.3%]) were considered to be at risk to initiate indoor tanning, while those who answered no were classified as being at low risk for future indoor tanning use.

Although the prevalence of indoor tanning was higher in the Minneapolis–St Paul area than the Boston area (40.0% vs 20.7%), preliminary analyses indicated no important differences between cities in the associations of interest nor did our results differ by sex or age. Therefore, all analyses are presented for the combined sample. We first compared adolescents who had ever tanned indoors with those who never had for each characteristic described earlier. We then repeated the analysis separately among nontanners and tanners, comparing adolescents who were at risk for future indoor tanning use (ie, those reporting intention to initiate or continue the behavior) with those in the respective low-risk group. Among tanners, we also assessed the relationship between tanning practices and attitudes about the practice with intention to continue indoor tanning use.

We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of interest. The significance of the observed associations was assessed by the likelihood ratio test; linear trends were evaluated by the Wald test. For personal characteristics associated with use or future use and for indoor tanning practices associated with intention to continue use, ORs were adjusted for age, sex, and city. For knowledge, attitudes (about tans, about indoor tanning), or social factors, we first obtained ORs adjusted for these confounders (data not shown). Then, for those found to be significantly associated with use and/or intention to use indoor tanning, we identified which factors were independent predictors of past or future indoor tanning by including all related characteristics simultaneously in logistic regression models. Odds ratios were not adjusted for socioeconomic status because only the parent's education was available and was missing for adolescents whose parent was not interviewed. However, ORs based on the subset of the sample that included parent education were unchanged from the results presented here.

Girls were more likely than boys to have ever tanned indoors and to report intention to either initiate or continue indoor tanning use (Table 1). In contrast, adolescents who reported using sun protection most of the time were the least likely to report indoor tanning use or be at risk for future use relative to adolescents who never used sun protection. For other personal characteristics, however, the associations were not consistent across outcomes. The prevalence of indoor tanning use increased with each additional year of age (P trend <.001). Among adolescents who had never tanned indoors, however, intention to initiate indoor tanning was less likely with increasing age (P trend = .09), while age was not a factor for intention to continue indoor tanning if adolescents had previously tanned indoors (P trend = .76). Smoking history was positively associated with having ever tanned indoors and with being at risk for future tanning among nontanners but not among tanners, whereas the observation that the likelihood of future indoor tanning decreased with higher skin cancer risk scores was found only among tanners. Neither body satisfaction nor depression were associated with any outcome (data not shown).

Knowledge, positive attitudes toward tans, and social factors were all significantly associated with having ever tanned indoors or with intention to tan indoors when we adjusted for age, sex, and city. When we considered all these characteristics simultaneously (Table 2), social influences (friends like to be tan, parents allow tanning) and perceived norms (proportion of friends or adults who have tanned indoors) generally remained strong predictors of ever use of indoor tanning as well as intention to initiate or to continue the behavior. For knowledge and positive attitudes, however, the results depended on whether we considered past use or intention to use indoor tanning. Among all adolescents, neither knowledge nor positive attitudes toward tans were associated with having ever tanned indoors once social factors were considered. Among nontanners and tanners, however, adolescents who were more knowledgeable about the potential risks of indoor tanning were still less likely to be at risk for initiation or continuation of indoor tanning, while those holding the view that people with tans look more attractive (but not healthier) were still more likely to be at risk for future indoor tanning after adjusting for social factors.

Recent or frequent use of indoor tanning were each strongly predictive of intention to continue the practice among adolescent tanners (Table 3). In addition, tanners who reported medium to extreme difficulty to stop tanning indoors were more likely to be at risk for future indoor tanning (adjusted OR, 11.52 [95% CI, 1.53-86.60]). However, neither asking a parent for consent to tan indoors nor having experienced adverse effects from indoor tanning appeared to decrease intention to continue tanning indoors, whereas compliance with regulations, such as wearing goggles, did. Among tanners, 2 of the 5 negative attitudes toward indoor tanning—agreement that tanning indoors is expensive or that it makes skin smell bad—were not associated with intention to continue indoor tanning after accounting for age, sex, and city. When we simultaneously considered all other attitudes found to be related to future indoor tanning (Table 4), only the 3 positive attitudes toward indoor tanning (compliments, lifts spirits, relaxation) remained independently associated with the likelihood of being in the at-risk group. When all 8 attitudes toward indoor tanning were combined into a summary scale, higher scores were strongly associated with intention to continue to tan indoors.

To our knowledge, our report is the first to examine predictors of indoor tanning among adolescents in relation to their stated intention to tan indoors. Although cross-sectional data limit us from concluding that our measure of intention predicts future indoor tanning, our results are notable for their consistency with early work to define adolescent "susceptibility" to tobacco use.³⁷ Just as adolescents susceptible to tobacco use resembled adolescent smokers, we found that at-risk nontanners and tanners were each more likely to be female, less likely to be frequent sunscreen users, less knowledgeable about skin cancer risks, more likely to agree that tans were attractive, and strongly influenced by social factors compared with their low-risk counterparts. Other studies have prospectively linked behavioral intention to indoor tanning among college students⁴² and sunscreen use among fourth graders and college students,^43,44 strengthening the possibility that self-reported intention to tan indoors may identify a group of adolescents who are likely to tan indoors sometime in the future.

Our findings also add further evidence to the growing recognition that indoor tanning is a socially determined behavior. In 2 recent national surveys of US adolescents, the probability of tanning indoors was much higher among adolescents whose friends³⁴ or parents³⁶ also tanned. Others have reported that social relationships influence the likelihood of sunbathing among adolescents^45,46 and that friends, parents, and social norms are important for encouraging adolescent sunscreen use⁴⁷ or intention to protect oneself from the sun.⁴⁸ Our data suggest that social influences and perceived norms may also be critical to initiating and maintaining the behavior. In particular, the perception of being surrounded by friends and adults who tan and believing that the behavior is sanctioned by their parents were each strongly predictive of indoor tanning behavior beyond the contribution of positive attitudes toward a tan.

Anecdotal reports suggest that some adolescents may be "addicted" to indoor tanning.⁴⁹ We found that tanners at risk to continue tanning indoors were much more likely to report difficulty giving up indoor tanning compared with low-risk tanners, warranting further investigation in longitudinal studies. The most common reasons for tanning indoors include relaxation^50-52 and appearance.^50,53 Appearance, relaxation, and social benefits have been correlated with the frequency of visits to tanning salons⁵⁴; being female or a recent tanner have been associated with intention to continue to tan indoors but experiencing adverse effects has not⁵³; and being female and believing that tans represent a healthy appearance or that tanning beds are safe distinguished current from past users.⁵⁵ Although these studies were conducted in college-aged or older populations, the observations are consistent with our own.

Our analysis of attitudes toward indoor tanning is more comprehensive than what has been previously reported and provides guidance for interventions to dissuade adolescents from continuing to tan indoors. Appearance, relaxation, and mood elevation outweighed negative reasons for continued tanning; thus, adolescents may benefit from alternative activities that provide similar benefits. Increasing the cost of indoor tanning through taxation⁵⁶ might be another strategy since clearly the cost of tanning was not a barrier to adolescents' intention to continue tanning. Although none of the negative attitudes toward indoor tanning was significant in the fully adjusted model, the view that indoor tans look fake almost approached statistical significance (fully adjusted OR, 0.62 [95% CI, 0.35-1.09]), and the strength of the relationship suggests that it may retain some merit as a message to counter the view that tans are attractive.

In recent national reports,^34-36 indoor tanning prevalence ranged from 2% to 11% among boys and from 12% to 37% among girls. Despite the use of a targeted list for sampling that could yield a more select group, our prevalence estimates are comparable with the upper range of prior studies. Our findings for age, sex, other health behaviors, positive attitudes, and social factors in relation to indoor tanning use are similar to other reports,^{34-36,45-48,52,57-59} providing additional evidence that our associations were not biased by sample selection methods. Other limitations include reliance on self-report to ascertain the behavior and the effect of nonresponse on the point estimates. However, high correspondence (r = 0.78) between self-report of indoor tanning and events recorded in diaries has been reported,⁶⁰ and our response rates were high—73% in Boston and 88% in Minnesota. If nonresponders were more likely to be indoor tanners, as might be expected since this behavior seems to parallel other high-risk behaviors associated with nonresponse such as smoking, then the strength of the associations reported herein may be underestimated.

Recommendations and interventions for skin cancer prevention have focused almost exclusively on reducing children's and adults' sun exposure,^6-8,61,62 understandably, because sun is ubiquitous and an established risk factor for skin cancer. Although the indoor tanning industry is subject to federal regulation and, in addition, about 27 states have some form of regulations on indoor tanning businesses, only 18 states limit adolescent use of indoor tanning,⁶³ and low industry compliance with such rules has been reported.^64,65 Our findings that a high proportion of adolescents believe that their parents would allow them to tan indoors and that parents often tan indoors themselves^36,66 suggest that public awareness of the dangers posed by indoor tanning is limited. In addition to increasing awareness of the potential risks of indoor tanning, our data provide support for interventions that increase knowledge and consider the social aspects of indoor tanning to prevent initiation or continuation of indoor tanning use. Until such time that epidemiologic studies can confirm or refute the link between modern indoor tanning devices and skin cancer, in particular melanoma, it would be prudent to find effective ways to limit adolescents' use of indoor tanning.

When this study was undertaken, little information was available about adolescent use of indoor tanning in the United States. Since then, 3 recently published articles have reported indoor tanning to be more prevalent among girls or older adolescents, among teens whose friends or parents tanned or who held positive attitudes toward the behavior, and among teens with other high-risk behaviors, such as alcohol or tobacco use. This report confirms earlier findings and extends this work by examining for the first time adolescent intention to initiate or continue to tan indoors among nontanners and tanners, respectively, based on a model of "susceptibility" to the behavior first proposed to identify adolescents at risk for tobacco use. Similar to the tobacco model, nontanners at risk for initiating and tanners at risk for continuing the behavior shared characteristics that may help to identify adolescents at risk for future indoor tanning. Associations between indoor tanning practices (eg, number of sessions, experience of symptoms, infrequent use of goggles) and attitudes related to intention to continue to tan indoors provide new evidence for concern about potential harmful effects of indoor tanning and possible messages to dissuade adolescents from the practice.

Correspondence: DeAnn Lazovich, PhD, Division of Epidemiology, University of Minnesota, 1300 S 2nd St, Suite 300, Minneapolis, MN 55454 (lazovich@epi.umn.edu).

Accepted for publication April 19, 2004.

This study was supported by grant 1 RO1 CA079593 from the National Cancer Institute, Bethesda, Md.