Skin cancer is the most common cancer in the United States. An estimated 96,480 cases of invasive melanoma and 5.4 million cases of nonmelanoma skin cancer were diagnosed in 2019 [1] Melanoma is the fifth most common malignancy in both men and women [2]. The rate of new melanoma cases has been rising by 1.5% on average each year over the last 10 years [2]. The incidence and mortality rates of non-melanoma squamous cell skin cancer are also increasing. The number of deaths caused by squamous cell skin cancer may soon be comparable to melanoma-related deaths. The rising number and per person costs of treatment for skin cancer has increased the average national annual treatment costs of skin cancer, estimated at US $8.2 billion per year [3]. On the basis of these facts, the United States Surgeon General’s Call to Action to Prevent Skin Cancer [4] emphasized that skin cancer is a serious public health concern and suggested heightened skin cancer prevention efforts, including research, surveillance, and evaluation.

The primary risk factor for skin cancer is excess exposure to UV light, and the majority of skin cancers could be prevented if people consistently engaged in sun protection [5-7], The American Cancer Society [1] and the Skin Cancer Foundation [8] recommend minimizing exposure between daily peak hours for UV exposure, using sunscreen with a sun protection factor (SPF) of 30 or higher regularly and wearing protective clothing. Engagement in these recommendations is low. Up to 72% of US population do not use sunscreen regularly, wear protective clothing, or avoid the sun while outdoors [9,10]. Many studies have evaluated individual factors that contribute to sun protection behaviors, including demographic variables, objective risk factors, and attitudes and beliefs. For example, fewer perceived benefits of sun protection, more barriers to sun protection, and lower self-efficacy for using sun protection predict less sun protection [11-14].

The majority of sun protection interventions also focus on individuals. The potential role of the marital relationship as a motivator for sun protection is a less-studied, yet important, factor. Couples live together and typically engage in activities together. Thus, they share situations where UV exposure occurs (eg, sports events, vacations to sunny places), share sun protection equipment (eg, sunscreen bottles), and share environmental support for sun protection habits (eg, a car where sunglasses are stored). Overall, the high correlation between partners’ sun protection practices (r=0.5-0.6) indicates significant couple similarity with regard to sun protection [15]. In terms of marital relationship influences, couples who discuss sun protection and endorse its benefits for the other partner and their relationship are more likely to engage in sun protection [15]. The marital relationship is an important influence on sun protection, and harnessing constructive marital influences offers a promising method to improve sun protection. Although no studies have evaluated the mechanisms of marital influence on sun protection, some have examined general family influence in persons with a family history of melanoma. These studies suggest that greater family support for sun protection is associated with higher levels of sun protection, and that communication about skin cancer occurs within families, particularly between parents and their minor children [16,17]. Additionally, family-focused behavioral interventions have shown efficacy in promoting health-related behaviors, including physical activity and diet as well as sun protection habits [18-20].

When considering how marital relationships may influence health behavior, Lewis et al [21] proposed an integrative framework based on an interdependence theory and communal coping framework to explain how couples’ interactions may influence engagement in risk-reducing health behavior. This framework proposes that a strong interdependence in long-term, successful close relationships (ie, partners’ influence on one another’s behaviors and outcomes) transforms their motivations from doing what is in their self-interest (self-centered) to doing what is in the best interest of their relationship (relationship-centered). The transformation from self- to relationship-centered motivation occurs when partners ascribe health threats and subsequent health changes as having meaning for the relationship and/or their spouse. The model by Lewis et al [21-24] proposed 4 contributors to behavioral change: (1) predisposing factors of the couple (eg, individual perceptions of the health threat), (2) how much partners agree that health changes should be made together, (3) partners’ commitment to the relationship, and (4) demographic factors. When relationship-centered motivation develops, communal coping begins. Communal coping efforts consist of joint decision making (eg, discussing the change) and planning how to make the change. Communal coping efforts lead to engagement in health behavior change for both partners [21-24]. In our prior work [15], we found high couple concordance with sun protection practices (r=0.5) and support for the interdependence and communal coping framework. Couples who reported that they discussed sun protection and endorsed its benefits for their partner and their relationship were more likely to engage in sun protection. Taken together, this suggests that harnessing constructive relationship influences via behavioral interventions may be a promising method for improving sun protection.

In a prior study, we developed and tested a couple-focused print and telephone counseling intervention called Sun Safe Partners [25]. Content was guided by the interdependence and communal coping framework. It included the provision of mailed small media materials, a couple-focused telephone counseling call, and a mailed summary letter. Results from a small, nonrandomized trial showed that couples’ sun protection behaviors significantly increased after the intervention. We also observed increases in attitudes about the importance of one’s own engagement in sun protection for the partner, relationship, and partner-centered motivations to engage in better sun protection [25]. However, intervention uptake was low, and implementation was challenging for our enrollees; it was difficult to schedule couples for the 1-hour phone call, deliver the content, and create implementation plans to improve sun protection for both partners.

To address these challenges, we created Sun Safe Partners Online and utilized a social media recruitment strategy rather than a web-based panel strategy. The web-based intervention allowed couples to work through the content at convenient times and at their own pace without the need for an interventionist. In addition to standard individual-focused behavior change strategies such as goal setting and planning better sun protection, Sun Safe Partners Online content targeted couple-level influences by (1) raising awareness of the partner’s skin cancer risk, (2) identifying benefits of improving sun protection for the partner and relationship, (3) helping partners learn and practice constructive communication to foster one another’s sun protection, (4) identifying ways the partner can assist in working on sun protection behavioral goals, and (5) providing home assignments to help the couple discuss sun protection and ways to support each other’s goals. Furthermore, content was added to address the risks of sun exposure to children, assess a child’s risk factors, and set sun protection goals for the child for couples who have children in the home. We chose a social media advertisement recruitment strategy to examine whether this strategy resulted in better uptake than our prior work [25].

In this study, we report on the development, feasibility, and pilot testing of Sun Safe Partners Online. In a pilot and randomized feasibility trial, we compared Sun Safe Partners Online with a Generic Sun Safety Information-Only Online condition. The study had 2 aims. The first aim was to evaluate the feasibility and acceptability of Sun Safe Partners Online as compared with the Generic Online intervention. Feasibility was measured as enrollment, retention, and intervention use. Acceptability was assessed by a self-report evaluation of both interventions. We also compared our social media recruitment approach to the web-based panel approach utilized in our previous study [25]. The second aim was to assess the impact of Sun Safe Partners Online on the primary outcomes of sun protection and sun exposure and our intervention processes, which were individual and relationship attitudes and practices about sun protection. A 1-month, postbaseline follow-up survey was administered to examine the short-term impact of the intervention.

Engagement in Sun Safe Partners Online was high, with the vast majority of participants using it, and more than two-third of participants completing all modules. Online delivery may have allowed couples to engage in the program at convenient times and places, at their own pace, and when they were together.

Using Facebook as a recruitment strategy resulted in rapid recruitment. Higher acceptance rates were observed (43%) relative to our prior telephone and print trial (22.4%) [25], which used a Qualtrics online panel recruitment. Compared with a Qualtrics panel, Facebook users may also have a preference for online interventions, which could explain the higher acceptance rate. Facebook is also a networking platform that may have yielded participants who placed a higher premium on a relationship-based intervention. It would be informative to see if samples recruited through general internet advertising or offline means would be as engaged with the Sun Safe Partners Online intervention as the current sample derived from Facebook. Follow-up survey completion was also high, although the return rate was lower in the Sun Safe Partners Online condition than in the Generic Online condition. Perhaps the participants from Facebook expected to be engaged for a shorter period of time, and thus, some of them felt they had devoted enough time to the study when completing the Sun Safe Partner Online intervention. Still, follow-up in the Sun Safe Partners Online condition was still high (87%), reducing concerns that loss to follow-up would create substantial selection biases.

Compared with the Generic Online intervention, Sun Safe Partners Online showed small magnitude increases in sun protection behaviors and sun exposure on weekends. However, it should be noted that there were increases in sun protection and reductions in sun exposure in the Generic Online intervention. This was encouraging and suggests that the provision of basic sun protection and skin cancer risk information to participants may motivate some increase in sun protection behaviors. However, these changes must be interpreted with caution. Owing to a very small sample, we avoided significance testing, and the effect size may be imprecise, as noted in the published advice on interpreting pilot studies [36,37]. The results hold promise due to Sun Safe Partners Online’s differential impact on relationship factors. Although both interventions showed increases in participants’ ability to view sun protection from a relational perspective, there were moderate-sized increases in the Sun Safe Partners Online condition and small magnitude effects for Sun Safe Partners Online on relationship motivations and support for the spouse’s sun protection. The results support the framework by Lewis et al [38]. These findings are corroborated by the fact that participants reported supportive behaviors to help their partner adopt sun protection behaviors. In terms of individual factors, there were medium effect sizes in favor of Sun Safe Partners on sun protection benefits and intentions, but there were no differential effects on sunscreen barriers, barriers to wearing sun-protective clothing, and perceived risk. Overall, the pattern of findings implies that Sun Safe Partners Online had an impact on the relationship constructs as intended. However, a fully powered randomized trial is needed to provide inferential tests on the effectiveness of Sun Safe Partners Online [36,37].

A comparison with our previous noncontrolled clinical trial in which Sun Safe Partners involved a tailored counseling call as well as print materials [25] illustrates some important points about Sun Safe Partners Online. In our prior study, we reported a larger effect size for sun protection behaviors (Cohen d=1.29) at the 6-month follow-up than the effect size for sun protection behaviors in this trial (Cohen d=.36) at the 1-month follow-up. However, these 2 effect sizes are not directly comparable in the sense that the effect size from this study compares baseline to follow-up differences between the intervention and control groups, and the effect size from the previous study compared only differences between baseline and follow-up for the intervention group (ie, there was no control). We recomputed both effect sizes using data from only those individuals in the intervention group who completed both waves of data collection. On the basis of these data, we again found that the current web-based study produced a much smaller overtime effect size (Cohen d=.43 vs Cohen d=1.41). There are several possible explanations for this difference. First, the mean baseline score on sun protection behaviors for the study was considerably higher (mean 2.88, SD 0.70) than in the previous study (mean 2.47, SD 0.47). Thus, these differences may reflect sampling. A second potential explanation for this finding is that the prior intervention was more intensive, and because all individuals participated in the counseling call, the intervention dose was more consistent.

Although both interventions were positively evaluated, Sun Safe Partners Online was rated as more helpful, valuable, and interesting than the Generic Online intervention. Participants felt that it was prepared for the couple, it was viewed as promoting the ability to talk to one’s spouse about better sun protection, and it was seen as fostering an understanding of why it is helpful for the relationship and spouse to engage in better sun protection. Participants felt Sun Safe Partners were easy to navigate, and their unique features were positively evaluated. These features may have increased partners’ engagement with the program and collaboration on homework, and made it more likely to impact relationship factors than the Generic Online intervention.

These conclusions should be considered in light of the study limitations. Data collection spanned the late summer through the winter months. For participants who resided in southern climates, the follow-up occurred in a warm, sunny time frame; however, for participants who resided in nonsouthern climates, follow-up occurred in the early fall when UV levels decreased. Thus, sun protection behaviors may not have been as useful among those residing in nonsouthern climates. Second, nearly 80% of the participants were non-Hispanic Whites. Thus, the sample size was not as diverse as the general population. However, skin cancer is far more prevalent among non-Hispanic Whites, especially those with highly sun-sensitive skin, so the sample undoubtedly contained a large number of high-risk participants, the key target population. Finally, our participants may have been more motivated to improve sun protection behaviors than the general population because they volunteered for an intervention on this topic.

This study leveraged a novel approach to facilitating engagement in sun protection by harnessing the relationship between spouses and cohabiting partners. A couple-focused intervention may hold promise as a way to improve sun protection behaviors by leveraging the concern, collaboration, and support among intimate partners and addressing relationship-based barriers to sun protection. Participants felt Sun Safe Partners Online was valuable, and most participants completed all of the modules. On the basis of the outcome of our pilot study, a fully powered trial with a larger, more diverse sample and a longer follow-up time frame is warranted to evaluate the efficacy of Sun Safe Partners Online, which has the potential in its web-based format to be scaled up to a larger population of adults at risk for skin cancer.