Table 3.

The trial measures captured with self-report surveys.

Construct		Description of measures
Primary outcomes (measured at 8-month follow-up)
	Indoor tanning	Open-ended reporting of the number of times participants used a tanning bed or booth in the past 8 months [85]
	Outdoor tanning	Open-ended reporting of the number of times spent outdoor tanning in the most recent summer (eg, between June 1, 2023, and August 31, 2023) [86]
Secondary outcomes
	Tanning intentions	Intentions to use indoor tanning or spend time outdoor tanning (2 separate questions) in the next 12 months [39,41,77]
	Long-term tanning	Indoor and outdoor tanning outcomes assessed at the 18-month follow-up
Primary mediators (measured at 3-month follow-up)
	Tanning expectancies	Beliefs related to tanning benefits (eg, tanning is attractive and relaxing) and risks (eg, appearance damage and skin cancer risk), tanning attitudes, and temptations to tan [87,88]
	Tanning-specific body-image factors	Items adapted from the Objectified Body Consciousness Scale to assess actively monitoring and comparing one’s tans with others [38,89] Internalization of the thin and tan ideal [21,35,38,88] Appearance conversations with friends [90] Items adapted from the Multidimensional Body Self-Relations Questionnaire to reflect tan dissatisfaction [38,91]
	Openness to changing tanning	Perceived difficulty in stopping indoor or outdoor tanning (2 separate questions) [92] The Readiness to Change Questionnaire adapted to tanning behavior [93]
Exploratory mediators
	Values and values-consistent living	Valued Living Questionnaire [94] Valuing Questionnaire [95]
	General body image acceptance	The Acceptance and Action Questionnaire II [96] Beliefs About Appearance Scale [97]
	Perceptions and use of tanning alternatives	For both sunless tanning products and spray-tanning, past 12 use, intention, attitudes, and self-efficacy [77,85]
	Mindfulness	Mindful Attention Awareness Scale [98]
Covariates
	Demographics	Age, education, race, ethnicity, urban, rural, and SESa
	Sun protection habits	Typical use of sun protection (eg, shade and sunscreen) [99]
	Use of social media	Frequency of use of popular social media sites and integration of Facebook within social behaviors and daily routines [67,100]
	Melanoma risk factors	Natural hair color, eye color, skin type, skin reactivity to the sun, and history of sunburns [101]
	Depression, anxiety, and stress	The Depression Anxiety Stress Scale-10 [102]
	Other health behaviors	Alcohol use [103] Cigarette use [104] Physical activity [105] Sedentary behavior [106] Sleep [107] Diet [108]

^aSES: socio-economic status.