Table 1.

The predictor variables in the modified HBM. Showing scale reliability, number of questions included in the indexes and examples of questions. The complete questionnaire with questions included in each predictor variable is available in Additional file 1

	Cronbach coefficient alpha (α)	Survey questions included	Examples
Susceptibility	0.62	3 items	“How likely do you think it is that you will develop melanoma during your lifetime?”
Severity	0.64	5 items	“Getting melanoma in the future worries me” and “It is important for me to prevent getting melanoma”
Benefits	0.76	6 items	“Regular use of sunscreen with SPF 15 or more, is an effective way of avoiding sunburns”
Barriers	0.81	14 items	“When I am tanning, using sunscreen is uncomfortable”
Self-efficacy	0.75	4 items	“I am able to recognize warning signs of melanoma at an early stage”
Empowerment	0.77	5 items	“I am usually confident about the decisions I make” and “I feel powerless most of the time”
Benefits of tanning	0.60	7 items	“I sunbathe because I feel better with a tanned skin”