Table 2. Bivariate analysis of demographic, clinical and psychological variables associated with performance of skin self-examination in the past 12 months.

	Test statistics
Variable	Mean SSE (s.d.)	Z	df	P
Demographic variables
Sex
Male	2.95 (1.41)	0.49		0.62
Female	2.82 (1.31)
Marital status
Currently married	2.85 (1.26)	0.22		0.82
Not married	2.97 (1.62)
Education level
University degree	3.00 (1.29)	0.40		0.69
No university degree	2.87 (1.37)
Agea		1.86	1	0.17
Occupational environmentb
Indoors	2.63 (1.27)	3.65	2	0.16
Outdoors	2.93 (1.27)
Even time indoors and outdoors	3.22 (1.50)
Clinical variables
Personal history of melanoma
Previous melanoma	3.39 (1.33)	2.71		0.007
No previous melanoma	2.67 (1.31)
Number of FDRs and SDRs affected by melanomaa		5.66	1	0.02
Number of FDRs and SDRs deceased owing to melanomaa		0.026	1	0.87
Objective CDKN2A mutation carrier riskb
100%	3.39 (1.34)	7.86	2	0.02
50%	2.75 (1.36)
25% or less	2.53 (1.24)
Doctor recommendation for SSE
Yes	3.31 (1.31)	4.20		<0.0001
No	2.27 (1.19)
Doctor instruction on SSE
Yes	3.49 (1.23)	3.62		<0.0001
No	2.57 (1.32)
Psychological variables		r s		P
Perceived risk		0.15		0.10
Causal attributions
Sun exposure		0.13		0.17
Genetics		0.05		0.59
Uncontrollable factors		0.02		0.82
Self-efficacy for SSE		0.52		<0.0001
Perceived efficacy of melanoma treatment		−0.25		0.007
Intention to engage in SSE in future		0.61		<0.0001
Melanoma-specific distress		0.25		0.006
General anxiety		0.09		0.34
General depression		0.06		0.53
Information-seeking stylec		Z		P
High monitor	2.80 (1.38)	0.66		0.51
Low monitor	2.94 (1.31)

Abbreviations: FDR=first-degree relatives; SDR=second-degree relatives; SSE=skin self-examination.

To interpret mean SSE scores, response options were: 1=‘not once’, 2=‘one to three times per year’, 3=‘four to eight times per year’, 4=‘once per month’ and 5=‘once per week’.

^aLinear-by-linear association test.

^bKruskall–Wallis.

^cMann–Whitney U. Bold type is used to indicate statistical significance at the P<0.05 level.