TABLE 2.

Descriptive Data and Univariable Analyses of Predictors of Adolescent Indoor Tanning in the Past 12 Months in the 100 Most Populous US Cities, Continuous Variables: CITY100, 2005–2007

			Mean (SD) by Tanning Outcome
Variablea	Mean (SD) for Sample	ICCb	Yes	No	OR (95% CI)	P
Psychosocial and individual levelc
% of adolescent's friends who have ever tanned indoors with tanning lamps (20% unit increase)	27.4 (29.9)	0.97	64.1 (28.9)	23.0 (26.8)	2.40 (2.20, 2.50)	<.001
How often adolescent protects skin in summer (1 = never to 5 = all the time)	3.0 (1.2)	0.96	2.9 (1.3)	3.03 (1.2)	0.91 (0.85, 0.98)	.007
Built-environmental leveld
City's tanning facility density (no. of salons per 100 000 people)	11.0 (5.4)	NA	12.1 (5.1)	10.9 (5.4)	1.05 (1.03, 1.07)	<.001
Log physical size of city + 3 mi buffere	6.7 (0.7)	NA	6.8 (0.7)	6.7 (0.7)	1.21 (1.01, 1.46)	.042
Policy leveld
Overall law stringency score	42.4 (26.9)	NA	39.5 (28.7)	42.5 (26.6)	1.00 (0.99, 1.00)	.082
% of tanning facilities in city requiring parental signature (10% unit increase)	86.2 (12.5)	NA	85.8 (13.1)	86.3 (12.5)	0.97 (0.88, 1.07)	.53
% of tanning facilities in city complying with FDA recommended tanning frequency (10% unit increase)	10.1 (11.0)	NA	9.9 (10.7)	10.2 (11.0)	0.96 (0.86, 1.08)	.54
Mean no. of d/wk facilities would allow adolescent to tan	6.0 (0.7)	NA	6.1 (0.6)	6.0 (0.7)	1.28 (1.06, 1.55)	.013

Notes. CI = confidence interval; CITY100 = Correlates of Indoor Tanning in Youth study; FDA = Food and Drug Administration; ICC = intraclass correlation coefficient; NA = data not available; OR = odds ratio.

^aVariables organized by levels of influence addressed by an ecological model of behavior.¹⁰

^bTest–retest reliability from pilot study with 32 female college students.

^cVariables in this category were analyzed at the individual level.

^dVariables in this category were analyzed at the city level.

^eUsed as a covariate in multivariate analyses.