Table 2 Odds ratios and confidence intervals for the interaction between year of survey (2002 vs 2001, 2003 vs 2001) and statistically significant (p<0.05) predictors on helmet use (1 = yes; 0 = no)*.

Predictor	Estimate	p Value
Age
2002	–0.01	0.06
2003	0.01	0.12
Equipment snowboard vs skis
2002	–0.01	0.82
2003	–0.06	0.24
Gender (male vs female)
2002	–0.06	0.18
2003	0.02	0.77
Education
Some college vs high school, 2002	–0.04	0.60
College vs high school, 2002	–0.11	0.09
Some college vs high school, 2003	–0.18	0.04
College vs high school, 2003	0.13	0.09
Days skied/snowboarded
4th quartile vs 1st quartile, 2002	0.01	0.91
3rd quartile vs 1st quartile, 2002	–0.11	0.12
2nd quartile vs 1st quartile, 2002	–0.03	0.75
4th quartile vs 1st quartile, 2003	–0.26	<0.01
3rd quartile vs 1st quartile, 2003	0.06	0.45
2nd quartile vs 1st quartile, 2003	0.18	0.07