Int. J. Environ. Res. Public Health 2009, 6 703 Finally, using a remote car starter in winter was most frequent among respondents who did not believe at all in the anthropogenic contribution to climate change over the last 50 years, compared to participants who believed in it. Among 31 multivariate sub-models (25-1), the most discriminant model included five of the variables associated with the use of a remote car starter (c index: 0.6239). This model seemed to differentiate users from non-users, on the basis of: (1) living in the peripheral regions; (2) respondents’ sex; (3) first language learned at home; (4) consultation of weather reports (temperature or humidity rate) in the media; (5) using a car every day. Table 5. Indicators differentiating respondents using a remote car starter in winter from non-users: multivariate analysis corrected for stratified sampling. Remote car starter in winter CI95%1 p value2 < 0.0001 Region of residence: Montréal and Laval central regions other than Montréal and Laval most peripheral regions of southern Québec Gender: men women First language learned at home: English only or other language in addition to French/English French only Allophone (other than French and English) Using a car: not every day every day Consultation weather reports (temperature or humidity rate) in the media: rarely/never at least sometimes OR1 1.5 2.7 1.5 2.2 2.6 1.2 1.5 reference group 1.2 ; 1.8 1.8 ; 3.5 reference group 1.2 ; 1.8 reference group 1.3 ; 3.5 1.3 ; 5.0 reference group 1.1 ; 1.5 reference group 1.0 ; 2.2 0.0002 0.0087 0.0426 0.0434 1 OR: odds ratio; CI95%: 95% confidence interval. The odds ratios presented in this table indicate the capacity of a variable to discriminate the participants using a car starter in winter from those that do not. For example, the odds of using a car starter was 1.5 times was higher for women than for men. The value of c index was 0.62, which is low. No collinearity between the independent variables was observed. 2 The p value associated with the Wald test was obtained using logistic regression. More specifically (Table 5), compared to the respondents living in the adjacent cities of Montréal and Laval, the odds of using a remote car starter was 1.5 times higher for the participants living in other central regions of southern Québec (e.g. regions 3-5 in Figure 1) and 2.7 times for those in the most peripheral regions (e.g. regions 2 or 9 in Figure 1). The odds were also 1.2 higher for the participants driving a car every day than for occasional drivers; 1.5 times higher for women than men; respectively 2.1 and 2.6 times higher for francophones and allophones, than for anglophones. Finally, the odds of using a remote car starter was 1.5 times higher for the respondents who consulted (at least sometimes) weather reports (temperature or humidity rate) than for respondents who rarely or never consulted it.