Background characteristics of the respondents

^† ‘All respondents’ refers to all respondents who had used substances in mainland China in the last year, including those who used substances both in Hong Kong and in mainland China (the HKMC group) and those who used substances only in mainland China (the OMC group).

^a About HK$ 7.8 = US$ 1.

^b In the last episode of substance use.

Factors associated with alcohol consumption and sexual activities in conjunction with substance use among all respondents, including both the HKMC and the OMC groups

^a In the last episode of substance use.

^b Univariate Odds Ratios.

^c Odds Ratios obtained from stepwise multivariate analyses (variables that were univariately significant, including those marginally significant, were used as candidate variables).

^b Answers included “no impact” and “negative impact”.

***p < 0.001; **p < 0.01; *p < 0.05; 0.05 < p < 0.1; NS = not significant.

–, not used as candidate variables in the stepwise multivariate model.

NA = not applicable (variables not considered).

Factors associated with alcohol consumption before substance use among the OMC respondents

^a In the last episode of substance use. ***p < 0.001; **p < 0.01; *p < 0.05; 0.05 < p < 0.1; NS = not significant.

–, not used as candidate variables in the stepwise multivariate model.

Factors associated with sexual activities subsequent to substance use among the OMC respondents

^a In the last episode of substance use. ***p < 0.001; **p < 0.01; *p < 0.05; 0.05 < p < 0.1; NS = not significant.

–, not used as candidate variables in the stepwise multivariate model.