Longitudinal trends in mental health among ethnic groups in Canada.

Introduction: Immigration continues to transform the ethnic composition of the Canadian population. We investigated whether longitudinal trends in mental distress vary between seven cultural and ethnic groups and whether mental distress within the same ethnic group varies by demographic (immigrant status, sex, age, marital status, place and length of residence), socio-economic (education, income), social support and lifestyle factors.

Method: The study population consisted of 14 713 respondents 15 years and older from the first six cycles of the National Population Health Survey (NPHS); 20% reported themselves to be immigrant at Cycle 1, in 1994/1995. The logistic regression model was fitted by modifying a multivariate quasi-likelihood approach, and robust variance estimates were obtained by using balanced repeated replication techniques.

Results: Based on the multivariable model and self-reported data, we observed that female respondents were more likely to report moderate/high mental distress than male respondents; younger respondents more than older respondents; single respondents more than those in a relationship; urban-dwellers more than rural-dwellers; less educated respondents more than more educated respondents; current and former smokers more than non-smokers; and those living in a smoking household more than those living in non-smoking households. The relationship between ethnicity and mental distress was modified by immigrant status, sex, social involvement score and education. Confirming other research, we found an inverted U-shaped relationship between length of stay and mental distress: those who had lived in Canada for less than 2 years were less likely to report moderate/high mental distress, while those who had lived in Canada for 2 to 20 years were significantly more likely to report moderate/high mental distress than those who had lived in Canada for more than 20 years.

Conclusion: There is a need to develop ethnicity-specific mental health programs targeting those with low education attainment and low social involvement. Policies and programs should also target women, the younger age group (15-24 years) and low-income adequacy groups.