Revisiting the immigrant paradox in reproductive health: The roles of duration of residence and ethnicity

https://doi.org/10.1016/j.socscimed.2012.02.013Get rights and content

Abstract

The immigrant paradox refers to the contrasting observations that immigrants usually experience similar or better health outcomes than the native-born population despite socioeconomic disadvantage and barriers to health care use.

This paradox, however, has not been examined simultaneously in relation to varying degrees of exposure to the receiving society and across multiple outcomes and risk factors. To advance knowledge on these issues, we analysed data of the Maternity Experiences Survey, a nationally representative cross-sectional survey of 6421 Canadian women who delivered singleton infants in 2006–07. We compared the prevalence of adverse pregnancy outcomes and related risk factors according to women's ethnicity and time since migration to Canada. We calculated prevalences and prevalence ratios (PR) with 95% confidence intervals.

Compared to Canadian-born women of European descent, recent immigrants were at lower risk of preterm delivery and morbidity during pregnancy despite having the highest prevalence of low income and low support during pregnancy among all groups, but the paradox was not observed among immigrants with a longer stay in Canada. In contrast, recent immigrants were at higher risk of postpartum depression. Immigrants of non-European origin also had higher prevalence of postpartum depression, irrespective of their length of residence in Canada, but immigrants from European-origin countries did not. Exposure to Canada was also positively associated with higher alcohol and tobacco consumption and body mass index. Canadian-born women of non-European descent were at higher risk of preterm birth and hospitalisation during pregnancy than their European-origin counterparts. Our findings suggest that the healthy migrant hypothesis and the immigrant paradox have limited generalisability. These hypotheses may be better conceptualised as outcome-specific and dependent on immigrants' ethnicity and length of stay in the receiving country.

Highlights

► We studied the healthy migrant effect and the immigrant paradox according to women's ethnicity and time living in Canada. ► The healthy migrant hypothesis and the immigrant paradox have limited generalisability in reproductive health indicators. ► These hypotheses should be regarded as outcome-specific and dependent on immigrants' ethnicity and time living in Canada. ► Favourable reproductive health indicators were observed among recent immigrants but not among long-term immigrants. ► Canadian-born women of non-European ethnicity had poorer reproductive outcomes than their European-origin counterparts.

Introduction

The terms “epidemiological paradox” or “immigrant paradox” have been used since the late 1960's to bring together two contrasting epidemiological observations (Karno & Edgerton, 1969; Markides & Coreil, 1986). On one hand, adverse health outcomes in general, and perinatal outcomes in particular, are usually more frequent among population groups positioned at the bottom of the social scale, including ethnic minorities (Bartley, Blane, & Montgomery, 1997; Blumenshine, Egerter, Barclay, Cubbin, & Braveman, 2010; Kramer, Seguin, Lydon, & Goulet, 2000). On the other hand, immigrants to industrialized countries usually exhibit better health outcomes (e.g., mental health, mortality, pregnancy outcomes) than the native-born population. This second observation, which led to the concept of the “healthy migrant effect” (Abraido-Lanza, Dohrenwend, Ng-Mak, & Turner, 1999; Rubalcava, Teruel, Thomas, & Goldman, 2008; Wingate, Alexander, Wingate, & Alexander, 2006), is counter-intuitive, since most immigrant groups in industrialized countries are economically disadvantaged with respect to the native-born population, experiencing lower levels of income and barriers to health care access and utilization, and higher levels of discrimination, factors known to be associated with adverse health outcomes (Karno & Edgerton, 1969; Markides & Coreil, 1986). Therein lies the paradox.

One of the most popular hypotheses formulated to explain the immigrant paradox is selective migration. The rationale behind the selection hypothesis is that good health status positively influences a person's propensity to emigrate. On the destination end, national immigration policies play a key role in narrowing the scope of eligible immigrants. Migrants are thus seen as a group selected (or self-selected) on the basis of characteristics associated with good health status and resilience to adverse living conditions after migration (Jasso, Massey, Rosenzweig, & Smith, 2004; Rubalcava et al., 2008; Wingate et al., 2006).

However, it has been suggested that the healthy migrant effect, at least for perinatal outcomes, may only apply to recent immigrants (Urquia, Frank, Moineddin, & Glazier, 2011). There is increasing evidence indicating that the health advantage of immigrants declines after migration, both within first-generation migrants (Goel, McCarthy, Phillips, & Wee, 2004; Hawkins, Lamb, Cole, & Law, 2008; Scribner & Dwyer, 1989; Urquia et al., 2011) and with subsequent generations (Abraido-Lanza et al., 1999; Fuentes-Afflick & Lurie, 1997; Rosenberg, Raggio, & Chiasson, 2005; Rumbaut, 1996). Such findings are at odds with the expectations and narratives that immigrants and their offspring should experience improvements in well-being as they integrate in the receiving society. This inconsistency has been referred to as the “acculturation paradox” (Ceballos & Palloni, 2010).

Despite evidence of changes in post-migration health status, the immigrant paradox has not been examined in relation to varying degrees of exposure to the receiving society, from recent migrants to long-term migrants to their descendants born in the new land.

A second limitation of the literature on the immigrant paradox in reproductive health is that it has focused on a limited set of outcomes usually available in birth certificate data, such as low birth weight and preterm birth (Buekens, Notzon, Kotelchuck, & Wilcox, 2000; Ceballos & Palloni, 2010; Fuentes-Afflick, Hessol, & Perez-Stable, 1999; Rosenberg et al., 2005; Rumbaut, 1996). However, other conditions such as gestational diabetes and severe maternal morbidity are more common among immigrant groups (Johnson, Reed, Hitti, & Batra, 2005; Knight, Kurinczuk, Spark, & Brocklehurst, 2009; Savitz, Janevic, Engel, Kaufman, & Herring, 2008; Zwart et al., 2010), suggesting that the existence of the healthy migrant effect may depend on the outcome under consideration. The examination of multiple pregnancy outcomes and related risk factors according to women's exposure to the receiving society may provide a more comprehensive picture and help gain valuable insights into the immigrant paradox in reproductive health.

We analysed data of the Canadian Maternity Experiences Survey (MES) with the purpose of advancing knowledge on these issues. The MES is a comprehensive population-based nationally representative survey aimed at filling gaps in our knowledge of a wide array of outcomes, risk factors and experiences of childbearing women in Canada (Public Health Agency of Canada, 2009b).

Our objective was twofold. First, we assessed whether the healthy migrant effect and the immigrant paradox differed according to immigrant groups with varying lengths of residence in Canada and ethnicity. Second, we examined several outcomes (and related risk factors) to see whether the healthy migrant effect and the immigrant paradox applied equally to all outcomes or were outcome-specific.

Section snippets

Canada's immigration context

Canada has the second largest proportion of foreign-born population in the world (19.8%), right after Australia (22.2%) (Statistics Canada, 2007). Until the 1960's virtually all immigrants to Canada originated from the United Kingdom, the United States and selected European countries, who accounted for most of the foreign-born population and about 95% of new immigrants. In the decade of 1960, governments amended restrictive immigration policies to eliminate discrimination based on race,

Data

The Maternity Experiences Survey (MES) is a population-based cross-sectional survey conducted in 2006–07 by the Public Health Agency of Canada in collaboration with Statistics Canada, with the goal of filling knowledge gaps on reproductive health. The MES target population consisted of biological mothers who were 15 years of age and older at the time of their babies' singleton live birth in Canada (between February 15, 2006 and May 15, 2006 in the provinces and between November 1, 2005 and

Results

Of all childbearing women, 24% were immigrants (14% recent immigrants, 6% long-term immigrants and 4% arrived during childhood) and 76% were non-immigrants (64% Canadian-born women of European descent and 12% of non-European ethnicity). Table 1 shows the distribution of maternal characteristics according to the mothers' level of exposure to the Canadian society. Among immigrant women, as length of stay in Canada increased their age at arrival decreased. By definition, there were no teenage

Discussion

Our analysis of a representative sample of Canadian childbearing women, in which women were classified according to their level of exposure to the Canadian society and ethnicity, provides new insights into the nature of the healthy migrant hypothesis and the immigrant paradox in reproductive health. First, our findings indicate that for reproductive outcomes the healthy migrant effect is outcome-specific, as it applies to preterm birth and illness during pregnancy but not to postpartum

Acknowledgements

The authors would like to thank the Maternity Experiences Study Group of the Public Health Agency of Canada's Canadian Perinatal Surveillance System who developed and implemented the MES.

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