During the past decades, the number of non-Western individuals moving to Western countries has increased rapidly due to economical factors and political conflicts in other parts of the world. Whereas a large group came as immigrants, other groups entered European countries as migrant workers of whom many later decided to stay and thereby became immigrants. Immigrants of diverse ethnic backgrounds living in Europe are reported to be at high risk for mental health problems, such as depression, anxiety disorders, and schizophrenia (Carta et al.
2005). The risk is seen among immigrants originating from non-Western countries, and to a lesser extent in those migrating within Europe. Research on this topic in school-aged children and adolescents, however, provides mixed results. Studies indicate that immigrant children of diverse national backgrounds tend to exhibit more behavioural problems than non-immigrants as measured with behaviour checklists completed by parents (Bengi-Arslan et al.
1997; Gross et al.
2006; Reijneveld et al.
2005; Stevens et al.
2003; Vollebergh et al.
2005). Conversely, other studies in Western countries show similar levels of problem behaviour in immigrant and native children (Alati et al.
2003; Kolaitis et al.
2003), or even point out that immigrants report lower rates of behavioural problems in their offspring than parents of native children (Beiser et al.
2002; Hackett et al.
1991). In general, many of the studies of behavioural problems among immigrant children are hampered by small sample sizes (Gross et al.
2006; Hackett et al.
1991; Kolaitis et al.
2003; Vollebergh et al.
2005). Moreover, the restriction to immigrants originating from one country only and the study of immigrants of different backgrounds as one group limits generalizability (Beiser et al.
2002; Bengi-Arslan et al.
1997; Hackett et al.
1991; Kolaitis et al.
2003; Reijneveld et al.
2005; Vollebergh et al.
2005). Finally, previous studies often controlled marginally for confounders (Beiser et al.
2002; Bengi-Arslan et al.
1997; Gross et al.
2006; Stevens et al.
2003; Vollebergh et al.
2005), while these factors possibly elucidate the association between immigrant status and mental health.
Well known risk factors of child behavioural problems (Campbell
1995; Rutter et al.
1975a,
b), such as low socioeconomic position, single parenthood, and parental psychopathology, possibly explain the elevated levels of behavioural problems among immigrant children. For instance, many immigrants end up in the lower socioeconomic strata of a host country and experience financial problems, largely due to language difficulties or lack of adequate education (Bhugra
2004). Generally, studies on parent reported behavioural problems among immigrant children control for socioeconomic status, but other family risk factors are rarely taken into account. Hence, their role in the association between national origin and behavioural problems remains unknown. Alternatively, the increased risk of mental health problems among first-generation adult and adolescent immigrants has been ascribed to characteristics of the immigration process. Immigration causes stress due to loss of the familiar environment and adaptation to a new situation (Bhugra
2004; Lerner et al.
2005). Moreover, immigrants may find it hard to identify with the host culture and may experience rejection by the mainstream society. For instance, a study among Moroccan adolescents in the Netherlands indicates that perceived discrimination predicted externalizing behavioural problems (Stevens et al.
2005). However, it is largely unknown how characteristics of the immigration process as experienced by immigrant parents affect behaviour in the offspring. Intergenerational effects of parental immigration characteristics may be involved; a study among Asian immigrants, for instance, indicates that the refugee process of parents was strongly related to violent behaviour in their children (Spencer and Le
2006). So, both immigration characteristics and family risk factors should be taken into account to disentangle the underlying mechanisms in the association between national origin and behavioural problems in children. Furthermore, it is important to study immigrants originating from different countries. Finally, the association between national origin and behavioural problems has, to our knowledge, not been examined in preschool children, while growing evidence suggests that behavioural problems early in life tend to persist into later ages and predict adverse outcomes during childhood (Carter et al.
2004).
We examined the association between maternal national origin and behavioural problems in toddlers aged 1½ years in a large, multi-ethnic cohort study. While the importance of ethnic minority as a risk factor for problem behaviour in children is well-recognized, research that may elucidate the mechanisms underlying the poor mental health among immigrant children is needed. Without insight into these mechanisms prevention is hardly possible and treatment may be less effective. Therefore, we also investigated whether family risk factors can explain the relation between national origin and behavioural problems. Moreover, we explored the association of maternal immigration characteristics, e.g. generational status, Dutch language skills, and feelings of acceptance by Dutch natives, with child behaviour. We hypothesized (a) that toddlers of non-Western origin would have higher behaviour problem scores than Dutch children and children of non-Dutch European descent, and that the latter two groups would not differ in problem scores; (b) that family risk factors would partly explain the higher levels of behavioural problems among non-Western toddlers; and (c) that immigration risk factors would also explain part of the tendency of non-Western immigrants to report high level of child behavioural problems.
Results
Characteristics of the mother-child dyads are presented in Table
2. Both children of European, χ
2(1, 3596) = 39,
p < 0.001, and of non-Western descent, χ
2(1, 4537) = 249,
p < 0.001 were more likely to have a borderline/clinical Total Problems score than children with a Dutch background. Non-Western toddlers were also more likely to have a borderline/clinical Total Problems score than non-Dutch European toddlers, χ
2(1, 1753) = 11,
p = 0.001. Non-Western mothers were more often low educated than their Dutch, χ
2(1, 3287) = 448,
p < 0.001, and European counterparts, χ
2(1, 1177) = 130,
p < 0.001. In contrast, Dutch and European mothers did not differ in distribution of educational level, χ
2(2, 3596) = 0.99,
p = 0.607. European and non-Western mothers did not differ with regard to generational status, χ
2(1, 1750) = 0.30,
p = 0.592, or Dutch language skills, χ
2(2, 1601) = 0.36,
p = 0.834. Mothers with a European background felt more often accepted by native Dutch people than the non-Western mothers, χ
2(1, 1254) = 38,
p < 0.001.
The mean scores on the CBCL scales per national origin are presented in Table
3. Compared to children of Dutch mothers, children of mothers from various non-Dutch backgrounds all had higher mean scores on Total Problems, indicating more behavioural problems. Particularly high behavioural problem scores were found in children of Cape Verdian and Turkish background (mean = 35.4, 95
% CI: 31.8, 38.9; mean = 34.2, 95
% CI: 31.9, 36.4, respectively). The effect sizes for the association between national origin (including only Dutch, European and non-Western) and behavioural problems were moderate for Total Problems (η
2=0.067) and Internalizing Problems (η
2=0.072), and small for Externalizing Problems (η
2=0.017).
Table
4 shows that positive correlations of confounders, family risk factors and maternal immigration characteristics with Total Problems scores ranged from 0.06 (smoking during pregnancy) to 0.30 (maternal psychopathology), whereas negative correlations ranged from −0.04 (gestational age) to −0.17 (maternal age). All correlation coefficients represented small effect sizes except for maternal psychopathology, which was moderate in size. Given the significant correlations with behavioural problems, all a priori confounders and family risk factors were included in the multivariate analyses.
Table
5 shows the series of hierarchical multiple regression analyses indicating the association between maternal national origin and CBCL scores adjusted for confounders and family risk factors. In model 1, the unadjusted differences between the Dutch reference group and the other national origins are shown. These differences correspond to the differences in mean Total Problems score, which are presented in Table
3 (e.g. mean behavioural score Dutch=20.7, Antillian=31.8, difference=11.1). National origin explained 8.5% of the variance in Total Problems score (Model 1). When the confounders (child characteristics) were entered in the model (model 2), there was a 0.7% increase in explained variance, resulting in an overall R
2 of 9.2%. As can be seen in the second column of Table
5, the effect estimates in Model 2 were similar to those in Model 1. Entering the sociodemographic family risk factors resulted in a further 2.4% increase in explained variance of the Total Problems score (overall R
2=11.5%). The attenuation of differences in CBCL score between Dutch and non-Dutch toddlers (model 2 to model 3) was especially evident in Antillean, Cape Verdian, Moroccan, Surinamese, Turkish, and Other Non-Western toddlers. Finally, when maternal psychopathology was entered in the model (model 4), there was a 2.8% increase in explained variance, resulting in an overall R
2 of 14.3%. As can be seen by comparing models 3 and 4, adjustment for maternal psychopathology resulted in substantial attenuation of the differences in mean behavioural problems scores between Dutch and non-Dutch toddlers. However, the confounders and family risk factors did not explain all differences in behavioural problems scores between Dutch and non-Dutch toddlers. For instance, the difference in mean CBCL Total problem score between Dutch and Cape Verdian origin decreased from a mean score of 14.7 to 8.7. This difference was still highly significant,
p < 0.001.
Table
6 shows the association between immigration characteristics of non-Dutch mothers and mean Total Problems score in the offspring. First generation mothers had children with higher behavioural problem scores than mothers who were born in the Netherlands. This difference was only significant in mothers of non-Western descent (difference in European: 2.2,
p = 0.180; in non-Western: 3.6,
p = 0.001). Poor Dutch language skills of non-Western mothers were also associated with higher behavioural problem scores in toddlers, as was lack of feelings of acceptance by Dutch natives (see Table
5). Among children of European origin we observed the same tendencies as in the non-Western group, although these associations did not reach statistical significance due to a small sample size.
The correlations between immigration characteristics ranged from 0.19 (feelings of acceptance and age at immigration,
p < 0.001) to 0.91 (generational status and age at immigration,
p < 0.001). To summarize the effect of correlated maternal immigration characteristics, a risk index (range 0–5) was calculated based on the maternal immigration characteristics that were associated with child behavioural problems. Figures
1 and
2 present the association between an accumulation of adverse immigration characteristics and child behavioural problems. European toddlers with 3–5 five immigration risks have significantly higher Total Problems scores than Dutch toddlers (Fig.
1a); after adjustment for family risk factors, these differences between European and Dutch toddlers attenuate, but remain statistically significant (Fig.
1b). European children with a few immigration risks (0–2) do not have higher Total Problems scores than toddlers of Dutch origin, this is especially apparent after adjustment for the family risk factors (Fig.
1b). Figure
2a points out that, independently of the amount of immigration risks, toddlers of non-Western origin have a higher mean Total Problems score than Dutch toddlers. The higher problem score among non-Western toddlers without any maternal immigration risk is explained by the family risk factors (adjusted difference=1.53, 95
% CI: −0.28, 3.35) (Fig.
2b). The difference in Total Problems scores between Dutch children and non-Western children with 1 or more immigration risks becomes smaller after adjustment, but remains statistically significant (Fig.
2b). Visual inspection of Figs.
1 and
2 suggests non-linear associations between the risk index and Total Problems scores in both the European and non-Western groups, the statistical analyses demonstrated significant linear associations only.
Acknowledgements
The Generation R Study is conducted by the Erasmus MC—University Medical Centre Rotterdam in close collaboration with the Erasmus University Rotterdam, School of Law and Faculty of Social Sciences; the Municipal Health Service Rotterdam area, Rotterdam; the Rotterdam Homecare Foundation, Rotterdam; and the Stichting Trombosedienst & Artsenlaboratorium Rijnmond (STAR), Rotterdam. We gratefully acknowledge the contribution of the participating pregnant women and their partners, general practitioners, hospitals, midwives and pharmacies in Rotterdam. The first phase of the Generation R Study is made possible by financial support from: Erasmus MC—University Medical Centre Rotterdam; Erasmus University Rotterdam; and the Netherlands Organization for Health Research and Development (ZonMW). The present study was supported by an additional grant from the Netherlands Organization for Health Research and Development (ZonMW “Geestkracht” program 10.000.1003).