Dataset Information

Bias in cohort-based comparisons of immigrants' health outcomes between countries: a simulation study.

ABSTRACT:

Background

Cohort-type data are increasingly used to compare health outcomes of immigrants between countries, e.g. to assess the effects of different national integration policies. In such international comparisons, small differences in cardiovascular diseases risk or mortality rates have been interpreted as showing effects of different policies. We conjecture that cohort-type data sets available for such comparisons might not provide unbiased relative risk estimates between countries because of differentials in migration patterns occurring before the cohorts are being observed.

Method

Two simulation studies were performed to assess whether comparisons are biased if there are differences in 1. the way migrants arrived in the host countries, i.e. in a wave or continuously; 2. the effects on health of exposure to the host country; or 3., patterns of return-migration before a cohort is recruited. In the first simulation cardiovascular disease was the outcome and immortality in the second. Bias was evaluated using a Cox regression model adjusted for age and other dependant variables.

Results

Comparing populations from wave vs. continuous migration may lead to bias only if the duration of stay has a dose-response effect (increase in simulated cardiovascular disease risk by 5% every 5 years vs. no risk: hazard-ratio 1.20(0.15); by 10% every 5 years: 1.47(0.14)). Differentials in return-migration patterns lead to bias in mortality rate ratios (MRR). The direction (under- or overestimation) and size of the bias depends on the model (MRR from 0.92(0.01) to 1.09(0.01)).

Conclusion

The order of magnitude of the effects interpreted as due to integration policies in the literature is the same as the bias in our simulations. Future studies need to take into account duration and relevance of exposure and return-migration to make valid inferences about the effects of integration policies on the health of immigrants.

SUBMITTER: Sauzet O

PROVIDER: S-EPMC6617948 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundStudies in immigrant youth have suggested differences in parenting patterns by immigration status. Knowledge of variation in recalled parenting pattern and its distinctive impact on mental health in adult immigrants, however, is limited. Therefore, the purpose of the current study was to investigate similarities and differences in recalled maternal and paternal rearing behavior and its association with depressiveness in adult 1st generation immigrants compared to non-immigrants.MethodsSeven hundred and forty-three 1st generation immigrants (M = 57.4, SD = 10.1 years) and 6518 non-immigrants (M = 60.3, SD = 10.7 years) participated in a population-based study. Regarding countries of origin, the largest subgroups were immigrants from Eastern-Europe, Former-SU, and Arabic-Islamic countries. All participants completed the ultra-short version of The Recalled Parental Rearing Behavior-questionnaire and the PHQ-9 assessing depressiveness. Multiple linear regressions with depressiveness as outcome variable were analyzed separately for each facet of parental rearing behavior adjusting for socio-demographic and migration-related variables.ResultsIn addition to differences in depressiveness and socioeconomic status, 1st generation immigrants recalled both their mothers and fathers as more controlling and overprotecting than non-immigrants. Parental emotional warmth was negatively associated with depressiveness across all groups. The relationship between parental control, respectively parental rejection and depressiveness, however, varied in direction and severity between the groups.ConclusionThe results support the notion that parental warmth is a universal protective factor against depressiveness, whereas the impact of parental control on mental health might be more culturally influenced. Analyses point to the importance of considering the unique contribution of fathers' rearing behavior on mental health, particularly in immigrant samples.

Project description:BackgroundMothers and children in families with one immigrant parent have been reported to be healthier than those in native families; however, the health of the fathers in these families has rarely been discussed in literature.ObjectiveWe aimed to comprehensively compare the health of all the family members between families with one immigrant parent (native fathers, immigrant mothers, and their children) and native families (native fathers, native mothers, and their children).MethodsWe conducted a cohort study by using the Taiwan Maternal and Child Health Database to recruit live-born children and their parents from 2004 to 2016. Overall, we identified 90,670 fathers, 91,270 mothers, and 132,457 children in families with one immigrant parent and 1,666,775 fathers, 1,734,104 mothers, and 2,637,191 children in native families and followed up with them from 2004 to 2017. The outcomes comprised common physical and mental disorders, catastrophic illnesses, mortality, and child adversities and accidents. The covariates comprised the child's year of birth, parental age, low-income status, and physical or mental disorder status. Logistic regression was performed to compare the risks of the outcomes between families with one immigrant parent and native families.ResultsThe parents in families with one immigrant parent were more likely to be of low-income status and were older than the parents in native families. After adjusting for the covariates, fathers in families with one immigrant parent were found to have higher risks of physical and mental disorders, catastrophic illness, and mortality than fathers in native families. Conversely, mothers in families with one immigrant parent had lower risks of physical and mental disorders, catastrophic illness, and mortality than mothers in native families. Finally, the children in families with one immigrant parent generally had better physical and mental health but higher risks for leukemia, liver diseases, autism spectrum disorder, and road traffic accidents than children in native families.ConclusionsThe health status of the members of families with one immigrant parent was nonhomogeneous, and the poorer general health of fathers in such families suggests health inequalities in families with one immigrant parent.

Project description:Background:Publication bias is a form of scientific misconduct. It threatens the validity of research results and the credibility of science. Although several tests on publication bias exist, no in-depth evaluations are available that examine which test performs best for different research settings. Methods:Four tests on publication bias, Egger's test (FAT), p-uniform, the test of excess significance (TES), as well as the caliper test, were evaluated in a Monte Carlo simulation. Two different types of publication bias and its degree (0%, 50%, 100%) were simulated. The type of publication bias was defined either as file-drawer, meaning the repeated analysis of new datasets, or p-hacking, meaning the inclusion of covariates in order to obtain a significant result. In addition, the underlying effect (β = 0, 0.5, 1, 1.5), effect heterogeneity, the number of observations in the simulated primary studies (N = 100, 500), and the number of observations for the publication bias tests (K = 100, 1,000) were varied. Results:All tests evaluated were able to identify publication bias both in the file-drawer and p-hacking condition. The false positive rates were, with the exception of the 15%- and 20%-caliper test, unbiased. The FAT had the largest statistical power in the file-drawer conditions, whereas under p-hacking the TES was, except under effect heterogeneity, slightly better. The CTs were, however, inferior to the other tests under effect homogeneity and had a decent statistical power only in conditions with 1,000 primary studies. Discussion:The FAT is recommended as a test for publication bias in standard meta-analyses with no or only small effect heterogeneity. If two-sided publication bias is suspected as well as under p-hacking the TES is the first alternative to the FAT. The 5%-caliper test is recommended under conditions of effect heterogeneity and a large number of primary studies, which may be found if publication bias is examined in a discipline-wide setting when primary studies cover different research problems.

Project description:BackgroundTo integrate immigrants into their societies, European countries have adopted different types of policies, which may influence health through both material and psychosocial determinants. Recent studies have suggested poorer health outcomes for immigrants living in countries with poorly rated integration policies.ObjectiveTo analyse mortality differences of immigrants from the same country of origin living in countries with distinct integration policy contexts.MethodsFrom the mortality dataset collected in the Migrant Ethnic Health Observatory (MEHO) project, we chose the Netherlands (linked data from 1996-2006), France (unlinked; 2005-2007) and Denmark (linked; 1992-2001) as representatives of the inclusive, assimilationist and exclusionist policy models, respectively, based on the Migrant Integration Policy Index. We calculated for each country sex- and age-standardized mortality rates for Turkish-, Moroccan- and local-born populations aged 20-69 years. Poisson regression was used to estimate the mortality rate ratios (MRRs) for cross-country and within-country comparisons. The analyses were further stratified by age group and cause of death.ResultsCompared with their peers in the Netherlands, Turkish-born immigrants had higher all-cause mortality in Denmark (MRR men 1.92; 95% CI 1.74-2.13 and women 2.11; 1.80-2.47) but lower in France (men 0.64; 0.59-0.69 and women 0.58; 0.51-0.67). A similar pattern emerged for Moroccan-born immigrants. The relative differences between immigrants and the local-born population were also largest in Denmark and lowest in France (e.g., Turkish-born men MRR 1.52; 95% CI 1.38-1.67 and 0.62; 0.58-0.66, respectively). These patterns were consistent across all age groups, and more marked for cardiovascular diseases.ConclusionsAlthough confounders and data comparability issues (e.g., French cross-sectional data) may affect the findings, this study suggests that different macro-level policy contexts may influence immigrants' mortality. Comparable mortality registration systems across Europe along with detailed socio-demographic information on immigrants may help to better assess this association.