Intergenerational transmission of the healthy immigrant effect (HIE) through birth weight: A systematic review and meta-analysis

Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience

Anisman, H., Doubad, D., Asokumar, A. & Matheson, K. Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience. NEUROSCI BIOBEHAV REV, XXXX. Immigration occurs between countries either to obtain employment, for family reunification or to escape violence and other life-threatening conditions. Refugees and asylum seekers are often obligated to overcome a uniquely challenging set of circumstances prior to and during migration. Settlement following immigration may pose yet another set of stressors related to acculturation to the host country, as well as financial insecurity, discrimination, language barriers, and social isolation. Here we discuss the multiple consequences of immigration experiences, focusing on the health disturbances that frequently develop in adults and children. Aside from the psychosocial influences, immigration-related challenges may cause hormonal, inflammatory immune, and microbiota changes that favor psychological and physical illnesses. Some biological alterations are subject to modification by epigenetic changes, which have implications for intergenerational trauma transmission, as might disruptions in parenting behaviors and family dysfunction. Despite the hardships experienced, many immigrants and their families exhibit positive psychological adjustment after resettlement. We provide information to diminish the impacts associated with immigration and offer strength-based approaches that may foster resilience.

Increasing U.S. Maternal Health Equity Among Immigrant Populations Through Community Engagement

Immigrant women in the United States are at an elevated risk of poor maternal health outcomes due to cultural, linguistic, or socioeconomic barriers that may lead to critical delays in obtaining adequate health care. Ensuring access to high-quality, culturally appropriate perinatal health care is crucial to improve the health and well-being of immigrant mothers and their children. Various aspects of perinatal health care for immigrant women can be improved through community engagement strategies. Barriers can be addressed by involving community members in designing and delivering culturally appropriate maternal health services. Some strategies discussed in this commentary include working with community health workers, encouraging telehealth through community health workers, providing breastfeeding and mental health support within cultural norms, and involving community-based doulas and midwives.

Intergenerational transmission of birth weight: a systematic review and meta-analysis

The objectives of this study were (1) to systematically review the literature on the association between birth weight in children born in the first and second generation and (2) to quantify this association by performing a meta-analysis. A systematic review was carried out in six databases (PubMed, Science Direct, Web of Science, Embase, Scopus, CINAHL and LILACS), in January 2021, for studies that recorded the birth weight of parents and children. A meta-analysis using random effects to obtain a pooled effect of the difference in birth weight and the association of low birth weight (LBW) between generations was performed. Furthermore, univariable meta-regression was conducted to assess heterogeneity. Egger's tests were used to possible publication biases. Of the 9878 identified studies, seventy were read in full and twenty were included in the meta-analysis (ten prospective cohorts and ten retrospective cohorts), fourteen studies for difference in means and eleven studies for the association of LBW between generations (twenty-three estimates). Across all studies, there was no statistically significant mean difference (MD) birth weight between first and second generation (MD 19·26, 95 % CI 28·85, 67·36; P = 0·43). Overall, children of LBW parents were 69 % more likely to have LBW (pooled effect size 1·69, 95 % CI (1·46, 1·95); I2:85·8 %). No source of heterogeneity was identified among the studies and no publication bias. The average birth weight of parents does not influence the average birth weight of children; however, the proportion of LBW among the parents seems to affect the offspring's birth weight.

Mortality among over 6 million internal and international migrants in Brazil: a study using the 100 Million Brazilian Cohort

Background

To understand if migrants living in poverty in low and middle-income countries (LMICs) have mortality advantages over the non-migrant population, we investigated mortality risk patterns among internal and international migrants in Brazil over their life course.

Methods

We linked socio-economic and mortality data from 1st January 2011 to 31st December 2018 in the 100 Million Brazilian Cohort and calculated all-cause and cause-specific age-standardised mortality rates according to individuals' migration status for men and women. Using Cox regression models, we estimated the age- and sex-adjusted mortality hazard ratios (HR) for internal migrants (i.e., Brazilian-born individuals living in a different Brazilian state than their birth) compared to Brazilian-born non-migrants; and for international migrants (i.e., people born in another country) compared to Brazilian-born individuals.

Findings

The study followed up 45,051,476 individuals, of whom 6,057,814 were internal migrants, and 277,230 were international migrants. Internal migrants had similar all-cause mortality compared to Brazilian non-migrants (aHR = 0.99, 95% CI = 0.98-0.99), marginally higher mortality for ischaemic heart diseases (aHR = 1.04, 95% CI = 1.03-1.05) and higher for stroke (aHR = 1.11, 95% CI = 1.09-1.13). Compared to Brazilian-born individuals, international migrants had 18% lower all-cause mortality (aHR = 0.82, 95% CI = 0.80-0.84), with up to 50% lower mortality from interpersonal violence among men (aHR = 0.50, 95% CI = 0.40-0.64), but higher mortality from avoidable causes related to maternal health (aHR = 2.17, 95% CI = 1.17-4.05).

Interpretation

Although internal migrants had similar all-cause mortality, international migrants had lower all-cause mortality compared to non-migrants. Further investigations using intersectional approaches are warranted to understand the marked variations by migration status, age, and sex for specific causes of death, such as elevated maternal mortality and male lower interpersonal violence-related mortality among international migrants.

Funding

The Wellcome Trust.

Differences in birth weight between immigrants' and natives' children in Europe and Australia: a LifeCycle comparative observational cohort study

OBJECTIVE

Research on adults has identified an immigrant health advantage, known as the 'immigrant health paradox', by which migrants exhibit better health outcomes than natives. Is this health advantage transferred from parents to children in the form of higher birth weight relative to children of natives?

SETTING

Western Europe and Australia.

PARTICIPANTS

We use data from nine birth cohorts participating in the LifeCycle Project, including five studies with large samples of immigrants' children: Etude Longitudinale Française depuis l'Enfance-France (N=12 494), the Raine Study-Australia (N=2283), Born in Bradford-UK (N=4132), Amsterdam Born Children and their Development study-Netherlands (N=4030) and the Generation R study-Netherlands (N=4877). We include male and female babies born to immigrant and native parents.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is birth weight measured in grams. Different specifications were tested: birth weight as a continuous variable including all births (DV1), the same variable but excluding babies born with over 4500 g (DV2), low birth weight as a 0-1 binary variable (1=birth weight below 2500 g) (DV3). Results using these three measures were similar, only results using DV1 are presented. Parental migration status is measured in four categories: both parents natives, both born abroad, only mother born abroad and only father born abroad.

RESULTS

Two patterns in children's birth weight by parental migration status emerged: higher birth weight among children of immigrants in France (+12 g, p<0.10) and Australia (+40 g, p<0.10) and lower birth weight among children of immigrants in the UK (-82 g, p<0.05) and the Netherlands (-80 g and -73 g, p<0.001) compared with natives' children. Smoking during pregnancy emerged as a mechanism explaining some of the birth weight gaps between children of immigrants and natives.

CONCLUSION

The immigrant health advantage is not universally transferred to children in the form of higher birth weight in all host countries. Further research should investigate whether this cross-national variation is due to differences in immigrant communities, social and healthcare contexts across host countries.

Severe Maternal Morbidity and Mortality Among Immigrant and Canadian-Born Women Residing Within Low-Income Neighborhoods in Ontario, Canada

IMPORTANCE

Evidence indicates that immigrant women and women residing within low-income neighborhoods experience higher adversity during pregnancy. Little is known about the comparative risk of severe maternal morbidity or mortality (SMM-M) among immigrant vs nonimmigrant women living in low-income areas.

OBJECTIVE

To compare the risk of SMM-M between immigrant and nonimmigrant women residing exclusively within low-income neighborhoods in Ontario, Canada.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used administrative data for Ontario, Canada, from April 1, 2002, to December 31, 2019. Included were all 414 337 hospital-based singleton live births and stillbirths occurring between 20 and 42 weeks' gestation, solely among women residing in an urban neighborhood of the lowest income quintile; all women were receiving universal health care insurance. Statistical analysis was performed from December 2021 to March 2022.

EXPOSURES

Nonrefugee immigrant status vs nonimmigrant status.

MAIN OUTCOMES AND MEASURES

The primary outcome, SMM-M, was a composite outcome of potentially life-threatening complications or mortality occurring within 42 days of the index birth hospitalization. A secondary outcome was SMM severity, approximated by the number of SMM indicators (0, 1, 2 or ≥3 indicators). Relative risks (RRs), absolute risk differences (ARDs), and odds ratios (ORs) were adjusted for maternal age and parity.

RESULTS

The cohort included 148 085 births to immigrant women (mean [SD] age at index birth, 30.6 [5.2] years) and 266 252 births to nonimmigrant women (mean [SD] age at index birth, 27.9 [5.9] years). Most immigrant women originated from South Asia (52 447 [35.4%]) and the East Asia and Pacific (35 280 [23.8%]) regions. The most frequent SMM indicators were postpartum hemorrhage with red blood cell transfusion, intensive care unit admission, and puerperal sepsis. The rate of SMM-M was lower among immigrant women (2459 of 148 085 [16.6 per 1000 births]) than nonimmigrant women (4563 of 266 252 [17.1 per 1000 births]), equivalent to an adjusted RR of 0.92 (95% CI, 0.88-0.97) and an adjusted ARD of -1.5 per 1000 births (95% CI, -2.3 to -0.7). Comparing immigrant vs nonimmigrant women, the adjusted OR of having 1 SMM indicator was 0.92 (95% CI, 0.87-0.98), the adjusted OR of having 2 indicators was 0.86 (95% CI, 0.76-0.98), and the adjusted OR of having 3 or more indicators was 1.02 (95% CI, 0.87-1.19).

CONCLUSIONS AND RELEVANCE

This study suggests that, among universally insured women residing in low-income urban areas, immigrant women have a slightly lower associated risk of SMM-M than their nonimmigrant counterparts. Efforts aimed at improving pregnancy care should focus on all women residing in low-income neighborhoods.

The Health of Immigrant Youth in Denmark: Examining Immigrant Generations and Origin

First-generation migrants tend to have better health than those of native ancestry, while second-generation migrants often are affected by negative health assimilation. Less is known about immigrants arriving before their teens, the 1.5 generation, or those with one native and one immigrant parent, the 2.5 generation. We apply logistic regression models to study physical and mental health outcomes for immigrant youth across generations using Danish register data. We take heterogeneities into account studying gender and origin differences. Our analysis shows that first- and 1.5-generation immigrants have better physical health than natives, while the physical health of the second and 2.5 generations is the same or worse than natives. For mental health, the 2.5 generation is the only group with worse outcomes than natives, which we relate to identification struggles translating into poorer mental health. When studying potential heterogeneities, we find that males belonging to the second generation with an African background have a higher likelihood of hospitalization for a mental health issue.

Birth Outcomes among Descendants of Foreign-Born and US-Born Women in California: Variation by Race and Ethnicity

This study quantifies the magnitude and persistence of differences in adverse birth outcomes between descendants of foreign-born and US-born women by race/ethnicity. Using 1978-2015 California birth records, I linked records of infants to those of their mothers to create an intergenerational sample (N = 501,323 second generation mothers and 633,102 third generation daughters). Prevalence of low birthweight and preterm birth were calculated in both generations by race/ethnicity, and foreign-born status. An initial foreign-born advantage in birth outcomes is present among most racial/ethnic groups with the exception of foreign-born Asian women. In the subsequent generation, the foreign-origin advantage diminishes for most groups and a foreign-origin disadvantage in low birthweight emerges for descendants of Asian women. Findings largely persist after adjustment for sociodemographic and healthcare-related characteristics. These results underscore the importance of disaggregating by race, ethnicity, and foreign origin when possible to better understand perinatal health disparities in the population.

Immigrant ancestry and birthweight across two generations born in Sweden: an intergenerational cohort study

INTRODUCTION

Differences in birthweight are often seen between migrants and natives. However, whether migrant-native birthweight inequalities widen, narrow or remain persistent across generations when comparing the descendants of immigrants and natives remains understudied. We examined inequalities in birthweight of mothers (G2) and daughters (G3) of foreign-born grandmothers (G1) compared with those of Swedish-born grandmothers.

METHODS

We used population registers with multigenerational linkages to identify 314 415 daughters born in Sweden during the period 1989-2012 (G3), linked to 246 642 mothers (G2) born in Sweden during 1973-1996, and to their grandmothers (G1) who were Swedish or foreign-born. We classified migrants into non-western, Eastern European, the rest of Nordic and Western. We used multivariable methods to examine mean birthweight and low birthweight (<2500 g; LBW).

RESULTS

Birthweight between individuals with Swedish background (G1) and non-western groups increased from -80 g to -147 g between G2 (mothers) and G3 (daughters), respectively. Furthermore, the odds of LBW increased among the G3 non-western immigrants compared with those with Swedish grandmothers (OR: 1.38, 95% CI 1.12 to 1.69). Birthweight increased in both descendants of Swedes and non-western immigrants, but less so in the latter (83 g vs 16 g).

CONCLUSION

We observed an increase in birthweight inequalities across generations between descendants of non-western immigrants and descendants of Swedes. This finding is puzzling considering Sweden has been lauded for its humanitarian approach to migration, for being one of the most egalitarian countries in the world and providing universal access to healthcare and education.

Understanding the Healthy Immigrant Effect in the Context of Mental Health Challenges: A Systematic Critical Review

The "Healthy Immigrant Effect" (HIE) suggests that immigrants have a health advantage over the domestic-born which vanishes with increased length of residency. Most HIE research focuses on physical health, with less attention given to mental health (MH). This systematic review of 58 MH studies examines whether there is a MH advantage among immigrants and explores changes in immigrants' MH, besides critically assessing the use of HIE theory. Inconsistent evidence was detected regarding the presence of MH advantage, whereas consistent, convincing evidence was revealed for a decline in immigrants' MH over years. Although the HIE theory can help reveal MH disparities, this theory alone does not explain the reasons for these disparities nor inform about potential avenues to improve immigrants' MH. A paradigm shift is needed to incorporate other potential theoretical concepts/frameworks, including the "Health Inequalities Action" framework, for a broader understanding of MH issues and to inform effective, culturally-sensitive interventions.

Quality of Care in US NICUs by Race and Ethnicity

BACKGROUND

Summary measures are used to quantify a hospital's quality of care by combining multiple metrics into a single score. We used Baby-MONITOR, a summary quality measure for NICUs, to evaluate quality by race and ethnicity across and within NICUs in the United States.

METHODS

Vermont Oxford Network members contributed data from 2015 to 2019 on infants from 25 to 29 weeks' gestation or of 401 to 1500 g birth weight who were inborn or transferred to the reporting hospital within 28 days of birth. Nine Baby-MONITOR measures were individually risk adjusted, standardized, equally weighted, and averaged to derive scores for African American, Hispanic, Asian American, and American Indian infants, compared with white infants.

RESULTS

This prospective cohort included 169 400 infants at 737 hospitals. Across NICUs, Hispanic and Asian American infants had higher Baby-MONITOR summary scores, compared with those of white infants. African American and American Indian infants scored lower on process measures, and all 4 minority groups scored higher on outcome measures. Within NICUs, the mean summary scores for African American, Hispanic, and Asian American NICU subsets were higher, compared with those of white infants in the same NICU. American Indian summary NICU scores were not different, on average.

CONCLUSIONS

With Baby-MONITOR, we identified differences in NICU quality by race and ethnicity. However, the summary score masked within-measure quality gaps that raise unanswered questions about the relationships between race and ethnicity and processes and outcomes of care.

Birth-weight differences at term are explained by placental dysfunction and not by maternal ethnicity. Study in newborns of first generation immigrants

Objective: The aim of the study was to investigate the influence of ethnicity and cerebroplacental ratio (CPR) on the birth weight (BW) of first generation Indo-Pakistan immigrants' newborns.Methods: This was a retrospective study in a mixed population of 620 term Caucasian and Indo-Pakistan pregnancies, evaluated in two reference hospitals of Spain and Italy. All fetuses underwent a scan and Doppler examination within two weeks of delivery. The influence of fetal gender, ethnicity, GA at delivery, CPR, maternal age, height, weight and parity on BW was evaluated by multivariable regression analysis.Results: Newborns of first generation Indo-Pakistan immigrants were smaller than local Caucasian newborns (mean BW mean= 3048 ± 435 g versus 3269 ± 437 g, p < .001). Multivariable regression analysis demonstrated that all studied parameters, but maternal age and ethnicity, were significantly associated with BW. The most important were GA at delivery (partial R² = 0.175, p < .001), CPR (partial R² = 0.032, p < .001), and fetal gender (partial R² = 0,029, p < .001).Conclusions: The propensity to a lower BW, explained by placental dysfunction but not by maternal ethnicity is transmitted to newborns of first generation immigrants. Whatever are the factors implied they persist in the new residential setting.

Influence of time since naturalisation on socioeconomic status and low birth weight among immigrants in Belgium. A population-based study

Background

Increasingly studies show that immigrants have different perinatal health outcomes compared to native-born women. Nevertheless, we lack a detailed examination of the combined effects of maternal immigrant trajectory and socioeconomic status on perinatal outcomes. Our objective was to analyze the influence of time since naturalization on low birth weight and maternal socioeconomic status in Belgium.

Methods

The data came from the linkage between the Brussels birth and death registers, the national register of migrant trajectories and the social security register for the years 2004–2010. We used logistic regression to estimate the odds ratios of the associations between low birth weight (LBW) and time since naturalization, by nationality groups, taking into account socioeconomic status (SES), parity and maternal age.

Results

Data relate to all singleton births to Belgian, Maghrebi, Sub-Saharan African and Turkish women (n = 76 312). The results show an U-shaped of LBW according to time since naturalization for all migrant groups. LBW declines for women naturalized since less than one year and increases significantly thereafter (p<0.0001). In parallel, we observe an increase of SES among all migrant groups. Compared to Belgians, we found a lower risk of LBW among women from Maghreb (p<0.0001) and this protection is maintained even after 10 years since naturalization. In contrast, the risk of LBW for Sub-Saharan African and Turkish mothers is lower than for Belgians after one year of naturalization but similar to that of Belgians after 10 years of naturalization.

Conclusion

Our results show that, despite an improvement of their SES, LBW increases among Maghrebi, Sub-Saharan African and Turkish women with time since naturalization. Mothers from Maghreb have lower rates of LBW compared to Belgians and maintain their protection even after more than 10 years of having acquired the Belgian nationality. Additional studies need to be carried out in order to gain a better understanding of the association between migration trajectories, SES and perinatal health of immigrants.

Stress across generations: A qualitative study of stress, coping, and caregiving among Mexican immigrant mothers

OBJECTIVE

Hispanic immigrants represent the largest and fastest growing ethnic minority within the US, justifying increased attention to identify factors that influence declining immigrant health across generations. This study investigates the range of psychosocial stress exposures and coping mechanisms of Mexican immigrant mothers, and implications for the health of their US-born children.

DESIGN

We conducted 10 focus groups with 1st generation Mexican-born immigrant mothers (n = 32 women) in Nashville, TN, in the summer of 2014. Focus groups elicited challenges and benefits of life as an immigrant mother. Data were analyzed using a modified grounded theory approach.

RESULTS

We identified four themes that indicate how maternal stressors could impact children's health: (1) work-family tradeoff, (2) limited freedom/mobility, (3) reduction of social networks, and (4) transmission of anxiety and fears to children. Women in our study also engage in a range of coping mechanisms, including the creation of new social networks, seeking support in religion, and seeking help from community resources.

CONCLUSION

These results highlight the importance of developing new questionnaires to elicit stress exposures for Mexican immigrant mothers. Findings also suggest the value of intervention strategies and social policies that would ultimately improve maternal and child health in this marginalized population.

Does acculturation affect the dietary intakes and body weight status of children of immigrants in the U.S. and other developed countries? A systematic review

OBJECTIVE

This paper reviews available studies on the relationship between acculturation and obesity among children of immigrants who have at least one foreign-born parent.

METHODS

A systematic review of relevant studies was undertaken using PubMed, Web of Science, and PsychInfo.

RESULTS

The initial search identified 1317 potentially relevant publications, of which 21 were retained after three rounds of screening. Most studies were conducted in the U.S. The majority of studies used BMI or overweight/obesity prevalence as the outcome variable, while two studies used dietary intake. Three studies used standardized acculturation scales, while most of the studies used generation, duration of residency in host country, and language as proxy measures of acculturation. The relationship between acculturation and outcomes varied between the host countries and origin countries for children of immigrants.

CONCLUSION

This study suggests children of immigrants with different cultural backgrounds may interact with host countries to varying degrees, ultimately influencing their diet behaviours and body weight status. Researchers are encouraged to adopt standardized acculturation scales to compare the results across countries and populations.

Disparities in access to care in marginalized populations

PURPOSE OF REVIEW

The current article reviews recent literature related to three groups whose health is affected by barriers to the healthcare system: refugee and immigrant populations; youth who are lesbian, gay, bisexual, transgender, queer, or questioning; and those with mental health problems.

RECENT FINDINGS

Refugee and immigrant populations are increasing worldwide, and recent work has focused on improving their access to mental, dental, and preventive care. Lesbian, gay, bisexual, transgender, queer, or questioning youth have unique healthcare needs but frequently lack a support system and may not be forthcoming about their sexuality or sex identity. A rising number of children are being diagnosed with mental health disorders, but due to multiple factors, youth are not receiving the care they need.

SUMMARY

Pediatric healthcare providers should be aware of the unique challenges faced by youth displaced from their country of origin, who are lesbian, gay, bisexual, or transgender or are questioning their sexuality or sex identity, and who struggle with mental health disorders. Toolkits, other educational resources, and novel technological advances can assist pediatricians in ensuring optimal health care of these at-risk groups.