Impact of Socio-economic Status on Low Birthweight: Decomposing the Differences Between Natives and Immigrants in Spain

Explaining immigrant-native differences in health at birth: The role of immigrant selectivity in Spain

Evidence shows that immigrants are often in better health than the native born-the so-called 'immigrant health paradox'-and this advantage may extend to their children's health. A commonly cited but rarely tested explanation is the 'selectivity hypothesis', positing that immigrants are healthier due to selection at origin based on health or socio-economic status (SES). Using 2007-19 Spanish birth registries, we investigate immigrant-native gaps in health at birth and whether they are explained by immigrants' educational selectivity. We find that babies born to immigrants are less likely to be low birthweight (LBW) but are disadvantaged in terms of macrosomia and gestational age. Selectivity is associated with reduced LBW even after accounting for parental SES, explaining the lower risk among children of Northern African and Latin American immigrants but not across other parental country-of-birth groups. Selectivity is not associated with other birth outcomes. We confirm the selectivity hypothesis but question its universality across groups and health outcomes.

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.

Latina paradox in Spain? Arrival-cohort effects on the birthweight of newborns of Latina mothers

This study analyses the arrival-cohort effects on the newborn birthweight of Latina women residing in Spain. First, it has been tested whether women of Latin American origin in Spain have an advantage in terms of birth outcomes, a pattern previously documented in the United States and referred to as the 'Latin American paradox'. Second, it has been examined whether this health advantage of Latina mothers varies by arrival cohort.A novel database provided by the Spanish National Statistics Office that links the 2011 Census with Natural Movement of the Population records from January 2011 to December 2015 has been used. Poisson regression models were applied to test for differences in the incidence rates of low birthweight (LBW) and high birthweight (HBW) among children of Latina and native mothers, controlling for various demographic, socio-economic, and birth characteristics.Two distinct arrival-cohort effects on perinatal health were observed. On one hand, first-generation Latina women were found to be at a lower risk of giving birth to LBW infants; however, they experienced a higher incidence of HBW during the study period. Second, Latina women of 1.5 generation, likely stressed by increased exposure to the receiving country, exhibited adverse birthweight results.

Social inequalities, advanced maternal age, and birth weight. Evidence from a population-based study in Spain

OBJECTIVE

To examine whether advanced maternal age (≥40 years) is linked to an increased likelihood of low or high birth weight among native and foreign-born mothers giving birth in Spain.

METHOD

A cross-sectional study was conducted using a novel database provided by the Spanish National Statistics Office which links the 2011 Census with information on individual births (2011-2015) from the Vital Statistics (Natural Movement of the Population). First, multinomial logistic regression models were used to estimate the potential association between maternal age and the likelihood of having a baby with low or high birth weight. Second, average adjusted predictions of giving birth to children with low, high, and adequate weight for the origin and the maternal age at birth were also calculated.

RESULTS

Findings indicate that women with advanced maternal age showed an increased probability of giving birth to low birth weight infants. Conversely, mothers aged below <30 years had an elevated risk for high birth weight infants. When considering maternal migratory status, the findings were mixed. On one hand, foreign-born mothers showed a higher likelihood of delivering infants with high birth weight; on the other, they displayed a lower risk of low birth weight among newborns in comparison to Spanish natives.

CONCLUSIONS

The study addresses two key aspects. First, it highlights the increased risk of low birth weight in mothers delivering at an advanced age. Second, it emphasizes the importance of accounting for maternal migratory status when investigating the association between age at birth and birth weight outcomes among immigrant mothers.

Relationship between historical developments in the percentages of low birthweight and fetal mortality in Spain

OBJECTIVE

To document the differences in low birthweight in different population subgroups and to analyze its possible relationship with fetal mortality rates in Spain.

METHOD

We used the microdata on live births and stillbirths since 1975 to 2020 from the Spanish National Statistics Institute to examine differentials in delivering a low birthweight controlling for different sociodemographic variables and to determine the relationship between low birthweight and fetal mortality. No statistical analysis was necessary beyond the calculation of percentages and rates.

RESULTS

The data at our disposal for Spain confirm the historical increase in the incidence of low birthweight and allow us to link trends in low birthweight with a decrease in the fetal mortality rate. When fetal mortality is high, the incidence of low birthweight is low, given that a natural selection effect takes place.

CONCLUSIONS

The surprising historical increase in the incidence of low birthweight in Spain can be explained by the improvement in mortality rates. As more fetuses of lower gestational age are born alive, cases of low birthweight also increase.

Partnership, living arrangements, and low birth weight: evidence from a population-based study on Spanish mothers

BACKGROUND

Birth weight is considered a crucial indicator of individual and population health, as it determines a newborn's growth and development. An extensive body of research has explored various determinants of perinatal health, including the impact of living arrangements. This population-based study analyzes the relationship between mothers' partnership status and household structure and children's low birth weights. It addresses two basic research objectives: on one hand, how living/not living in a couple affects birth weight; on the other, how partnership status impact on birthweight when mothers live in extended households with other non-nuclear members.

METHODS

A novel database provided by the Spanish Office for National Statistics (INE), which links the 2011 census with births registered from 2011 to 2015 (sample size 22,433) is used. Llogistic regression models are estimated tto obtain adjusted odds ratios (OR) for the relative effects of living arrangements and other covariates such as characteristics of births and mothers' socioeconomic profiles, on birth weight.

RESULTS

Differences in low-birth-weight rates may be attributed to the dissimilar socio-demographic characteristics of the groups of mothers in the different coresidential situations. Although our models revealed that the impact of the covariates on birth weight was similar to that shown by previous studies, this was not the case for the effect of the main explanatory variable. Contrary to expectations, the presence/absence of a male partner in nuclear or in extended households does not reveal significant protection against low birth weight. Children born in households in which the male partner was absent were not more likely to have a low birth weight. On the other hand, analyzing the possible protective effect of extended households, we did not detect significant differences in the likelihood of low birth weight between single mothers without and with non-nuclear coresidents in their households.

CONCLUSIONS

Our analysis provides novel evidence regarding the effect of partnership status and household type on perinatal health in Spain. First, contrary to what has been observed in previous studies in Spain and elsewhere, our study shows that living without a partner has no effect on low birth weight. Second, we reveal that households including non-nuclear coresidents are associated with low birth weight suggesting that even in a basically familist societal context such as the Spanish one, the extended family does not fully protect against poor perinatal outcomes.

Beyond the healthy immigrant paradox: decomposing differences in birthweight among immigrants in Spain

Background

The healthy immigrant paradox refers to the unexpected health advantages of immigrant groups settled in host countries. In this population-based study we analyze immigrant advantages in birthweight decomposing differences between infants born to immigrant mothers from specific origins.

Method

Using publicly available data from Spanish Vital Statistics for the period 2007–2017, differential birthweights among several groups of immigrants were estimated with an ordinary least squares regression. The Oaxaca–Blinder regression-based decomposition method was then applied to identify the extent to which differences in birthweight between groups corresponded to compositional disparities or to other factors.

Results

Our analysis of singleton live births to migrant mothers in Spain between 2007 and 2017 (N = 542,137) confirmed the healthy immigrant paradox for certain immigrant populations settled in Spain. Compared with infants born to mothers from high-income countries, the adjusted birthweight was higher for infants born to mothers from non-high- income European countries (33.2 g, 95% CI: 28.3–38.1, P < 0.01), mothers from African countries (52.2 g, 95% CI: 46.9–57.5, P < 0.01), and mothers from Latin American countries (57.4 g, 95% CI: 52.9–61.3, P < 0.01), but lower for infants born to mothers from Asian non-high-income countries (− 31.4 g, 95% CI: − 38.4 to − 24.3, P < 0.01). Decomposition analysis showed that when compared with infants born to mothers from high-income countries, compositional heterogeneity accounts for a substantial proportion of the difference in birthweights. For example, it accounts for 53.5% (95% CI: 24.0–29.7, P < 0.01) of the difference in birthweights for infants born to mothers from non-high-income European countries, 70.9% (95% CI: 60–66.7, P < 0.01) for those born to mothers from African countries, and 38.5% (95% CI: 26.1–29.3, P < 0.01) for those born to mothers from Latin American countries.

Conclusions

Our results provide strong population-based evidence for the healthy immigrant paradox in birthweight among certain migrant groups in Spain. However, birth outcomes vary significantly depending on the origins of migrant subpopulations, meaning that not all immigrant groups are unexpectedly healthier. A significant portion of the perinatal health advantage of certain immigrant groups is only a by-product of their group composition (by age, parity, marital status, socioeconomic status, and citizenship of mother, age and migratory status of father and type of delivery) and does not necessarily correspond to other medical, environmental, or behavioral factors.