Adiposity and hyperglycaemia in pregnancy and related health outcomes in European ethnic minorities of Asian and African origin: a review

Ethnic Differences in Preferences for Lifestyle Intervention among Women after Childbirth: A Multi-Methods Study in Australia

Postpartum weight retention contributes to maternal obesity and varies by ethnicity. Despite the well-established benefits of lifestyle intervention on weight management, little is known about how to engage postpartum women effectively, especially among ethnic minority groups. This multi-methods study aimed to explore ethnic differences in women's preferences for lifestyle intervention after childbirth. Women within five years of childbirth and living with their youngest child in Australia were recruited in an online survey (n = 504) and semi-structured interviews (n = 17). The survey and interview questions were structured based on the Template for Intervention Description and Replication (TIDieR) framework. Ethnic groups were categorized as Oceanian, Asian and Other according to the Australian Bureau of Statistics. Chi-square tests were used to compare the preferred intervention characteristics between groups. Qualitative data were thematically analysed. The survey showed that most women across all ethnic groups were interested in receiving lifestyle support in the early postpartum period (from 7 weeks to 3 months postpartum). All ethnic groups preferred a regular lifestyle intervention delivered by health professionals that promotes accountability and provides practical strategies. However, Asian women had a higher desire for infant care and a lower desire for mental health in the intervention content compared with Oceanian women. Moreover, Asian women were more likely to favour interventions that are initiated in a later postpartum period, over a shorter duration, and with less intervention frequency, compared with Oceanian women. The interviews further indicated the need for intervention adaptations in the Asian group to address the cultural relevance of food and postpartum practices. These ethnic-specific preferences should be considered in the development of culturally appropriate intervention strategies to optimize engagement in healthy lifestyles among the targeted ethnic groups.

The association of pre-pregnancy BMI on leptin, ghrelin, adiponectin and insulin-like growth factor-1 in breast milk: a case-control study

The nutrient composition of breast milk alters during lactation, and maternal BMI adds more intricacy into its complexity. We aimed to compare leptin, ghrelin, adiponectin and insulin-like growth factor-1 (IGF-1) levels of pre-feed and post-feed breast milk in mothers with obesity and normal weight, and tried to determine their effects on infants' growth over weight for length z-score. Twenty obese and twenty normal weight mothers with 2-month-old infants were enrolled in this case-control study. Five millilitre pre-feed breast milk and 5 ml post-feed breast milk were collected. Breast milk leptin, ghrelin, adiponectin and IGF-1 were measured by commercial kits. The pre-feed breast milk of mothers with obesity had significantly higher levels of ghrelin than mothers with normal weight (P = 0·025), whereas the post-feed breast milk of mothers with normal weight had higher levels of adiponectin than the mothers with obesity (P = 0·010). No significant differences were observed in leptin and IGF-1 levels between the two groups. Post-feed breast milk IGF-1 levels of mothers with obesity were correlated with infant's weight for length z-score at 2 months (r -0·476; P = 0·034). In linear regression models, parity affected the ghrelin in pre-feed breast milk (P = 0·025). Our results revealed that maternal pre-pregnancy BMI was associated with breast milk components.

Gestational diabetes mellitus: Major risk factors and pregnancy-related outcomes: A cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major pregnancy endocrine problem that has several confirmed risk factors and is associated with adverse pregnancy-related outcomes (PRO).

OBJECTIVE

To evaluate the relationship between GDM diagnosis and the associated risk factors of PRO (maternal, intrapartum, perinatal, and neonatal) in accordance with International Association of Diabetes and Pregnancy Study Groups criteria.

MATERIALS AND METHODS

This prospective cohort study was performed with 531 singleton parturient (265 GDM and 266 non-GDM). They were selected consecutively from referral hospitals, and the maternal, intrapartum, perinatal, and neonatal outcomes were assessed.

RESULTS

The major risk factors influencing the GDM diagnosis were maternal age, obesity, family history of diabetes, previous history of GDM, and previous history of macrosomia. In the comparison of PRO between the groups, significant associations were detected for emergency cesarean delivery, preeclampsia, polyhydramnios, premature rupture of membrane, preterm delivery, and neonatal hyperbilirubinemia in the GDM group. In the multivariate logistic regression analysis, a previous history of stillbirth was significantly associated with maternal and perinatal outcomes. The odds ratios (CI 95%) of the PRO in the women with a GDM diagnosis were: maternal = 2.43 (1.51-3.90), intrapartum = 2.05 (1.35-3.11), perinatal = 2.00 (1.29-3.10), and neonatal = 1.68 (1.08-2.62). The PRO was significantly correlated with GDM diagnosis, but not with the risk factors.

CONCLUSION

The adverse pregnancy outcomes were significantly correlated with GDM diagnosis, and the outcomes were not directly affected by the risk factors. Given the related adverse outcomes for mothers and offspring, early screening and management of GDM is necessary especially in Asians and in low-/middle-income countries.

Offspring birthweight and placental weight in immigrant women from conflict-zone countries; does length of residence in the host country matter? A population study in Norway

INTRODUCTION

We aimed to estimate differences in offspring birthweight and placental weight between Norwegian women and immigrants in Norway from countries with armed conflicts. We also studied whether length of residence in Norway was associated with offspring birthweight and placental weight.

MATERIAL AND METHODS

We included in our study all singleton births in Norway at gestational week 28 or beyond during the years 1999-2014, to mothers who were born in Somalia, Afghanistan, Iraq (total immigrants n = 18 817), or Norway (n = 668 439). Data were obtained from The Medical Birth Registry of Norway and the Central Person Registry of Norway. We estimated the differences between Norwegian and immigrant women in mean offspring birthweight and mean placental weight by applying linear regression analyses. Adjustments were made for maternal age, parity, year of delivery, gestational age at delivery, preeclampsia, and diabetes.

RESULTS

The immigrant women had 206 g (95% CI 199 to 213 g) lower mean offspring birthweight and 16 g (95% CI 14 to 18 g) lower mean placental weight than Norwegian women. Immigrant women with ≥5 years of residence in Norway had higher offspring birthweight (40 g) and higher placental weight (17 g) than immigrant women with <5 years of residence.

CONCLUSIONS

Immigrant mothers from Somalia, Afghanistan, and Iraq gave birth to infants and placentas with lower weight than Norwegian women. However, the difference between Norwegian women and immigrant women was reduced by length of residence in Norway.

One size does not fit all: Examining ethnicity in gestational weight gain guidelines

Pregnancy-related metrics vary by race/ethnicity, yet most gestational weight gain (GWG) guidelines are ethnicity-blind. We estimated small-for-gestational age (SGA) risk in a Japanese population, examining GWG adequacy categorized by Institute of Medicine (IOM) and Japanese guidelines in male (N  = 192) and female (N = 191) full-term singleton infants. For predicting SGA, IOM guidelines had high sensitivity ( ≥ 0.75), but low specificity ( ≤ 0.25); Japanese guidelines had high specificity ( ≥ 0.80) but low sensitivity ( ≤ 0.50). GWG guidelines' implicit notions of Caucasian-Americans as optimal may lead to 'One Size Fits All' recommendations that can obscure important biocultural factors contributing to maternal child health outcomes.

Vitamin D, Gestational Diabetes, and Measures of Glucose Metabolism in a Population-Based Multiethnic Cohort

OBJECTIVE

We explored associations between maternal 25-hydroxyvitamin D (25(OH)D) status during pregnancy and gestational diabetes (GDM) and other measures of glucose metabolism.

METHODS

We analysed 25(OH)D at 15 and 28 gestational weeks (GW) in 745 multiethnic pregnant women attending antenatal care units in Oslo, Norway, between 2008 and 2010. GDM was diagnosed with a 75 g oral glucose tolerance test at 28 GW. Separate regression analyses were performed to investigate associations between 25(OH)D and GDM and measures of glucose metabolism.

RESULTS

A higher proportion of ethnic minority women had GDM (p < 0.01) and low 25(OH)D (p < 0.01) compared to Europeans. In logistic regression analyses, 25(OH)D < 50 nmol/L was associated with GDM after adjusting for age, parity, education, and season (OR 1.6; 95% CI 1.1-2.2). After additional adjustments for variables reflecting fat mass (skinfolds or BMI) and ethnicity, the association disappeared with ethnicity having a much stronger effect than the adiposity variables. We got similar results exploring effects on other measures of glucose metabolism and when change in 25(OH)D from inclusion to 28 GW was taken into account.

CONCLUSIONS

Vitamin D deficiency was not associated with GDM or glucose metabolism in a multiethnic population-based study, after adjustments for confounding factors, in particular ethnicity.

Pre-pregnancy body mass index and inter-pregnancy weight change among women of Russian, Somali and Kurdish origin and the general Finnish population

Objectives: We studied the differences in the mean pre-pregnancy body mass index (BMI) and mean inter-pregnancy weight change in women of Russian, Somali and Kurdish origin and women in the general Finnish population. Methods: The population-based samples were from the Migrant Health and Wellbeing Study and the Health 2011 Survey conducted in six cities in Finland in 2010–2012. This study included women with at least one birth in Finland. Data on their previous pregnancies in Finland were obtained from the National Medical Birth Register for 318 Russian, 584 Somali and 373 Kurdish origin women and for 243 women in the general Finnish population (reference group). Data on pre-pregnancy weight and height were self-reported in early pregnancy. Linear logistic regression was the main method of analysis. Results: The unadjusted mean pre-pregnancy BMI was higher in Somali (27.0 kg/m2, p<0.001) and Kurdish (25.8 kg/m2, p<0.001) women, but lower in Russian (22.2 kg/m2, p<0.001) women than in the reference group (24.1 kg/m2). The adjusted coefficients for the difference in the mean pre-pregnancy BMI were −1.93 (95% CI −2.77 to −1.09) for Russian, 1.82 (95% CI 0.89–2.75) for Somali and 1.30 (95% CI 0.43–2.17) for Kurdish women compared with the reference group. Among women with at least two births, no statistically significant difference was observed in the mean inter-pregnancy weight change between the migrant groups and the reference group. Conclusions: Somali and Kurdish women had higher mean pre-pregnancy BMIs than women in the general Finnish population and may need special support and health promotion strategies for weight management.

Fetal growth trajectories in pregnancies of European and South Asian mothers with and without gestational diabetes, a population-based cohort study

Objective

Our aim was to examine the impact of gestational diabetes (GDM), from before the GDM-diagnosis is made, on fetal growth trajectories, and to compare it in Europeans and South Asians; two ethnic groups with dissimilar fetal growth patterns.

Methods

We studied European (n = 349) and South Asian (n = 184) pregnant women, from the population-based STORK-Groruddalen cohort in Oslo, Norway. Mothers were enrolled in early pregnancy, screened for GDM in gestational week 28 ±2, and classified as “non-GDM”, “mild GDM” or “moderate/severe GDM”. We measured fetal head circumference, abdominal circumference and femur length by ultrasound, and estimated fetal weight in gestational week 24, 32 and 37, and performed corresponding measurements at birth.

Results

In non-GDM pregnancies, South Asian fetuses (n = 156) had a slower growth from gestational week 24, compared with Europeans (n = 310). More than two thirds of the European mothers later diagnosed with GDM were overweight or obese in early pregnancy, while this was not observed in South Asians. Fetuses of GDM mothers tended to be smaller than fetuses of non-GDM mothers in week 24, but thereafter grew faster until birth. This pattern was especially pronounced in fetuses of South Asian mothers with moderate/severe GDM. In week 24 these fetuses had a -0.95 SD (95% CI: -1.53, -0.36) lower estimated fetal weight than their non-GDM counterparts. In contrast, at birth they were 0.45 SD (0.09, 0.81) larger.

Conclusions

Offspring of GDM mothers were smaller in mid pregnancy, but subsequently grew faster until birth, compared with offspring of non-GDM mothers. This pattern was most prominent in South Asian mothers with moderate to severe GDM. However, the most remarkable characteristic of these fetuses was not a large size at birth, but the small size in mid pregnancy, before the GDM diagnosis was set.

Development and evaluation of an intervention for the prevention of childhood obesity in a multiethnic population: the Born in Bradford applied research programme

Background

There is an absence of evidence about interventions to prevent or treat obesity in early childhood and in South Asian populations, in whom risk is higher.

Objectives

To study patterns and the aetiology of childhood obesity in a multiethnic population and develop a prevention intervention.

Design

A cohort of pregnant women and their infants was recruited. Measures to compare growth and identify targets for obesity prevention, sensitive to ethnic differences, were collected. A feasibility randomised controlled trial (RCT) was undertaken.

Setting

Bradford, UK.

Participants

A total of 1735 mothers, 933 of whom were of South Asian origin.

Intervention

A feasibility trial of a group-based intervention aimed at overweight women, delivered ante- and postnatally, targeting key modifiable lifestyle behaviours to reduce infant obesity.

Main outcome measures

The feasibility and acceptability of the pilot intervention.

Data sources

Routine NHS data and additional bespoke research data.

Review methods

A systematic review of diet and physical activity interventions to prevent or treat obesity in South Asian children and adults.

Results

Routine measures of growth were accurate. The prevalence of risk factors differed between mothers of white British ethnicity and mothers of Pakistani ethnicity and weight and length growth trajectories differed between Pakistani infants and white British infants. Prediction equations for risk of childhood obesity were developed. An evidence-based intervention was evaluated in a pilot RCT and was found to be feasible and acceptable.

Limitations

This was a single-centre observational study and a pilot evaluation.

Conclusions

The programme has been successful in recruiting a unique multiethnic childhood obesity cohort, which has provided new evidence about modifiable risk factors and biethnic growth trajectories. A novel group-based behavioural change intervention has been developed and successfully piloted. A multisite cluster RCT is required to evaluate effectiveness.

Trial registration

Current Controlled Trials ISRCTN56735429.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Ethnic differences in fetal size and growth in a multi-ethnic population

OBJECTIVES

Impaired or excessive fetal growth is associated with adverse short- and long-term health outcomes that differ between ethnic groups. We explored ethnic differences in fetal size and growth from mid pregnancy until birth.

METHODS

Data are from the multi-ethnic STORK-Groruddalen study, a population-based, prospective cohort of 823 pregnant women and their offspring in Oslo, Norway. Measures were z-scores of estimated fetal weight (EFW), head circumference (HC), abdominal circumference (AC) and femur length (FL), in gestational week 24, 32 and 37, measured by ultrasound, and similar measures at birth. Differences in fetal size and growth were assessed using separate Linear Mixed Models including all four time points, with ethnic Europeans as reference.

RESULTS

In week 24 South Asian fetuses had smaller AC, but larger FL than Europeans, and slightly lower EFW (-0.17 SD (-0.33, -0.01), p=0.04). Middle East/North African fetuses also had larger FL, but similar AC, and hence slightly higher EFW (0.18 (0.003, 0.36), p=0.05). Both groups had slower growth of AC, FL and EFW from this time until birth, and had -0.61 SD (-0.73, -0.49) and -0.28 SD (-0.41, -0.15) lower birth weight respectively. Ethnic East Asians, on the other hand, were smaller throughout pregnancy and had -0.58 SD (-0.82, -0.34) lower birth weight. Significant ethnic differences remained after adjusting for maternal factors.

CONCLUSION

We observed ethnic differences in fetal size and body proportions already in gestational week 24, and in fetal growth from this time until birth, which were only partly explained by key maternal factors.

The educational gradient of obesity increases among Swedish pregnant women: a register-based study

Background

Overweight or obesity is detrimental during pregnancy. We studied time trends in the educational gradient of overweight and obesity among pregnant women. Differences in overweight and obesity by area of residence and country of birth were also examined.

Methods

The study was based on the Swedish Medical Birth Register between 1992 and 2010 and included 1,569,173 singleton pregnancies. Weight and height were registered during the first visit at the antenatal-care clinic. Data on education, country of birth, and area of residence were derived from registers with national coverage.

Results

In 2008–2010, 32% of Swedish nulliparous pregnant women were overweight or obese. The relative risk of obesity among lower educated women compared to women with higher education increased from 1.91 (95% confidence interval: 1.85-1.97) in 1992–1995 to 2.09 (95% confidence interval: 2.05-2.14) in 2008–2010. There was an inverse linear relationship between risks of overweight or obesity, and population density and type of residence municipality. An excessive gestational weight gain according to the American Institute of Medicine was observed among 57-63% of the overweight or obese women, but there were small differences by education. Pregnant women born in Africa, Middle East or Latin America had higher risks of being overweight or obese compared to women born in Sweden.

Conclusions

The prevalence of obesity as well as the social inequalities in obesity during pregnancy increased in Sweden between 1992 and 2010. Further understanding of social inequalities and geographical differentials in health behaviours of pregnant women is needed when planning public health interventions.

The prevalence of pre-eclampsia in migrant relative to native Norwegian women: a population-based study

OBJECTIVE

To compare the prevalence of pre-eclampsia in migrant women with Norwegian women, and to study the prevalence of pre-eclampsia by length of residence in Norway.

DESIGN

Observational study.

SETTING

The Medical Birth Registry of Norway.

POPULATION

All Norwegian, Pakistani, Vietnamese, Somali, Sri Lankan, Filipino, Iraqi, Thai and Afghan women who gave birth after 20 weeks of gestation during the period 1986-2005 in Norway.

METHODS

The prevalence of pre-eclampsia was calculated by country of birth. The association of country of birth and length of residence in Norway with pre-eclampsia was estimated as the odds ratio (OR) with 95% confidence interval (CI), using Norwegian women as a reference. We made adjustments for maternal age, parity, multifetal pregnancy, year of delivery and maternal diabetes in multivariable analysis.

MAIN OUTCOME MEASURE

Pre-eclampsia.

RESULTS

Migrant women had a lower prevalence of pre-eclampsia than Norwegian women (2.7% versus 3.7%, P < 0.001). Vietnamese (OR, 0.36; CI, 0.29-0.45), Afghan (OR, 0.52; CI, 0.30-0.90) and Thai (OR, 0.57; CI, 0.45-0.73) women had the lowest risk of pre-eclampsia relative to Norwegian women. Adjustment for the variables above or separate analyses for nulliparous women did not change the estimates notably. Using Norwegian women as the reference, the risk of pre-eclampsia increased by length of residence for migrant women: adjusted OR of 0.64 (0.59-0.70) at <5 years and 0.91 (0.84-0.99) at ≥5 years of residence.

CONCLUSIONS

The risk of pre-eclampsia was lower in migrants relative to Norwegian women, but increased by length of residence in Norway.

Pregnancy, parturition and preeclampsia in women of African ancestry

Maternal and associated neonatal mortality rates in sub-Saharan Africa remain unacceptably high. In Mulago Hospital (Kampala, Uganda), 2 major causes of maternal death are preeclampsia and obstructed labor and their complications, conditions occurring at the extremes of the birthweight spectrum, a situation encapsulated as the obstetric dilemma. We have questioned whether the prevalence of these disorders occurs more frequently in indigenous African women and those with African ancestry elsewhere in the world by reviewing available literature. We conclude that these women are at greater risk of preeclampsia than other racial groups. At least part of this susceptibility seems independent of socioeconomic status and likely is due to biological or genetic factors. Evidence for a genetic contribution to preeclampsia is discussed. We go on to propose that the obstetric dilemma in humans is responsible for this situation and discuss how parturition and birthweight are subject to stabilizing selection. Other data we present also suggest that there are particularly strong evolutionary selective pressures operating during pregnancy and delivery in Africans. There is much greater genetic diversity and less linkage disequilibrium in Africa, and the genes responsible for regulating birthweight and placentation may therefore be easier to define than in non-African cohorts. Inclusion of African women into research on preeclampsia is an essential component in tackling this major disparity of maternal health.

Ethnic differences in maternal dietary patterns are largely explained by socio-economic score and integration score: a population-based study

Background

The impact of socio-economic position and integration level on the observed ethnic differences in dietary habits has received little attention.

Objectives

To identify and describe dietary patterns in a multi-ethnic population of pregnant women, to explore ethnic differences in odds ratio (OR) for belonging to a dietary pattern, when adjusted for socio-economic status and integration level and to examine whether the dietary patterns were reflected in levels of biomarkers related to obesity and hyperglycaemia.

Design

This cross-sectional study was a part of the STORK Groruddalen study. In total, 757 pregnant women, of whom 59% were of a non-Western origin, completed a food frequency questionnaire in gestational week 28±2. Dietary patterns were extracted through cluster analysis using Ward's method.

Results

Four robust clusters were identified where cluster 4 was considered the healthier dietary pattern and cluster 1 the least healthy. All non-European women as compared to Europeans had higher OR for belonging to the unhealthier dietary patterns 1–3 vs. cluster 4. Women from the Middle East and Africa had the highest OR, 21.5 (95% CI 10.6–43.7), of falling into cluster 1 vs. 4 as compared to Europeans. The ORs decreased substantially after adjusting for socio-economic score and integration score. A non-European ethnic origin, low socio-economic and integration scores, conduced higher OR for belonging to clusters 1, 2, and 3 as compared to cluster 4. Significant differences in fasting and 2-h glucose, fasting insulin, glycosylated haemoglobin (HbA_1c), insulin resistance (HOMA-IR), and total cholesterol were observed across the dietary patterns. After adjusting for ethnicity, differences in fasting insulin (p=0.015) and HOMA-IR (p=0.040) across clusters remained significant, despite low power.

Conclusion

The results indicate that socio-economic and integration level may explain a large proportion of the ethnic differences in dietary patterns.

Adiposity and hyperglycaemia in pregnancy and related health outcomes in European ethnic minorities of Asian and African origin: a review

BACKGROUND

Ethnic minorities in Europe have high susceptibility to type 2 diabetes (T2DM) and, in some groups, also cardiovascular disease (CVD). Pregnancy can be considered a stress test that predicts future morbidity patterns in women and that affects future health of the child.

OBJECTIVE

TO REVIEW ETHNIC DIFFERENCES IN: 1) adiposity, hyperglycaemia, and pre-eclampsia during pregnancy; 2) future risk in the mother of obesity, T2DM and CVD; and 3) prenatal development and possible influences of maternal obesity, hyperglycaemia, and pre-eclampsia on offspring's future disease risk, as relevant for ethnic minorities in Europe of Asian and African origin.

DESIGN

Literature review.

RESULTS

Maternal health among ethnic minorities is still sparsely documented. Higher pre-pregnant body mass index (BMI) is found in women of African and Middle Eastern descent, and lower BMI in women from East and South Asia compared with women from the majority population. Within study populations, risk of gestational diabetes mellitus (GDM) is considerably higher in many minority groups, particularly South Asians, than in the majority population. This increased risk is apparent at lower BMI and younger ages. Women of African origin have higher risk of pre-eclampsia. A GDM pregnancy implies approximately seven-fold higher risk of T2DM than normal pregnancies, and both GDM and pre-eclampsia increase later risk of CVD. Asian neonates have lower birth weights, and mostly also African neonates. This may translate into increased risks of later obesity, T2DM, and CVD. Foetal overgrowth can promote the same conditions. Breastfeeding represents a possible strategy to reduce risk of T2DM in both the mother and the child.

CONCLUSIONS

Ethnic minority women in Europe with Asian and African origin and their offspring seem to be at increased risk of T2DM and CVD, both currently and in the future. Pregnancy is an important window of opportunity for short and long-term disease prevention.