Ethnic Differences In Birth Weight Research Articles

Fetal growth and the ethnic origins of type 2 diabetes.

Birthweight is known to differ by ethnicity, with South Asian, black African and Caribbean, and Hispanic ethnic groups having lower birthweight on average, when compared with people of white European ethnicity. Birthweight is the most frequently used proxy of fetal growth, and represents the net effect of a host of genetic, physiological and pathophysiological factors. These same ethnic groups that have lower average birthweight also tend to have a higher prevalence of type 2 diabetes in adulthood. It is not unreasonable to propose that the well-established inverse association between birthweight and risk of type 2 diabetes may at least partially contribute to these differences in prevalence of type 2 diabetes between ethnic groups. This hypothesis would rely on the mechanisms that drive the ethnic differences in birthweight aligning with those that modify the risk of type 2 diabetes. In this issue of Diabetologia (DOI: 10.1007/s00125-014-3474-7), Nightingale et al have furthered this field by determining whether ethnic differences in markers of cardio-metabolic risk are consistent with the differences in birthweight in an ethnically diverse cohort of children. The likely contribution of fetal growth to ethnic differences in risk of type 2 diabetes and cardiovascular disease is discussed, particularly in light of the magnitude of the birthweight differences, as are implications for the prevention of type 2 diabetes.

Ethnic differences in growth in early childhood: an investigation of two potential mechanisms

There are clear ethnic differences in birthweight. This study examines whether and how these disparities are replicated in a later marker of physical development, height at 5 years. Observational data from the UK Millennium Cohort Study, constructed to over-represent ethnic minority (Indian, Pakistani, Bangladeshi, Black African, Black Caribbean and Other) children. Mean birthweight of ethnic minority children was lower than that of the ethnic majority (3.06-3.34 kg vs. 3.41 kg), but ethnic minority children were not shorter at 5 years. Pakistani, Caribbean and African children were actually taller on average (by 0.5 cm, 1.4 cm and 3.5 cm). Controlling for parental height and birthweight did not affect height differentials. Two mechanisms were hypothesized: (i) a cramped intrauterine environment given the short stature of some minority children's mothers resulted in catch-up growth; and (ii) conditions during the parents' childhood led to a reduced capacity to reach their height potential. A reparameterization of parent heights showed that mother's height contributed more to predicting child height than joint parental height alone. Birthweight was positively related to height and attenuated the extra contribution from mothers' heights. Decomposing the effects into their constituent parts found some support for both hypotheses. These results suggest that children from ethnic minority backgrounds are not disadvantaged with respect to height growth compared with the ethnic majority. However, if adiposity is more likely when children are tall for their age, then ethnic inequalities in adult health could increase as the current generation of children mature.

Ethnic differences in term birthweight: the role of constitutional and environmental factors

It is not clear to what extent ethnic differences in the term birthweight distribution are constitutional or pathological. This study explored term birthweight heterogeneity between ethnic groups and the explanatory role of constitutional and environmental factors. As part of a prospective cohort study, the Amsterdam Born Children and their Development study, 8266 pregnant women filled out a questionnaire during early pregnancy. Ethnic groups were categorised as: native Dutch group; first and second generation Surinamese, Antillean, Turkish, Moroccan, Ghanaian and other non-Dutch groups. Only singleton livebirths with >or=37.0 weeks of gestation and with complete data were included for analysis (n = 7118). We performed linear regression analyses to estimate the association between ethnicity and, for gestational age, standardised birthweight at term, adjusted for constitutional (fetal gender, parity, maternal age, maternal height) and environmental (education, cohabitation status, maternal body mass index, smoking, alcohol consumption, depression, work stress) determinants respectively. Mean birthweight ranged from 3223 g (second generation Surinamese newborns) to 3548 g (Dutch newborns). Adjustment for constitutional factors substantially reduced the ethnic differences in birthweight, while adjustment for environmental factors provided little additional explanation. Surinamese [first generation: regression coefficient (b) = -98.3 g, P < 0.001; second generation: b = -159.3 g, P < 0.001], first generation Antillean (b = -102.0 g, P = 0.037), and Ghanaian newborns (b = -120.7 g, P = 0.001) remained significantly smaller than Dutch newborns after adjustment for all determinants. Term birthweight differences between Dutch newborns and Turkish, Moroccan and other non-Dutch newborns were largely explained by constitutional rather than environmental determinants, limiting the need for prevention. Surinamese, Antillean and Ghanaian (mainly black) newborns remained unexplainably smaller after adjustment, leaving the possibility of either unknown constitutional or pathological underlying mechanisms.

Ethnic differences in birth weight and cesarean deliveries in Zaria, Nigeria

Ethnic differences in birth weight and cesarean deliveries in Zaria, Nigeria

Ethnic differences in birth weight: maternal effects emerge from an analysis involving mixed-race us couples.

Ethnic differences in birth weight, a predictor of developmental outcomes and health, have remained largely unexplained. Using data collected by the US National Center of Health Statistics, we first cross-tabulate birth weight according to whether the mother or father was African American, European American, Native American, or Mexican American. Results confirm findings from other studies indicating the importance of maternal effects. Furthermore, traditional health and socioeconomic variables account for only a modest part of the group differences, and mothers who presumably lived in the most advantageous environments did not give birth to the heaviest babies. Next, we discuss the possible nature of the relevant maternal factors. Specific candidates include cultural differences in lifestyle that are traditionally not measured in large-scale surveys. Multiple lines of evidence in the literature also suggest that maternal genes are involved.

What's Driving the Racial and Ethnic Differences in Birthweight in the U.S.?

What's Driving the Racial and Ethnic Differences in Birthweight in the U.S.?

Ethnic differences in birth weight by gestational age: at least a partial explanation for the Hispanic epidemiologic paradox?

Objective The purpose of this study was to evaluate ethnic differences in low birth weight and gestational age–dependent birth weight. Study design A retrospective cohort study of 47,669 newborn infants was conducted with the use of the perinatal database of the Memorial Health Care System. Logistic regression was used to estimate the odds ratio for low birth weight by ethnic group, which took into account gestational age at delivery. Multiple linear regression models were then developed to predict ethnic differences in birth weight by gestational age. Results When compared with white women, the adjusted odds ratio for low birth weight in of Mexican origin women (1.16; 95% CI, 1.02-1.32) was substantially lower than that of African American women (2.21; 95% CI, 1.87-2.60). An analysis of birth weight by gestational age suggested that African American neonates were intrinsically smaller than Hispanic neonates (difference, 4.22%). Conclusion At least some of the differences in low birth weight that are noted among ethnic minorities may be attributable to ethnic differences in birth weight by gestational age.

Influence of maternal glucose level on ethnic differences in birth weight and pregnancy outcome.

Minority ethnicity increases the risk of a poor pregnancy outcome in the United States. The mechanism(s) whereby this occurs is unknown. One possibility is physiologic variation in levels of maternal glucose, the major substrate for fetal growth, which is metabolized from the maternal diet and endogenous gluconeogenic sources. The authors examined whether postload glucose concentration at week 28 was associated with maternal ethnicity or altered the ethnic difference in birth weight after adjustment for duration of gestation (to index fetal growth) and pregnancy outcome (large- and small-for-gestational-age births) among 2,072 diabetes-free gravidas in Camden, New Jersey (1990-2001). After data were controlled for potentially confounding factors, maternal glucose level was significantly lower for African Americans than for Hispanics (mainly Puerto Ricans) or Whites. Maternal glucose was associated with infant birth weight to a similar extent within each ethnic group (1.5-2.0 g of birth weight per mg/dl of maternal glucose). A comparison of regression coefficients from models with and without glucose indicated small but statistically significant effects of glucose on the ethnic difference in birth weight and the risk of large-for-gestational-age birth between African Americans and Whites. Maternal glucose concentration did not differ between Hispanics and Whites; consequently, glucose did not influence this ethnic difference in birth weight and pregnancy outcome.

Mediators of ethnic-associated differences in infant birth weight.

To examine whether ethnic differences in low birth weight babies of low-income women may be explained in part by group differences in prenatal health behaviors and psychosocial factors. A prospective, survey of 1,071 low-income, primiparous African-American and Mexican-origin women was conducted in Los Angeles County, California. In face-to-face interviews, data were obtained on substance use, prenatal stress, social support, attitudes toward pregnancy, initiation of prenatal care, and medical risk. Medical chart data were abstracted regarding medical risk factors and labor, delivery, and neonatal data. Interview data were linked with birth outcome data retrieved from maternal medical records. Structural equation modeling was used to test a hypothesized model in which differences in birth weight were expected to be mediated by ethnic differences in substance use, psychosocial factors, and medical risk. As expected, African-American women delivered babies of earlier gestational age and lower birth weight than did women of Mexican origin. Direct predictors of low birth weight were use of drugs and cigarettes, prenatal stress, and positive attitudes toward pregnancy; together, these factors accounted for the observed ethnic differences in birth weight. These data contribute to our understanding of the factors that may account for ethnic-associated differences in low birth weight.

Ethnic differences in birthweight: the role of lifestyle and other factors.

The purpose of this study was to expand the search for risk factors for low birthweight and to find new explanations for the ethnic-group disparities in birth outcomes. The subjects were 1150 pregnant women from six ethnic groups (African American, Chinese, Dominican, Puerto Rican, Mexican, and White) who received prenatal care at clinics in New York and Chicago between December 1987 and December 1989. Two interviews were conducted during the second and third trimesters of pregnancy. The study, after controlling for poverty and other birthweight correlates, showed that living in public housing and believing that chance plays a major role in determining one's health status were negatively associated with birthweight. Having a stable residence was positively related to birthweight. Material hardship, social adversity, perceived racial discrimination, physical abuse, anxiety, and depression were not associated with birthweight. The negative role of an impoverished living environment and feelings of helplessness, as well as the positive role of having a stable form of social support, suggest new directions for research on the causes of low birthweight and the ethnic disparities in US birth outcomes.

Racial and Ethnic Differences in Birthweight: The Role of Income and Financial Assistance

This paper attempts to explain the differences in birthweight observed between blacks, white Anglos, Chicanos, and other racial and ethnic groups. The analysis focuses on the role of income and financial assistance from relatives and public programs. Using data from the NLS Youth Panel, I construct a casual model of birthweight containing exogenous social and demographic risk factors and intervening proximate determinants of birthweight. A substantial part of the gap in birthweight between white Anglos and other ethnic groups (especially blacks) can be explained by the unfavorable socioeconomic and demographic characteristics of the latter. On the other hand, blacks and other minorities smoke less and have other favorable proximate characteristics that depress differences in birthweight. When these proximate determinants are controlled, large ethic differences in birthweight remain unexplained by income and other sociodemographic factors.

Birth weight from pregnancies dated by ultrasonography in a multicultural British population.

To produce standard curves of birth weight according to gestational age validated by ultrasonography in the British population, with particular reference to the effects of ethnic origin. Retrospective analysis of computerised obstetric database. Three large maternity units associated with Nottingham University with over 16,000 deliveries a year. 41,718 women with ultrasound dated singleton pregnancies and delivery between 168 and 300 days' gestation. Length of gestation, ethnic origin, parity, maternal height and weight at booking, smoking during pregnancy; the effect of these variables on birth weight. Birth weights from ultrasound dated pregnancies have a higher population mean and show less flattening of the birthweight curve at term than those of pregnancies dated from menstrual history. Significant differences were observed in mean birth weights of babies of mothers of European origin (3357 g), of Afro-Caribbean origin (3173 g), and from the Indian subcontinent (3096 g). There were also significant interethnic differences in length of gestation, parity, maternal height, booking weight, and smoking habit which affected birth weight. The ethnic differences in birth weight were even greater when the effect of smoking was excluded. Birthweight standards require precise dating of pregnancy and should describe the population from which they were derived. In a heterogeneous maternity population the accurate assessment of an individual baby's weight needs to take the factors which affect birthweight standards into consideration.

Improving obstetric outcomes in ethnic minorities: an evaluation of health advocacy in Hackney

Ethnic differences in birthweight, perinatal mortality and other obstetric outcomes are now well known. In some districts with a significant ethnic minority population, services are provided for non-English-speaking women using maternity units. Various models have developed, including translators, interpreters, Linkworkers, the Department of Health funded Asian Mother and Baby Campaign and health advocates. This paper describes the evaluation of a health advocacy programme in Hackney, East London. The advocates do more than simply interpret language. Anecdotal examples of how this approach changes clinical practice encouraged the project steering group to commission a study to test the hypothesis that health advocacy could improve obstetric outcomes in non-English-speaking women. A retrospective study was carried out comparing 1000 non-English-speaking women delivering at the Mothers' Hospital, Hackney, in 1986 who had been accompanied by an advocate with women delivering at the same hospital in 1979 and at a reference hospital, Whipps Cross. The study found significant differences between the groups in three outcomes: antenatal length of stay, induction and mode of delivery. The changes in Caesarean section were of particular note. The rates rose from 11 to 17 per cent at the reference hospital, whereas they fell from 10.8 to 8.5 per cent at the Mothers' Hospital. This is highly statistically significant. Although these changes cannot be directly attributed to health advocacy, it was considered reasonable to deduce that improved communication could have influenced clinical practice. These findings suggest that health advocacy may offer a mechanism to address some of the adverse obstetric outcomes observed in ethnic minorities.

Birth weight of Italian infants of 30 weeks' gestation or less.

Mean birth weights and percentile charts are given for 161 singleton infants born between 24 and 30 weeks' gestation at the 2nd School of Medicine of Naples. This chart is the first for a Mediterranean population. Our data are similar to those reported from a United Kingdom population and from Japan, suggesting that ethnic differences in birth weight at this gestational age are unimportant.

Birth Weight among Women of Different Ethnic Groups

Differences in mean birth weight and low birth weight (less than 2.5 kg) are analyzed among Asians, blacks, Hispanics, and whites who were enrolled in the Northern California Kaiser-Permanente Birth Defects Study, a prospective study of 29,415 pregnancy outcomes. Large differences in birth weight among babies of different ethnic groups persist after controlling for the joint effects of maternal smoking and alcohol use during pregnancy, sex of child, parity, length of prenatal care, and maternal weight-for-height percentile. Compared with whites, the relative mean differences in birth weight are estimated as -246 g for blacks, -210 g for Asians, -105 g for Hispanics, and -140 g for others. The low-birth-weight rates and crude odds ratios are 7.70% (2.17) for blacks; 5.57% (1.57) for Asians; 5.52% (1.55) for others; 4.00% (1.13) for Hispanics; and 3.55% (1.00) for whites. After controlling for the effects of 22 factors, the odds ratios for a low-birth-weight infant are 2.41 for blacks, 1.37 for Asians, 1.93 for others, and 1.25 for Hispanics. It is concluded that factors currently used to control for ethnic differences in birth weight are insufficient to explain the observed differences.

Birth Weight Among Women of Different Ethnic Groups

Differences in mean birth weight and low birth weight (less than 2.5 kg) are analyzed among Asians, blacks, Hispanics, and whites who were enrolled in the Northern California Kaiser-Permanente Birth Defects Study, a prospective study of 29,415 pregnancy outcomes. Large differences in birth weight among babies of different ethnic groups persist after controlling for the joint effects of maternal smoking and alcohol use during pregnancy, sex of child, parity, length of prenatal care, and maternal weight-for-height percentile. Compared with whites, the relative mean differences in birth weight are estimated as -246 g for blacks, -210 g for Asians, -105 g for Hispanics, and -140 g for others. The low-birth-weight rates and crude odds ratios are 7.70% (2.17) for blacks; 5.57% (1.57) for Asians; 5.52% (1.55) for others; 4.00% (1.13) for Hispanics; and 3.55% (1.00) for whites. After controlling for the effects of 22 factors, the odds ratios for a low-birth-weight infant are 2.41 for blacks, 1.37 for Asians, 1.93 for others, and 1.25 for Hispanics. It is concluded that factors currently used to control for ethnic differences in birth weight are insufficient to explain the observed differences.

589 BIRTH WEIGHT AMONG WOMEN OF DIFFERENT ETHNIC GROUPS

Differences in mean birth weight and low birth weight (< 2.5 Kg.) are analyzed among Asians, Blacks, Hispanics, and Whites who were enrolled in the Northern California Kaiser-Permanente Birth Defects Study, a prospective study of 29,415 pregnancy outcomes. Large differences in birth weight among babies of different ethnic groups persist after controlling for the joint effects of maternal smoking and alcohol use during pregnancy, sex of child, parity, length of prenatal care, and maternal weight-for-height percentile. Compared to Whites, the relative mean differences in birth weight are estimated as -246 grams for Blacks, -210 grams for Asians, -105 grams for Hispanics, and -140 grams for Others. The low birth weight rates and crude odds ratios are 7.70%. (2.17) for Blacks, 5.57% (1.57) for Asians 5.52% (1.55) for Others, 4.007. (1.13) for Hispanics, and 3.55% (1.00) for Whites. After controlling for the effects of 21 factors, the odds ratios for a low birth weight infant are 2.41 for Blacks, 1.37 for Asians, 1.93 for Others, and 1.25 for Hispanics. It is concluded that factors currently used to control for ethnic differences in birth weight are insufficient to explain the observed differences.