A population-based cohort study of the relation between maternal birthweight and risk of gestational diabetes mellitus in four racial/ethnic groups.

Intrauterine growth retardation and low birthweight have been associated with an increased risk of insulin resistance and type II diabetes later in life. We hypothesised that maternal low birthweight is associated with an increased risk of gestational diabetes mellitus (GDM). Study subjects comprised women giving birth in Washington State between 1987 and 1995. Information for 21,528 births to non-Hispanic white women, 6359 to African-American women, 7456 to Native American women and 6496 to Hispanic women was available for analysis. All information was derived from statewide computerised vital records and hospital discharge summaries of obstetric and neonatal admissions with linkage to birth certificates of mothers. Maternal birthweight was collected from subjects' birth certificates. Information from both the birth certificates and the obstetric and neonatal admissions database was used to determine whether subjects developed GDM. Poisson regression models were estimated to calculate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for GDM by categories of maternal birthweight. The cumulative incidence of GDM among non-Hispanic white, African-American, Native American and Hispanic women was 2.8, 2.6, 2.7 and 3.0% respectively. After adjusting for maternal age, parity, cigarette smoking, history of chronic hypertension and participation in the Medicaid programme, non-Hispanic white women with a birthweight < 2000 g were 1.7 times more likely to have had their pregnancy complicated by GDM (RR = 1.7; 95% CI 0.8, 3.3) than those with a birthweight 3000-3999 g. The corresponding adjusted RRs for African-American, Native American, and Hispanic women were 2.8 [95% CI 1.2, 6.1], 3.1 [95% CI 1.2, 8.2] and 2.4 [95% CI 0.9, 6.0] respectively. Among African-American women, those with a birthweight > or = 4000 g also experienced a twofold increased risk of GDM (RR = 2.1; 95% CI 1.0, 4.1). This association of high birthweight and increased GDM risk was not found among women in the other three racial/ethnic groups. These findings suggest that individuals with low birthweight constitute a group at increased risk for GDM.

The Washington State Intergenerational Study of Birth Outcomes: methodology and some comparisons of maternal birthweight and infant birthweight and gestation in four ethnic groups.

A statewide database of vital records and hospital discharge summaries of obstetric and neonatal admissions for Washington State in 1987-95 was linked to the birth certificates of mothers born in the state. A total of 46,000 births to mothers of four racial/ethnic groups were studied: Whites, African-Americans, Native Americans and Hispanics. For all four groups inverse associations were found between maternal birthweight and infant low birthweight and preterm birth. The birthweight distribution of African-American mothers was displaced markedly downwards compared with the Whites; this difference in maternal birthweight is offered as a partial explanation of the greater prevalence of suboptimal pregnancy outcomes in the former. In contrast, the maternal birthweight distributions of Whites, Native Americans and Hispanics are similar; differences in pregnancy outcomes are probably more related to maternal preconceptional and postnatal factors in these groups as well as differences in pregnancy-related factors. Mothers' birthweight may have clinical value in identifying high-risk pregnancies.

The antecedents of teen fatherhood: a retrospective case-control study of Great Britain youth.

Historically, researchers have focused on identifying risk factors for teen motherhood, largely ignoring teen fathers. This study uses the 1958 National Child Development Study of Great Britain to examine antecedents of teen fatherhood. Teen fathers were compared with later fathers and nonfathers by using epidemiological methods. Results indicate that boys who became fathers while in their teens were at increased risk for experiencing problems at home and at school and were more likely to demonstrate aggressive, truant, and law-breaking behaviors. Many of these risk factors were also evident among those who became fathers while in their early 20s.

Genetic polymorphisms in the white population of Victoria, Australia.

Genetic variation in the rural population of the State of Victoria, Australia, is demonstrated through the analysis of eight genetically independent red cell antigen, red cell enzyme and plasma protein systems in a sample of more than 2000 blood donors. The polymorphisms investigated were ABO, RH, KEL, esterase D (ESD), glyoxalase 1 (GLO1), phosphoglucomutase locus 1 (PGM1), haptoglobin (HP) and the third component of complement (C3). For genetic distance analysis the sample was subdivided into nine regions using the Victorian Government's Statistical Divisions. Considerable regional genetic heterogeneity exists; with the Goulburn and the Central Highlands divisions being the most distinct, not only from the other seven divisions, but also from each other. The pattern of micro-differentiation is complex and cannot be easily explained, but there is evidence of varying levels of systematic evolutionary pressure on the Victorian divisions. The investigation of the proportion born overseas in each division, and their respective countries of origin, did not help in the interpretation of the findings. Overall, rural Victorians exhibited allele frequencies very similar to the populations of both Melbourne, the Victorian capital, and the island State of Tasmania.

Infant mortality among moderately low birth weight infants in Alabama, 1980 to 1983.

A previous study of postneonatal deaths among normal birth weight infants in Alabama indicated that rural residence increased the risk of postneonatal death, the magnitude of the excess risk in the black population, and the risk of death from preventable causes. To determine whether this pattern persisted in a group presumably at higher than usual risk of infant death, patterns of mortality among infants weighing 1500 to 2499 g at birth and born in Alabama between 1980 and 1983 were examined by race, residence, and cause of death. Neonatal and infant mortality rates were higher for black infants; postneonatal mortality rates were higher for black infants. Neonatal mortality was highest for white infants from the rural part of the state; post-neonatal mortality was highest for black infants from the rural part of the state. There was little variation in the proportion of preventable postneonatal deaths by race or residence (17.6% for all) but almost twice as many white deaths were not preventable as black ones (39.0 vs 21.9%). It is posited that rural residence may actually be a surrogate measure for lack of access to health services.

Poor birth outcomes of American black women: an alternative explanation.

The dramatic excess of low birthweight and infant deaths among black babies compared to whites cannot be completely explained by differences either in sociodemographic factors or in prenatal care patterns. It is suggested that part of the explanation resides in characteristics of the mothers' own intrauterine and childhood environment which interfere with their optimal growth and development and become manifest later in suboptimal reproductive outcome. Conditions in the adult environment under which pregnancies occur also appear to interfere with fetal development. This evidence points to the need for programs to care for children as they grow and develop and for women before and during their pregnancies. Research should be encouraged which may help to elucidate the biological mechanisms by which intrauterine, childhood and adult environments of one generation translate into health hazards for the next generation.

Postneonatal mortality among normal birth weight infants in Alabama, 1980 to 1983.

To identify reasons for the racial differential in postneonatal deaths and possible intervention strategies, Alabama's linked birth-death file was used to evaluate causes of postneonatal mortality for the 1980 to 1983 cohorts of normal birth weight infants. Causes were aggregated into six categories, and cause-specific rates were compared by race and by urban-rural residence. Both total and cause-specific postneonatal mortality rates among black infants were two or more times higher than for white infants, except for congenital anomalies. The greatest differential was for infection-related deaths. Rural residence increased both the risk of postneonatal death and the magnitude of the racial differential. The risks were especially elevated for deaths due to infection and "systemic causes" (including those in the perinatal category). Only 26% of postneonatal deaths were probably not preventable, and nearly one third were clearly preventable. Potential prevention strategies include injury control, prevention of infectious diseases, and prompt treatment of infectious diseases.

Neonatal deaths in Alabama. III. Out-of-hospital births, 1940-1980.

Out-of-hospital births in Alabama are characterized with special emphasis on the period from 1970 to 1980. Women having an out-of-hospital birth were more likely to be nonwhite, aged greater than or equal to 35, and multiparous and to have little or no prenatal care. However, within the group of women having out-of-hospital delivery, characteristics which predicted neonatal death included being white, aged less than 20, primiparous, and unmarried and having little or no prenatal care. Both the risk factors for and outcomes of out-of-hospital birth differed markedly by race. In all, out-of-hospital births, which declined from 25% to 0.5% of all births from 1940 to 1980, were associated with a twofold increase in neonatal mortality. The major care provider for out-of-hospital births, the "granny" midwife, was found to have little knowledge about, or ability to provide, modern obstetric care. High-risk status of the patients, limited capability of the care-givers, and lack of appropriate medical resources are suggested as the likely reasons for the excess neonatal mortality in out-of-hospital births.

Lethal congenital anomalies as a cause of birth-weight-specific neonatal mortality.

The percentage of neonatal mortality caused by lethal congenital anomalies and the distribution of specific anomalies in various birth-weight groups are presented. State vital statistics data and autopsy-confirmed data from a single hospital are compared. Of neonates who died, less than 5% who were born weighing between 500 and 999 g died of a congenital anomaly, and nearly 45% who were born weighing more than 2,500 g died of a congenital anomaly. Most deaths associated with congenital anomalies in infants born weighing more than 2,500 g are cardiac in origin. Twenty-three percent of all neonatal deaths in Alabama are attributed to a lethal congenital anomaly. Use of these data to define limits to future improvements in neonatal mortality by standard medical care is discussed.

Neonatal deaths in Alabama. II. Policy and research implications derived from a comparison of birth weight-specific state and medical center neonatal mortality rates.

An analysis of Alabama's recent neonatal mortality rate was performed to answer questions pertaining to projected changes in the neonatal mortality rate in the next decade. With current technology these questions include: (1) Can the current decline in the neonatal mortality rate continue? (2) Which infants not now surviving are potentially able to be saved? (3) What types of new programs may further reduce the neonatal mortality rate? (4) For which infants may research provide technology leading to further reductions in the neonatal mortality rate? In this analysis, birth weight-specific neonatal mortality rates for Alabama were compared with the lowest birth rate-specific neonatal mortality rates achieved in perinatal centers. Specific causes of neonatal death for each birth weight group were determined. Data suggest that 20% of current neonatal deaths would be preventable with available technology through expanded regionalization of perinatal care for infants born weighing less than 2,500 gm. Since lethal congenital anomalies cause the majority of neonatal deaths in infants born weighing greater than 2,499 gm, there is apparently little room for an improved neonatal mortality rate in this group. Without successful research leading to a reduction in preterm delivery rates, a reduction in lethal congenital anomalies or better survival of low-birth weight infants. Alabama's neonatal mortality rate is likely to level off at five to six per 1,000.

Neonatal deaths in Alabama, 1970-1980: an analysis of birth weight- and race-specific neonatal mortality rates.

Alabama birth and death certificate tapes for the years 1970-1980 were linked and analyzed to determine race-specific birth weight and neonatal mortality rate distributions. Changes which occurred over time were evaluated. Our analyses demonstrated that there were no substantial changes in birth weight distributions which could account for the nearly 50% reduction in the neonatal mortality rate in Alabama during this period. Birth weight changes did result in a 12% decrease in the white neonatal mortality rate but resulted in no decrease in the nonwhite neonatal mortality rate. All other improvement in the neonatal mortality rate is attributed to better survival within birth weight groups. Eighty percent of the reduction in the neonatal mortality rate during this period of time occurred in low-birth weight infants with most of the reduction found in infants weighing between 1,000 and 2,000 gm. Improvements in the quality of medical care and better access to medical care through regionalization of perinatal services, especially for low-birth weight infants, are suggested as the major reasons for this improvement.