PubMed Health⌕ Search

Biomedical subjects

H Needleman

Publications and source records attributed to H Needleman.

At least 19 recordsLinked to original sources
PubMed1997

Reducing bias in language assessment: processing-dependent measures.

One potential solution to the problem of eliminating bias in language assessment is to identify valid measures that are not affected by subjects' prior knowledge or experience. In this study, 156 randomly selected school-age boys (31% majority; 69% minority) participated in three "processing-dependent" language measures, designed to minimize the contributions of prior knowledge on performance; and one traditional "knowledge-dependent" language test. As expected, minority subjects obtained significantly lower scores than majority participants on the knowledge-dependent test, but the groups did not differ on any of the processing- dependent measures. These results suggest that processing-dependent measures hold considerable promise for distinguishing between children with language disorders, whose poor language performance reflects fundamental psycholinguistic deficits, and children with language differences attributable to differing experiential backgrounds.

Achievement↗
PubMed1995

A longitudinal study of chronic lead exposure and physical growth in Boston children.

We investigated the cross-sectional and longitudinal relationships between chronic exposure to lead and physical growth among a cohort of children reassessed 13 years after initial examination. We measured weight, height, and dentin lead levels of 270 children in 1975-78. In 1989-1990 we reexamined 79 of these children for measurement of weight, height, and bone lead levels by means of in vivo K X-ray fluorescence. To avoid potential confounding by race and chelation history, analysis was restricted to white subjects without a history of lead chelation therapy. A total of 236 subjects provided complete information for the study of cross-sectional relationship between dentin lead levels and changes in physical growth: 58 subjects for the study of longitudinal relationship between dentin lead levels and changes in physical growth and 54 subjects for the study of longitudinal relationship between bone lead levels and changes in physical growth. Dentin lead levels averaged 14.9 micrograms/g; tibia and patella lead levels averaged 1.2 and 5.0 micrograms/g, respectively. With control for potential confounders including age, sex, baseline body size, and mother's socioeconomic status, log10 dentin lead level was positively associated with body mass index as of 1975-1978 (beta = 1.02, p = 0.03) and increase in body mass index between 1975-78 and 1989-90 (beta = 2.65, p = 0.03). Bone lead levels were not significantly associated with physical growth. This is the first study relating chronic lead exposure to body mass index. The results suggest that chronic lead exposure in childhood may result in obesity that persists into adulthood.

Adolescent↗
PubMed1993

Pre- and postnatal low-level lead exposure and children's dysfunction in school.

The contributions of pre- and postnatal low-level lead exposures to the risk of learning problems were evaluated among 1923 children who were born in one Boston hospital in 1979-1980 and followed to age 8 years. In this relatively privileged group, more than 20% of the children had a mother with some formal postgraduate education. Prenatal lead exposure was estimated with a measurement of umbilical cord blood lead content, and postnatal lead exposure was approximated with measurement of lead in the dentin of an exfoliated deciduous tooth. Information about potential confounders and effect modifiers was obtained from maternal interview shortly after delivery and from a mailed questionnaire completed and returned when the child was approximately 6 years old. An assessment of each child's function in school was provided by the teacher, who completed a questionnaire near the end of the school year in which the child reached the age of 8 years. We considered a learning problem to be related to lead exposure if its adjusted prevalence increased with each loge increase in lead, and if the adjusted prevalence was elevated among children with high levels (i.e., approximating the highest decile) of umbilical cord blood lead (i.e., > or = 10 micrograms/dl) or dentin lead (i.e., > or = 5 micrograms/g). Girls with elevated umbilical cord blood lead levels were more likely than their peers to be dependent and inpersistent and to display an inflexible and inappropriate approach to tasks (defined as the "tasks" cluster). Boys with elevated umbilical cord blood lead levels were more likely than others to have difficulty with both simple directions and sequences of directions. Among girls, elevated deciduous tooth dentin lead content was associated with reading and spelling difficulties, the tasks cluster, and with "not functioning as well as peers." Elevated dentin lead levels were not overrepresented among boys with any of the assessed learning clusters. These findings are consistent with the inference that lead levels still prevalent among children (i.e., blood < 15 micrograms/dl) are associated with some learning problems in girls.

Child↗
PubMed1991

Weight gain and maturity in fetuses exposed to low levels of lead.

The relationship between prenatal low-level lead exposure and fetal growth was evaluated in a sample of 4354 pregnancies in which the mean umbilical cord blood lead level was 7.0 micrograms/dl (SD = 3.3; 10th percentile, 3.4 micrograms/dl, 90th percentile, 10.9 micrograms/dl). Higher cord blood lead levels were significantly associated with gestations of slightly longer duration. Comparing infants with cord blood lead levels greater than or equal to 15 micrograms/dl to those with levels less than 5 micrograms/dl, adjusted risk ratios of 1.5 to 2.5 were observed for low birth weight (less than 2500 g) and for fetal growth indices that express birth weight as a function of length of gestation (e.g., small-for-gestational age, intrauterine growth retardation). The 95% confidence intervals of these risk ratios included 1, however, precluding rejection of the null hypothesis of no association. We conclude that the risk of adverse fetal growth is not increased at cord blood lead levels less than 15 micrograms/dl but that modest increases in risk may be associated with levels greater than or equal to 15 micrograms/dl.

Body Weight↗
PubMed1987

Longitudinal analyses of prenatal and postnatal lead exposure and early cognitive development.

In a prospective cohort study of 249 children from birth to two years of age, we assessed the relation between prenatal and postnatal lead exposure and early cognitive development. On the basis of lead levels in umbilical-cord blood, children were assigned to one of three prenatal-exposure groups: low (less than 3 micrograms per deciliter), medium (6 to 7 micrograms per deciliter), or high (greater than or equal to 10 micrograms per deciliter). Development was assessed semiannually, beginning at the age of six months, with use of the Mental Development Index of the Bayley Scales of Infant Development (mean +/- SD, 100 +/- 16). Capillary-blood samples obtained at the same times provided measures of postnatal lead exposure. Regression methods for longitudinal data were used to evaluate the association between infants' lead levels and their development scores after adjustment for potential confounders. At all ages, infants in the high-prenatal-exposure group scored lower than infants in the other two groups. The estimated difference between the overall performance of the low-exposure and high-exposure groups was 4.8 points (95 percent confidence interval, 2.3 to 7.3). Between the medium- and high-exposure groups, the estimated difference was 3.8 points (95 percent confidence interval, 1.3 to 6.3). Scores were not related to infants' postnatal blood lead levels. It appears that the fetus may be adversely affected at blood lead concentrations well below 25 micrograms per deciliter, the level currently defined by the Centers for Disease Control as the highest acceptable level for young children.

Child Development↗
PubMed1987

Pregnancy hypertension, blood pressure during labor, and blood lead levels.

Pregnancy hypertension, blood pressure during labor, and the umbilical cord blood lead concentration were assessed in 3851 women for whom additional demographic, medical, and personal information was available. Lead levels correlated with both systolic (Pearson r = 0.081, p = 0.0001) and diastolic (r = 0.051, p = 0.002) blood pressures during labor. The incidence of pregnancy hypertension increased with lead level. Multivariate models of pregnancy hypertension and systolic blood pressure as a function of maternal age, parity, hematocrit, ponderal index, race, and diabetes were improved by including lead as a predictor variable. At these observed levels of exposure (mean blood lead, 6.9 +/- 3.3 [SD] micrograms/dl), lead appears to have a small but demonstrable association with pregnancy hypertension and blood pressure at the time of delivery, but not with preeclampsia.

Adult↗
PubMed1986

Correlates of low-level lead exposure in urban children at 2 years of age.

The blood lead levels of a large number of US preschool children approach the value regarded as the upper limit of normal. To reduce the number of children whose levels increase into the range thought to be toxic, the antecedents and correlates of levels in the 0- to 25-micrograms/dL range must be identified. In a large longitudinal study of middle and upper-middle class children living in metropolitan Boston, we evaluated how well five sets of variables predicted children's blood lead levels at 2 years of age: environmental lead sources, mouthing activity, home environment/care giving, prior developmental status, and sociodemographic characteristics. A series of bivariate and multivariate analyses indicated that only environmental lead sources and, to a lesser extent, mouthing activity accounted for significant portions of the variance in blood lead levels. Environmental lead sources were not significantly related to the home environment/care-giving variables or to sociodemographic characteristics. The most promising approach for achieving community-wide reductions in children's blood lead levels is reduction in the amount of lead in the proximate environment.

Analysis of Variance↗
PubMed1985

Environmental correlates of infant blood lead levels in Boston.

From a blood lead survey of 11,837 births, 249 newborns were enrolled in a 2-year, longitudinal study. Their blood leads (PbB) were measured semiannually, and their homes were visited for repeated collections of dust, soil, indoor air, tap water, and paint. Recent refinishing activity and the sizes of nearby streets were recorded. Overall mean PbB was 7.2 micrograms/dl (SD = 5.3) at birth. PbB did not vary systematically with age. Each subject's average postnatal PbB correlated highly with the amount of lead in dust (r = 0.4, P less than 0.0001) and soil (r = 0.3, P less than 0.001), and with the lead in paint (r = 0.2, P less than 0.01). Dust, soil and air lead levels correlated with one another. Refinishing activity in the presence of lead paint was associated with elevations of PbB. Water lead, proximate traffic, weight of recovered dust, race, maternal age and education, and sex were not predictive of PbB. Multivariate models of PbB were constructed that become increasingly predictive with age (r2 = 20 to 37%). Indoor dust lead, lead in soil, refinishing activity, and season were the independent variables.

Air Pollutants↗
PubMed1981

Microsomal enzyme induction and gingival enlargement in subjects taking phenytoin.

Subjects taking the anticonvulsant phenytoin were examined for gingival enlargement and skin-fold thickness. Induced synthesis of their hepatic microsomal enzymes was estimated by measuring urinary D-glucaric acid. Gingival enlargement was positively correlated (p less than 0.05) with urinary D-glucaric acid. Although skin-fold thickness was not correlated with either urinary D-glucaric acid or gingival enlargement, mean gingival enlargement was greater in some subjects who did have an increased skin thickness than in those with normal skin thickness. The results suggest that induction of microsomal enzyme synthesis, as estimated by urinary D-glucaric acid, is related to taking phenytoin, as is gingival enlargement, and that there are other factors that affect both phenomena.

Adolescent↗
PubMed1975

Dental management of the patient with biliary atresia.

Biliary atresia is a disease of unknown origin characterized by partial or total absence of the biliary tract. While this condition is rare, the medical and surgical management makes the ramifications for dental treatment increasingly complex. This article reviews the disease and its complications and documents dental treatment of two patients.

Bile Ducts↗
PubMedDate not supplied

Low-level lead exposure, social class, and infant development.

A prospective cohort study was conducted to assess the association between early development and low-level prenatal and postnatal lead exposure. Infants' performance between 6 and 24 months on the Mental Development Index of the Bayley Scales of Infant Development declined with increasing concentration of lead in blood, but the decline varied with children's age at exposure, level of exposure, and socioeconomic status. Within the second year of life, the performance of children in lower socioeconomic strata was adversely affected at lower levels of prenatal exposure (blood lead levels of 6 to 7 micrograms/dl) than was the performance of children in higher socioeconomic strata. However, even the performance of these advantaged infants was lower when cord blood lead level exceeded 10 micrograms/dl, well below the figure currently regarded as the maximum permissable level for young children. Exploratory analyses suggested that early postnatal blood lead levels between 10 and 25 micrograms/dl were also associated with lower Mental Development Index scores, but only among children in lower socioeconomic strata.

Aging↗
PubMedDate not supplied

Variability of blood lead concentrations during infancy.

As part of a study of early childhood development, more than 200 children had their blood lead concentrations (PbB) determined semiannually during the first 2 yr of life. These children were selected from 11,837 consecutive births surveyed for umbilical cord PbB at Boston Lying-In Hospital. Candidate subjects were drawn from the highest, lowest, and middle deciles of PbB. The mean PbB was 7.2 +/- 5.3 (standard deviation) micrograms/dl at birth and did not change appreciably with age. However, the average change in an individual's PbB every 6 months was 4 micrograms/dl, which was several fold in excess of the analytical reproducibility. Only 25% of the children in the highest category at birth were in the highest category at 2 yr of age. Approximately 40% of the children remained in their immediately previous PbB tertile category. A stochastic description of these patterns of change fits the data. Our results should caution investigators who might wish to rely on a single determination to categorize children with PbB.

Fetal Blood↗
PubMedDate not supplied

Lead in umbilical blood, indoor air, tap water, and gasoline in Boston.

A strong statistical correlation was found among the monthly averages of lead concentrations in umbilical cord blood (about 500 births/month), indoor air (12 sites/month), and gasoline lead sales between March, 1980 and April, 1981 in Boston. Tap water lead (24/month) variations did not correlate with blood lead in this population.

Air Pollutants↗
PubMedDate not supplied

Lead in milk and infant blood: a dose-response model.

As part of a longitudinal study of the sources and developmental effects of current urban lead exposure, lead was measured in tap water from the homes of 249 infants, in 100 breast milk samples, and in 73 samples of the infant formula used by non-nursing mothers. Also, the blood lead levels of the infants who received these fluids were determined at birth and at 6 months of age. Among the infants who were breast fed, the lead content of their milks correlated very well with their 6-month blood lead levels (r = .42, P = .0003). The mean lead content of infant formulas and breast milk were not significantly different, nor was the blood lead of children fed one or the other. Lead levels in maternal milk correlated poorly with umbilical cord blood lead (r = .18, P = .10). Tap water and infant blood lead levels correlated minimally (r = .11, P = .10). Since milk represents much of the diet of young infants and because breast milk lead levels are stable, it is possible to relate blood lead and daily dosage in this population.

Female↗
PubMedDate not supplied

Longitudinal relationship between dentin lead levels in childhood and bone lead levels in young adulthood.

A retrospective cohort study was conducted to examine the relationship between tooth lead in children and bone lead levels in young adults. Members of a cohort of young adults were reassessed 13 y after initial examination at an ambulatory clinical research center. Dentin lead levels were measured by anodic stripping voltammetry during the years 1975-1978, and bone lead levels of the tibia and patella were measured by K-x-ray fluorescence technique during 1989 and 1990. A total of 63 subjects who had no history of chelation or had no missing information on potential confounders were studied. The median follow-up interval was 13.2 y. Dentin lead levels averaged 13.4 micrograms/g (standard deviation [SD] = 10.7 micrograms/g, range = 2.9-51.8 micrograms/g), and bone lead levels averaged 1.3 micrograms/g (SD = 4.4 micrograms/g, range = -9-13 micrograms/g) for tibia and 5.4 micrograms/g (SD = 8.4 micrograms/g, range = -10-25 micrograms/g) for patella. The authors controlled for age, sex, race, and mother's socioeconomic status, and dentin lead levels were predictive of higher tibia, patella, and mean bone lead levels in 32 subjects (follow-up interval of 11.8-13.2 y). A correction for measurement errors in dentin lead measurements was made, and it was determined that a 10-micrograms/g increase in dentin lead levels in childhood was predictive of a 1-microgram/g increase in tibia lead levels, a 5-micrograms/g increase in patella lead levels, and a 3-micrograms/g increase in mean bone lead levels among the young adults. It was concluded, therefore, that lead exposure in early life may be used to predict elevated body burden up to 13 y later.

Adolescent↗
PubMedDate not supplied

Year one dental visit.

Explore the source record for details and available documents.

Child, Preschool↗