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Biomedical subjects

Nigel Paneth

Publications and source records attributed to Nigel Paneth.

At least 19 recordsLinked to original sources
PubMed2007

Physical activity and fetal growth during pregnancy.

OBJECTIVE: To assess the separate and combined relationships of aerobic physical activity during pregnancy, maternal weight gain during pregnancy, and height to the fetal growth ratio. METHODS: The aerobic physical activity of 51 healthy, nonsmoking pregnant women was assessed for 48 hours at both 20 and 32 weeks of pregnancy by accelerometry, heart rate monitoring, and physical activity recall. We analyzed the relationship between maternal physical activity and the fetal growth ratio. RESULTS: All women included in the analysis completed healthy, uncomplicated pregnancies and delivered infants with a weight range of 2,743-4,943 g. Aerobic physical activity assessed by accelerometry was strongly and inversely associated with fetal growth ratio (r=-0.42; P<.002). Infants born to women in the highest quartile of physical activity weighed 608 g less than infants born to women in the lowest quartile. The inverse relationship between physical activity and fetal growth ratio was moderated by maternal height; virtually all the effect was seen in mothers taller than the sample median (1.65 m). Similar relationships were found across methods of physical activity measurement. CONCLUSION: Aerobic physical activity in pregnancy may be an important determinant of birth weight within the normal range, especially in taller mothers. LEVEL OF EVIDENCE: II.

Birth Weight↗
PubMed2007

Ambient manganese exposure is negatively associated with human sperm motility and concentration.

BACKGROUND: Occupational and experimental animal studies indicate that exposure to high levels of manganese impairs male fertility, but the effects of ambient manganese in humans are not known. METHODS: We measured blood levels of manganese and selenium in 200 infertility clinic clients in a cross-sectional study. Correlations between metals and semen variables were determined, adjusting for other risk factors. Outcomes were low motility (<50% motile), low concentration (<20 million/mL), or low morphology (<4% normal). We also investigated dose-response relationships between quartiles of manganese exposure and sperm parameters. RESULTS: High manganese level was associated with increased risk of low sperm motility (odds ratio = 5.4; 95% confidence interval = 1.6-17.6) and low sperm concentration (2.4; 1.2-4.9). We saw a U-shaped dose-response pattern between quartiles of manganese exposure and all 3 sperm parameters. CONCLUSION: Ambient exposure to manganese levels is associated with a reduction in sperm motility and concentration. No adverse effects were seen for high selenium.

Adult↗
PubMed2006

Growth trajectories of extremely low birth weight infants from birth to young adulthood: a longitudinal, population-based study.

We compared sex-specific growth attainment of a population-based cohort of 147/166 (89%) extremely low birthweight (ELBW < 1000 g) and 131/145 (90%) sociodemographically comparable normal birthweight (NBW) cohort at young adulthood, and examined the pattern of growth trajectories and correlates of growth at ages 1, 2, 3, and 8 y, and teen and young adulthood (mean age, 23.3 versus 23.6 y). The proportion considered small for gestational age was ELBW 25% versus NBW 3%; and 26% versus 2% had neurosensory impairments. Weight for age z-scores for ELBW showed substantial decline to age 3 y, with subsequent significant catch-up to adolescence and smaller gains to adulthood. Height for age z-scores showed both sexes of ELBW were disadvantaged at every age compared with NBW and their expected mid-parental height. The BMI z-scores for ELBW showed a sustained incline from age 3 to adulthood, where both sexes normalized to above zero, and were comparable to their peers. ELBW children showed growth failure during infancy, followed by accelerated weight gain and crossing of BMI percentiles at adolescence, a pattern that may increase the risk of insulin resistance and coronary heart disease. However, normalization of BMI for both sexes at adulthood suggests that final growth was proportionate.

Adult↗
PubMed2006

Transition of extremely low-birth-weight infants from adolescence to young adulthood: comparison with normal birth-weight controls.

CONTEXT: Traditionally, educational attainment, getting a job, living independently, getting married, and parenthood have been considered as markers of successful transition to adulthood. OBJECTIVE: To describe and compare the achievement and the age at attainment of the above markers between extremely low-birth-weight (ELBW) and normal birth-weight (NBW) young adults. DESIGN, SETTING, AND PARTICIPANTS: A prospective, longitudinal, population-based study in central-west Ontario, Canada, of 166 ELBW participants who weighed 501 to 1000 g at birth (1977-1982) and 145 sociodemographically comparable NBW participants assessed at young adulthood (22-25 years). Interviewers masked to participant status administered validated questionnaires via face-to-face interviews between January 1, 2002, and April 30, 2004. MAIN OUTCOME MEASURES: Markers of successful transition to adulthood, including educational attainment, student and/or worker role, independent living, getting married, and parenthood. RESULTS: At young adulthood, 149 (90%) of 166 ELBW participants and 133 (92%) of 145 NBW participants completed the assessments at mean (SD) age of 23.3 (1.2) years and 23.6 (1.1) years, respectively. We included participants with neurosensory impairments (ELBW vs NBW: 40 [27%] vs 3 [2%]) and 7 proxy respondents. The proportion who graduated from high school was similar (82% vs 87%, P = .21). Overall, no statistically significant differences were observed in the education achieved to date. A substantial proportion of both groups were still pursuing postsecondary education (47 [32%] vs 44 [33%]). No significant differences were observed in employment/school status; 71 (48%) ELBW vs 76 (57%) NBW young adults were permanently employed (P = .09). In a subanalysis, a higher proportion of ELBW young adults were neither employed nor in school (39 [26%] vs 20 [15%], P = .02 by Holm's correction); these differences did not persist when participants with disabilities were excluded. No significant differences were found in the proportion living independently (63 [42%] vs 70 [53%], P = .19), married/cohabitating (34 [23%] vs 33 [25%], P = .69), or who were parents (16 [11%] vs 19 [14%], P = .36). The age at attainment of the above markers was similar for both cohorts. CONCLUSION: Our study results indicate that a significant majority of former ELBW infants have overcome their earlier difficulties to become functional young adults.

Achievement↗
PubMed2006

Motor and cognitive outcomes in nondisabled low-birth-weight adolescents: early determinants.

OBJECTIVES: To describe motor and cognitive outcomes in nondisabled low-birth-weight (LBW) adolescents and to determine the relation of specific prenatal, perinatal, and neonatal risk factors to these outcomes. DESIGN: A prospective epidemiological study. SETTING: An adolescent follow-up of a regional LBW (<2000 g) cohort born in or admitted to 3 hospitals between September 1, 1984, and June 30, 1987 (n = 1105). Of 862 eligible survivors, 628 (72.9%) underwent assessment at a mean age of 16 years; of these, 33 had severe disability that precluded psychometric evaluation. The 474 nondisabled adolescents undergoing assessment at home had slightly less social risk at birth than did all other nondisabled eligible adolescents. PARTICIPANTS: The 474 nondisabled LBW adolescents assessed at home. Main Exposures Basic birth characteristics (social risk, sex, fetal growth ratio, and gestational age), neonatal cranial ultrasound abnormalities, and other early medical complications. MAIN OUTCOME MEASURES: Riley Motor Problems Inventory and Wechsler Abbreviated Scales of Intelligence. RESULTS: Nondisabled LBW adolescents had an excess of motor problems compared with the normative sample. The IQ scores, although within the normal range, were significantly lower than population norms. Independent predictors of total motor problems included male sex, white matter injury on neonatal ultrasound, and days of ventilation. Independent predictors of lower Full Scale IQ scores included social disadvantage, fetal growth ratio, and white matter injury on neonatal ultrasound. CONCLUSIONS: Specific prenatal, perinatal, and neonatal risk factors influence motor and cognitive performance in nondisabled LBW survivors well into adolescence, even when controlling for social risk. Advances in maternal-fetal and neonatal care can substantially improve these long-term outcomes.

Adolescent↗
PubMed2006

The descriptive epidemiology of cerebral palsy.

The prevalence of cerebral palsy (CP) ranges from 1.5 to 2.5 per 1000 live births with little or no variation among western nations, although data from the Americas are sparse. Time trends in overall CP prevalence for the past 40 years are most notable for their stability, but a modest increase in prevalence probably occurred in the last decades of the twentieth century. European countries have pioneered the development of CP registries, and as a result, CP is a condition that is enumerated regularly in several parts of the world. The United States has no CP registries, although ongoing surveillance of CP, along with other developmental disabilities, is performed by the Centers for Disease Control and Prevention in metropolitan Atlanta.

Cerebral Palsy↗
PubMed2006

Reports of birthweight by adolescents and their mothers: comparing accuracy and identifying correlates.

Birthweight is associated with health outcomes throughout the lifespan. Official birthweight records are not always available, and researchers must rely on self-reports for birthweight information. This study evaluates the accuracy of adolescent self-reports of birthweight, using medical records as a standard, and compares it with maternal reports. It also examines potential correlates of accuracy. Respondents are 17-year-old adolescents and their mothers, who participated in a follow-up study of randomly selected samples from newborn discharge lists (1983-85) of two major hospitals in south-east Michigan. Nearly one-quarter of the adolescents stated that they did not know their own birthweight, with males twice as likely as females to respond 'don't know'. In addition, self-reports of birthweight among the remaining adolescents were inaccurate, and accuracy was inversely related to birthweight. While maternal reports of offspring's birthweight are highly accurate across diverse subgroups of the population, adolescent self-reports of birthweight are unlikely to be useful in medical research.

Adolescent↗
PubMed2006

Self-perceived health-related quality of life of former extremely low birth weight infants at young adulthood.

OBJECTIVES: The goals were to compare the self-reported, health-related quality of life of former extremely low birth weight and normal birth weight infants at young adulthood and to determine whether there were any changes over time. METHODS: A prospective, longitudinal, population-based study with concurrent control subjects was performed. We interviewed 143 of 166 extremely low birth weight survivors (birth weight: 501-1000 g; 1977-1982 births) and 130 of 145 sociodemographically comparable, normal birth weight, reference subjects. Neurosensory impairments were present for 27% extremely low birth weight and 2% normal birth weight young adults. Health Utilities Index 2 was used to assess health status, and standard gamble technique was used to measure directly the self-reported, health-related, quality of life and 4 hypothetical health states. RESULTS: Extremely low birth weight young adults reported more functional limitations in cognition, sensation, mobility, and self-care, compared with control subjects. There were no differences between groups in the mean self-reported, health-related, quality of life or between impaired (n = 38) and nonimpaired (n = 105) extremely low birth weight subjects. However, with a conservative approach of assigning a score of 0 for 10 severely disabled, extremely low birth weight subjects, the mean health-related quality of life was significantly lower than control values. Repeated-measures analysis of variance to compare health-related quality-of-life measurements obtained for young adults and teens showed the same decline in scores over time for both groups. There were no differences between groups in the ratings provided for the hypothetical health states. CONCLUSIONS: At young adulthood, health-related quality of life was not related to size at birth or to the presence of disability. There was a small decrease in health-related quality-of-life scores over time for both groups.

Adult↗
PubMed2006

Neonatal thyroxine supplementation for transient hypothyroxinemia of prematurity : beneficial or detrimental?

Extremely low birth-weight newborns (<1000g) experience low levels of thyroid hormone that vary inversely with the severity of neonatal illness and the extent of developmental immaturity with levels reaching a nadir at approximate, equals7 days after birth; this phenomenon can persist for several weeks. In the absence of transplacental passage, 30-50% of these neonates cannot generate sufficient quantities of thyroid hormone to meet postnatal demands, placing them at an increased risk for developmental delay and cerebral palsy. Population surveys and interventional trials suggest that a therapeutic opening exists during a 'window of opportunity' corresponding to this period of diminished capacity. Variables to consider before intervention focus on the consideration that supplementation of both the substrate thyroxine and the active hormone triiodothyronine may be necessary in quantities that do not suppress thyroid-stimulating hormone release, yet overcome the persistence of increased conversion to 3,3'5'-triodo-L-thyronine, terminal deiodination, and activity of the sulfation inactivation pathways, as well as the diminished capacity of the newborn to accommodate postnatal physiologic changes. Single daily replacement doses may suppress levels of converting enzymes in the brain, suggesting that physiologic 'mimicry' provided by a constant infusion may be the preferred dosing option. Properly powered clinical trials targeting long-term developmental outcomes are needed to discern whether these interventions will do more than simply elevate blood levels of thyroid hormones to the target values of either the fetus or developing neonate. Identifying the appropriate indications for supplementation may alleviate individual pain and distress due to disability for several hundred extremely low birth-weight neonates each year in the US alone, and save society a pro-rated lifetime cost of nearly $US1 million per child.

Humans↗
PubMed2005

Maternal smoking during pregnancy and offspring IQ.

BACKGROUND: Maternal smoking in pregnancy lowers birthweight. It is unclear, however, whether smoking during pregnancy lowers offspring IQ, and, if it does, whether it is through the smoking effect on fetal growth. METHOD: Representative samples of low birthweight (<2500 g) and normal birthweight children born in 1983-85 from inner-city and suburban communities in southeast Michigan, USA were assessed at ages 6, 11, and 17, using Wechsler intelligence tests. Smoking during pregnancy was ascertained from mothers at the first assessment; and smoking at any time was ascertained at the first and second assessment. Generalized estimating equation models were used, with children's IQ at all three assessments as outcomes (n = 798). RESULTS: Without adjustment, offspring of mothers who smoked during pregnancy scored 6.8 IQ points lower than offspring of mothers who never smoked, on average. Low birthweight children scored 5.4 IQ points lower than normal birthweight children, on average. The statistical association of maternal smoking with offspring IQ was confounded by maternal characteristics, chiefly, maternal cognitive ability as measured by IQ and education; adjustment for these factors eliminated the association. By contrast, adjustment for maternal IQ and education as well as smoking during pregnancy had a negligible effect on the low birthweight-related IQ deficit. Low birthweight did not mediate the association of smoking and lowered IQ in offspring. CONCLUSION: Maternal smoking during pregnancy is a proxy for a matrix of vulnerabilities for adverse child cognitive development and has no direct causal effect on child's IQ. The relationship of low birthweight and IQ is independent of maternal smoking and maternal cognitive abilities.

Adolescent↗
PubMed2005

Proposed definition and classification of cerebral palsy, April 2005.

Because of the availability of new knowledge about the neurobiology of developmental brain injury, information that epidemiology and modern brain imaging is providing, the availability of more precise measuring instruments of patient performance, and the increase in studies evaluating the efficacy of therapy for the consequences of injury, the need for reconsideration of the definition and classification of cerebral palsy (CP) has become evident. Pertinent material was reviewed at an international symposium participated in by selected leaders in the preclinical and clinical sciences. Suggestions were made about the content of a revised definition and classification of CP that would meet the needs of clinicians, investigators, and health officials, and provide a common language for improved communication. With leadership and direction from an Executive Committee, panels utilized this information and have generated a revised Definition and Classification of Cerebral Palsy. The Executive Committee presents this revision and welcomes substantive comments about it.

Cerebral Palsy↗
PubMed2004

Special education services and school performance in a regional cohort of low-birthweight infants at age nine.

Previous research has shown that low birthweight is a predictor of several adverse educational outcomes, including special educational placement, by middle school age. Most low-birthweight follow-up studies that have extended to school age have focused on very small infants-- < 1500 or < 1000 g; less is known of the school age outcomes for infants with only moderately low birthweight (1500-2000 g). This study examines the prevalence of special educational placement and the relationship of such placement to grade retention, verbal and performance scores on tests of general intelligence, reading and maths achievement scores and classroom hyperactivity among low-birthweight children. In a regional birth cohort of 1105 infants born between 1984 and 1987 and weighing 500-2000 g, 868 children were available for follow-up at age nine. Information on special education placement as well as grade retention, intelligence, academic achievement and classroom behaviour was available on 645 (74% completion rate). Nearly a third of the cohort was classified as needing special education. Special education placement followed a birthweight gradient, occurring among 29.3% of children with birthweights 1500-2000 g, among 32.5% in children 1000-1500 g and 49.4% in children < 1000 g. Among children in special education, a similar birthweight gradient was found for maths achievement and hyperactivity, but not for reading achievement or IQ scores. Among children not in special education, only maths achievement showed such a decline with birthweight. A substantial proportion of low-birthweight children, including those of moderate low birthweight, receive special education services, although the need is greatest among those with the lowest birthweights. Maths achievement declined with birthweight regardless of educational placement. The medical and social risk factors that accompany low birthweight and may account for these findings, require further study.

Attention Deficit Disorder with Hyperactivity↗
PubMed2003

When are observational studies adequate to assess the efficacy of therapeutic interventions?

Four conditions are proposed under which observational research may be adequate to access the efficacy of therapeutic interventions. First, a randomized controlled trail is unethical, not feasible, or not cost-effective. Second, the study design is rigorous, optimal to test the a priori hypothesis, and faithfully executed. The cohort study is the analytical observational design least susceptible to biases and confounding. Even this design, however, may be impractical when the outcome is relatively rare or the interval between the exposure and outcome is relatively long. In these circumstances, the case-control study yields more timely information with less resource expenditure. Third, additional evidence supports the interpretation that the association between the therapeutic intervention and the health outcome is very likely to be causal (ie, the exposure is documented to precede the outcome; the effect size is large; a dose-responses relationship can be demonstrated; the outcome is associated only with the exposure and the exposure produces only the outcome of interest; the relationship is consistently identified in different populations with different experimental designs; or an etiologic mechanism for the association can be proposed). Fourth, certain features of the treatment-health outcome relationship are favorable to drawing inferences from observational research. These features include a large effect size; treatment assignment that is not a function of clinician or patient choice (as in ecologic designs); an outcome that follows the exposure closely in time; and the circumstance in which few other variables affect the risk of the outcome and these variables are well known and easily controllable in the study design or analysis. A useful exercise for large-scale changes in treatment is to examine population-wide health trends for their consistency or inconsistency with the proposition that the new intervention is effective.

Cohort Studies↗
PubMed2003

Reliability of classification of cerebral palsy in low-birthweight children in four countries.

The reliability of classification of cerebral palsy (CP) in low-birthweight children was assessed by using clinical and research study records sampled from population-based cohort studies in the USA, The Netherlands, Canada, and Germany. Records of neurological examination findings and functional motor assessments were submitted to up to five pediatricians with expertise in CP diagnosis, who grouped children into categories referred to as 'disabling' CP, 'non-disabling' CP, and no CP. Each study provided between 31 and 51 records of children assessed between 2 and 8 years of age, approximately equally divided among the three groupings. The discrimination between 'any CP' and 'no CP' was only fair (mean Kappa coefficients 0.37 to 0.69). However, when more detailed information describing motor function was used, children with 'disabling' CP could be distinguished, on the basis of records, from those without CP or with 'non-disabling' CP with good to excellent reliability (mean Kappa coefficients 0.69 to 0.88). Because of the substantially higher agreement observed when these functional distinctions are made, we recommend that reports or comparisons of rates of CP should include levels of motor function of children with CP, and not simply total CP, among the outcomes of interest.

Canada↗
PubMed2003

Labor and delivery factors in brain damage, disabling cerebral palsy, and neonatal death in low-birth-weight infants.

OBJECTIVE: We assessed the relationships between active labor and neonatal death, neonatal brain damage, and disabling cerebral palsy in low-birth-weight infants. STUDY DESIGN: A population-based cohort of 961 infants with birth weights of 580 to 2000 g and gestational ages >or=26 completed weeks. Neonatal brain damage was assessed by ultrasound scanning in the first weeks of life; disabling cerebral palsy was assessed at 2 years of age (corrected for gestational age). RESULTS: After being controlled for possible confounders, active labor was associated significantly with an increased risk of parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 2.3; 95% CI, 1.2-4.5) but not with germinal matrix/intraventricular hemorrhage (odds ratio, 1.3; 95% CI, 0.8-2.1), neonatal death (odds ratio, 1.8; 95% CI, 0.8-4.0), or disabling cerebral palsy (odds ratio, 1.6; 95% CI, 0.7-3.7). In vertex presentations only, active labor was associated with a nearly 4-fold increase in risk of neonatal death (odds ratio, 3.8; 95% CI, 1.3-10.9). In nonvertex presentations only, active labor was associated strongly with parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 4.3; 95% CI, 1.2-15.6) and disabling cerebral palsy (odds ratio, 8.2; 95% CI, 1.4-49.9). CONCLUSION: The only adverse outcome that was associated consistently with active labor was parenchymal echodensities/lucencies and/or ventricular enlargement. Fetal presentation modified the relationships between active labor and adverse outcomes. Delivery mode (whether vaginal or cesarean delivery) was not associated with any of the outcomes that were evaluated.

Brain Damage, Chronic↗