Thesis (M.S.)--University of Michigan, 1993.

Thesis (D.P.H.)--University of Oklahoma. / Bibliography: leaves 71-75.

Thesis (M.S.)--University of Michigan, 1993.

The Hispanic birthweight paradox, whereby Hispanic women exhibit a comparable or lower risk of bearing a low birthweight infant than their white counterparts despite relative socioeconomic disadvantage, has been observed across a number of research studies. However, the majority of evidence for the paradox has focused on Hispanics in aggregate form or on populations with primarily Mexican ancestry and has relied largely on outcome measures with important methodological shortcomings. Furthermore, studies have identified the variation of birthweight risk among Hispanics by nativity, maternal education and neighborhood composition, but the evidence has been scarce and inconsistent. The overall goal of this dissertation was to investigate the Hispanic health paradox with relation to measures of birthweight and infant size in births to women residing in New York City aged 20 years and older, using birth records for years 2003 through 2007 collected by the Office of Vital Statistics of the New York City Department of Health and Mental Hygiene (N=460,881). The main outcomes of interest in this study were mean birthweight, low birthweight (LBW, defined as < 2500 grams versus ≥ 2500 grams) and small for gestational age (SGA, calculated as the 10th percentile for birthweight at each week of gestational age and by sex). Multilevel logistic models with random effects were used to estimate odds ratios for the association between race/ethnicity and measures of birthweight and infant size, while controlling for individual-level and contextual factors and accounting for the correlation between observations within the same neighborhood. Analyses were conducted with Hispanics as an aggregate group as well as with race/ethnic-nativity subgroups. In addition, effect measure modification by maternal education and by neighborhood proportion of Hispanic population (NPHP) were examined. This research confirmed the Hispanic paradox in SGA analyses for Hispanics overall and for both U.S.-born and foreign-born Hispanics, but not in analyses with LBW or with mean birthweight. As compared to white women, black women exhibited 50% greater risk (OR:1.50;95%CI:1.45,1.55) and Hispanic women comparable risk (OR:1.03;95%CI:1.00,1.06) of having an SGA infant, in a fully adjusted model. With regard to LBW, the risk was more than double for black women (OR:2.25;95%CI:2.16,2.35) and close to 50% greater for Hispanic women (OR:1.46;95%CI:1.40,1.53) as compared to that of their white counterparts. In addition, the mean birthweight of infants born to Hispanic women was significantly lower compared to those born to white women. Furthermore, the relationship between race/ethnicity and all three measures of birthweight and infant size varied by maternal nativity status (p<0.0001), with infants of foreign-born women experiencing more favorable outcomes relative to their U.S.-born counterparts. The paradox with SGA was also apparent across most Hispanic race/ethnicity-nativity subgroups, The odds were greatest among black and Puerto Rican women overall (OR:1.52;95%CI:1.47,1.57 and OR:1.17;95%CI:1.13,1.22, respectively) and lowest among Mexican and South American women overall, (OR:0.91;95%CI:0.87,0.95 and OR:0.85;95%CI:0.80,0.89) as compared to white women in a fully adjusted model. The odds of SGA for infants born to Dominicans, Central Americans and Cubans in the fully adjusted model were similar to those born to whites. In addition, SGA varied by maternal nativity status (p<0.0001), with more favorable SGA odds observed among infants of most foreign-born women, as compared to whites. The exception was U.S.-born Puerto Ricans who consistently exhibited elevated risk of SGA relative to whites. The association of race/ethnicity-nativity with SGA varied by maternal educational attainment (p<0.0001), but the influence varied by subgroup. The observed advantage of foreign birth was stronger among less educated women of all Hispanic subgroups other than Puerto Ricans and Cubans. Similarly, the variation of SGA risk by neighborhood proportion of Hispanic population (NPHP) differed across subgroups (p<0.0001). NPHP did not appear to influence the association between race/ethnicity-nativity and SGA in a consistent pattern, but among black women and US-born Puerto Rican women greater NPHP was associated with a higher risk of SGA. Findings from this study underscore the importance of using SGA an accurate measure of infant size and of conducting analyses disaggregating race/ethnicity and nativity subgroups. Future research should focus on factors that contribute to the resilience of Hispanic subgroups in the face of adverse economic circumstances, such as the role of social support networks and acculturation. Greater understanding of the salubrious circumstances that lower the risk of adverse birth outcomes has major public health benefits, especially for a wide-ranging population of mothers, Hispanic and non-Hispanic, and their infants.

published_or_final_version / Public Health / Master / Master of Public Health

No description available.

Impairments in executive function have been posited to account for some of the poor cognitive and educational outcomes associated with very preterm birth. As part of a prospective, longitudinal study, this research examined executive function in a regionally representative sample of 103 children born very preterm and/or very low birth weight (<33 weeks GA / <1500g) and a comparison sample of 108 full term children at age 6 years (corrected for prematurity). The specific aims of the study were 1) to describe the performance of children born very preterm and full term on a range of executive function measures, 2) to identify the antecedent medical, neurological and socio-familial factors associated with executive function performance within the very preterm group, and 3) to examine linkages between children’s executive function performance and their academic achievement at age 6 years. Children underwent a comprehensive developmental assessment, including standardised tests of IQ and academic achievement in mathematics, reading and receptive language. Additionally, they completed a number of executive function tasks selected to assess verbal working memory (Digit Span), spatial working memory (Corsi Blocks), planning and problem-solving (Tower of Hanoi), selective attention (Visual Search), shifting and inhibitory control (Detour Reaching Box) and sustained attention and inhibition (Kiddie-Conner’s Continuous Performance Task; K-CPT). Parents and teachers of these children also completed the Behavioural Rating Inventory of Executive Function and teachers rated children’s performance in reading, arithmetic and comprehension in relation to their classroom peers. Results revealed a pervasive pattern of impairment across multiple measures of executive function in children born very preterm relative to their full term peers. Specifically, children born very preterm were less likely to be able to complete any backward Digit Span trials (p<0.05) and showed lower raw scores on this task (p<0.1) than children in the full term group. Children born very preterm showed lower spatial span scores on the Corsi Blocks Task (p<0.01). They also showed lower planning performance, as assessed by the Tower of Hanoi (p<0.05). Children born very preterm made more inhibitory control/shift errors on the Detour Reaching Box and demonstrated less accuracy in their Visual Search (p<0.001) than children born full term. Finally, they showed lower levels of sustained attention on the K-CPT (p<0.001). Parents, teachers and examiners rated these children as having greater difficulties across multiple areas of executive function. These differences remained significant after controlling for group differences in socioeconomic status and after exclusion of children with severe cognitive and motor impairments. Within the very preterm group, antecedent predictors of poorer working memory and planning performance included male gender (p<0.001), intrauterine infection (p<0.05) and severity of cerebral white matter abnormality on term-equivalent MRI (p<0.05). Lower gestational age (p<0.05) and male gender (p<0.001) were related to poorer executive attention performance. Familial predictors of poorer executive performance included instability in parenting (p<0.05), higher levels of parental intrusiveness (p<0.1) and lower levels of interactional synchrony (p<0.05) between parent and child, recorded at earlier follow-up points. Finally, children’s executive function performance was highly correlated with school achievement in reading, arithmetic and language comprehension (p<0.001). Findings suggest a global pattern of executive impairment amongst children born very preterm, with these difficulties placing children at risk for poor academic performance and learning difficulties. Findings also suggest that both neurological pathology and early parenting experiences are important mediators of the relationship between very preterm birth and poor executive function, highlighting the importance of these areas for early intervention.

No description available.

MSc, Child Health Neurodevelopment, Faculty of Health Sciences, University of the Witwatersrand / Background: Prematurely born very low birth weight (VLBW) infants are at high risk for neurodevelopmental problems and require regular follow up. Within the South African context, one needs a reliable and user-friendly screening tool to identify those who require intervention. The Molteno Adapted Scale (MAS) is used for this purpose in many clinics, but it has never been validated. Aim: To assess if the MAS performed on young prematurely born infants reliably predicts the neurodevelopmental outcome at 2 years of age as determined by the Griffiths Mental Development Scales (GMDS). Methods: A retrospective study of records of VLBW infants between 1998 and 2006, from the Panorama Medi-Clinic Neonatal Intensive Care Unit follow up clinic. Infants with birth weights < 1500g and accurately assessed gestation < 34 weeks were included. Those who suffered brain insults e.g. meningitis, between the early assessments and the GMDS were excluded. For each child, quotients obtained from the MAS at early assessments were compared to quotients obtained on the GMDS after 2 years of age using Spearman correlations. Results: Fifty-two (27 boys) VLBW infants were included in the study, with a mean birth weight of 981.2 ± 225.5 g and mean gestation of 27.7 ± 1.9 weeks. Thirteen (25%) infants had cerebral palsy and two had visual impairment. MAS assessments were performed at mean ages of 5.1, 10.1 and 16.8 months and the GMDS at a mean age of 28.8 months. Correlations between the MAS and the GMDS ranged from 0.1 - 0.43 at the first assessment, 0.29 - 0.46 at the second assessment and 0.52 - 0.63 at the third assessment. Correlations were statistically significant for the Fine Motor quotient on the MAS at the first assessment, the General quotient and Personal Social quotient at the second assessment, and all quotients except Personal Social at the third assessment. Conclusion: Developmental quotients on the MAS at 5.1 and 10.1 months have a weak positive correlation with the GMDS at 28 months. The MAS at 16.8 months significantly correlated with the developmental outcome as assessed on the GMDS at a mean age of 28 months in prematurely born VLBW infants.

A Dissertation Submitted to the Faculty of Medicine, University of the Witwatersrand, Johannesburg for the degree of Master of Medicine. / Disturbed mineral and bone metabolism is frequently found in very low-birth-weight infants fed breast-milk during the first three months of life. The study was designed to assess the prevalence of this disturbed mineral homeostasis in a very low-birth-weight populatiun at Baragwanath Hospital and to determine whether the addition of a preterm infant formula to the feeds reduced the prevalence and increased the rate of weight gain. Fifty three neonates weighing less than 1200g born at Baragwanath Hospital were monitored for weight gain, growth and for biochemical and radiological evidence of metabolic bone disease. The infants were randomized to receive either breast-milk only feeds or a combination of breast-milk and a premature formula in order to assess the effect of the different feeds on the development of bone disease. Weight gain and growth were similar in both groups. Calcium and phosphorus intakes were higher in the mixed feeding group. However, serum calcium and phosphorus values were similar in the two groups throughout the study. The breast-milk group had significantly higher alkaline phosphatase levels. Radiological rickets was uncommun in both groups, although periosteal reactions and osteopenia occurred frequently and with similar prevalence in both groups. Overt rickets is not a major problem in very-low birth- weight infants born at Baragwanath Hospital, although raised serum alkaline phosphatase values occur frequently. Feeding with breast-milk and a premature infant formula in equal proportions (as opposed to breast-milk only) does not appear to have any effect on weight gain and growth in very low-birth-weight infants, but does partially prevent the pathological rise in alkaline phosphatase levels. / Andrew Chakane 2019