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Biomedical subjects

Robert S Byrd

Publications and source records attributed to Robert S Byrd.

6 recordsLinked to original sources
PubMed2006

Urban asthma.

PURPOSE OF REVIEW: To review the possible reasons why the prevalence and morbidity of asthma are greater in those living in an urban setting. RECENT FINDINGS: Urban asthma is associated with exposure to air pollution, urban allergens, and violence. Outdoor air pollution is a particular problem in urban areas and affects children more than adults. Asthma has been shown to be exacerbated by ozone, respirable particulates, and nitrogen dioxide. Exposure to high point sources of pollutants such as heavy traffic is of particular concern. Urban allergens include cockroach, mouse, and rat. Cockroach exposure increases the risk of asthma exacerbations and may increase the risk of developing asthma. Although mouse allergen is also found in suburban homes, the concentration is a log-fold higher in inner-city homes at levels known to elicit symptoms in workers in animal facilities. Rat allergen is found in a third of inner-city homes and is associated with asthma morbidity. A recent interventional study showed that comprehensive environmental control of cockroach allergen reduced asthma morbidity. Finally, stress elicits asthma symptoms and exposure to violence is associated with greater asthma morbidity. SUMMARY: The increase in prevalence and morbidity of asthma associated with urban living is associated with at least three plausible causative factors each of which is amenable to intervention, raising the issue of environmental justice issues: controlling air pollution in general and exposure to point sources in particular; reducing cockroach, mice, and rat infestations; and preventing violence.

Air Pollution↗
PubMed2006

Development and validation of the Rapid Estimate of Adolescent Literacy in Medicine (REALM-Teen): a tool to screen adolescents for below-grade reading in health care settings.

OBJECTIVE: The magnitude and consequences of low literacy in adolescent health and health care are unknown. The purpose of this study was to validate the Rapid Estimate of Adolescent Literacy in Medicine (REALM-Teen), a word-recognition test in English that can be used as a brief literacy-screening tool in health care settings. PATIENTS AND METHODS: A total of 1533 adolescents aged 10 to 19 years attending 1 of 5 middle schools, 3 high schools, 1 pediatric clinic, or 2 summer programs in Louisiana and North Carolina participated in face-to-face interviews. Demographic information was solicited, and participants were administered a battery of reading tests, including the REALM-Teen, Wide Range Achievement Test-Revised (WRAT-3), and Slosson Oral Reading Test-Revised (SORT-R). Internal consistency for the REALM-Teen was determined using Cronbach's alpha, and criterion validity was established through correlations with both the WRAT-R and SORT-R. Using reading below grade level (according to SORT-R scores) as an outcome, instrument accuracy and corresponding cutoff scores were calculated by plotting receiver operating characteristic curves and stratum-specific likelihood ratios. RESULTS: Participants were 50% black and 53% female; 34% were enrolled in middle school and 66% in high school. The average time required to administer the REALM-Teen was 3 minutes. Internal consistency was excellent, as was test-retest reliability. The REALM-Teen is strongly correlated with both the WRAT-R and SORT-R. Five reading level categories were identified: 3rd grade and below, 4th to 5th grade, 6th to 7th grade, 8th to 9th grade, and 10th grade and above. Forty-six percent of participants were reading below grade level according to the SORT-R and 28% had repeated at least 1 grade. CONCLUSION: The REALM-Teen is a brief, reliable instrument for assessing adolescent literacy skills and reading below grade level.

Adolescent↗
PubMed2004

Lactation among adolescent mothers and subsequent bone mineral density.

OBJECTIVE: To investigate the association of breastfeeding during adolescence with bone mineral density (BMD) during young adulthood. METHODS: Secondary analysis of data from the National Health and Nutrition Examination Survey III, a nationally representative cross-sectional survey conducted from 1988 through 1994, was performed. The BMDs for 5 regions of the proximal femur as measured by dual energy x-ray absorptiometry were compared for 5 groups of women aged 20 to 25 years (n = 819); the groups included those who had been: (1) adolescent mothers and had breastfed (n = 94), (2) adolescent mothers and had not breastfed (n = 151), (3) mothers who first gave birth as adults and breastfed (n = 67), (4) mothers who first gave birth as adults and had not breastfed (n = 89), and (5) nulliparous (n = 418). SUDAAN software was used to account for the complex sampling design of the National Health and Nutrition Examination Survey. Adjusted mean differences in BMD were estimated using least-squares linear regression. RESULTS: During young adulthood, women who breastfed during adolescence had higher adjusted BMDs, which was statistically significant in 4 of the 5 regions, than those who had not breastfed (total proximal femur area difference, 0.049 gm/cm(2) [95% confidence interval, 0.002-0.095]) and BMDs equivalent to nulliparous women (total proximal femur area difference, 0.024 gm/cm(2) [95% confidence interval, -0.023 to 0.071]). Adjusting also for obstetric variables, women who breastfed during adolescence had higher BMDs in all 5 regions compared with their peers who had not breastfed (total proximal femur area difference, 0.053 gm/cm(2) [95% confidence interval, 0.029-0.077]). CONCLUSIONS: In this nationally representative sample, breastfeeding by adolescent mothers was associated with greater BMD in the proximal femur during young adulthood. Lactation was not found to be detrimental and may be protective to the bone health of adolescent mothers.

Absorptiometry, Photon↗
PubMed2003

Growth, survival and viral load in symptomatic childhood human immunodeficiency virus infection.

BACKGROUND: The relationships among weight and height growth, viral load and survival in HIV-infected children remain unclear. OBJECTIVES: To determine whether weight or height growth velocity independently predicts survival and to investigate associations of weight, height and head circumference growth velocities with viral loads in symptomatic HIV-infected children. METHODS: We analyzed data from a prospective antiretroviral study utilizing clinical endpoints (PACTG 152). Viral load [log(RNA PCR)] and anthropometric measures 12 weeks before and after viral load measures were available in 494 of 831 children. Interval changes during 24 weeks in z-scores for weight-for-age (DeltaWAZ), height-for-age (DeltaHAZ) and head circumference-for-age (DeltaHCZ) were used as growth velocity surrogates. Logistic regression determined whether DeltaWAZ and/or DeltaHAZ correlated with survival when age, viral load and CD4+ cell count were controlled. Bivariate analysis assessed correlation among viral load and DeltaWAZ, DeltaHAZ and/or DeltaHCZ. RESULTS: Survival related significantly to height growth velocity (P = 0.03, n = 434) but not to weight growth velocity (P = 0.84, n = 446) or head circumference growth velocity (P = 0.67, n = 148). Viral load was not significantly associated with changes in weight-, height-, or head circumference-for-age z scores (P = 0.86, n = 235; P = 0.07, n = 226; and P = 0.09, n = 165, respectively) in children <30 months of age or with changes in weight- or height-for-age z scores (P = 0.27, n = 259; P = 0.11, n = 251) in older children. CONCLUSIONS: Height growth velocity predicted survival independently of age, viral load and CD4+ cell count. Weight, height and head circumference growth velocities were not significantly associated with viral load in symptomatic HIV-infected children in this large prospective trial of nucleoside reverse transcriptase therapy.

Adolescent↗
PubMedDate not supplied

The effects of tobacco exposure on children's behavioral and cognitive functioning: implications for clinical and public health policy and future research.

A growing body of literature indicates that maternal smoking during pregnancy is associated with neurotoxic effects on children. Both animal model studies and human epidemiologic studies demonstrate similar effects in terms of increased activity, decreased attention, and diminished intellectual abilities. Epidemiologic studies also suggest that prenatal tobacco exposure is associated with higher rates of behavior problems and school failure. These findings are explored and their implications for child health policy and practice, and for research, are discussed.

Animals↗