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Biomedical subjects

Amy Herring

Publications and source records attributed to Amy Herring.

7 recordsLinked to original sources

The healthy men study: design and recruitment considerations for environmental epidemiologic studies in male reproductive health.

OBJECTIVE: To describe study design, conduct and response, and participant characteristics. DESIGN: Prospective cohort study. SETTING: Participants were male partners of women who were enrolled in a community-based prospective cohort study of drinking water disinfection by-products and pregnancy health. PATIENT(S): Two hundred thirty presumed fertile men recruited from 3 study sites in the United States. INTERVENTION(S): Men completed a telephone interview about demographics, health history, and exposures and provided a semen sample that was express mailed to the study laboratory. MAIN OUTCOME MEASURE(S): Response and participation rates, participant demographics, and lifestyle exposures. RESULT(S): We obtained a high participation rate (84%) among men who were located, but a low overall response rate (25%). Participants were more likely to be white, more highly educated, be married, and have a higher household income than the underlying study cohort. CONCLUSION(S): Our multisite study design may be applicable to the study of community environmental factors and reproductive health of men. Our design was efficient in that men from geographically disparate sites could be recruited, a semen sample was collected at home, and a telephone interview was conducted from a central study site. Despite these design features, the low response rates may suggest selection bias that can be addressed partially in the analysis.

Adolescent↗

Violent crime exposure classification and adverse birth outcomes: a geographically-defined cohort study.

BACKGROUND: Area-level socioeconomic disparities have long been associated with adverse pregnancy outcomes. Crime is an important element of the neighborhood environment inadequately investigated in the reproductive and public health literature. When crime has been used in research, it has been variably defined, resulting in non-comparable associations across studies. METHODS: Using geocoded linked birth record, crime and census data in multilevel models, this paper explored the relevance of four spatial violent crime exposures: two proximal violent crime categorizations (count of violent crime within a one-half mile radius of maternal residence and distance from maternal residence to nearest violent crime) and two area-level crime categorizations (count of violent crimes within a block group and block group rate of violent crimes) for adverse birth events among women in living in the city of Raleigh NC crime report area in 1999-2001. Models were adjusted for maternal age and education and area-level deprivation. RESULTS: In black and white non-Hispanic race-stratified models, crime characterized as a proximal exposure was not able to distinguish between women experiencing adverse and women experiencing normal birth outcomes. Violent crime characterized as a neighborhood attribute was positively associated with preterm birth and low birth weight among non-Hispanic white and black women. No statistically significant interaction between area-deprivation and violent crime category was observed. CONCLUSION: Crime is variably categorized in the literature, with little rationale provided for crime type or categorization employed. This research represents the first time multiple crime categorizations have been directly compared in association with health outcomes. Finding an effect of area-level violent crime suggests crime may best be characterized as a neighborhood attribute with important implication for adverse birth outcomes.

Analysis of Variance↗

Inhibition of leukocyte function and interleukin-2 gene expression by 2-methylarachidonyl-(2'-fluoroethyl)amide, a stable congener of the endogenous cannabinoid receptor ligand anandamide.

Arachidonylethanolamide (anandamide, AEA) has been identified as an endogenous ligand for cannabinoid receptors CB1 and CB2. Characterization of the direct cannabimimetic actions of anandamide has been hampered by its short duration of action and rapid degradation in in vivo and in vitro systems to arachidonic acid, a precursor in the biosynthesis of a broad range of biologically active molecules. In the present studies, we utilized 2-methylarachidonyl-(2'-fluoroethyl)amide (F-Me-AEA), an analog of anandamide resistant to enzymatic degradation, to determine whether F-Me-AEA modulated T cell function similar to that of plant-derived cannabinoids. Indeed, F-Me-AEA at low micromolar concentrations exhibited a marked inhibition of phorbol ester plus calcium ionophore (PMA/Io)-induced IL-2 protein secretion and steady state mRNA expression. Likewise, a modest suppression of the mixed lymphocyte response was observed in the presence of F-Me-AEA indicating an alteration in T cell responsiveness to allogeneic MHC class II antigens. F-Me-AEA was also found to modestly inhibit forskolin-stimulated adenylate cyclase activity in thymocytes and splenocytes, a hallmark of cannabinoid receptor agonists. Further characterization of the influence of F-Me-AEA on the cAMP signaling cascade revealed an inhibition of CREB-1/ATF-1 phosphorylation and subsequently, an inhibition of CRE DNA binding activity. Characterization of nuclear binding proteins further revealed that NF-AT and, to a lesser extent, NF-kappaB DNA binding activities were also suppressed. These studies demonstrate that F-Me-AEA modulates T cell function in a similar manner to plant-derived and endogenous cannabinoids and therefore can be utilized as an amidase- and hydrolysis-resistant endogenous cannabinoid.

Animals↗

Second trimester folate status and preterm birth.

OBJECTIVE: The purpose of this study was to show that maternal folate status during pregnancy may be related to preterm birth. STUDY DESIGN: Women were recruited at 24 to 29 weeks' gestation from 1995 to 2000 into the Pregnancy, Infection, and Nutrition Study. Those who completed an interview and a food frequency questionnaire, or provided a blood sample for radioassay of serum (n = 2026) and red blood cell (n = 1034) folate were included. RESULTS: Mean daily dietary folate intake was 463 microg (SD +/- 248). Intake </=500 microg was associated with increased preterm delivery (RR = 1.8, 95% CI 1.4-2.6) controlling for total energy intake. Serum folate levels <16.3 ng/mL and red blood cell folate levels </=626.6 ng/mL yielded adjusted risk ratios of 1.8 (95% CI 1.3-2.5) and 1.7 (95% CI 1.1-2.6), respectively. Patterns were similar for spontaneous and overall preterm birth. CONCLUSION: These results support the hypothesis that low folate levels during the second trimester of pregnancy are associated with an increased risk of preterm birth.

Adult↗

The effect of weight change on nursing care facility admission in the NHANES I Epidemiologic Followup Survey.

Data from the first National Health and Nutrition Examination Survey Epidemiologic Followup Survey were used to examine whether weight change was associated with an increased relative risk of nursing care facility admission. Hazard ratios were calculated with Cox proportional hazards models and stratified by overweight status at baseline. Moderate and large weight loss was associated with an increased risk of nursing care facility admission in overweight and non-overweight subjects. Large weight gain was associated with an increased relative risk in only overweight subjects. In the process of functional decline that results in nursing care facility admission, weight loss may be a sign of acute illness, starvation, or aging. Preventing weight loss may help delay this process of decline. In overweight subjects, preventing weight gain may also be important in delaying this process of decline.

Aged↗

Indicators of cocaine exposure and preterm birth.

OBJECTIVE: To identify predictors of cocaine exposure during pregnancy, using hair and urine assays and self-report, and the association with preterm birth. METHODS: A nested case-control study was conducted in a cohort of 2611 black and white women enrolled in prenatal care in central North Carolina. Cocaine exposure was ascertained by self-report (263 cases, 612 controls), urine assays at 24-29 weeks' gestation (226 cases, 564 controls) and postpartum (160 cases, 408 controls), and postpartum hair assays (169 cases, 435 controls). The major metabolite of cocaine, benzoylecgonine, was measured in urine. Cocaine and benzoylecgonine were measured in hair. RESULTS: Cocaine exposure was identified in 2% based on self-report, 5-6% based on urine assays, and 13-15% based on hair assays. Black ethnicity, lower education, and poverty were strongly predictive of positive hair assays. Hair cocaine and benzoylecgonine were not associated with preterm birth, with the possible exception of higher levels of cocaine and benzoylecgonine and birth before 34 weeks' completed gestation. The urine screen at 24-29 weeks' gestation also gave some indication of a possible association (odds ratio 1.7, 95% confidence interval 0.9, 3.5). CONCLUSION: The study corroborates the incompleteness of cocaine exposure assessment by self-report and urine screens relative to hair assays. The strong demographic predictors of exposure suggest where intervention efforts should be targeted. The most sensitive markers of exposure, hair cocaine and benzoylecgonine, are not associated with preterm birth, perhaps because they reflect different patterns of cocaine exposure than the other measures.

Case-Control Studies↗

Obesity affects nursing-care facility admission among whites but not blacks.

OBJECTIVE: This study examines whether obese individuals have a greater rate of nursing care facility admission than normal weight individuals. RESEARCH METHODS AND PROCEDURES: Data from the National Health and Nutrition Examination Survey Epidemiological Follow-up Survey were analyzed. Cox proportional hazards models were used to examine the relationship between baseline weight status and subsequent time to first nursing home admission while adjusting for sex, age, race, marital status, height, presence of children, smoking status, education, region, urban residence, income, and physical activity. RESULTS: Of 5960 adults 45 to 74 years old, 989 individuals were admitted to a nursing care facility over the subsequent 20 years. Body mass index (BMI) was studied using five categories: < 18.5, 18.5 to <25, 25.0 to <30, 30.0 to <35, > or =35 kg/m(2). The effects of BMI differed by race: compared with those with a BMI of 18.5 to < 25 kg/m(2), adults with a BMI > or =30 kg/m(2) or a BMI <18.5 kg/m(2) had a greater rate of nursing home admission in whites, whereas no relationship was found in blacks. The inclusion of time to death with nursing home admission as a joint outcome yielded similar results. DISCUSSION: The large increase in the prevalence of obesity coupled with the rapid expansion of the number of older Americans will likely increase the demand for nursing facility use. More research is needed to understand differences in factors related to nursing home admission among ethnic groups.

Aged↗