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1.
J Fish Biol ; 91(6): 1623-1641, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29023720

RESUMO

In the present study, pop-off data storage tags (pDST) without any transmitting capabilities were attached to 118 adult salmonids in a 19 000 km2 freshwater system (Lake Ontario). The 9·3 cm long cylindrical tags were externally attached to fishes using a backpack-style harness, set to record pressure (dBar ≈ depth in m) and temperature every 70 s (and at some key times, every 5 s) and programmed to release from the harness and float to the surface after c. 1 year. Recapture of the bright-orange tags for data retrieval relied on members of the public finding tags on shore, or on anglers capturing fishes with tags attached and using the contact information displayed on each tag to mail tags to the research team in exchange for a monetary reward. Thirty-seven tags were found and returned from the 118 released (31%), while 26 of the 118 tags (22%) remained scheduled to pop-off in summer 2017. Of the 37 tags returned, 23 were from wild-caught fishes (out of 88 wild-caught and tagged fishes; 26%) and yielded useful data whereas 14 were from hatchery-reared fishes that were opportunistically tagged and appear to have been unable to acclimate to life in the wild and died days to weeks after release. The field study described here thus demonstrated that pDSTs can be a viable option for collecting large amounts of high-resolution depth and temperature data for salmonids in freshwater systems. Technical challenges, limitations and unknowns related to the use of pDSTs with freshwater fishes are discussed. In addition, pDSTs are compared with alternate electronic tagging technologies and assessed for their potential as a more widespread tool in research on freshwater fishes.


Assuntos
Salmonidae/fisiologia , Telemetria/métodos , Animais , Comportamento Animal , Ecossistema , Água Doce , Armazenamento e Recuperação da Informação , Lagos , Estações do Ano , Temperatura
2.
J Fish Biol ; 88(6): 2144-56, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27245624

RESUMO

In Bimini, Bahamas, the consistent employment of longlines, beginning in 1982, provided a rare opportunity to explore population trends for large resident sharks. This study assessed three shallow water longline survey periods at this location; 1982-1989, 1992-2002 and 2003-2014, with the aim of determining trends in annual catch per unit effort (CPUE) for an IUCN listed near-threatened species, the lemon shark Negaprion brevirostris. A general additive model (GAM) was used to analyse the non-linear annual CPUE values over the entire 32-year research period. The GAM displayed high variability of annual CPUE, with a peak value of 0·026 N. brevirostris per hook day (hooks day(-1) ) in 2000. The temporal pattern of CPUE indicated an abundance trend with a complete cycle, from trough to trough, occurring over a period of approximately 18 years. The 1982-1989 survey period saw the highest proportion of mature individuals (19·8%) and the smallest average pre-caudal length (LPC ; 124·8 cm). The 1992-2002 survey period had the highest average annual CPUE (0·018 hooks day(-1) ), while the 2003-2014 research period saw largest average LPC size (134·8 cm) and the lowest average CPUE values (0·009 hooks day(-1) ) of the entire research period. The long-term trend identified in this study provides a baseline for future assessment.


Assuntos
Tubarões/fisiologia , Migração Animal , Animais , Oceano Atlântico , Bahamas , Ecossistema , Espécies em Perigo de Extinção , Densidade Demográfica , Comportamento Sexual Animal
3.
J Fish Biol ; 87(6): 1371-88, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26709212

RESUMO

A longline survey was conducted from 2004 to 2014 to investigate the demographic population structure and seasonal abundance of the blacktip shark Carcharhinus limbatus in the Bimini Islands, the Bahamas. All individuals sampled (n = 242) were sub-adult or adults [70·1-145·1 cm pre-caudal length (LPC) range] with no neonates or YOY recorded in Bimini. Carcharhinus limbatus abundance peaked in September, coincident with the largest ratio of female to male sharks and a peak in fresh mating wounds on females. Mitochondrial control region (mtCR) DNA sequences were obtained from C. limbatus at Bimini to test whether Bimini C. limbatus are most closely related to geographically proximate populations sampled on the south-eastern coast of the U.S.A., the closest known nursery areas for this species. Nine mtCR haplotypes were observed in 32 individuals sampled at Bimini [haplotype diversity (h) = 0·821, nucleotide diversity (π) = 0·0015]. Four haplotypes observed from Bimini matched those previously found in the northern Yucatan (Mexico)-Belize and two matched a haplotype previously found in the U.S.A. Four haplotypes were novel but were closely related to the northern Yucatan-Belizean haplotypes. Pair-wise ΦST analysis showed that Bimini was significantly differentiated from all of the populations previously sampled (U.S.A. Atlantic, U.S.A. Gulf of Mexico, northern Yucatan, Belize and Brazil). This indicates that C. limbatus sampled from Bimini are unlikely from the described, proximate U.S.A. nurseries.


Assuntos
Tubarões/genética , Animais , Bahamas , DNA Mitocondrial/química , Feminino , Haplótipos , Masculino , Densidade Demográfica , Estações do Ano , Razão de Masculinidade , Tubarões/fisiologia
5.
J Anim Sci ; 86(11): 2903-12, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18599666

RESUMO

This study was conducted to investigate individual metabolic and endocrine adaptation to lactation under conditions of identical housing and feeding conditions in high-yielding dairy cows. Forty-five cows were studied on a research farm under standardized but practical conditions. From wk 2 before calving until wk 14 postpartum, blood samples were collected at weekly intervals and assayed for blood chemistry and various metabolites and hormones. Body weight, BCS, and backfat thickness were also recorded weekly. Milk yield, milk composition, and feed intake and energy balance were accordingly measured during the postpartum phase. The animals were retrospectively classified according to their plasma concentration of beta-hydroxybutyrate (BHB): cows in which a BHB threshold of 1 mM was exceeded at least once during the experiment were classified as BHB positive (BHB+); cows with BHB values consistently below this threshold were classified as BHB negative (BHB -). Using this classification, differences for NEFA and glucose concentrations were observed, but the mean calculated energy balance did not differ between the groups during the experimental period (-22.2 MJ of NE(1)/d +/- 4.7 for BHB+ and -18.9 MJ of NE(1)/d +/- 4.9 for BHB-). In BHB+ cows, the peripartum decrease (P < 0.05) of BW, BCS, and backfat thickness was more pronounced than in BHB- cows. Mean milk yields did not differ between groups. However, BHB+ cows had greater milk fat and lesser milk protein contents (P < 0.05), resulting in a greater (P < 0.05) fat:protein ratio than in BHB- cows. Thus, to some extent, cows were able to compensate for the negative energy balance by adjustments in performance. Milk acetone concentrations followed BHB concentrations in blood. Insulin-like growth factor-I and leptin concentrations were greater (P < 0.05) in BHB- cows during the time of observation than in the BHB+ cows. Comparing the reproductive variables recorded (first increase of progesterone, first service conception rate, number of services per conception, interval from calving to first AI, interval from first AI to conception, and days open) between the 2 groups yielded no significant differences. Our findings imply that despite comparable energy balance, there is considerable individual variation of the adaptive ability of cows during early lactation based on a variety of metabolic and endocrine variables.


Assuntos
Adaptação Fisiológica/fisiologia , Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação/fisiologia , Estresse Fisiológico/fisiologia , Ácido 3-Hidroxibutírico/sangue , Tecido Adiposo/diagnóstico por imagem , Animais , Aspartato Aminotransferases/sangue , Constituição Corporal/fisiologia , Peso Corporal/fisiologia , Bovinos/metabolismo , Ingestão de Alimentos/fisiologia , Gorduras/análise , Feminino , Hormônios/sangue , Leite/química , Leite/metabolismo , Proteínas do Leite/análise , Gravidez , Reprodução/fisiologia , Fatores de Tempo , Ultrassonografia , gama-Glutamiltransferase/sangue
6.
Z Geburtshilfe Neonatol ; 211(5): 185-90, 2007 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-17960516

RESUMO

BACKGROUND: One of the therapeutic aims in gestational diabetes (GDM) is to prevent the development of fetal hypertrophy by adaptation of maternal glycemic control. Relating to this context, maternal blood glucose daily profiles and fetal biometry ultrasound parameters were analysed for a possible correlation. A special focus was given to the question as to whether a latency period exists for this possible connection. PATIENTS AND METHODS: 152 pregnancies affected by GDM, without fetal malformations or aneuploidies, were enrolled. Altogether, 746 ultrasound examinations consisting of 7 fetometric parameters each and 1 288 blood glucose daily profiles originating from the 20 (th) to 40 (th) gestational week were systematically investigated for interrelation by correlation and multiple regression analysis. RESULTS: No robust, constant correlation between the analysed parameters could be observed. However, marked differences between latency periods were noticed. Blood glucose parameters, which revealed significant regressions with fetal abdominal circumference, had an average time lag of 6.2 +/- 2.5 weeks, whereas the latency period for head circumference averaged 2.4 +/- 1.2 weeks. The overall small-for-gestational-age (SGA) rate was 20 %, pregnant women with a body mass index > 30 kg / m (2) revealed the highest rate of 28 %. CONCLUSIONS: Therapeutic intervention depending on sonographically detected hypertrophy must be considered as being delayed. The currently valid therapeutic criteria including intended normoglycemia and regular fetometric ultrasound controls cannot prevent markedly high SGA rates, especially among obese women, in adequately treated GDM.


Assuntos
Glicemia/metabolismo , Diabetes Gestacional/sangue , Macrossomia Fetal/sangue , Ultrassonografia Pré-Natal , Adulto , Peso ao Nascer , Índice de Massa Corporal , Diabetes Gestacional/diagnóstico por imagem , Diabetes Gestacional/terapia , Feminino , Macrossomia Fetal/diagnóstico por imagem , Humanos , Recém-Nascido , Gravidez
8.
Toxicol Lett ; 95(3): 155-63, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9704817

RESUMO

1-Naphthylisothiocyanate (ANIT) produces cholangiolitic hepatitis in rats. This injury is characterized by periportal bile duct and hepatic parenchymal cell necrosis with inflammatory cell involvement. In contrast, 2-naphthylisothiocyanate (BNIT) does not induce cholangiolitic hepatitis. The mechanism(s) involved in ANIT-induced hepatic injury remain to be elucidated. To investigate this difference in toxicity further, we examined the cytotoxicity of ANIT and BNIT in primary rat hepatocyte cultures. Since neutrophils (PMNs) are required for the development of ANIT-induced cholangiolitic hepatitis in vivo, we also examined the potential for PMNs to modulate ANIT and BNIT cytotoxicity in rat hepatocyte-PMN cocultures. Both ANIT and BNIT injured rat hepatocytes within the range of concentrations examined (0-100 microM); however, BNIT was more potent. The presence of PMNs did not significantly influence the hepatocellular injury produced by either naphthylisothiocyanate (NIT). In an attempt to clarify the disparity between these results in vitro and observations reported in vivo, we examined, in hepatocyte PMN cocultures, the cytotoxic potential of bile collected from NIT-treated rats. Bile from BNIT-treated rats was markedly more cytotoxic to hepatocytes than was bile from ANIT-treated rats. As was observed in earlier experiments, the inclusion of PMNs had no effect on the hepatocellular toxicity of bile from NIT-treated rats. These findings prompted evaluation of the effect of NITs on rat PMNs. ANIT (1 and 10 microM) had no effect on phorbal myristate acetate (PMA)-induced superoxide production by PMNs, whereas BNIT (1 and 10 microM) markedly inhibited PMA-induced superoxide production. In contrast, ANIT and BNIT were equally effective at inhibiting f-met-leu-phe (fMLP)-induced PMN degranulation (beta-glucuronidase release). Altogether, the relative NIT toxicity observed in hepatocyte primary cultures is contrary to reports of hepatotoxic potential of these NITs in vivo. The PMN-dependence of ANIT hepatotoxicity in vivo was not reproduced in hepatocyte-PMN cocultures exposed to ANIT, suggesting that the PMN dependence in vivo involves factors not present in hepatocyte PMN cocultures. The greater PMN inhibitory effect of BNIT may, in part, underlie its inability to elicit the PMN-dependent liver injury in vivo that characterizes ANIT-induced cholangiolitic hepatitis.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/patologia , Isotiocianatos/toxicidade , Fígado/patologia , Naftalenos/toxicidade , Neutrófilos/efeitos dos fármacos , Animais , Bile/efeitos dos fármacos , Degranulação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Fígado/citologia , Espectroscopia de Ressonância Magnética , Masculino , Ratos , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta
9.
Pediatrics ; 101(5): 895-902, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9565422

RESUMO

OBJECTIVE: This study is one of the first to examine the association between sexual orientation and health risk behaviors among a representative, school-based sample of adolescents. DESIGN: This study was conducted on an anonymous, representative sample of 4159 9th- to 12th-grade students in public high schools from Massachusetts' expanded Centers for Disease Control and Prevention 1995 Youth Risk Behavior Survey. Sexual orientation was determined by the following question: "Which of the following best describes you?" A total of 104 students self-identified as gay, lesbian, or bisexual (GLB), representing 2.5% of the overall population. Of GLB youth, 66.7% were male and 70% were white (not Hispanic). Health risk and problem behaviors were analyzed comparing GLB youth and their peers. Those variables found to be significantly associated with GLB youth were then analyzed by multiple logistic regression models. RESULTS: GLB youth were more likely than their peers to have been victimized and threatened and to have been engaged in a variety of risk behaviors including suicidal ideation and attempts, multiple substance use, and sexual risk behaviors. Four separate logistic regression models were constructed. Model I, Onset of Behaviors Before Age 13, showed use of cocaine before age 13 years as strongly associated with GLB orientation (odds ratio [OR]: 6.10; 95% confidence interval [CI] = 2.45-15.20). Early initiation of sexual intercourse (2.15; 10.6-4.38), marijuana use (1.98; 1.04-4.09), and alcohol use (1.82; 1.03-3.23) also was associated with GLB orientation. Model II, Lifetime Frequencies of Behaviors, showed that frequency of crack cocaine use (1.38; 1.06-1.79), inhalant use (1.30; 1.05-1.61), and number of sexual partners (1.27; 1.06-1.43) was associated with GLB orientation. Model III, Frequency of Recent Behaviors, showed smokeless tobacco use in the past 30 days (1.38; 1. 20-1.59) and number of sexual partners in the previous 3 months (1. 47; 1.31-1.65) were associated with GLB orientation. Model IV, Frequency of Behaviors at School, showed having one's property stolen or deliberately damaged (1.23; 1.08-1.40) and using marijuana (1.29; 1.05-1.59) and smokeless tobacco (1.53; 1.30-1.81) were associated with GLB orientation. Overall, GLB respondents engaged disproportionately in multiple risk behaviors, reporting an increased mean number of risk behaviors (mean = 6.81 +/- 4.49) compared with the overall student population (mean = 3.45 +/- 3.15). CONCLUSION: GLB youth who self-identify during high school report disproportionate risk for a variety of health risk and problem behaviors, including suicide, victimization, sexual risk behaviors, and multiple substance use. In addition, these youth are more likely to report engaging in multiple risk behaviors and initiating risk behaviors at an earlier age than are their peers. These findings suggest that educational efforts, prevention programs, and health services must be designed to address the unique needs of GLB youth.


Assuntos
Comportamento do Adolescente , Comportamentos Relacionados com a Saúde , Assunção de Riscos , Comportamento Sexual , Adolescente , Comportamento do Adolescente/psicologia , Vítimas de Crime , Coleta de Dados , Feminino , Humanos , Modelos Logísticos , Masculino , Massachusetts , Comportamento Sexual/psicologia , Suicídio/psicologia
10.
Dent Mater ; 14(4): 277-80, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10379256

RESUMO

OBJECTIVES: At the October 1996 meeting of the ISO/TC106/SC 2/WG 1 working group, a special three-point flexure test for the characterization of the metal-ceramic bond was incorporated in the standard (ISO CD 9693). Due to the fabrication process, like real porcelain-fused-to-metal (PFM) restorations, the specimens contain thermal (eigen-) stresses upon which the load stresses are superimposed in the actual test. This study is devoted to the determination of these residual thermal stresses. METHODS: The residual thermal stresses in the specimen were calculated with the aid of the finite element method (FEM) using an especially fine mesh in the vicinity of the edge of initial debonding. Young's modulus, EM, of the alloy was varied within the interval 80 GPa < or = EM < or = 220 GPa which covers the spectrum of dental alloys. The analysis also allows the calculation of thermal stresses as a function of the difference delta alpha = alpha M - alpha C of the coefficients of thermal expansion of alloy and ceramic and the glass transition temperature theta G of porcelain. RESULTS: The thermal shear and normal stresses at the bond interface concentrate at the end of the ceramic veneer and practically vanish over about three quarters of the central part of the layer. The larger the Young's modulus, EM, of the alloy, the higher both stresses. SIGNIFICANCE: The results permit a deeper comprehension of the debonding process in the test: shear stress induced by loading increases the overall shear stress at the end of the bond interface, whereas load tensile stress is buffered by thermal compressive stress.


Assuntos
Colagem Dentária , Análise do Estresse Dentário , Teste de Materiais/métodos , Ligas Metalo-Cerâmicas/química , Falha de Restauração Dentária , Elasticidade , Análise de Elementos Finitos , Temperatura Alta , Ligas Metalo-Cerâmicas/normas , Maleabilidade , Padrões de Referência , Reprodutibilidade dos Testes , Estresse Mecânico
11.
J Am Acad Child Adolesc Psychiatry ; 36(3): 316-22, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9055511

RESUMO

OBJECTIVE: To investigate the associations between sexual abuse and human immunodeficiency virus (HIV)-related attitudes and behaviors of adolescents with a psychiatric disorder. METHOD: HIV-related knowledge, attitudes, and behaviors were examined by self-report assessment of adolescents admitted to a psychiatric hospital (N = 100). A subsample (n = 30) completed a role-playing exercise regarding HIV-preventive behavior that was scored for the degree of effective communication by raters blind to the subjects' abuse history. RESULTS: HIV-related risk behaviors were prevalent, including unprotected sexual intercourse (67%) and multiple partners (27%) among the sexually active (71% of the total). Also frequent were alcohol and drug use (25%) and sharing cutting instruments (22%) among those engaged in self-cutting behavior (62%). The 38% of the sample identified as having a history of sexual abuse indicated significantly poorer self-efficacy concerning condom use than their peers. Abused females scored significantly lower on the self-efficacy of condom use scale and reported significantly more frequent alcohol use than nonabused females (p = .003). A hierarchical multiple regression that controlled for consistency of condom use and tolerance of people with acquired immunodeficiency syndrome found that abuse history uniquely accounted for 16% of the variance in condom use self-efficacy. Analysis of the videotaped role-play found that abused adolescents were significantly less competent and had more difficulty in effective communication than their peers (p = .003). CONCLUSION: A history of sexual abuse is associated with impaired safe sexual decision-making and HIV-preventive communication skills, even in this already at-risk group. This study also underscores the importance of actively addressing these issues in the context of clinical care.


Assuntos
Atitude Frente a Saúde , Abuso Sexual na Infância/psicologia , Infecções por HIV/prevenção & controle , Pacientes Internados/psicologia , Transtornos Mentais/psicologia , Assunção de Riscos , Adolescente , Criança , Tomada de Decisões , Feminino , Humanos , Masculino , Negociação , Testes Psicológicos , Análise de Regressão , Fatores Sexuais , Comportamento Sexual
15.
Am J Obstet Gynecol ; 165(1): 15-22, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1853892

RESUMO

The United States Linked Birth/Infant Death Data Sets: 1983 and 1984 Birth Cohorts from the National Center for Health Statistics were used to identify maternal and infant characteristics related to twin infant mortality; 41,554 white and 10,062 black live-born matched twin pairs were evaluated. Twin birth weight distribution was skewed with 48% of white and 63% of black twins born weighing less than 2500 gm. Overall infant mortality rates were 47.1 and 79.3 deaths per 1000 live births for white and black twins, respectively (five times the rates for singletons). Three fourths of deaths were among twins weighing less than 1500 gm. White like-gender twins had about twice the risk of both twins dying compared with unlike-gender twins. Likewise, white twin pairs with greater than 25% birth weight disparity had a 40% to 80% increased risk of both twins dying, compared with twins whose weights were within 10% of each other. Twins born to high-risk women (on the basis of demographic factors) were twice as likely to die as twins born to low-risk women. Thus strategies to decrease twin infant mortality must address both maternal and infant risk factors.


Assuntos
Mortalidade Infantil , Gêmeos , População Negra , Causas de Morte , Estudos de Coortes , Humanos , Recém-Nascido , Fatores de Risco , Estados Unidos/epidemiologia , População Branca
16.
Am J Obstet Gynecol ; 165(1): 2-6, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1677235

RESUMO

At an interdisciplinary workshop on home monitoring of uterine activity, participants reviewed the basis of this technology and its use in the identification of women at high risk of preterm delivery and in the prevention of preterm birth. Although the guard-ring devices in current use appear capable of detecting uterine activity, they do not clearly distinguish between Braxton Hicks contractions and the contractions of early labor. There was agreement that women destined for preterm delivery have more uterine activity on average than do other women of comparable gestational age but that there is substantial overlap between the two groups. Thus it is uncertain whether this difference can be used effectively for screening purposes. Conferees agreed that there is considerable evidence that twice-daily monitoring of very-high-risk women, in conjunction with daily nursing support and high-quality obstetric care, may prevent preterm births. Available evidence does not clearly distinguish the contribution of tocodynamometry from that of nursing support. A number of areas were identified in which further research is needed.


Assuntos
Serviços de Assistência Domiciliar , Monitorização Fisiológica , Contração Uterina , Cardiotocografia , Feminino , Humanos , Monitorização Fisiológica/tendências , National Institutes of Health (U.S.) , Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Pesquisa , Estados Unidos
17.
Am J Epidemiol ; 133(2): 133-43, 1991 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-1985443

RESUMO

Infant mortality among US black and white twins and singletons was compared for 1960 and 1983 using the Linked Birth/Infant Death Data Sets from the National Center for Health Statistics. Both twin and singleton infant mortality rates showed impressive declines since 1960 but almost all of the improvement in survival for both twins and singletons was related to increased birth weight-specific survival rather than improved birth weight distribution. One-half of white twins and two-thirds of black twins weighed less than 2,500 g at birth, and 9% of white twin births and 16% of black twin births were in the very low (less than 1,500g) birth weight category. In 1983, twin infant mortality rates were still four to five times that of singletons. However, twins had a survival advantage in the 1,250-3,000 g range, which persisted after adjustment for gestational age. Cause-specific mortality among twins was considerably higher for every major cause of death: twin mortality risks due to newborn respiratory disease, maternal causes, neonatal hemorrhage, and short gestation/low birth weight were six to 15 times that of singletons. The lowest twin-to-singleton mortality ratios observed were for congenital anomalies and sudden infant death syndrome with relative risks twice that of singletons. The data underscore the need to develop effective strategies to decrease infant mortality among twins.


Assuntos
Peso ao Nascer , População Negra , Mortalidade Infantil , Gêmeos , População Branca , Causas de Morte , Humanos , Lactente , Recém-Nascido , Fatores de Risco , Taxa de Sobrevida , Estados Unidos
19.
Clin Perinatol ; 15(4): 745-54, 1988 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3208478

RESUMO

Black mothers in the United States are twice as likely as their white counterparts to experience a wide variety of adverse pregnancy outcomes, including prematurity, low birth weight, and infant and fetal death. Although blacks have higher proportions of births with maternal risk factors such as young age, high birth order, low education, and unmarried mothers, these differences do not account for their higher rates of adverse outcomes; the reasons for the excess remain largely unknown. To develop effective interventions to reduce the racial disparities in pregnancy outcome, we must further our understanding of the mechanisms underlying premature onset of labor and intrauterine growth.


Assuntos
Etnicidade , Mortalidade Infantil/tendências , Resultado da Gravidez , Negro ou Afro-Americano , Peso ao Nascer , Feminino , Humanos , Recém-Nascido , Gravidez , Fatores de Risco , Estados Unidos , População Branca
20.
N Engl J Med ; 317(12): 749-53, 1987 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-3627185

RESUMO

To identify the risk factors responsible for differences in birth weight between blacks and whites, we investigated the effects of four maternal characteristics (age, parity, marital status, and education) on rates of very low birth weight (less than 1500 g) and moderately low birth weight (between 1500 and 2500 g). Using 1983 national data, we found that the black:white rate ratio was 3.0 for very low birth weight and 2.3 for moderately low birth weight. The four maternal factors had directionally similar but quantitatively different effects on very low and moderately low birth weight among blacks and whites. Furthermore, the racial differences in infants' birth weights were greater among low-risk than among high-risk mothers, especially for very low birth weight (black:white ratios of 3.4 and 1.7, respectively). We also examined secular trends in the rates of low birth weight among blacks and whites. Between 1973 and 1983, births of infants with moderately low birth weights decreased more among whites than among blacks, whereas births of infants with very low birth weights increased among blacks and decreased among whites. Fifteen percent of the decline in the rate of moderately low birth weight among whites could be attributed to favorable changes in maternal characteristics (primarily an increase in educational level). Among blacks, adverse changes in maternal characteristics (primarily an increase in births to unmarried women) accounted for 35 percent of the increase in the rate of very low birth weight. The adverse effects of childbearing by teenagers on the outcome of pregnancy among blacks appear to have been overemphasized. The persistence of large racial differences in birth weight, even among mothers at low risk, emphasizes the need for specific targeted interventions to achieve further improvements in infant health.


Assuntos
Negro ou Afro-Americano , Recém-Nascido de Baixo Peso , Adolescente , Adulto , Escolaridade , Feminino , Humanos , Recém-Nascido , Casamento , Idade Materna , Paridade , Gravidez , Estados Unidos
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