RESUMO
BACKGROUND: The parental age at conception has been reported to be a risk factor for childhood acute leukaemia (AL); however, the relationship is controversial. The aim of the present study was to investigate the association between parental age at conception and the risk of AL in Mexican children, a population with a high incidence of the disease and a high prevalence of pregnancies in adolescents and young adults. METHODS: A multicentre case-control study was conducted. Incident AL cases younger than 17 years of age diagnosed between 2010 and 2015 were included. Controls were matched with cases according to age, sex, and health institution. Using logistic regression analysis, adjusted odds ratios (aOR) and 95 % confidence intervals (95 % CI) were calculated for each maternal stratum after adjusting for paternal age at conception of index child. The maternal age between 25 and 29.99 years was selected as the reference category. RESULTS: In most strata where maternal and paternal ages were assessed, no association was found with the risk of developing acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) in their offspring. An increased risk for AML was observed when the mother was between 20 and 24.99 years of age and the father aged 25-29.99 years (aOR, 1.94; 95 % CI, 1.03-3.67). In addition, there was a positive association for ALL when the mother´s age was between 20 and 24.99 years and the father was <20 years of age, however, a very wide confidence interval was noted (aOR, 12.26; 95 % CI, 1.41-106.83). CONCLUSION: In the present study, maternal and paternal ages assessed in different strata showed little association with risk of developing ALL and AML in children. Positive associations between risk of both types of childhood AL were observed with younger paternal and maternal ages.
Assuntos
Fertilização , Leucemia Mieloide Aguda/epidemiologia , Idade Materna , Idade Paterna , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , México/epidemiologia , Razão de Chances , Gravidez , Fatores de Risco , Adulto JovemRESUMO
Several factors influence mammalian sex ratio. In this study, the effects of parental age and litter size on the offspring sex ratio in dogs were evaluated in 602 puppies born from 101 German Shepherd litters from a breeding facility. The data was obtained from recordings of the kennel and Studbook from 1996 to 2016. A linear mixed-model analysis was performed using dam age, sire age and litter size as predictors of the percentage of males in litter. Dam age and litter size has direct effect on sex ratio. Dam age * sire age and dam age * litter size interactions are significant. When evaluating dam age by sire age, the expected male percentage in the litter is higher for old dams mated with young sires and young dams mated with old sires. Smaller percentage of males is expected for young dams mated with young sires and old dams mated with old sires. When evaluating dam age by litter size, the expected percentage of males in the litter is higher for young dams delivering big litters and old dams delivering small litters. Smaller percentage of males is expected for young dams delivering small litters and old dams delivering big litters. Dam aging increased proportion of males in litters. We concluded that offspring sex ratio is determined partially by the dam age, sire age and litter size interactions in German Shepherd dogs.
Assuntos
Envelhecimento , Cães/fisiologia , Tamanho da Ninhada de Vivíparos , Prenhez , Razão de Masculinidade , Animais , Feminino , Masculino , GravidezRESUMO
The present study evaluated different selection strategies to improve the growth performance and carcass traits of Japanese quails. To this end, 540 Japanese quails previously selected for high body weight at three ages (10, 12 and 14 weeks) from four close-bred flocks (Major, Kaleem, Saadat and Zahid) were subjected to three selection strategies: pedigree-based, mass selection or random-bred (controls). For pedigree-based selection, 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1 bird each) with full pedigree and selected for high body weight were used, whereas in mass selection 324 birds (4 close-bred flocks × 3 age groups × 9 replicates × 3 birds each) with high body weight were selected to be the parents of next generation. Random-bred controls included 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1bird each) which were not previously submitted to selection. The effects of selection strategies of Japanese quail parents from four close-bred flocks (CBF) at three ages on the performance growth and carcass traits of their progenies were measured. The parent flocks were selected at three ages (10, 12 and 14 weeks) and reared for 20 weeks, and their progenies were reared for four weeks. The progeny of pedigree-based selected parents presented better feed intake (g), body weight gain (g), feed conversion ratio, live and carcass weights (g), and carcass yield. The progeny of 10- and 14-week-old parents showed better growth performance and carcass traits, respectively. Moreover, there was no influence of CBF on growth and carcass traits. It was concluded that pedigree-based selection had pronounced effect on the growth performance and carcass traits of the progeny compared with mass selection and random breeding. It is suggested that parental ages of 10 and 14 weeks of age promote better progeny growth performance and carcass traits.(AU)
Assuntos
Animais , Coturnix/crescimento & desenvolvimento , Coturnix/genética , Seleção Genética , Aumento de Peso , Fatores EtáriosRESUMO
The present study evaluated different selection strategies to improve the growth performance and carcass traits of Japanese quails. To this end, 540 Japanese quails previously selected for high body weight at three ages (10, 12 and 14 weeks) from four close-bred flocks (Major, Kaleem, Saadat and Zahid) were subjected to three selection strategies: pedigree-based, mass selection or random-bred (controls). For pedigree-based selection, 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1 bird each) with full pedigree and selected for high body weight were used, whereas in mass selection 324 birds (4 close-bred flocks × 3 age groups × 9 replicates × 3 birds each) with high body weight were selected to be the parents of next generation. Random-bred controls included 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1bird each) which were not previously submitted to selection. The effects of selection strategies of Japanese quail parents from four close-bred flocks (CBF) at three ages on the performance growth and carcass traits of their progenies were measured. The parent flocks were selected at three ages (10, 12 and 14 weeks) and reared for 20 weeks, and their progenies were reared for four weeks. The progeny of pedigree-based selected parents presented better feed intake (g), body weight gain (g), feed conversion ratio, live and carcass weights (g), and carcass yield. The progeny of 10- and 14-week-old parents showed better growth performance and carcass traits, respectively. Moreover, there was no influence of CBF on growth and carcass traits. It was concluded that pedigree-based selection had pronounced effect on the growth performance and carcass traits of the progeny compared with mass selection and random breeding. It is suggested that parental ages of 10 and 14 weeks of age promote better progeny growth performance and carcass traits.
Assuntos
Animais , Aumento de Peso , Coturnix/crescimento & desenvolvimento , Coturnix/genética , Seleção Genética , Fatores EtáriosRESUMO
ABSTRACT The present study evaluated different selection strategies to improve the growth performance and carcass traits of Japanese quails. To this end, 540 Japanese quails previously selected for high body weight at three ages (10, 12 and 14 weeks) from four close-bred flocks (Major, Kaleem, Saadat and Zahid) were subjected to three selection strategies: pedigree-based, mass selection or random-bred (controls). For pedigree-based selection, 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1 bird each) with full pedigree and selected for high body weight were used, whereas in mass selection 324 birds (4 close-bred flocks × 3 age groups × 9 replicates × 3 birds each) with high body weight were selected to be the parents of next generation. Random-bred controls included 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1bird each) which were not previously submitted to selection. The effects of selection strategies of Japanese quail parents from four close-bred flocks (CBF) at three ages on the performance growth and carcass traits of their progenies were measured. The parent flocks were selected at three ages (10, 12 and 14 weeks) and reared for 20 weeks, and their progenies were reared for four weeks. The progeny of pedigree-based selected parents presented better feed intake (g), body weight gain (g), feed conversion ratio, live and carcass weights (g), and carcass yield. The progeny of 10- and 14-week-old parents showed better growth performance and carcass traits, respectively. Moreover, there was no influence of CBF on growth and carcass traits. It was concluded that pedigree-based selection had pronounced effect on the growth performance and carcass traits of the progeny compared with mass selection and random breeding. It is suggested that parental ages of 10 and 14 weeks of age promote better progeny growth performance and carcass traits.
RESUMO
The stochastic nature of biochemical processes is a source of variability that influences developmental stability. Developmental instability (DI) is often estimated through fluctuating asymmetry (FA), a parameter that deals with within-individual variation in bilateral structures. A relevant goal is to shed light on how environment, physiology and genotype relate to DI, thus providing a more comprehensive view of organismal development. Using Drosophila melanogaster isogenic lines, we investigated the effect of parental age, parental diet and offspring heterozygosity on DI. In this work, we have uncovered a clear relationship between parental age and offspring asymmetry. We show that asymmetry of the progeny increases concomitantly with parental age. Moreover, we demonstrate that enriching the diet of parents mitigates the effect of age on offspring symmetry. We show as well that increasing the heterozygosity of the progeny eliminates the effect of parental age on offspring symmetry. Taken together, our results suggest that diet, genotype and age of the parents interact to determine offspring DI in wild populations. These findings provide us with an avenue to understand the mechanisms underlying DI.
Assuntos
Drosophila melanogaster/crescimento & desenvolvimento , Fatores Etários , Fenômenos Fisiológicos da Nutrição Animal , Animais , Drosophila melanogaster/genética , Extremidades/anatomia & histologia , Extremidades/crescimento & desenvolvimento , Feminino , Heterozigoto , Masculino , Fenótipo , Fenômenos Reprodutivos Fisiológicos , Asas de Animais/anatomia & histologia , Asas de Animais/crescimento & desenvolvimentoRESUMO
PIP: The introduction of mechanized technology into a rural Maya agricultural community in the mid 1970s markedly increased the technology with which maize could be ground and water collected, which in turn introduced a possible savings in the time spent working. This study investigated the response of female fertility to the introduction of this labor-saving technology. Using two proximate determinants of female fertility, the association between the advent of modern technology and changes in the age at which women give birth to their first child and the length of mothers' birth intervals was examined. Analyses showed that women begin their reproductive careers at a younger age after the laborsaving technology was introduced. Estimate of the median age at first birth from the distribution function dropped from 21.2 years before the introduction to 19.5 years after the introduction of the technology. In addition, modeling results show that the probability of a woman giving birth to her first child doubles for any age after the introduction of laborsaving technology. However, changes in birth intervals are less conclusive since the differences of smoothed probability distributions are not significant. Moreover, findings indicate that women who initiate reproduction at a younger age can potentially have longer reproductive careers and larger families.^ieng
Assuntos
Agricultura , Intervalo entre Nascimentos , Emprego , Fertilidade , Idade Materna , População Rural , Tecnologia , Mulheres , Fatores Etários , América , Coeficiente de Natalidade , Demografia , Países em Desenvolvimento , Economia , Mão de Obra em Saúde , América Latina , México , América do Norte , Pais , População , Características da População , Dinâmica PopulacionalRESUMO
Findings from Chile, Barbados, Guatemala, and Mexico are reviewed in this article to shed light on the consequences of adolescent childbearing for mothers' economic and social opportunities and the well-being of their first-born children. The studies include retrospective information and a comparison group of adult childbearers to account for the effects of background factors (poverty) and the timing of observations. The findings show that early childbearing is associated with negative economic rather than social effects, occurring for poor rather than for all mothers. Among the poor, adolescent childbearing is associated with lower monthly earnings for mothers and lower child nutritional status. Also, among this group of women only, improvements in the child's well-being are associated with mother's education and her contribution to household income. These findings suggest that social policy that expands the educational and income-earning opportunities of poor women could help to contain the intergenerational poverty associated with early childbearing among the poor.
PIP: The consequences of adolescent childbearing for women's social and economic opportunities and the well-being of their first-born child were investigated in studies conducted in Barbados (n = 303), Chile (n = 505), Guatemala (n = 2850), and Mexico (n = 462). The studies included retrospective information and a comparison group of adult childbearers. There was no evidence that early childbearing has negative consequences on the marriage options of young women. Adolescent childbearing was associated with higher fertility, a greater tendency to be a boarder, father absence and lack of financial support, and more grandparents taking over responsibility for child care. Adolescent motherhood was further associated with poor earning opportunities for the teenage mother and poverty. The first-born child's height-for-age was below the norm only when the mother was poor. Overall, these findings suggest that social policies aimed at significantly expanding the educational and income-earning opportunities of young mothers and providing them with access to high-quality reproductive health services could contribute to breaking the cycle of poverty associated with early childbearing.
Assuntos
Proteção da Criança , Efeitos Psicossociais da Doença , Gravidez na Adolescência , Saúde da Mulher , Adolescente , Adulto , Barbados , Chile , Comparação Transcultural , Escolaridade , Feminino , Seguimentos , Guatemala , Humanos , México , Estado Nutricional , Pobreza , Gravidez , Gravidez na Adolescência/estatística & dados numéricos , Estudos Retrospectivos , Salários e Benefícios , Fatores SocioeconômicosRESUMO
Fang women are known to practice virtually no contraception but for them induced abortion is not an acceptable option. Their reproductive behaviour consequently is governed by the ability to conceive, spontaneous intrauterine mortality and child spacing (due to prolonged breast-feeding and sexual abstinence). In a sample of 587 women from one hospital and one clinic in Nsork, there was a positive correlation between maternal age and the number of pregnancies, resulting in a mean of 5.52 pregnancies per female and one child born every 2.5 years. The reported spontaneous abortion rate was 28.6%.
PIP: Data were collected in the only hospital built in the Nsork district of Equatorial Guinea. Group A comprised deliveries at Nsork Hospital from March 1988 to July 1990 (29 months). Maternal age, number of previous pregnancies, and number of fetal losses from the fourth month of pregnancy were recorded. The total sample comprised 157 women aged 15-40 years who had a total of 555 pregnancies. Group B data were collected from May 1987 to December 1988 (20 months) from the prenatal clinic at a primary health post from a total of 430 pregnant women aged 14-45 years. Group A women represented 15.6% of all women in the district between 15 and 39 years of age; Group B, 36.5% between 15 and 44 years of age. There was a high level of prenatal attendances in Group B; however, only 20.2% of clinic visitors gave birth at the hospital. In Group A, the number of reported pregnancies continued to rise in direct relation to the woman's age (correlation coefficient r = .91). The reproductive age range of this population was 15 to 40 years with a mean of 5.52 pregnancies. The average number of reported abortions per female was .48 for each age group (p .05). The total incidence of fetal loss was 28.3%, 23.9% of which was reported by women with one abortion and 4.4% by women with at least two abortions. Group A had effective child spacing, achieved by a combination of sexual abstinence and prolonged breast feeding. Sexual abstinence was practiced after the seventh month of pregnancy until breast feeding ceased, and breast feeding was continued until the newborn was aged 16-21 months. The pattern of child spacing calculated from the regression between mean number of conceptions per woman and maternal age (r = .91, p .05) was around one pregnancy every 30 months. The data represented a population with close to natural fertility, since their reproduction was not deliberately controlled and there was no cessation of reproduction once the desired family size had been attained.
Assuntos
Aborto Espontâneo/epidemiologia , Intervalo entre Nascimentos , Aleitamento Materno/estatística & dados numéricos , Gravidez/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Aleitamento Materno/psicologia , Coleta de Dados , Guiné Equatorial/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , ParidadeRESUMO
PIP: Household interview in 8 Shipibo communities on the Ucayali and Pisqui Rivers in Peru in 1983 and 1984 were conducted in order to obtain reproductive histories of 386 women aged 13 years and older. Polygyny was defined in three ways: as ever experienced, as operant during a specific birth interval, and as the mean length of closed birth intervals and the proportion polygynous. The aim was to determine the effect of the decline in polygyny on increased fertility. The results showed that of 1445 individuals in 8 villages, 585 (over 33%) lived in Paoyhan village. The sex ratio was 104 men to 100 women and varied among the villages. 49.3% were younger than 15 years and 60.3% younger than 20 years. Crude birth rates varied from 42.6 to 89.6/1000. Crude death rates ranged from 14 to 63.8/1000. Infant mortality was 138/1000. The village of 9 de Octubre had the lowest compared fertility and also had the highest rate of polygyny. Irazola village had the highest man completed fertility, and the lowest polygyny. The median reported age at marriage was 14 years; median reported age at menarche was 13 years. Age at menarche was the same regardless of marriage type, but polygynous women tended to marry about a year earlier. First delivery averaged about 15.6 years and was lower for polygynous women. 75 (19.4%) had ever engaged in a polygynous unions. The highest polygynous unions were in 9 de Octubre, Vencedor, Tupac Amaru, and charashmanan villages, and ranged from 56.5% to 5.3%. The proportion of men in polygynous unions ranged from 3.4% in Paoyhan to 21.9% in Vencedor. 84.5% of women aged 15 years and older had had at least one pregnancy. The mean reproductive span was 13 years. The mean age at delivery was 28.8 years. The mean birth interval was 31.5 months; mean interval for women aged 45 years and older was 36.2 years. There was found no correlation between birth interval number and birth interval length, or mother's age at birth interval and length of birth interval. Polygynous unions had a mean birth interval length 4 months longer, and lower fertility: 4.7 births versus 6.0 births. Regression analysis showed a straight line positive correlation between mean birth intervals and polygyny, even excluding Paoyhan, and a negative relationship between the prevalence of polygyny and fertility.^ieng
Assuntos
Intervalo entre Nascimentos , Etnicidade , Fertilidade , Indígenas Sul-Americanos , Casamento , Idade Materna , Ajustamento Social , Estatística como Assunto , Fatores Etários , América , Comportamento , Coeficiente de Natalidade , Cultura , Demografia , Países em Desenvolvimento , América Latina , Pais , Peru , População , Características da População , Dinâmica Populacional , Comportamento Social , América do SulRESUMO
A sample based on hospital birth records from the Latin American Collaborative Study on Congenital Malformations (ECLAMC) was used in this study. ECLAMC, which covers 11 countries (Uruguay, Chile, Argentina, Brazil, Bolivia, Peru, Paraguay, Ecuador, Venezuela, Colombia, and Costa Rica), registered 1,037,272 live births in the period 1982-1986. We applied several multivariate analysis models to the data and found that the sex ratio was significantly affected by secular, spatial (countries), biological (maternal age, birth order, and ethnic group), and socioeconomic (evaluated by hospital payment) variables. The black ethnic component carried sufficient weight to remove the spatial effect (Brazil and Venezuela) in certain cases. The Amerindian admixture effect on the sex ratio was negative and significant.
PIP: A sample based on hospital birth records from the Latin American Collaborative Study on Congenital Malformations (ECLAMC) was used. ECLAMC, which covers Uruguay, Chile, Argentina, Brazil, Bolivia, Peru, Paraguay, Ecuador, Venezuela, Colombia, and Costa Rica, registered 1,037,272 live births in the period 1982-1986. Weighted stepwise multiple regression analyses were used, and in all models the sex ration was the dependent variable. Maternal ages were grouped in categories of 5-year intervals, from mothers up to 19 years of age to mothers over 45 years of age. The 1st analysis of the sex ratio used biological (maternal age, birth order), temporal (year), and spatial (country) factors as independent variables. The sex ratio was significantly affected by secular, spatial, biological (maternal age, birth order, and ethnic group), and socioeconomic (evaluated by hospital payment) variables. The black ethnic component removed the spatial effect (Brazil and Venezuela) in certain cases. The Amerindian admixture effect on the sex ratio was negative and significant. Sex ratios were highest in mothers under 17 years old, gradually declined with age up to about 27 years, and thereafter increased slightly. Sex ratios decreased as birth order increased. In addition, a positive secular trend was observed (regression coefficient = 0.00082/yr). Other analyses included black and Amerindian components to verify whether the observed spatial effects were caused by different ethnic compositions. A final model with all the variables together with ethnic group indicated that ethnic stratification and form of payment had a negative correlation to sex ratio without any dramatic change compared to the previous analysis. Both the black and the Amerindian components are capable of removing the spatial effects of Brazil and Venezuela on the sex ratio.
Assuntos
Declaração de Nascimento , Análise Multivariada , Razão de Masculinidade , Ordem de Nascimento , Anormalidades Congênitas/epidemiologia , Etnicidade , Feminino , Humanos , Recém-Nascido , América Latina/epidemiologia , Masculino , Idade Materna , Características de Residência , Fatores de Risco , Fatores SocioeconômicosRESUMO
PIP: Results of the Dominican Republic's four most important fertility surveys were used to analyze how relations between selected sociodemographic factors and infant mortality have changed in recent decades, and to evaluate the contribution of changes in the distribution of these factors to mortality decline. The empirical analysis was carried out in four parts, the first of which analyzed trends in infant mortality in the Dominican Republic between 1960 and 1990. The second part established the importance of each determinant in each period studied and used logistic regression to analyze changes in the structure of the relationship between the variables and infant mortality. The third section analyzed changes in the relative weight of the categories of determinants during the study period. The final section standardized the risk of death in 1964-69 using the composition of births in 1985-90 and vice versa to evaluate the influence of each determinant in the infant mortality decline. The number of study variables was limited to six by lack of comparability in the four fertility surveys. The six variables were region and zone of residence, education and age of the mother, and birth order and interval. The results of this research did not indicate any clear pattern of change in the structure of relations between determinants and infant mortality. It appears plausible that there are various routes toward the transition leading to low mortality. In the Dominican Republic, maternal education was most important from 1964 to 1969, when infant mortality was high, and became relatively less important as a determinant in subsequent years. The changing relationship between maternal education and infant mortality suggests that there are no generalized patterns but rather the weight of each variable differs from one context to another and depends on the influence of other socioeconomic, medical, and demographic determinants.^ieng
Assuntos
Intervalo entre Nascimentos , Ordem de Nascimento , Coeficiente de Natalidade , Escolaridade , Geografia , Mortalidade Infantil , Idade Materna , Mortalidade , Fatores Etários , América , Região do Caribe , Demografia , Países em Desenvolvimento , República Dominicana , Economia , Características da Família , Relações Familiares , Fertilidade , América Latina , América do Norte , Pais , População , Características da População , Dinâmica Populacional , Classe Social , Fatores SocioeconômicosRESUMO
The prevalence and determinants of primary caesarean section in Jamaica were estimated from a survey of women aged 14-49 years. Among 2328 women reporting 2395 live hospital births during the period January 1984 to May 1989, the prevalence of caesarean section was 4.1%. Repeat caesarean sections accounted for 1.3% of the hospital births during that period. Of the medical complications studied, prolonged labour and/or cephalopelvic disproportion carried the highest risks of primary caesarean section, followed by breech presentation, maternal diabetes, a high birth-weight baby, maternal hypertension, and a low birth-weight baby. The risk of primary caesarean section increased with maternal age, decreased with parity, was higher for urban than for rural residents, and was higher for births in private versus government hospitals.
PIP: Researchers analyzed data on 2395 hospital births which occurred to 2328 14-49 year old women between January 1984 and May 1989 living in 7 parishes of Jamaica to determine the prevalence and factors of cesarean section. The primary cesarean section rate for the 5.5-year period was 4.1% which is lower than the rates of some developing countries and of some developed countries such as the US. The repeat cesarean section rate was 1.3%. Cephalopelvic disproportion and/or prolonged labor (abnormal labor) accounted for 17.4% of all primary cesarean sections. Abnormal labor carried the greatest risk of primary cesarean section (logistic regression model beta=1.9). Other delivery complications which posed considerable risk of cesarean section included breech presentation (beta=1.68), maternal diabetes (beta=0.84), maternal hypertension (beta=0.47), large birth weight infant (beta=0.4), and low birth weight infant (beta=-0.15). These complications made up 22.3%, 7.1%, 7.4%, and 5.3% of all primary cesarean sections, respectively. Nonmedical determinants of primary cesarean section included 30-year old women (beta=1.04), 1-2 births (beta=-1.27), urban residence (beta=0.75), and delivering in a private hospital (beta=0.59). 5.3% of 30-year old mothers underwent a cesarean section compared with 3.8% of 30-year old mothers. 5.2% of women of parity 1-2 had a cesarean section whereas only 2.3% of those of parity =or 3 did. Urban mothers were more likely to have a cesarean section than were rural mothers (5.4% vs. 3.3%). 7.6% of mothers delivering at a private hospital underwent a cesarean section compared with 3.9% of those delivering at a government hospital. Well-designed studies of infant mortality in Jamaica can determine whether the country can attain low levels of early infant mortality while keeping its current low rate of cesarean section.
Assuntos
Cesárea/estatística & dados numéricos , Adolescente , Adulto , Feminino , Humanos , Jamaica , Pessoa de Meia-Idade , Gravidez , Prevalência , Fatores de RiscoRESUMO
Ten independent variables were used to predict death before the first birthday for 4411 births that took place from 1878 to 1976 to 978 women of native ancestry on the island of St. Barthélemy. Significant predictors of death include the death of the mother within a year, the birth year, multiple birth, whether the preceding child also died before 1 year of age, and whether the next child was conceived before the index child was 1 year old. Unlike most prior studies, birth-spacing variables were only weakly related to death in the first year. The relative absence of contraceptive techniques to control birth spacing in the study population and the use of vital records rather than survey data distinguish this project from others and may account at least partly for the unusual findings.
PIP: A study of infant mortality using vital records from the Caribbean island of St. Bart, including 4411 births to 978 island-born women from 1878 to 1976, produced some atypical results. The population comprises poor subsistence farmers with a French culture with virtually no socioeconomic variation or modern contraception throughout the period. Stepwise multiple regression analysis was performed on the following 11 independent variables: birth year, birth order, mother's age at birth, child's sex, sex of previous child, preceding birth interval, previous child's death at less than 1 year, previous child was living at time of child's conception, next child was conceived while index child was living, mother's death during child's 1st year, and single or multiple pregnancy. Significant predictors of infant mortality were: mother's death within 1 year, birth year, multiple year, whether the preceding child died before 1 year of age, and whether the next child was conceived before the index child reached 1 year. This study, which did not rely on interview data, was remarkable for no significant effect of birth spacing variables. Maternal death was highly significant, a finding that rarely appears in interview surveys. Use of vital records and the interpretation of the determinants of birth spacing and infant death were discussed.
Assuntos
Intervalo entre Nascimentos , Mortalidade Infantil/tendências , Análise de Regressão , Atestado de Óbito , Feminino , Fertilização , Humanos , Recém-Nascido , Mortalidade Materna , Valor Preditivo dos Testes , Gravidez , Gravidez Múltipla , Índias Ocidentais/epidemiologiaRESUMO
PIP: The most recent contraceptive prevalence survey in Colombia indicated that over 2/3 of couples at risk of conception used some contraceptive method in 1990. This figure is close to the 80% or over common in developed countries and far exceeds the rates of 10% or even less in sub-Saharan African countries. Colombia's prevalence rate of around 15% in 1965, the 1st year of institutionalized family planning programs, included many users of ineffective traditional methods. Family planning, the possibility of determining the number and spacing of children, can be analyzed from various perspectives including its legal foundation as a human right and the demographic benefits of reproductive moderation. A stable population size would substantially simplify the problems of health, education, housing, and employment faced by developing countries. From a humanitarian perspective, family planning satisfies the ancient desire of human beings to separate reproduction and sex and also opens the door to different techniques of medically assisted conception. Some of the most significant benefits of family planning are those in the area of health. The positive effects on maternal and infant health and survival of avoiding pregnancy at the extremes of the reproductive period as well as pregnancies that are too numerous or closely spaced are now recognized. Colombia's infant mortality rate has fallen from 100/1000 live births in 1965 to 24 in 1990. Many factors besides family planning were involved, and the exact contribution of higher educational levels of mothers, use of oral rehydration therapy, promotion of breastfeedings, greater availability of potable water, and vaccination programs as well as of family planning are difficult to assess. But it is clear that child survival programs that neglect to include modern contraception as a principal component are shortsighted. Infants of adolescent mothers face mortality rates that are 15-40% higher than those of mothers over 20. Beyond 35 years, the risk of producing offspring with genetic disorders or other serious pathologies begins to rise sharply. The mortality risk of these infants is 20% higher than among those of younger mothers. Too close spacing of infants increases the risk of mortality through 2 principal mechanisms; the mother's body has insufficient time to recover from the 1st birth, consequently increasing the risk of low-birth weight and associated morbidity and mortality, and the older child is prematurely weaned and otherwise displaced by the younger child. The maternal risk of death in developing countries is estimated to increase by 30% with each succeeding pregnancy. Simply avoiding births before 20 years and after 35 would lead to decline of 20-25% in the maternal death rate.^ieng
Assuntos
Anticoncepção , Serviços de Planejamento Familiar , Planejamento em Saúde , Mortalidade Infantil , Idade Materna , Mortalidade Materna , Bem-Estar Materno , Mortalidade , Fatores Etários , América , Colômbia , Comportamento Contraceptivo , Demografia , Países em Desenvolvimento , Saúde , América Latina , Pais , População , Características da População , Dinâmica Populacional , América do SulRESUMO
PIP: Infant growth records of the National Center for Research in Maternal-Child Health were analyzed to compare malnutrition among children of adolescent mothers and of mothers over age 20. 235 children of adolescent mothers were the cases, and 470 children of mothers over age 20 were controls, with low birth weight, prematurity, educational level, and marital status controlled. Infants were considered malnourished at one year if their weight was below one standard deviation for their age, according to US National Center for Health Statistics norms. 49.8% of children of adolescent mothers were malnourished at 1 year by this criterion, compared to 40.2% of children of older mothers, indicating a risk of malnutrition 1.47 times greater for children of adolescent mothers. The odds ratio was 2.5 for low birth weight children of adolescent mothers compared to 0.4 for children of older mothers. It was 1.88 for children of adolescent mothers with primary education or less compared to 1.51 for older mothers with primary or less. Prematurity and marital status were not significantly associated with differential risk of malnutrition.^ieng
Assuntos
Adolescente , Estudos de Casos e Controles , Lactente , Idade Materna , Distúrbios Nutricionais , Fatores Etários , América , Região do Caribe , Demografia , Países em Desenvolvimento , Doença , República Dominicana , América Latina , América do Norte , Pais , População , Características da População , PesquisaRESUMO
In 1984 a prospective study of 1645 women and 1677 births in a rural community in north-eastern Brazil showed the infant mortality rate to be 65 per 1000 live births. Neonatal, post-neonatal and infant mortality are analysed to determine the most important risk factors for each period. Post-neonatal survival depends largely on factors relating to child care, while neonatal deaths are more likely to be associated with biological factors. The principal cause of death, diarrhoeal disease, was responsible for a third of the deaths.
PIP: In 1984 a prospective study of 1645 women and 1677 births in a rural community in north-eastern Brazil showed the infant mortality rate to be 65/1000 live births. Neonatal, post-neonatal and infant mortality are analyzed to determine the most important risk factors for each period. Data were obtained from all women in Trairi who gave birth between May 1984 and April 1985, and all mothers were followed-up on 4 occasions by hospital personnel or a TBA when the child reached 6 weeks and 6, 12, and 18 months of age. When an infant death occurred, community leaders and TBAs notified hospital personnel and a physician visited the mother, completing a questionnaire on the cause of death. Neonatal deaths were related to problems associated with pregnancy and low birthweight, factors associated with post-neonatal mortality are related to infants of younger women and of mothers of high parity. Low birthweight babies had an increased risk of post-neonatal death when mothers only had 1-3 prenatal visits; they were 14 times more likely to die during the post- neonatal period than those whose mothers had 4-5 visits and weighed 2500-4999 g. Infant mortality could be prevented by child survival interventions such as breastfeeding, oral rehydration therapy, and early diagnosis. Post-neonatal survival seems to depends on factors relating to child care, while neonatal deaths are more likely to be associated with biological factors. Diarrhea was responsible for 1/3 of all deaths.
Assuntos
Causas de Morte , Diarreia Infantil/mortalidade , Mortalidade Infantil , Brasil , Diarreia Infantil/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Fatores de Risco , População Rural/estatística & dados numéricosRESUMO
This paper uses life table methods to analyze the process of family formation in Puerto Rico. Despite a continuing decline in fertility, the pattern of birth spacing is very rapid with a big proportion of short intergenesic intervals. This indicates a clear distinction between spacing and stopping behavior. Some possible health implications are discussed.
PIP: The life table method is used to analyze the process of family formation in Puerto Rico. The method approaches family formation in a cohort of women as a series of transitions between successive statuses in which each transition has a measurable probability of occurring. The method allows detained analysis of changes in fertility by separating changes in the intensity or number of births and the timing or spacing of births. The data were from the 1982 Puerto Rico Fertility and Family Planning Assessment Survey, a retrospective survey with detailed information on 3175 women aged 15-49. The analysis is limited to women ever in union. The births occurred during a period of more than 30 years, from around 1950-82, during which the total fertility rate declined by almost 50%, from 5.2 to 2.7 children/woman. Each birth interval was divided into 4 age groups to avoid the overrepresentation of women marrying younger and with shorter birth intervals. Analysis of the 1st 5 birth intervals for the 4 age categories in each clearly shows that the fertility reduction was reflected in the reduction in higher order births, a reduction already clearly visible in the transition to the 2nd birth. But contrary to the pattern in other low fertility populations, in Puerto Rico there does not seem to be a very consistent relationship between the decline in the probabilities of transition between birth orders and a more prolonged spacing. Women who reach each interval at the younger ages have a higher probability of having another child, and they do it more rapidly, which indicates the close relationship between age at the beginning of family formation, the size of the family, and the speed of the reproductive process. But even among older women the intervals are still very brief, indicating a pattern of rapid spacing independent of the number of children already born and perhaps of desired family size. The pattern indicates a clear distinction between behavior associated with terminating childbearing and that of spacing births. An analysis of changes in the intensity and calendar of births of different orders in 3 time periods, 1965-1969, 11970-1974, and 1975-1982, shows a clear trend toward longer intervals after 1965. Women who began childbearing at younger ages had shorter intervals than those who began later. In view of the abundant existing evidence on the adverse effects of short birth intervals, the process of family formation in Puerto Rico should be studied in greater detail, especially considering its possible impact on infant mortality.
Assuntos
Intervalo entre Nascimentos , Coeficiente de Natalidade/tendências , Fatores Etários , Humanos , Idade Materna , Porto Rico , Estatística como AssuntoRESUMO
PIP: Results of Mexico's 1987 National Survey of Fertility and Health (ENFES) shows significant changes in total fertility rates (TFR) and contraceptive prevalence rates. These changes are due i large part to the institutionalization of a population policy enacted in 1972 that has continued to receive strong support from the government. The TFR declined from 6.3 to 3.8 with urban rates falling 50% and rural rates 3/4. Between 1976-86 use of modern contraception doubled, going from 23-45%. Use of the pill declined while female sterilization increased for 9-36%; IUD's remained the 2nd most popular method at 18%. Contraceptive prevalence rates mirror changes in desired family sizes; women between 15-19 now desire 2.6 children while women at the end of their reproductive cycle expect to have 4. Infant mortality rates dropped from 85 to 47/1000 between 1970 and 1987. 62% of illiterate women wish to stop childbearing as compared with 49% of women with secondary schooling. This difference is related to differences in the ages of the 2 groups; as education has spread, women without any schooling tend to be older and have higher parity; and in spite of wanting to stop childbearing, they are 10 times less likely to use contraception than their more educated counterparts. 67% of the women interviewed received prenatal care from a doctor, with higher rates among the urban population. Between 80-90% of women breastfed their children, with higher rates among the rural poor.^ieng
Assuntos
Coeficiente de Natalidade , Comportamento Contraceptivo , Escolaridade , Inquéritos Epidemiológicos , Mortalidade Infantil , Idade Materna , Aceitação pelo Paciente de Cuidados de Saúde , Características da População , Política Pública , Estatística como Assunto , Fatores Etários , América , Anticoncepção , Demografia , Países em Desenvolvimento , Economia , Serviços de Planejamento Familiar , Fertilidade , Saúde , Planejamento em Saúde , América Latina , México , Mortalidade , América do Norte , Pais , População , Dinâmica Populacional , Pesquisa , Classe Social , Fatores SocioeconômicosRESUMO
Nuñoa is a high altitude rural Peruvian community characterized by socioeconomic stratification and differential access to the market economy. Nursing practices and the effects of nursing are also stratified; this translates into a risk of menses at 12 months post-partum nearly seven times greater in wealthier than in poorer women. Most nursing occurs in the morning, among those who practice on-demand breast-feeding. Nursing episodes are clustered into sessions; the amount of breast-feeding is regulated by varying the number of episodes per session rather than by changing the duration of suckling episodes or the frequency of sessions per hour. Thus, resumption of ovulation is not dependent on the variable spacing of nursing episodes or sessions. The components of nursing activity most likely to be responsible for variation in the duration of post-partum amenorrhoea in these nursing women are mean session duration and mean number of episodes per session. The mean duration of morning nursing sessions is negatively associated with infant's age, reflecting the greater reliance of younger children on breast-milk. The mean duration of afternoon nursing sessions is positively associated with mother's age, independent of infant's age, possibly reflecting maternal age-related variation in milk production capabilities. Baby minding by older daughters may also help to explain variation in afternoon nursing.