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Search Results: 1 - 10 of 8488 matches for " Aluísio JD Barros "
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Alternatives for logistic regression in cross-sectional studies: an empirical comparison of models that directly estimate the prevalence ratio
Aluísio JD Barros, Vania N Hirakata
BMC Medical Research Methodology , 2003, DOI: 10.1186/1471-2288-3-21
Abstract: We compared Cox regression with constant time at risk, Poisson regression and log-binomial regression against the standard Mantel-Haenszel estimators. Models with robust variance estimators in Cox and Poisson regressions and variance corrected by the scale parameter in Poisson regression were also evaluated.Three outcomes, from a cross-sectional study carried out in Pelotas, Brazil, with different levels of prevalence were explored: weight-for-age deficit (4%), asthma (31%) and mother in a paid job (52%). Unadjusted Cox/Poisson regression and Poisson regression with scale parameter adjusted by deviance performed worst in terms of interval estimates. Poisson regression with scale parameter adjusted by χ2 showed variable performance depending on the outcome prevalence. Cox/Poisson regression with robust variance, and log-binomial regression performed equally well when the model was correctly specified.Cox or Poisson regression with robust variance and log-binomial regression provide correct estimates and are a better alternative for the analysis of cross-sectional studies with binary outcomes than logistic regression, since the prevalence ratio is more interpretable and easier to communicate to non-specialists than the odds ratio. However, precautions are needed to avoid estimation problems in specific situations.Epidemiologic studies found in the literature are frequently cross-sectional, as this is a simple, fast and inexpensive design alternative. Often the outcomes are binary, and logistic regression is used for the analysis. This results in the odds ratio being frequently reported in situations where incidence or prevalence ratios are estimable, despite the fact that it is "biologically interpretable only insofar as it estimates the incidence-proportion or incidence-density ratio" [1].From a survey done by the authors in the International Journal of Epidemiology and in the Revista de Saúde Pública (S?o Paulo, Brazil) published in 1998, 221 original articles were
Can mothers rely on the Brazilian health system for their deliveries? An assessment of use of the public system and out-of-pocket expenditure in the 2004 Pelotas Birth Cohort Study, Brazil
Aluísio JD Barros, Iná S Santos, Andréa D Bertoldi
BMC Health Services Research , 2008, DOI: 10.1186/1472-6963-8-57
Abstract: All deliveries occurring in the city of Pelotas, Brazil, during 2004, were recruited for a birth cohort study. All mothers were interviewed just after birth and three months later. Comprehensive data on the pregnancy, delivery, birth conditions and newborn health were collected, along with detailed information on expenses related to the delivery.The majority of the deliveries (81%) were financed by the public health system, a proportion that increased to more than 95% among the 40% poorest mothers. Less than 1% of these mothers reported some out-of-pocket expenditure. Even among those mothers covered by a private health plan, nearly 50% of births were financed by the SUS. Among the 20% richest, a third of the deliveries were paid by the SUS, 50% by private health plans and 17% by direct payment.The public health system offered services in quantity and quality enough to attract even beneficiaries of private health plans and spared mothers from the poorest strata of the population of practically any expense.Health costs in low and middle income countries can be an important source of expenditure and it has been shown that they can consume a high proportion of family income, up to catastrophic proportions. Brazil was identified as one of the countries with the highest proportion of households suffering from catastrophic health expenditure in a study comparing 59 countries[1]. This study showed that 10% of Brazilian households spent more than 40% of their capacity to pay (as catastrophic expenditure was defined), compared to 6% in Argentina and Colombia, 1.5% in Mexico, 0.5% in the US and practically zero in France and the UK. The only country with a similar result was Vietnam. Such a result is surprising given that Brazil offers comprehensive and free health services to all citizens through its national health system, the SUS (acronym for what could be translated into English as Unified Health System).The SUS was created in 1988, within the new Constitution, to offer f
Baixa prevalência de déficit de peso para estatura: compara??o de crian?as brasileiras com e sem déficit estatural
Post,Cora LA; Victora,Cesar G; Barros,Aluísio JD;
Revista de Saúde Pública , 1999, DOI: 10.1590/S0034-89101999000600009
Abstract: objectives: the aim of this study was to investigate the relationship between abdominal circumference and weight-for-height in children. the average of 18 anthropometric and body proportionality indexes were compared among four groups of children: stunted and non-stunted brazilians, peruvians and north-americans. methods: there were studied 386 children aged 6-59 months living in a poor neighborhood in pelotas, brazil. anthropometric measurements (weight, recumbent length or height, sitting height or crown-rump length; head, chest, upper arm and abdominal circumferences; triceps, biceps, subescapular and suprailiac skinfold tickness; biacromial and biiliac breadths) were obtained. muscle, fat, total upper arm areas, leg length and body proportionality indexes were calculated. results and conclusions: the study sample showed high levels of morbidity, low parental educational levels, poor access to health services and poor housing conditions. stunted brazilian children had lower means for most of the anthropometric measurements when compared to non-stunted brazilians and north-american children. however, stunted children showed larger abdominal, head and thoracic circumference in relation to their stature than non-stunted children. the low prevalence of weight-for-height among the children of this study is not a result of excess of fat or muscle tissue, and may be partly explained by an increase in head and trunk dimensions (including abdominal circumference) relative to the child's stature.
Baixa prevalência de déficit de peso para estatura: compara o de crian as brasileiras com e sem déficit estatural
Post Cora LA,Victora Cesar G,Barros Aluísio JD
Revista de Saúde Pública , 1999,
Abstract: OBJETIVO: Avaliar a associa o entre o perímetro abdominal e o índice peso para estatura em crian as, comparando as médias de índices antropométricos e de proporcionalidade corporal entre crian as pelotenses com e sem déficit linear, peruanas e norte-americanas, por faixa etária. MéTODOS: Foram estudadas 386 crian as de 6 a 59 meses, residentes em bairro pobre de Pelotas, RS. Foram medidos e calculados 18 índices antropométricos. RESULTADOS E CONCLUS ES: Crian as com déficit linear apresentaram índices antropométricos inferiores, comparativamente àquelas sem déficit e às norte-americanas; proporcionalmente à sua estatura, maiores perímetros abdominal, cefálico e torácico. As baixas prevalências de déficit de peso para estatura n o resultam de excesso de tecido adiposo ou de massa muscular e podem ser parcialmente explicadas por um aumento nas dimens es da cabe a e do tronco (inclusive do perímetro abdominal) em rela o à estatura da crian a.
Breastfeeding patterns and exposure to suboptimal breastfeeding among children in developing countries: review and analysis of nationally representative surveys
Jeremy A Lauer, Ana Betrán, Cesar G Victora, Mercedes de Onís, Aluísio JD Barros
BMC Medicine , 2004, DOI: 10.1186/1741-7015-2-26
Abstract: We reviewed nationally representative surveys that collected data on breastfeeding rates in 94 developing countries. Surveys were categorized by completeness and comprehensiveness of data. Complete and comprehensive data were analysed with minimum chi-square regression. With a fitting procedure, estimated parameters were used to impute missing observations for incomplete or non-comprehensive surveys. Breastfeeding indicators were calculated and are reported for 135 developing countries by UN region.Amongst infants aged six months or younger in the developing world, the prevalence of exclusive breastfeeding is 39% and the prevalence of no breastfeeding is 5.6%. The prevalence of continued breastfeeding is 86% and 68% for infants and children aged 6–11 and 12–23 months, respectively, in the developing world. Imputation expands population coverage of indicators, especially for infants. Breastfeeding trends are highly linear and estimated parameters defining the age-specific attrition hazard are robust. Survey-reported rates, particularly for exclusive breastfeeding, appear to have systematic upward bias, and exposure estimates must be considered conservative.Compliance with breastfeeding recommendations in developing countries is low, and more attention should be given to increasing breastfeeding – especially exclusive breastfeeding – and to monitoring trends. Although the introduction of more standardized and better validated survey instruments is desirable, since data coverage, completeness and comprehensiveness are extensive, global exposure assessment is relatively robust. Moreover, the regularity of breastfeeding patterns show existing survey data capture real biological and social phenomena. Our method for the analysis of breastfeeding rates provides a potent tool for summarizing trends, validating observations, translating and extrapolating indicators (as well as projecting and imputing estimates when necessary) and should support more effective child health mon
Experiências de discrimina??o entre universitários do Rio de Janeiro
Bastos,Jo?o Luiz; Gon?alves,Helen; Faerstein,Eduardo; Barros,Aluísio JD;
Revista de Saúde Pública , 2010, DOI: 10.1590/S0034-89102010000100003
Abstract: objective: to understand experiences of discrimination lived by undergraduate students and to analyze their applicability to the construction of a brazilian discrimination scale. methodological procedures: in a qualitative study five focus groups were conducted with 43 university students from the city of rio de janeiro, southeastern brazil, in 2008. students from undergraduate courses with different candidate/place ratios; of both sexes; self-identified as white, mixed or black; and belonging to two public higher education institutions were selected. an interview guide focusing on issues related to "prejudice" and "discrimination" and asking participants about their experiences of discrimination was used. the method of interpretation of meanings was adopted, seeking to understand the context, reasons and logics of participants' speech. analysis of results: prejudice was interpreted as something belonging to the field of ideas, probably equivocated, and which could be either positive or negative. discrimination was attributed to the field of observable behaviors and with an invariably negative connotation. the interpretation of a discriminatory event as such was influenced by subjective factors, such as personal interests and the level of affectivity established between individuals. however, the limit between what was interpreted as discriminatory or not depended strongly on the specific context in which the interaction among individuals occurred. different situations and, at times, more than one motivation were simultaneously indicated as regards discriminatory experiences. participants saw themselves as both victims and perpetrators of discrimination. conclusions: the interpretation of an event as discriminatory involves great complexity and the experiences of discrimination can hardly be generalized. when evident, the reasons for which individuals suppose they have been discriminated against may be multiple and associated with each other. such aspects must be con
Contraceptivos orais e cancer de mama: estudo de casos e controles
Tessaro,Sérgio; Béria,Jorge U; Tomasi,Elaine; Barros,Aluísio JD;
Revista de Saúde Pública , 2001, DOI: 10.1590/S0034-89102001000100005
Abstract: objective: to investigate the association between breast cancer and the duration of use of oral contraceptives (oc), and age it started to be used in a population of pelotas, southern brazil. methods: there were identified 250 incident cases of breast cancer in patients aged 20 to 60 years from records of pathology laboratories and there were enrolled 1,020 controls drawn from hospital and neighbourhood population. for 90 cases identified in pelotas, 270 hospital controls and 270 neighbourhood controls were selected, for another 78 cases in pelotas, 234 controls were selected, and for 82 cases from other municipalities, 246 hospital controls were selected. controls were matched by age. adjusted analysis was performed using conditional logistic regression. results: no association between oral contraceptive use and breast cancer was found (or=1.1;ci95% 0.7?1.6 for hospital controls, and or=0.9;ci95% 0.6?1.6 for neighbourhood controls) neither for different duration of use or starting age. to increase the test power, 250 cases and all 1020 controls were analyzed together, and an odds ratio of 1.6 (ci95% 1.0?2.4) was found for women older than 45 years of age who had been using oral contraceptives for five years or more. conclusions: no evidence was found of a general association between oral contraceptive use and breast cancer. when analyzing the whole date set, with all neighbourhood and hospital controls together, for women older than 45 years of age who had been using oral contraceptives for more than 5 years, it was found an increased risk almost statistically significant (p=0.05).
Contraceptivos orais e cancer de mama: estudo de casos e controles
Tessaro Sérgio,Béria Jorge U,Tomasi Elaine,Barros Aluísio JD
Revista de Saúde Pública , 2001,
Abstract: OBJETIVO: Investigar a associa o entre uso de contraceptivos orais (CO) e cancer de mama. MéTODOS: Identificaram-se 250 casos incidentes de cancer de mama, com 20 a 60 anos de idade, a partir de laboratórios de patologia, e 1.020 controles-hospitalares e de vizinhan a. Os controles foram pareados aos casos por idade. A análise ajustada foi realizada por regress o logística condicional para estimar as raz es de odds (RO). RESULTADOS: N o se encontrou associa o entre uso de contraceptivos orais e cancer de mama (RO=1,1; IC 95% 0,7-1,6 para controles hospitalares e RO=0,9; IC 95% 0,6-1,6 para controles de vizinhan a) e nem para diferentes tempos de uso ou idades de início. Ao separar os casos por idade de diagnóstico do cancer de mama e tempo de uso dos CO, verificou-se que mulheres com mais de 45 anos, que haviam utilizado contraceptivos por cinco anos ou mais, tiveram RO de 1,6 (IC 95% 0,9-3,0) entre controles-hospitalares e de 1,3 (IC 95% 0,7-2,6) entre controles de vizinhan a. Para aumentar o poder do estudo, realizou-se análise com os 250 casos e os 1.020 controles, resultando uma RO de 1,6 (IC 95% 1,0-2,4) sem significancia estatística. CONCLUS ES: N o foi encontrada associa o entre uso de CO e cancer de mama em geral, assim como entre faixas etárias e tempo de uso do CO. Ao analisar todos os casos e controles conjuntamente, evidenciou-se um risco aumentado no subgrupo de mulheres usuárias por mais de cinco anos e com idade superior a 45 anos, porém n o houve significancia estatística, embora ela estivesse muito próxima (p=0,05).
Racial discrimination and health: a systematic review of scales with a focus on their psychometric properties
Jo?o Luiz Bastos,Roger Keller Celeste,Eduardo Faerstein,Aluísio JD Barros
Saúde & Transforma??o Social , 2011,
Abstract: The literature addressing the use of the race variable to study causes of racial inequities in health is characterized by a dense discussion on the pitfalls in interpreting statistical associations as causal relationships. In contrast, fewer studies have addressed the use of racial discrimination scales to estimate discrimination effects on health, and none of them provided a thorough assessment of the scales’ psychometric properties. Our aim was to systematically review self-reported racial discrimination scales to describe their development processes and to provide a synthesis of their psychometric properties. A computer-based search in PubMed, LILACS, PsycInfo, Scielo, Scopus and Web of Science was conducted without any type of restriction, using search queries containing free and controlled vocabulary. After initially identifying 3,060 references, 24 scales were included in the review. Despite the fact that discrimination stands as topic of international relevance, 23 (96%) scales were developed within the United States. Most studies (67%, N = 16) were published in the last 12 years, documenting initial attempts at scale development, with a dearth of investigations on scale refinements or cross-cultural adaptations. Psychometric properties were acceptable; sixteen of all scales presented reliability scores above 0.7, 19 out of 20 instruments confirmed at least 75% of all previously stated hypotheses regarding the constructs under consideration, and conceptual dimensional structure was supported by means of any type of factor analysis in 17 of 21 scales. However, independent researchers, apart from the original scale developers, have rarely examined such scales. The use of racial terminology and how it may influence self-reported experiences of discrimination has not yet been thoroughly examined. The need to consider other types of unfair treatment as concurrently important health-damaging exposures, and the idea of a universal instrument, which would permit cross-cultural adaptations, should be discussed among researchers in this emerging field of inquiry.
Late preterm birth is a risk factor for growth faltering in early childhood: a cohort study
Ina S Santos, Alicia Matijasevich, Marlos R Domingues, Aluísio JD Barros, Cesar G Victora, Fernando C Barros
BMC Pediatrics , 2009, DOI: 10.1186/1471-2431-9-71
Abstract: In 2004, all births taking place in Pelotas (Southern Brazil) were recruited for a cohort study. Late preterm (34/0-36/6 weeks of gestational age) and term children (37/0-42/6 weeks) were compared in terms of weight-for-age, length-for-age and weight-for-length z-scores. Weight-for-age, length-for-age and weight-for-length z-scores below -2 were considered, respectively, underweight, stunting and wasting. Singleton newborns with adequate weight for gestational age at birth, successfully followed-up either at 12 or 24 months of age were analyzed and adjusted odds ratios with 95% confidence intervals calculated through logistic regression.3285 births were included, 371 of whom were late preterm births (11.3%). At 12 months, prevalence of underweight, stunting and wasting were, respectively, 3.4, 8.7 and 1.1% among late preterm children, against 1.0, 3.4 and 0.3% among term children. At 24 months, correspondent values were 3.0, 7.2 and 0.8% against 0.8, 2.9 and 0.4%. Comparing with the term children, adjusted odds of being underweighted among late preterm children was 2.57 times higher (1.27; 5.23) at 12 months and 3.36 times higher (1.56; 7.23) at 24; of being stunted, 2.35 (1.49; 3.70) and 2.30 (1.40; 3.77); and of being wasted, 3.98 (1.07; 14.85) and 1.87 (0.50; 7.01). Weight gain from birth to 12 and 24 months was similar in late preterm and term children, whereas length gain was higher in the former group in both periods.Late preterm children grow faster than children born at term, but they are at increased risk of underweight and stunting in the first two years of life. Failure to thrive in the first two years may put them at increased risk of future occurrences of serious morbidity in late childhood and of chronic disease development in adult life.Gestational age is among the most important aspects that dictate short and long-term health of a newborn. As the fetus needs time to grow, and to develop tissues and organs, premature birth can have adverse consequence
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