The epidemiological transition in maternal and child health in a Brazilian city, 1982-93: a comparison of two population-based cohorts.

Two studies carried out in 1982 and 1993 in the city of Pelotas, Southern Brazil, provide a unique opportunity for assessing the impact on maternal and child health of the economic and health care changes, which took place in Brazil in this period. The cohorts of mothers and infants of 1982 and 1993 were studied from the time of delivery. In both years, all mothers identified in the city's maternity hospitals answered a standardised questionnaire and their infants were examined. Over 99% of all children born in the city in each of the 2 years were included in the cohorts. Deaths occurring among these children were monitored prospectively, as well as all hospital admissions in the 1993 cohort. In the 1982 study, attempts were made to locate a 25% sample of the children at the mean age of 12 months using the addresses collected at the hospital (82% of the children were located), and all of the cohort children at the mean age of 20 months and 42 months, through a city census (87% were located in both follow-ups). In the 1993 study, 20% of all children plus all low birthweight infants were sought at 12 months of age, using the addresses collected at the hospital, and 95% were successfully traced. There was a 12% fall in the number of births occurring in 1993 (5,304 births), in comparison with 1982 (6,011 births), in spite of the increase in the population of reproductive age in the city during the decade. There was a marked difference in maternal height and weight at the beginning of pregnancy, with women giving birth in 1993 being, on average, 3.4 cm taller and 2.5 kg heavier than those who gave birth in 1982. The proportion of preterm babies (<37 weeks), measured by the date of last menstrual period, increased from 5.6% in 1982 to 7.5% in 1993. The median duration of breast feeding increased from 3.1 months in 1982 to 4.0 months in 1993. At 12 months of age, the prevalence of deficit of weight for age decreased from 5.4% in 1982 to 3.7% in 1993. The prevalence of deficit of height for age, however, increased from 5.3% to 6.1%. The perinatal mortality rate dropped 31%, from 32.2 per 1,000 births in 1982 to 22.1 deaths per 1,000 births in 1993. There was also a marked reduction in the infant mortality rate, from 36.4 per 1,000 livebirths in 1982 to 21.1 per 1,000 livebirths in 1993. The findings of the study indicate that there were improvements in the decade for most of the indicators evaluated, with the exception of birthweight and gestational age. It appears that improvements in perinatal and infant mortality rates are largely due to improvements in the health care sector.

Explaining trends in inequities: evidence from Brazilian child health studies.

There is considerable international concern that child-health inequities seem to be getting worse between and within richer and poorer countries. The "inverse equity hypothesis" is proposed to explain how such health inequities may get worse, remain the same, or improve over time. We postulate that as new public-health interventions and programmes initially reach those of higher socioeconomic status and only later affect the poor, there are early increases in inequity ratios for coverage, morbidity, and mortality indicators. Inequities only improve later when the rich have achieved new minimum achievable levels for morbidity and mortality and the poor gain greater access to the interventions. The hypothesis was examined using three epidemiological data sets for time trends in child-health inequities within Brazil. Time trends for inequity ratios for morbidity and mortality, which were consistent with the hypothesis, showed both improvements and deterioration over time, despite the indicators showing absolute improvements in health status between rich and poor.

Epidemiologia para municípios: manual para gerenciamento dos distritos sanitários / Epidemiology for municipalities: manual for management of sanitary districts

Guia sobre epidemiologia e sua relaçäo com o planejamento, gerenciamento e avaliaçäo, enfatizando o uso de informaçöes epidemiológicas no planejamento ao nível municipal e distrital.

Land tenure and child health in Rio Grande do Sul: the relationship between agricultural production, malnutrition and mortality.

"Four different approaches were applied to test the hypothesis that patterns of land tenure and agricultural production in Rio Grande do Sul [Brazil] are important infant mortality determinants. These studies have employed various data sources on distinct analytical levels.... The results...provide reliable evidence of there being a strong relationship between the degree of concentration of land tenure and agricultural production on the one hand, and malnutrition and infant mortality on the other."

[Longitudinal study of the mother and child population in an urban region of southern Brazil, 1993: methodological aspects and preliminary results]. / Estudo longitudinal da população materno-infantil da região urbana do Sul do Brasil, 1993: aspectos metodológicos e resultados preliminares.

All babies born in the hospitals of the city of Pelotas, Brazil, in 1982 were studied soon after delivery and followed up prospectively during the first years of their lives. In 1993, this study was repeated with a similar methodology, with the aim of assessing eventual changes in the level of maternal and child health. All five maternity hospitals in the city were visited daily and the 5,304 babies born included in the study. They were weighed and measured, and their gestational age was assessed using the Dubowitz method. Their mothers were examined and interviewed regarding a large number of risk factors. The mortality of these children was studied through the surveillance of all hospitals, cemeteries and death registries, and all hospital admissions were also recorded. Two nested case-control studies were carried out to assess risk factors for mortality and hospital morbidity. A systematic sample of 655 children were examined at home at one and three months of age, and these infants, as well as another sample of 805 children including all low-birthweight babies were also examined at the ages of six and twelve months. Their psychomotor development was also assessed. Losses to follow-up were only 6.6% at twelve months. Relative to the 1982 indicators, perinatal mortality fell by about 30% and infant mortality by almost 50%. The median duration of breastfeeding increased from 3.1 to 4.0 months. On the other hand, there was little change in the prevalences of low birthweight or of length for age at twelve months. The article that refers this abstract describes the methodology of the study and forthcoming publications will present detailed results.

PIP: All babies born in the hospitals of the city of Pelotas, Brazil, in 1982 were studied soon after delivery and followed up prospectively during the first years of their lives. In 1993 this study was repeated with a similar methodology, with the aim of assessing eventual changes in the level of maternal and child health. All five maternity hospitals in the city were visited daily and the 5304 babies born included in the study. They were weighed and measured, and their gestational age was assessed using the Dubowitz method. Their mothers were examined and interviewed regarding a large number of risk factors. The mortality of these children was studied through the surveillance of all hospitals, cemeteries, and death registries, and all hospital admissions were also recorded. Two nested case-control studies were carried out to assess risk factors for mortality and hospital morbidity. A systematic sample of 655 children was examined at home at 1 and 3 months of age, and these infants, as well as another sample of 805 children including all low-birth-weight babies, were also examined at the ages of 6 and 12 months. Their psychomotor development was also assessed. Losses to follow-up were only 6.6% at 12 months. Relative to the 1982 indicators, perinatal mortality fell by about 30% and infant mortality by almost 50%. The median duration of breast feeding increased from 3.1 to 4.0 months. On the other hand, there was little change in the prevalences of low birth weight or of length for age at 12 months. The methodology of the study is described, and forthcoming publications will present detailed results. (author's modified)

Early childhood mortality in a Brazilian cohort: the roles of birthweight and socioeconomic status.

The deaths of children aged 1-4 years were studied in a cohort of 5914 Brazilian liveborns. A total of 29 early childhood deaths were recorded (cumulative mortality risk of approximately 6 per 1000), 17 of which (59%) were due to infectious diseases. The death rate was highest in the second year. Deaths were highly concentrated in children from low income (< US $50/month) families, where the cumulative risk of early childhood death was about 10 per 1000; on the other hand, there were no deaths among the 616 children from families with a monthly income of US $300 or more. Birthweight was also associated with mortality: the cumulative risk of children weighing less than 2000 g at birth was 21 per 1000, compared to 4 per 1000 among those with birthweights of 3500 g or more. Simultaneous adjustment for income and birthweight did not substantially change these differentials. These findings confirm the strong association between early childhood mortality and socioeconomic conditions, but also make evident the long-term effects of low birthweight.

PIP: Mortality was studied among a cohort of 5914 Brazilian live-borns aged 1-4 years. 29 early childhood deaths were recorded, 17 of which were due to infectious diseases. The highest death rate was observed in the 2nd year. Deaths were highly concentrated among children of families with income US$50/month, with a 10/1000 cumulative risk of early childhood death. No deaths, however, occurred among the 616 children from families with monthly income or= US$300. As for birth weight, the cumulative risk of death among children weighing 2000 gm at birth was 21/1000, compared with 4/1000 among those with birth weights of 3500 gm or more. Simultaneous adjustments for both income and birth weight failed to substantially change mortality differentials. Study results therefore confirm the strong association between early childhood mortality, income, and low birth weight.

Comparison of the causes and consequences of prematurity and intrauterine growth retardation: a longitudinal study in southern Brazil.

A cohort of 5914 liveborns (99% of the city births) was followed up to the age of 4 years in Pelotas, southern Brazil. Besides the perinatal evaluation, the cohort children were examined again at mean ages of 11, 23, and 47 months. During each visit the children were weighed and measured and information on morbidity was collected. Also, multiple sources of information were used for monitoring mortality throughout the study. Of the babies with known gestational age, 9.0% were classified as intrauterine growth-retarded and 6.3% as preterm. Excluding those of unknown gestational age, 62% of low birth weight babies were intrauterine growth-retarded and 36% were preterm. Intrauterine growth retardation was statistically associated with maternal height, prepregnancy weight, birth interval, and smoking, whereas preterm births were associated with maternal prepregnancy weight and maternal age. Preterm babies had a perinatal mortality rate 13 times higher than that of babies of appropriate birth weight and gestational age and 2 times higher than that of intrauterine growth-retarded babies. Infant mortality rates presented a similar pattern, with the differentials being more pronounced during the neonatal than in the postneonatal period. In the first 2 years of life intrauterine growth-retarded children were at almost twice the risk of being hospitalized for diarrhea compared with appropriate birth weight, term children, while preterm children experienced only a slightly greater risk. For pneumonia, however, both groups of children were hospitalized significantly more than appropriate birth weight, term children. In terms of growth, despite their earlier disadvantage, preterm children gradually caught up with their appropriate birth weight, term counterparts.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth spacing and child health in urban Brazilian children.

The associations between birth interval and a range of child health outcomes were examined in a population-based cohort of approximately 3500 urban Brazilian children. The effects of several socioeconomic and maternal confounding factors were controlled for in the analyses. Children born after shorter birth intervals (less than 18 and 18 through 23 months) were disadvantaged with respect to most of the health outcomes when compared with children born after intermediate birth intervals (24 through 35, 36 through 47, and 48 through 71 months). Effects were particularly marked for birth weight, postneonatal mortality, and anthropometric status at mean age 19 months. Children born after a long birth interval (greater than 71 months) also showed some disadvantage for birth weight, perinatal mortality, and infant mortality. However, this group experienced lower risks of hospitalizations during the first 19 months of life and better anthropometric status at mean age 19 months. This study provides data that are scarce from such settings and contributes to the quantification of associations between birth spacing and child health. This information is important in the planning of appropriate intervention strategies.

Maternal education in relation to early and late child health outcomes: findings from a Brazilian cohort study.

In a population-based cohort of approximately 6000 Brazilian children, the associations between maternal education and a number of child health outcomes were studied while controlling for potentially confounding variables such as family income and education of the husband. In the crude analyses, maternal education was associated with perinatal and infant mortality, hospital admissions in the first 20 months of life and the three nutritional indicators (length-for-age, weight-for-age and weight-for-length) at mean age 20 months. After adjustment for confounding, the apparent associations with outcomes in early infancy--birthweight and perinatal mortality--were no longer present, while that with infant mortality persisted despite being reduced. Strong associations remained with later outcomes including hospital admissions, length-for-age and weight-for-age at mean age 20 months. Among infants born to women with little or no schooling, deaths due to diarrhoea, pneumonia and other infectious diseases were particularly common. These findings support the hypothesis that maternal education has an effect on child health which is partly independent from that of other socioeconomic factors; they also suggest that maternal care is more important than the biological characteristics of the mothers since stronger effects were observed for the late (postneonatal mortality, hospital admissions and nutritional status) than for the early (birthweight, perinatal mortality) outcomes.

Breast feeding duration in consecutive offspring: a prospective study from southern Brazil.

The association between breast feeding duration in two consecutive pregnancies was studied in a prospective study in southern Brazil. In a population-based sample of 5960 women giving birth in 1982, 1386 delivered a second child within 4 years. The data were analyzed using life table techniques. The duration of breast feeding of the second child increased directly according to the duration the previous child had been breast fed. In particular, when the previous child had been breast fed for 6 months or more, the subsequent child was clearly more likely to be breast fed. However, when the previous child had been breast fed for under 6 months, the differences among subsequent children disappeared after 3-6 months. These differences were still present after stratification by family income, maternal education and parity. Mothers with a previous unsuccessful or problematic breast feeding experience should receive special priority in promotion campaigns.

Epidemic of caesarean sections in Brazil.

Brazil has one of the highest rates of caesarean section in the world. Patterns of caesarean sections were studied in a cohort of 5960 mothers followed from 1982 to 1986 in southern Brazil. Overall, 27.9% were delivered by caesarean section in 1982, this proportion being 30% for nulliparae, 80% for second deliveries when the first was by caesarean, and over 99% for third births when the first two were by caesarean. Socioeconomic status and requests for sterilisation by tubal ligation were important underlying factors. 9.4% of the women were sterilised during a caesarean section (3.7% in the lowest income group and 20.2% in the highest). 31% of women who had had their first child by a caesarean section and who were having a second operative delivery were sterilised. The high rates of caesarean sections and accompanying sterilisations reflect the lack of appropriate reproductive and contraceptive policies in the country.

Prolonged breastfeeding and malnutrition: confounding and effect modification in a Brazilian cohort study.

We examined the association between prolonged breastfeeding and anthropometric status in a population-based cohort study of 5,914 liveborns from the city of Pelotas in Southern Brazil. When children from all socioeconomic groups were studied, there was no important association between current breastfeeding and anthropometric status at age 12 months. Children who were still breastfed at age 20 months--and, to a lesser extent, at 43 months--presented with poorer anthropometric status than their nonbreastfed counterparts. We did not find the same pattern in all socioeconomic groups, however. Children from low-income families who were breastfed tended to present better anthropometric status than those who were not, whereas the reverse was observed for children of middle- and high-income families. After controlling for confounding variables, the nutritional advantage of breastfeeding among low-income families was no longer clear, while the superiority of nonbreastfed infants amongst middle- and high-income children persisted. These findings indicate that some of the controversy regarding the nutritional effects of prolonged breastfeeding may have been caused by confounding and effect modification. Any decisions on whether or not breastfeeding should be encouraged after the first year of life should take into account the characteristics of the population as well as the anti-infective and birth-spacing properties of breastfeeding.

The timing of nutritional status determination: implications for interventions and growth monitoring.

A population-based birth cohort of 1226 urban Brazilian children underwent anthropometric examinations at, on average, ages 11, 23 and 47 months. Multiple regression analyses showed that while birth weight was the single most important factor in predicting nutritional status at age 11 months, a wide range of other social, biological and morbidity factors also appeared to play a significant role. Environmental and dietary factors, however, showed no significant association. Nutritional status at age 11 months was a very strong predictor of nutritional status at ages 23 and 47 months and the other explanatory factors made a minimal additional contribution to the regression models. These results suggest that, in this population, childhood nutritional status is primarily determined before the end of the first year of life. These findings have implications for the timing and nature of nutritional interventions and for mechanisms for identifying those children who will suffer from poor nutritional status later in childhood.

Do mothers overestimate breast feeding duration? An example of recall bias from a study in southern Brazil.

The problem of recall bias when reporting breast feeding duration is investigated. Data are presented from the follow-up of over 1,000 children from a birth cohort (1982) in southern Brazil, when they were on average 11, 23, and 47 months of age. Compared with the response given at 11 months of age, 24% of mothers misclassified the duration (grouped into 3-month categories) at age 23 months and 30% at age 47 months. Women who were richer and/or better educated were significantly more likely to report longer durations, while those poorer and less educated did not tend to misclassify more in one direction than in the other.

Pneumonia, diarrhea, and growth in the first 4 y of life: a longitudinal study of 5914 urban Brazilian children.

The synergism between nutrition status and hospital admissions due to diarrhea and pneumonia was studied in a population-based birth cohort of greater than 5000 children in southern Brazil. Children were identified soon after birth in 1982, and data on nutrition status (weight and length) and hospital admissions were collected in 1984 and in 1986. Diarrhea admissions were stronger predictors of malnutrition than were pneumonia admissions, but malnutrition was a more important risk factor for pneumonia than for diarrhea. All associations were stronger in the first 2 y of life, although the early effect of severe diarrhea and pneumonia on nutrition status could still be detected in the fourth year of life.