Is overweight a risk factor for wheezing in pre-school children? A study in 14 Brazilian communities.

OBJECTIVE: To evaluate the association between overweight and wheezing in pre-school children in 14 small Brazilian communities. METHODS: Cross-sectional epidemiological study, conducted between 2001 and 2002. A sample of 3453 children under 5 years of age was taken from nine communities in the state of Bahia and five in the state of São Paulo. Data on housing, family and children were obtained by applying structured questionnaires in loco. Weight and height for each child were also measured. The association between wheezing and overweight was assessed by unconditional logistic multivariate regression models. RESULTS: Overweight children had a greater frequency of wheezing and an odds ratio of 2.57 (95% confidence interval 1.51-4.37) was estimated after controlling for several potential confounding variables. The magnitude of the risk was not affected by several different model specifications. CONCLUSION: Excess weight is associated with increased risk for wheezing in this population of children below 5 years of age.

Obesity and weight change related to parity and breast-feeding among parous women in Brazil.

OBJECTIVE: Studies on the independent role of parity in long-term body weight change in economically developing countries are scarce and inconclusive, and only a few studies have taken into account patterns of breast-feeding. This association was examined in a national cross-sectional survey representative of Brazilian parous women. DESIGN AND SETTING: The survey conducted in 1996 measured women's height and weight in the household and data on weight prior to the first pregnancy, parity and breast-feeding were recalled. SUBJECTS: A sample of 2338 parous women, 15 to 49 years of age, 29 months after last delivery on average, had current body mass index (BMI, in kg m(-2)) modelled through hierarchical multiple linear regression analysis. Explanatory variables included parity, days of predominant breast-feeding, BMI pre-pregnancy, socio-economic, geographic, demographic and other reproductive variables. RESULTS: Prevalences of overweight (BMI = 25.0-29.9 kg m(-2)) and obesity (BMI > or = 30.0 kg m(-2)) were 25.2% and 9.3%. The overall mean weight gain per year after the first pregnancy was 0.90 kg for an average time since first pregnancy of eight years. BMI pre-pregnancy modified the association between current BMI and parity. Therefore, weight change attributed to parity calculated for a woman of average height (1.56 m) was 0.60 kg greater for primiparous women with a BMI pre-pregnancy of 30 kg m(-2), compared with women with BMI pre-pregnancy of 25 kg m(-2). This greater weight retention among obese women was 1.21 kg for women with two children and 1.82 kg for women with three or more children. Parity reduced the effect of weight loss associated with lactation (1.75 kg for six months of lactation among primiparous women and 0.87 kg among women with three or more children). For the sub-sample of 793 primiparous women, a weight decrease of 300 g was associated with each month of predominant breast-feeding for all prior BMI levels. CONCLUSIONS: In this study, weight change associated to reproduction was highly dependent on BMI previous to pregnancy and the effects of parity and lactation were small.

Shifting obesity trends in Brazil.

OBJECTIVE: To describe secular trends in obesity in various settings and socio-economic groups of the adult population of Brazil. METHODS: Trend analysis of the prevalence of obesity in adults aged over 20 y (body mass index >/=30.0 kg/m2) applied to anthropometric and socio-economic data collected by three comparable household surveys undertaken in the two most populated Brazilian regions in 1975 (n=95,062), 1989 (n=15,585) and 1997 (n=10,680). RESULTS: While previous trends (1975-1989) showed increasing obesity prevalence for all population groups except for men in rural areas, recent trends (1989-1997) have pointed to a much more complex picture where increases in obesity tend to be more intense in men than in women, in rural than in urban settings and in poorer than in richer families. Particularly notable was the fact that, in the recent period, obesity was actually reduced for women belonging to the upper income groups, especially in urban settings. CONCLUSION: Earlier obesity trends in Brazil entirely agree with what has been described for both developed and developing countries where reliable secular trend information exists, but the 1989-1997 trend of a substantial reduction in the prevalence of obesity among upper income urban women (12.8-9.2%, or a 28% reduction), is unique in a developing country and, indeed, up to now has only been detected in Scandinavian populations. It is speculated that this declining obesity trend may be a result of an intense mass media work focused on combating a sedentary life style and promoting better food habits.

[Secular trends in birth weight in the city of São Paulo, Brazil (1976-1998)]. / Tendência secular do peso ao nascer na cidade de São Paulo (1976-1998).

OBJECTIVE: Data from two household surveys on infant and child health status undertaken in the mid-80s and mid-90s, complemented with previous data collected from maternity hospitals records and more recent data provided by the state system on birth registries, allowed to characterize and analyse secular trends in birth weight in the city of S. Paulo, Brazil. METHODS: The household surveys included random samples of children under 5 years old (n = 1,016 children in 1984-85 and n = 1,280 children in 1995-96). A random sample of births that took place in the city's hospitals in the year of 1976 (n = 5,734) was drawn from the hospital records. Birth registries refer to children born in the city between 1993 and 1998 (around 200,000 per year). The study of the social distribution of birth weight took into account the per capita family income and maternal schooling. For the analysis of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied. RESULTS/CONCLUSIONS: Birth weight distribution in S. Paulo city (an average of 3,160 g and 8.9% of the values < 2,500 g) is below the expected for optimum fetal growth conditions (average 3,400-3,500 g and 4-5% of the values < 2,500 g). The birth weight distribution did not change substantially along the study period (1976-1998). However, there are evidences of changes when different socioeconomic strata are considered separately. Among the lower strata trends have been positive and this seems to be due to increases in intrauterine growth as a result of an improvement in family's purchasing power, women's weight and height, prenatal care and, possibly, the reduction in smoking. Among the higher socioeconomic strata, birth weight trends have been negative apparently due to an increase in premature births of unknown origin.

[Secular trends in diarrhea disease of childhood in the city of São Paulo, Brazil (1984-1996)]. / Tendência secular da doença diarréica na infância na cidade de São Paulo (1984-1996).

OBJECTIVE: Data from two consecutive household surveys undertaken in mid-80s and mid-90s allow to characterize and analyse secular trends in infant and child diarrhea in the city of S. Paulo, Brazil. METHODS: The two surveys included random population samples aged from zero to 59 months of age (1,016 in the period of 1984-85 and 1,280 in 1995-96). In both surveys the instant prevalence of diarrhea (proportion of examined individuals reporting three or more episodes of liquid stools in 24 hours) and the annual incidence of hospitalizations due to the disease were calculated. These two indicators were estimated from household interviews conducted by pediatricians with the children's mothers. In both surveys the interviews were distributed throughout a period of almost 12 months to assure a uniform coverage of the various areas of the city during the four seasons. For each survey, the study of the social distribution of the disease took into account tertiles of the per capita family income. For the study of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied. RESULTS/CONCLUSIONS: In the time span from the first to the second survey, there was substantial reduction in both the prevalence of diarrhea (from 1.70% to 0.90%) and the hospitalizations due to the disease (from 2.21 to 0.79 hospitalizations per 100 children-year). A more significant reduction was observed among the third poorest families, narrowing the social gradient relative to the disease. An increase in family income and improvement in water supply could substantially explain part of the decline in the disease and, for children under two years of age, a discrete increase in breast-feeding may have also played a positive role.

[Secular trends in respiratory diseases of childhood in the city of São Paulo, Brazil (1984-1996)]. / Tendência secular da doença respiratória na infância na cidade de São Paulo (1984-1996).

OBJECTIVE: Data from two consecutive household surveys undertaken in mid-80s and mid-90s allow to characterize and analyse secular trends in infant and child respiratory diseases in the city of S. Paulo, Brazil. METHODS: The two surveys included random population samples aged from zero to 59 months (1,016 in the period of 1984-85 and 1,280 in 1995-96). In both surveys the instant prevalence of high respiratory diseases (above the epiglottis) and low respiratory diseases with or without wheezing were calculated. All sampled children were examined in their household at a random day by trained pediatricians using standardized procedures. The examinations included medical history, past respiratory diseases and a complete physical examination. In both surveys the examinations were distributed throughout a period of almost 12 months to assure a uniform coverage of the various areas of the city along the four seasons of the year. For each survey, the study of the social distribution of the diseases took into account tertiles of the per capita family income. For the study of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied. RESULTS/CONCLUSIONS: In the time span from the first to the second survey, there was a substantial increase in the prevalence of both low (from 22.2% to 38.8%) and high respiratory diseases (from 6.0% to 10.0% and from 0.8% to 2.8%, without and with wheezing, respectively). In the case of high respiratory disease and low respiratory disease without wheezing, an increase in prevalence was observed among all social strata, which did not interfere with the slightly less favourable situation of the lower income groups. In the case of low respiratory disease with wheezing, the increase was only observed among middle and low-income groups, being particularly high among the lower income group, yielding a significant inverse gradient between income and respiratory disease. Positive changes in distal (family income and maternal schooling) and in intermediate determinants related to housing characteristics would have resulted in a decline, not an increase, in the prevalence of respiratory diseases in the city. The duplication in the attendance rate to day care nurseries seen in the period could have counterbalanced the positive effect due to socioeconomic and housing variables but would not be enough to explain an increase in the disease.

Secular growth trends in Brazil over three decades.

This study describes secular trends in physical growth in Brazil over a period of three decades. The study is based on two comparable national surveys undertaken in the mid-seventies and late eighties. Mean heights at ages 7 and 22 are estimated for three cohorts of males and females born around 1952, 1967 and 1982, respectively. Positive secular trends are found both between 1952 and 1967 and between 1967 and 1982. Modest height gains of around 1.0 cm per decade comparable to those described in developed countries during the second half of the 19th century are observed in the first period (1952-67). Outstanding height increments of around 2.4 cm per decade and comparable only to those described for Japanese children after 1950 are detected in the second period (1967-82). Height increments tending to higher values in the second period are seen for both sexes in the five Brazilian macroregions and in different economic strata. Even so, a large gap still separates the physical growth as observed in the north and northeast regions (and, generally speaking, among the poorest third of the Brazilian population) from the normal growth pattern expected when living conditions are adequate. Substantial income improvements over the seventies plus the continuous progress in the availability of sanitation, health and education services during the seventies and eighties are consistent with the exceptional height gains observed between the cohorts of 1967 and 1982. On the other hand, the tragic performance of the Brazilian economy during recent years plus the evidence that infant mortality rates did not decline in the eighties as they had done in the seventies may suggest a reduction in the speed of the positive trends in growth. If this hypothesis is true, the full development of the genetic growth potential of a large part of the Brazilian population will be postponed to a very remote future.

[ENDEF and PNSN: trends in physical growth of Brazilian children]. / ENDEF e PNSN: para onde caminha o crescimento físico da criança brasileira?

This paper compares the results of two nationally representative nutritional surveys carried out in Brazil: the "Estudo Nacional de Despesa Familiar (ENDEF)" (National Survey on Household Expenses), conducted in 1974-77, and the "Pesquisa Nacional de Saúde e Nutrição (PNSN)" (National Survey on Health and Nutrition), conducted in 1989. The findings point to a reduction of more than 60% in the prevalence of undernutrition, as evaluated by anthropometric parameters. The results from regional surveys and the trends in infant mortality throughout the 1970s and 1980s are consistent with the improvements in nutritional status. Less striking reductions in undernutrition rates were observed in certain regions of the country (e.g., the North and Northeast), where prevalences were higher in the 1970s, resulting in a widening of regional differences. The improvements in child nutrition are attributed to moderate increases in family income, particularly in the 1970s, and to the expansion of sanitation, public health, and educational services, as well as food supplementation programs, which were also favored by a fall in fertility levels. The authors call attention to the fact that the lack of clear-cut indications of economic recovery in Brazil recently, coupled wih cuts in government budgets for social services and the persistence of inequality in income distribution, among other factors, make it unlikely that improvements in nutritional status, as observed in the 1970, will take place in the upcoming years.

Nutritional status of Brazilian children: trends from 1975 to 1989.

The prevalence of malnutrition among under-5-year-olds in Brazil fell by more than 60% between 1975 and 1989. The benefits were smaller for population strata that were more affected by malnutrition in the 1970s, i.e., children from the North and North-east regions and those from poor families in general. Regional and socioeconomic differentials in the prevalence of malnutrition therefore increased between 1975 and 1989. Trends in family income indicate extraordinary economic gains in the 1970s, some losses in the 1980s, and a modest net gain over the period 1975-89. The availability of sanitation, health, and education services, and the provision of preschool supplementary feeding programmes increased markedly in the 1970s and 1980s. Demographic trends were also positive, reducing the demand for services and programmes, increasing the economic efficiency of families, and concentrating the population in urban areas, where incomes, job opportunities, and social and material infrastructures are better. The observed nutritional improvement was therefore probably due to a moderate increase in family income associated with a substantial expansion in the provision of services and programmes, both of which were facilitated by favourable demographic trends. Also, the nutritional improvement was probably concentrated during the 1970s, while little, if any, occurred after 1980; prospects for the 1990s point to a stagnant situation. This is a reason for great concern particularly in the North and North-east regions of the country, where high rates of child malnutrition are still found.

PIP: Nutritionists used 2 surveys (1975 and 1989) to determine the trends in the nutritional status of children 5 years old in Brazil. Malnutrition rates fell by 61.4% between 1975 and 1989 (18.4% vs. 7.1%). Improvements in child nutrition occurred countrywide, but they were less in the North and the Northeast (56.7% and 52.6% respectively) than in the other regions (69.2%-78.6%). In fact, the gap between these regions and the other regions was wider in 1989 than it was in 1975 (e.g., prevalence ratio between the Northeast and the South, 2.5 in 1975 and 5 in 1989). In the Southeast and the South, nutrition improvement occurred basically equally for rural and urban children, but the percentage of rural malnourished children was still higher than it was for urban malnourished children (6.2% vs. 3.7% and 3% vs. 2.1% respectively). In the Northeast, rural children suffered more relative excess malnutrition in 1989 than they did in 1975. A sizable reduction in childhood malnutrition prevalence rates occurred in all 4 income groups, but the poorest children benefited the least (55.6% vs. 77% for the richest group). Since children most affected by malnutrition in the 1970s (i.e., children from the North and Northeast and the poor) gained the least, regional and socioeconomic differences in the prevalence of malnutrition expanded between 1975 and 1989. Modest increases in income linked to considerable expansion of sanitation, health, and education services and of preschool supplementary feeding programs were most likely responsible for nutritional improvement. In addition, fertility rates fell (5.8-3) during this period. Improvement was largely restricted to the 1970s, however. After 1980, little or no improvement occurred. Little hope for economic recovery, continued economic inequalities, and reduced spending on social programs indicated a stagnant situation for the 1990s.

[Maternal anemia and malnutrition and their relation to birth weight]. / Anemia e desnutrição maternas e sua relação com o peso ao nascer.

With a view to evaluating the effect of anemia and maternal undernourishment on birth weight, a sample of 691 pregnant women, from an assistential maternity hospital, in S. Paulo, Brazil, were studied at delivery. Anemia was found in 29.1% and undernourishment in 17.2% of the women, though no association was detected between these nutritional deficiencies. Neither was any association detected between institutional ante-natal care and anemia or undernourishment. Among single newborns the incidence of low birth weight (LBW) was of 12.9%. LBW was observed in 23.6% of children born to women who came to the end of their pregnancy with a low weight for height ratios while among adequate weight for height women the percentage was 10.8. Children of women who remained undernourished throughout their pregnancy had a relative risk of being born with LBW 2.8 times greater than the children of those who recovered normal weight by the end of their pregnancy. Our results emphasize the need for implementation of nutritional status control activities in programs of ante-natal care.

Better prospects for child survival.

Infant and childhood mortality rates in São Paulo fell by about 50% and 70% respectively between 1973 and 1983. However, surveys in 1973-74 and 1984-85 showed no change in the prevalence of protein-energy malnutrition, nor were there marked changes in the socioeconomic characteristics of the population. Improvements in water supply and the duration of breast-feeding possibly accounted for a 20% decrease in the infant mortality rate. It is proposed that the markedly improved coverage of health services may have played a large role in explaining the rest of the decrease. The control of malnutrition may not always be essential for lowering infant and child mortality in developing societies.

PIP: Between 1973-83 infant and child mortality rates in Sao Paulo, Brazil fell about 50% and 70% 2 health surveys were done: one in 1973-74 and a second one in 1984-85. Results from both surveys showed that moderate and severe cases of malnutrition were rare; the prevalence of severe cases was below 1%. The most important finding regarding causes of declines in mortality rates for children under 5 was that this was not accompanied by any significant changes in the prevalence of malnutrition. Therefore, reductions in the prevalence of malnutrition may not be an essential ingredient in lessening the death rates in developing countries. The authors used data on the relative risks for infant mortality (IM) from 2 studies in similar urban areas to assess the possible impact of other factors on mortality. The 1st study was a cohort study of risk factors for IM and the 2nd was a case-control study of IM due to infectious diseases. The indicators used were socioeconomic status, demographic, environmental, health care, and breastfeeding. The outcomes of the study demonstrated that changes in socioeconomic variables and in the prevalence of malnutrition do not explain reductions in infant and child mortality in Sao Paulo. However, expansion of the water supply and increase in breastfeeding could account for 20% of the IMR. One can also state that the expansion and quality of health care were instrumental in lowering the mortality rates.

Mejores perspectivas para la supervivencia de los niños / Better prospects for child survival

Las tasas de mortalidad de lactantes y niños pequeños disminuyeron en Sao Paulo en alrededor de un 50 por ciento y un 70 por ciento respectivamente entre 1973 y 1983. Sin embargo, las encuestas realizadas en 1973-1974 y 1984-1985 no mostraron cambios en la prevalencia de malnutrición proteicoenergética y tampoco hubo cambios marcados en las características socioeconómicas de la población. Es posible que las mejoras realizadas en los sistemas de abastecimiento de agua y en la duración de la alimentación al pecho expliquen hasta un 20 por ciento de la reducción de la tasa de mortalidad de lactantes, Se sugiere que la notable mejora en la cobertura de los servicios de salud puede haber desempeñado una función importante en el resto de esta disminución. Es posible que la lucha contra la malnutrición no siempre sea indispensable para reducir la mortalidad de lactantes y niños pequeños en las sociedades en desarrollo

Better prospects for child survival

Infant and childhood mortality rates in Sao Paulo fell by about 50 per cent and 70 per cent respectively between 1973 and 1983. However, surveys in 1973-74 and 1984-85 showed no change in the prevalence of protein-energy malnutrition, nor were there marked changes in the socioeconomic characteristics of the population. Improvements in water supply and the duration of breast-feeding possibly accounted for a 20 per cent decrease in the infant mortality rate. It is proposed that the markedly improved coverage of health services may have played a large role in explaining the rest of the decrease. The control of malnutrition may not always be essential for lowering infant and child mortality in developing societies