Uterine vascular resistance and other maternal factors associated with the risk of developing hypertension during pregnancy

Gestational hypertension and pre-eclampsia are important causes of perinatal morbidity. The objective of the present study was to determine the increase in relative risk for developing hypertensive disorders of pregnancy based on the evaluation of pregnant women between 20 and 25 weeks of gestation, and to correlate the findings at this period with the outcome of pregnancy. We conducted a prospective cohort study, with a convenience sample of 1417 patients evaluated at this gestational age, of which 1306 were contacted at childbirth. We detected an increased relative risk of 2.69 (95%CI: 1.86 to 3.89) associated with pulsatility index of the uterine arteries, a 2.8 increase (95%CI: 1.58 to 5.03) in relative risk attributed to maternal age above 35 years, a 1.68 increase (95%CI: 1.17 to 2.40) attributed to parity greater than or equal to 3, and a 5.35 increase (95%CI: 4.18 to 6.85) attributed to chronic hypertension and obesity, with a progressive increase in relative risk according to the degree of overweight, i.e., grades 1, 2, 3, and morbid obesity (2.58, 3.06, 5.84, and 7.28, respectively).

Body image dissatisfaction and symptoms of depression disorder in adolescents

The objective of this study was to evaluate the effect of body image dissatisfaction on symptoms of depressive disorder in adolescents. This is a cross-sectional study that included 2,162 adolescents ages 18-19 born in São Luís, Maranhão, Brazil, which was part of the joint RPS cohort (Brazilian birth cohorts of Ribeirão Preto-SP, Pelotas-RS, and São Luís-MA). Socioeconomic characteristics, nutritional status, mental health, and body image characteristics were evaluated. Body image was assessed by Stunkard's silhouettes scale. The presence of symptoms indicative of depressive disorder was investigated through a diagnostic interview MINI (Mini International Neuropsychiatric Interview). A theoretical model was built in a Directed Acyclic Graph (DAG) in order to investigate the relationship between the variables of the study. The relationship was estimated weighting the inverse probability of selection for the variables of adjustment: sex and nutritional status. Among the dissatisfied adolescents due to overweight, 66.54% were girls, 32.85% were overweight, and 11.99% were obese (P<0.01). There was a significant association between dissatisfaction due to overweight and symptoms of depressive disorder (P=0.01), and there was no evidence of the same association with dissatisfaction due to thinness. Therefore, only dissatisfaction due to overweight was associated with the symptoms of depressive disorder in the evaluated adolescents.

Is birth weight associated with pregestational maternal BMI? BRISA Cohort, Ribeirão Preto, Brazil

Given the increase of women with excess weight or obesity and its possible effects on birth weight, the present study aimed to investigate the association between pregestational maternal body mass index (BMI) and birth weight in a birth cohort from Ribeirão Preto, SP, Brazil. This was a prospective study conducted on 1362 mother-child pairs involving singleton births. The women were evaluated using standardized questionnaires during the second trimester of pregnancy and at the time of childbirth. Information about the newborns was obtained from their medical records. The dependent variable was birth weight, categorized as low, adequate, or high. The independent variable was pregestational maternal BMI, categorized as malnutrition, adequate weight, overweight, and obesity. A multinomial regression model was used to estimate the crude and adjusted relative risk (RR) of low and high birth weight. A high frequency of pregestational excess weight (39.6%) was detected and found to be independently associated with high birth weight (RR=2.13, 95%CI: 1.19-3.80 for overweight and RR=3.34, 95%CI: 1.80-6.19 for obese pregnant women). There was no association between pregestational malnutrition and low birth weight (RR=1.70; 95%CI: 0.81-3.55). The present data showed a high rate of women with excess pregestational weight, supporting the hypothesis that pregestational BMI may contribute to high birth weight babies and indicating the need for actions aiming to prevent excessive weight in women at reproductive age.

Metabolic profile during pregnancy in BRISA birth cohorts of Ribeirão Preto and São Luís, Brazil

During pregnancy, metabolic changes that develop in women may increase the risk of diseases and conditions that may also harm the life of the growing fetus. The aim of the present study was to identify and compare the metabolic profile (MP) during pregnancy in two birth cohorts in 2010 in the cities of Ribeirão Preto (RP) and São Luís (SL), Brazil. Pregnant women (1393 in RP and 1413 in SL) were studied; information was obtained through questionnaires in addition to anthropometric, biochemical, and blood pressure measurements. Data are presented as means and proportions. To compare the characteristics of pregnant women in both cities, chi-squared and Student's t-tests were applied, with 5% significance level. Ribeirão Preto presented higher mean values than SL for pre-gestational body mass index (24.5 vs 23 kg/m2, P<0.001), systolic (108.4 vs 102.8 mmHg, P<0.001) and diastolic (65.9 vs 61.8 mmHg, P<0.001) blood pressure, total cholesterol (226.3 vs 213.7 mg/dL, P<0.001) and fractions, and glycemia (84.5 vs 80.2 mg/dL, P<0.001), except for triglycerides (P=0.135). Women from RP also showed higher rates of pre-gestational overweight and obesity compared with SL (40.1 vs 25.8%). In the present study, pregnant women in RP had a worse gestational metabolic profile than those in SL, with higher pre-gestational excess weight, indicating that nutritional transition was more advanced in the more developed city.

Association of genitourinary infections and cervical length with preterm childbirth

A prospective cohort study was conducted on a convenience sample of 1370 pregnant women with a gestational age of 20 to 25 weeks in the city of Ribeirão Preto. Data on obstetrical history, maternal age, parity, smoking habit, and a history of preterm delivery was collected with the application of a sociodemographic questionnaire. Cervical length was determined by endovaginal ultrasound, and urine and vaginal content samples were obtained to determine urinary tract infection (UTI) and bacterial vaginosis (BV), respectively. The aim of this study was to verify the association of cervical length and genitourinary infections with preterm birth (PTB). Ultrasound showed no association of UTI or BV with short cervical length. PTB rate was 9.63%. Among the women with PTB, 15 showed UTI (RR: 1.55, 95%CI: 0.93-2.58), 19 had BV (RR: 1.22, 95%CI: 0.77-1.94), and one had both UTI and BV (RR: 0.85, 95%CI: 0.13-5.62). Nineteen (14.4%) PTB occurred in women with a cervical length ≤2.5 cm (RR: 2.89, 95%CI: 1.89-4.43). Among the 75 patients with PTB stratified as spontaneous, 10 showed UTI (RR: 2.02, 95%CI: 1.05-3.86) and 14 had a diagnosis of BV (RR: 1.72, 95%CI: 0.97-3.04). A short cervical length between 20 and 25 weeks of pregnancy was associated with PTB, whereas UTI and BV determined at this age were not associated with short cervical length or with PTB, although UTI, even if asymptomatic, was related to spontaneous PTB.

Association of genitourinary infections and cervical length with preterm childbirth.

A prospective cohort study was conducted on a convenience sample of 1370 pregnant women with a gestational age of 20 to 25 weeks in the city of Ribeirão Preto. Data on obstetrical history, maternal age, parity, smoking habit, and a history of preterm delivery was collected with the application of a sociodemographic questionnaire. Cervical length was determined by endovaginal ultrasound, and urine and vaginal content samples were obtained to determine urinary tract infection (UTI) and bacterial vaginosis (BV), respectively. The aim of this study was to verify the association of cervical length and genitourinary infections with preterm birth (PTB). Ultrasound showed no association of UTI or BV with short cervical length. PTB rate was 9.63%. Among the women with PTB, 15 showed UTI (RR: 1.55, 95%CI: 0.93-2.58), 19 had BV (RR: 1.22, 95%CI: 0.77-1.94), and one had both UTI and BV (RR: 0.85, 95%CI: 0.13-5.62). Nineteen (14.4%) PTB occurred in women with a cervical length ≤2.5 cm (RR: 2.89, 95%CI: 1.89-4.43). Among the 75 patients with PTB stratified as spontaneous, 10 showed UTI (RR: 2.02, 95%CI: 1.05-3.86) and 14 had a diagnosis of BV (RR: 1.72, 95%CI: 0.97-3.04). A short cervical length between 20 and 25 weeks of pregnancy was associated with PTB, whereas UTI and BV determined at this age were not associated with short cervical length or with PTB, although UTI, even if asymptomatic, was related to spontaneous PTB.

Is birth weight associated with pregestational maternal BMI? BRISA Cohort, Ribeirão Preto, Brazil.

Given the increase of women with excess weight or obesity and its possible effects on birth weight, the present study aimed to investigate the association between pregestational maternal body mass index (BMI) and birth weight in a birth cohort from Ribeirão Preto, SP, Brazil. This was a prospective study conducted on 1362 mother-child pairs involving singleton births. The women were evaluated using standardized questionnaires during the second trimester of pregnancy and at the time of childbirth. Information about the newborns was obtained from their medical records. The dependent variable was birth weight, categorized as low, adequate, or high. The independent variable was pregestational maternal BMI, categorized as malnutrition, adequate weight, overweight, and obesity. A multinomial regression model was used to estimate the crude and adjusted relative risk (RR) of low and high birth weight. A high frequency of pregestational excess weight (39.6%) was detected and found to be independently associated with high birth weight (RR=2.13, 95%CI: 1.19-3.80 for overweight and RR=3.34, 95%CI: 1.80-6.19 for obese pregnant women). There was no association between pregestational malnutrition and low birth weight (RR=1.70; 95%CI: 0.81-3.55). The present data showed a high rate of women with excess pregestational weight, supporting the hypothesis that pregestational BMI may contribute to high birth weight babies and indicating the need for actions aiming to prevent excessive weight in women at reproductive age.

Metabolic profile during pregnancy in BRISA birth cohorts of Ribeirão Preto and São Luís, Brazil.

During pregnancy, metabolic changes that develop in women may increase the risk of diseases and conditions that may also harm the life of the growing fetus. The aim of the present study was to identify and compare the metabolic profile (MP) during pregnancy in two birth cohorts in 2010 in the cities of Ribeirão Preto (RP) and São Luís (SL), Brazil. Pregnant women (1393 in RP and 1413 in SL) were studied; information was obtained through questionnaires in addition to anthropometric, biochemical, and blood pressure measurements. Data are presented as means and proportions. To compare the characteristics of pregnant women in both cities, chi-squared and Student's t-tests were applied, with 5% significance level. Ribeirão Preto presented higher mean values than SL for pre-gestational body mass index (24.5 vs 23 kg/m2, P<0.001), systolic (108.4 vs 102.8 mmHg, P<0.001) and diastolic (65.9 vs 61.8 mmHg, P<0.001) blood pressure, total cholesterol (226.3 vs 213.7 mg/dL, P<0.001) and fractions, and glycemia (84.5 vs 80.2 mg/dL, P<0.001), except for triglycerides (P=0.135). Women from RP also showed higher rates of pre-gestational overweight and obesity compared with SL (40.1 vs 25.8%). In the present study, pregnant women in RP had a worse gestational metabolic profile than those in SL, with higher pre-gestational excess weight, indicating that nutritional transition was more advanced in the more developed city.

Body image dissatisfaction and symptoms of depression disorder in adolescents.

The objective of this study was to evaluate the effect of body image dissatisfaction on symptoms of depressive disorder in adolescents. This is a cross-sectional study that included 2,162 adolescents ages 18-19 born in São Luís, Maranhão, Brazil, which was part of the joint RPS cohort (Brazilian birth cohorts of Ribeirão Preto-SP, Pelotas-RS, and São Luís-MA). Socioeconomic characteristics, nutritional status, mental health, and body image characteristics were evaluated. Body image was assessed by Stunkard's silhouettes scale. The presence of symptoms indicative of depressive disorder was investigated through a diagnostic interview MINI (Mini International Neuropsychiatric Interview). A theoretical model was built in a Directed Acyclic Graph (DAG) in order to investigate the relationship between the variables of the study. The relationship was estimated weighting the inverse probability of selection for the variables of adjustment: sex and nutritional status. Among the dissatisfied adolescents due to overweight, 66.54% were girls, 32.85% were overweight, and 11.99% were obese (P<0.01). There was a significant association between dissatisfaction due to overweight and symptoms of depressive disorder (P=0.01), and there was no evidence of the same association with dissatisfaction due to thinness. Therefore, only dissatisfaction due to overweight was associated with the symptoms of depressive disorder in the evaluated adolescents.

Uterine vascular resistance and other maternal factors associated with the risk of developing hypertension during pregnancy.

Gestational hypertension and pre-eclampsia are important causes of perinatal morbidity. The objective of the present study was to determine the increase in relative risk for developing hypertensive disorders of pregnancy based on the evaluation of pregnant women between 20 and 25 weeks of gestation, and to correlate the findings at this period with the outcome of pregnancy. We conducted a prospective cohort study, with a convenience sample of 1417 patients evaluated at this gestational age, of which 1306 were contacted at childbirth. We detected an increased relative risk of 2.69 (95%CI: 1.86 to 3.89) associated with pulsatility index of the uterine arteries, a 2.8 increase (95%CI: 1.58 to 5.03) in relative risk attributed to maternal age above 35 years, a 1.68 increase (95%CI: 1.17 to 2.40) attributed to parity greater than or equal to 3, and a 5.35 increase (95%CI: 4.18 to 6.85) attributed to chronic hypertension and obesity, with a progressive increase in relative risk according to the degree of overweight, i.e., grades 1, 2, 3, and morbid obesity (2.58, 3.06, 5.84, and 7.28, respectively).

Can increased resistance to uterine artery flow be a risk factor for adverse neurodevelopmental outcomes in childhood? A prospective cohort study.

A prospective cohort study was conducted to determine whether an increased uterine artery pulsatility index (UtA-PI) in the second trimester of pregnancy is a risk factor for neurodevelopmental outcomes in children 2-3 years of age. A group of pregnant women with a UtA-PI below the 90th percentile (P90) and a second group with a UtA-PI ≥ P90 in the second trimester were included in this study. The children of these women were evaluated during their second or third year of life using the Bayley III Screening Test. A total of 858 pregnancies with UtA-PI < P90 and 96 pregnancies with UtA-PI ≥ 90 were studied. The differences between the groups related to UtA-PI ≥ 90 were detected in relation to the variables of the Caucasian ethnicity, hypertension, newborn weight and stay in the intensive care unit after birth. However, adjusted neurodevelopmental outcomes did not differ between the groups: OR 0.53 (95% CI 0.27-1.04%). This study failed to demonstrate that the UtA-PI is a risk factor for adverse neurodevelopment in children.Impact statementWhat is already known on this subject? Early interventions in children at high risk for neurodevelopmental deficiency have proved to be beneficial. The complications associated with gestation and delivery negatively influence neurodevelopment. Several studies have shown that some adverse pregnancy outcomes such as preeclampsia, foetal growth restriction and foetal death can be predicted by increased resistance to flow in the uterine artery in the second trimester. However, there are no studies evaluating the association of the uterine artery with neurodevelopmental results.What do the results of this study add? This study concludes that neurodevelopment is influenced by multiple environmental and intrinsic factors and cannot be predicted by only one variable, such as the uterine artery blood flow. The brain has repair mechanisms to attenuate insults that occur during gestation and delivery.What are the implications of these findings for clinical practice and/or further research? This study was unable to demonstrate that blood flow in the uterine artery is a risk factor for neurodevelopment. Different, larger studies should be conducted by combining other factors with the uterine artery in an algorithm to allow the early identification of children at risk for neurodevelopmental impairment.

Role of plasma PlGF, PDGF-AA, ANG-1, ANG-2, and the ANG-1/ANG-2 ratio as predictors of preeclampsia in a cohort of pregnant women.

INTRODUCTION: Preeclampsia affects 3-5% of pregnancies worldwide and is the primary cause of maternal-fetal and neonatal mortality. Previous studies show that alterations in maternal concentrations of angiogenic factors, such as PlGF, PDGF AA, ANG-1, and ANG-2, may play fundamental roles in the pathophysiology of the disease. OBJECTIVE: Determine whether the PlGF, PDGF AA, ANG-1, and ANG-2 are predictors of preeclampsia occurrence in a prenatal cohort study. PATIENTS AND METHODS: This is a case-control study associated with a prospective cohort of pregnant women, with gestational ages between 20 and 25 weeks, composed of 30 pregnant women with preeclampsia (PE) and 90 healthy pregnant women (HP). The plasma concentrations of the markers were determined using the ELISA method. The comparison between the case and control groups was performed using the t test on the SAS® 9.4 software. Also, ROC curves were constructed to evaluate the predictive potential of the biomarkers. RESULTS: Differences in the concentrations of PlGF, PDGF AA, ANG-1 and ANG-2, and the ANG-1/ANG-2 ratio were not observed between the PE and the HP groups. The predictive capacity of the biomarkers was assessed using ROC curves, in which the area under the curve for PlGF AUC = 0.55; PDGF AA AUC = 0.55; ANG-1 AUC = 0.47; ANG-2 AUC = 0.51, and the ANG-1/ANG-2 ratio AUC = 0.57. CONCLUSION: In pregnant women, with gestational ages between 20 and 25 weeks significant differences in biomarker concentrations between groups PE and HP were not observed. The ROC curves showed that the biomarkers were ineffective as preeclampsia predictors in the analyzed cohort.

Author Correction: Myeloperoxidase is not a good biomarker for preeclampsia prediction.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Myeloperoxidase is not a good biomarker for preeclampsia prediction.

Myeloperoxidase is a proinflammatory enzyme found to be increased in patients with established preeclampsia but never investigated before the disease onset. Here we examined myeloperoxidase concentration and activity in plasma and urine samples from pregnant women who remained normotensive throughout pregnancy and those who developed preeclampsia in order to assess its potential to predict this disorder. Our sample consisted of 30 cases who developed preeclampsia (14 severe and 16 mild) and 57 controls who remained healthy throughout pregnancy, derived from the Brazilian Ribeirão Preto and São Luís prenatal cohort (BRISA). Myeloperoxidase concentration were assessed using a commercial ELISA kit and enzymatic activity through tetramethylbenzidine oxidation. No statistical differences were found in myeloperoxidase levels nor activity between plasma or urine samples from controls, severe and mild cases. Myeloperoxidase did not seem to have a potential application for preeclampsia prediction.

Childhood socioeconomic position, adult socioeconomic position and social mobility in relation to markers of adiposity in early adulthood: evidence of differential effects by gender in the 1978/79 Ribeirao Preto cohort study.

BACKGROUND: Longitudinal studies drawn from high-income countries demonstrate long-term associations of early childhood socioeconomic deprivation with increased adiposity in adulthood. However, there are very few data from resource-poor countries where there are reasons to anticipate different gradients. Accordingly, we sought to characterise the nature of the socioeconomic status (SES)-adiposity association in Brazil. METHODS: We use data from the Ribeirao Preto Cohort Study in Brazil in which 9067 newborns were recruited via their mothers in 1978/79 and one-in-three followed up in 2002/04 (23-25years). SES, based on family income (salaries, interest on savings, pensions and so on), was assessed at birth and early adulthood, and three different adiposity measures (body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR)) ascertained at follow-up. The association between childhood SES, adult SES and social mobility (defined as four permutations of SES in childhood and adulthood: low-low, low-high, high-low, high-high), and the adiposity measures was examined using linear regression. RESULTS: There was evidence that the association between SES and the three markers of adiposity was modified by gender in both adulthood (P<0.02 for all outcomes) and childhood SES (P<0.02 for WC and WHR). Thus, in an unadjusted model, linear regression analyses showed that higher childhood SES was associated with lower adiposity in women (coefficient (95% confidence intervals) BMI: -1.49 (-2.29,-0.69); WC: -3.85 (-5.73,-1.97); WHR: -0.03 (-0.04,-0.02)). However, in men, higher childhood SES was related to higher adiposity (BMI: 1.03 (0.28,-1.78); WC: 3.15 (1.20, 5.09); WHR: 0.009 (-0.001, 0.019)) although statistical significance was not seen in all analyses. There was a suggestion that adult SES (but not adult health behaviours or birthweight) accounted for these relationships in women only. Upward mobility was associated with protection against greater adiposity in women but not men. CONCLUSION: In the present study, in men there was some evidence that both higher childhood and adulthood SES was related to a higher adiposity risk, while the reverse gradient was apparent in women.

High prevalence of polycystic ovary syndrome in women born small for gestational age.

BACKGROUND: There is evidence that intrauterine growth restriction, resulting in newborn girls that are small for gestational age (SGA), may be related to the onset of polycystic ovary syndrome (PCOS). Thus, we studied whether women born SGA have a higher prevalence of PCOS than women born appropriate for gestational age (AGA). METHODS: This was a prospective birth cohort study of 384 women born at term between June 1, 1978, and May 31, 1979, in Ribeirão Preto, Brazil. After exclusion, 165 women effectively participated in this study, of whom 43 were SGA and 122 were AGA. The prevalence of PCOS was analysed. At a mean age of 29 years, the women agreed to follow the study protocol, which included: anamnesis, physical examination, serum tests [follicle stimulating hormone, luteinizing hormone, total and free testosterone, dehydroepiandrostenedione sulphate, 17-OH-progesterone, fasting insulin, sex steroid-binding globulin (SHBG) and fasting glucose] and pelvic ultrasound. Data regarding gestational age, birthweight, age at menarche and maternal data were obtained from the files of the cohort. The adjusted relative risk (RR) values of the SGA, insulin resistance, body mass index, maternal smoking and parity variables were analysed using Poisson regression with robust adjustment of variance for the prediction of PCOS. RESULTS: The prevalence of PCOS was higher in the SGA group than in the AGA group [adjusted RR = 2.44, 95% CI (1.39-4.28)]. Hyperandrogenism was more prevalent in the SGA women than in the AGA women (P = 0.011). Circulating SHBG was lower in the SGA women than in the AGA women (P = 0.041), but fasting insulinemia was similar in both groups. CONCLUSIONS: The prevalence of PCOS in SGA women was twice as high as in AGA women in our study population.

Profile of three Brazilian birth cohort studies in Ribeirão Preto, SP and São Luís, MA

We describe three birth cohort studies, respectively carried out in 1978/79 and 1994 in Ribeirão Preto, a city located in the most developed region of Brazil, and in 1997/98 in São Luís, a city located in a less developed region. The objective of the present report was to describe the methods used in these three studies, presenting their history, methodological design, objectives, developments, and difficulties faced along 28 years of research. The first Ribeirão Preto study, initially perinatal, later encompassed questions regarding the repercussions of intrauterine development on future growth and chronic adult diseases. The subjects were evaluated at birth (N = 6827), at school age (N = 2861), at the time of recruitment for military service (N = 2048), and at 23/25 years of age (N = 2063). The study of the second cohort, which started in 1994 (N = 2846), permitted comparison of aspects of perinatal health between the two groups in the same region, such as birth weight, mortality and health care use. In 1997/98, a new birth cohort study was started in São Luís (N = 2443), capital of the State of Maranhão. The 1994 Ribeirão Preto cohort and the São Luís cohort are in the second phase of joint follow-up. These studies permit comparative temporal analyses in the same place (Ribeirão Preto 1978/79 and 1994) and comparisons of two contrasting populations regarding cultural, economic and sociodemographic conditions (Ribeirão Preto and São Luís).

Are birth weight and maternal smoking during pregnancy associated with malnutrition and excess weight among school age children?

In the late 1980's child malnutrition was still prevalent in Brazil, and child obesity was beginning to rise in the richest regions of the country. To assess the extent of the nutritional transition during the period and the influence of birth weight and maternal smoking on the nutritional condition of schoolchildren, we estimated the prevalence of excess weight and malnutrition in a cohort of Brazilian schoolchildren from 1987 to 1989. We calculated the body mass index (BMI) of 8- to 10-year-old schoolchildren born in Ribeirão Preto in 1978/79. We considered children with a BMI <5th percentile (P5) to be malnourished, children with P5³BMI

Are birth weight and maternal smoking during pregnancy associated with malnutrition and excess weight among school age children?

In the late 1980's child malnutrition was still prevalent in Brazil, and child obesity was beginning to rise in the richest regions of the country. To assess the extent of the nutritional transition during the period and the influence of birth weight and maternal smoking on the nutritional condition of schoolchildren, we estimated the prevalence of excess weight and malnutrition in a cohort of Brazilian schoolchildren from 1987 to 1989. We calculated the body mass index (BMI) of 8- to 10-year-old schoolchildren born in Ribeirão Preto in 1978/79. We considered children with a BMI <5th percentile (P5) to be malnourished, children with P5 > or = BMI or = P85 to be overweight. We evaluated the association of these nutritional disorders with birth factors (infant weight, sex, preterm delivery, number of pregnancies, maternal smoking during pregnancy, marital status, and schooling) and type of school using nominal logistic regression. A total of 2797 schoolchildren were evaluated. There was a significant prevalence of malnutrition (9.5%) and excess weight already tended to increase (15.7%), while 6.4% of the children were obese. Excess weight was more prevalent among children attending private schools (odds ratio, OR = 2.27) and firstborn children (OR = 1.69). Maternal smoking during pregnancy protected against malnutrition (OR = 0.56), while children with lower birth weight were at higher risk for malnutrition (OR = 4.23). We conclude that a nutritional transition was under way while malnutrition was still present, but excess weight and related factors were already emerging.

Profile of three Brazilian birth cohort studies in Ribeirão Preto, SP and São Luís, MA.

We describe three birth cohort studies, respectively carried out in 1978/79 and 1994 in Ribeirão Preto, a city located in the most developed region of Brazil, and in 1997/98 in São Luís, a city located in a less developed region. The objective of the present report was to describe the methods used in these three studies, presenting their history, methodological design, objectives, developments, and difficulties faced along 28 years of research. The first Ribeirão Preto study, initially perinatal, later encompassed questions regarding the repercussions of intrauterine development on future growth and chronic adult diseases. The subjects were evaluated at birth (N = 6827), at school age (N = 2861), at the time of recruitment for military service (N = 2048), and at 23/25 years of age (N = 2063). The study of the second cohort, which started in 1994 (N = 2846), permitted comparison of aspects of perinatal health between the two groups in the same region, such as birth weight, mortality and health care use. In 1997/98, a new birth cohort study was started in São Luís (N = 2443), capital of the State of Maranhão. The 1994 Ribeirão Preto cohort and the São Luís cohort are in the second phase of joint follow-up. These studies permit comparative temporal analyses in the same place (Ribeirão Preto 1978/79 and 1994) and comparisons of two contrasting populations regarding cultural, economic and sociodemographic conditions (Ribeirão Preto and São Luís).