Validity of partial protocols to evaluate the prevalence of developmental defects of enamel in permanent dentition: a birth cohort study in Southern Brazil.

OBJECTIVES: To evaluate the validity of partial protocols (PP) to assess the prevalence of developmental defects of enamel (DDE) in permanent teeth and identify the strength of the association between DDE and some risk factors, using PP compared to the full-mouth (FM) exam. MATERIALS AND METHODS: This study was conducted in a population-based birth cohort of children born in 2004 in Pelotas, Southern Brazil. Socioeconomic, demographic, pre-, per-, and post-birth variables were collected. A subsample of 994 children was clinically examined for DDE in 2017, using the modified DDE index, using the "full- mouth" (FM) protocol. After FM had been performed, a dataset was created. Two different partial protocols (PP) were simulated from FM data: "only buccal surfaces (BS)" and "incisive and molars only (IM)." Sensitivity, absolute and relative bias, and inflation factors were calculated. RESULTS: For any DDE, FM had prevalence of 40.8%. The prevalence of DDE was 38.8% and 36.0%, for BS and IM protocols, respectively. When tested for any DDE, PP "BS" and "IM" showed high sensitivity. The underestimation of the true prevalence did not exceed 6.9% for PP "BS" and 16.1% for PP "IM." All protocols showed similar magnitude of association with the selected risk factors. CONCLUSION: Both PP "BS" and "IM" can be used to estimate the prevalence of DDE in epidemiological studies. CLINICAL RELEVANCE: Oral health surveys now have the option of using PP to collect DDE prevalence and investigate their association with risk factors, being less time-consuming, expensive, and labor intensive.

Influence of maternal excess weight before pregnancy on breast-feeding and weaning: pooled analyses of four population-based cohorts born between 1982 and 2015.

To investigate the associations of maternal excess weight before pregnancy with (1) weaning at 3 months of age, (2) duration of exclusive breast-feeding at 6 months of age, (3) duration of any breast-feeding at 12 months of age and (4) to compare the magnitude of these associations over four decades. Data were from participants in the Pelotas (Brazil) Birth Cohorts born in 1982 (n 5334), 1993 (n 1442), 2004 (n 4092) and 2015 (n 4102). Maternal pre-pregnancy weight was collected after the delivery and breast-feeding status was assessed when children were 3 and 12 months old. Only in the most recent cohort (2015), women with excess weight (BMI ≥ 25 kg/m2) before pregnancy had higher risk of discontinuing exclusive breast-feeding within the first 6 months postpartum than women with normal weight (hazard ratio = 1·22 (95 % CI 1·15, 1·30)). Duration of any type of breast-feeding until 12 months of age was not affected by pre-pregnancy weight. Excess weight before pregnancy is associated with exclusive breast-feeding only in the most recent birth cohort coinciding with increases in excess weight and breast-feeding over time.

Maternal and child-health outcomes in pregnancies following Assisted Reproductive Technology (ART): a prospective cohort study.

BACKGROUND: Studies comparing the outcome of spontaneous versus assisted reproductive technologies (ART) pregnancies report heterogeneous results. Despite the success of ART to overcome infertility, concern is growing regarding both its safety and its effect on maternal and child health. The objective of this study was to compare maternal and child-health outcomes after ART relative to natural conception. METHODS: A population-based birth cohort study was carried out among pregnant women expected to deliver in 2015 in Pelotas, southern Brazil. Maternal outcomes included pregnancy complications and gestational weight gain. Gestational age, weight, intrauterine growth restriction, length and head circumference, and 1-min and 5-min Apgar, as well as health problems at birth and breastfeeding were defined as offspring outcomes. Statistical analyses were performed using linear and logistic regression. G-formula was used to perform mediation analysis. RESULTS: The study included 4252 babies born by spontaneously pregnancies and 23 babies born after ART. Adjusted analyses showed that children conceived from ART presented lower means of gestational age (p = 0.001), birth weight (p = 0.002), length (p < 0.001), and head circumference at birth (p = 0.02). However, more than 90% of the effect of ART over these outcomes was mediated by multiple pregnancy. CONCLUSION: Our findings suggest that the possible negative effect on the child-health outcomes is due mainly to the higher incidence of multiple pregnancies and not because of ART. The reasons for the increase in adverse pregnancy outcomes associated with ART singleton pregnancies are still uncertain and warrants further research. Further large-population studies are needed to confirm these results.

Maternal depression is associated with injuries in children aged 2-4 years: the Pelotas 2004 Birth Cohort.

INTRODUCTION: Injuries during childhood, which mostly consist of falls, burns, drowning, poisonings and car crashes, are among the main causes of death among children and young adults in several countries. OBJECTIVES: To investigate the association between maternal depression and the incidence of injuries during childhood. METHODS: In 2004, children who were born in the municipality of Pelotas, Brazil, were enrolled in a population-based birth cohort, with evaluations at birth and at 3, 12, 24 and 48 months of age. Maternal depression during pregnancy was evaluated at the time of delivery. At 12 and 24 months post partum, the Edinburgh Postnatal Depression Scale (EPDS) was used. The injuries incidence rates at ages of 24-48 months and the crude and adjusted IRRs were calculated with 95% CI through Poisson's regression. RESULTS: A total of 3533 children were analysed. The incidence of injuries was higher among children whose mothers presented depressive symptoms during pregnancy and at 12 and 24 months compared with those whose mothers did not present any symptoms. In the adjusted analysis, the IRR among girls whose mothers presented depressive symptoms during pregnancy and EPDS ≥13 at 12 and 24 months was 1.31 (1.15-1.50); and, among boys, 1.18 (1.03-1.36). INTERPRETATION: Maternal depression is associated with higher incidence of injuries between 24 and 48 months of age, in both sexes.

Epidemiology of Acne Vulgaris in 18-Year-Old Male Army Conscripts in a South Brazilian City.

BACKGROUND: Prevalence of acne varies worldwide. Several factors (age, skin color, body fat, diet, and smoking) have been investigated as risk factors. OBJECTIVE: A total of 2,201 18-year-old males living in Pelotas, South Brazil, were evaluated in order to examine the prevalence of acne and associated factors. METHODS: A cross-sectional population-based study was conducted. A dermatologist performed the clinical examination of the face and trunk for identification of acne lesions. Acne was evaluated as clinically noninflammatory, inflammatory, and acne with both types of lesions. Skin color, schooling, height, smoking, skinfolds, waist circumference, BMI, and dietary dairy intake were the independent variables used. RESULTS: A response rate of 97.2% was obtained. Individuals without any acne lesion were 241 (10.9%); 161 (7.3%) only had noninflammatory lesions, 404 (18.4%) only inflammatory lesions; and 1,395 (63.4%) presented both types of lesions. In multivariate analysis, the type of lesions was different in light and dark skin phototype adolescents, with more common inflammatory lesions in the light phototype and noninflammatory ones in the dark phototype patients. Height was directly associated with the occurrence of all types of acne, whereas lower fat mass was associated with the occurrence of noninflammatory acne. While daily consumption of whole milk or yogurt was found to be associated with inflammatory acne in crude analysis, the association with milk was not detected and that with yogurt was low in multivariate analysis. CONCLUSION: Our results suggest that future studies should explore determinants of noninflammatory and inflammatory acne separately, especially if mixed populations are studied.

Accuracy and adequacy of waist circumference cut-off points currently recommended in Brazilian adults.

OBJECTIVE: To evaluate the adequacy and accuracy of cut-off values currently recommended by the WHO for assessment of cardiovascular risk in southern Brazil. DESIGN: Population-based study aimed at determining the predictive ability of waist circumference for cardiovascular risk based on the use of previous medical diagnosis for hypertension, diabetes mellitus and/or dyslipidaemia. Descriptive analysis was used for the adequacy of current cut-off values of waist circumference, receiver operating characteristic curves were constructed and the most accurate criteria according to the Youden index and points of optimal sensitivity and specificity were identified. SETTING: Pelotas, southern Brazil. SUBJECTS: Individuals (n 2112) aged ≥20 years living in the city were selected by multistage sampling, since these individuals did not report the presence of previous myocardial infarction, angina pectoris or stroke. RESULTS: The cut-off values currently recommended by WHO were more appropriate in men than women, with overestimation of cardiovascular risk in women. The area under the receiver operating characteristic curve showed moderate predictive ability of waist circumference in men (0.74, 95% CI 0.71, 0.76) and women (0.75, 95% CI 0.73, 0.77). The method of optimal sensitivity and specificity showed better performance in assessing the accuracy, identifying the values of 95 cm in men and 87 cm in women as the best cut-off values of waist circumference to assess cardiovascular risk. CONCLUSIONS: The cut-off values currently recommended for waist circumference are not suitable for women. Longitudinal studies should be conducted to evaluate the consistency of the findings.

Maternal mental health and offspring's IQ: Evidence from two Brazilian birth cohorts.

Maternal mental health during different stages of life can have a significant impact on a child's cognitive development. This study aimed to investigate the association between maternal CMD at two distinct stages of the offspring's life (at 3 months and 11 years) and their IQ scores at 6 and 18 years across two birth cohorts. The study utilized data from two Brazilian birth cohorts: the 1993 cohort (full sample: N = 3719, subsample: N = 436), and the 2004 Pelotas Birth Cohort (N = 3440). IQ assessments were conducted at ages 18 and 6, employing the Wechsler Adult Intelligence Scale, third version (WAIS-III), and Wechsler Intelligence Scale for Children, third version (WISC-III), respectively. The presence of maternal CMD at 3 months and 11 years of age was evaluated using the Brazilian version of the Self-Reporting Questionnaire (SRQ-20). After adjustment, participants whose mothers experienced CMD at 3 months had average IQ scores 1.74 (95 % CI: -2.83 to -0.67) and 2.79 (95 % CI: -5.54 to -0.04) points lower at ages 6 (2004 cohort) and 18 (1993 cohort subsample), respectively. Furthermore, in the 1993 cohort (both full and subsample), maternal CMD at 11 years was associated with lower IQ scores at age 18. Understanding the mechanisms underlying this association, emphasized by these findings, is crucial for promoting children's cognitive development, educational achievement, and overall well-being.

Ultra-processed food consumption and dental caries in adolescents from the 2004 Pelotas Birth Cohort study.

OBJECTIVE: To investigate the relationship between ultra-processed food (UPF) consumption and dental caries in adolescents. METHODS: Data from 996 adolescents aged 12-13 years who participated in an oral health sub-study of the 2004 Pelotas Birth Cohort in southern Brazil were analysed. The main exposure was daily UPF consumption at age 10-11 years, measured by a food frequency questionnaire containing 24 UPF items defined based on the NOVA system. UPF consumption was calculated in frequency, grams and calories, in general and for six types of food (biscuits, savoury snacks and sugar-sweetened cereals; ultra-processed meats and fats; sweets; fast food and instant noodles; soft drinks and artificially flavoured drinks; and sweetened milk and powdered chocolate). The outcome was dental caries, measured according to the decayed, missing and filled indexes (DMFS and dmfs) at age 12-13 years. Poisson regression models were used to analyse the association between UPF consumption and dental caries, adjusting for socioeconomic and demographic variables, dental visits and oral hygiene. RESULTS: Overall, the daily UPF consumption in frequency, grams and calories was associated with caries. The findings were consistent for UPF consumption for all six food groups. The higher the UPF consumption, the higher the probability of having caries in adolescence. The associations between ultra-processed meats and fats, and fast food and instant noodles intake with dental caries alert to the cariogenic potential of such UPF foods. CONCLUSION: Ultra-processed food consumption was associated with greater caries burdens in young adolescents. The findings reinforce the need for interventions and public policies to reduce UPF consumption in adolescence.

Gestational age at birth and morbidity, mortality, and growth in the first 4 years of life: findings from three birth cohorts in Southern Brazil.

BACKGROUND: We assessed anthropometric status, breastfeeding duration, morbidity, and mortality outcomes during the first four years of life according to gestational age, in three population-based birth cohorts in the city of Pelotas, Southern Brazil. METHODS: Total breastfeeding duration, neonatal mortality, infant morbidity and mortality, and anthropometric measures taken at 12 and 48 months were evaluated in children of different gestational ages born in 1982, 1993 and 2004 in Southern Brazil. RESULTS: Babies born <34 weeks of gestation and those born between 34-36 weeks presented increased morbidity and mortality, were breastfed for shorter periods, and were more likely to be undernourished at 12 months of life, in comparison with the 39-41 weeks group. Children born with 37 weeks were more than twice as likely to die in the first year of life, and were also at increased risk of hospitalization and underweight at 12 months of life. Post-term infants presented an increased risk of neonatal mortality. CONCLUSION: The increased risks of morbidity and mortality among preterm (<37 weeks of gestation) and post-term (>41 weeks) are well known. In our population babies born at 37 also present increased risk. As the proportion of preterm and early term babies has increased markedly in recent years, this is a cause for great concern.

Corrigendum: Trends and Inequalities in Unplanned Pregnancy in Three Population-Based Birth Cohorts in Pelotas, Brazil.

[This corrects the article DOI: 10.1007/s00038-020-01505-0.].

Trends and inequalities in unplanned pregnancy in three population-based birth cohorts in Pelotas, Brazil.

OBJECTIVES: To assess time trends in unplanned pregnancy, stratified by sociodemographic status, reproductive history, and inequalities in family income and women's skin color, in Pelotas, Brazil. METHODS: Data from mothers of participants of the 1993 (N = 5264), 2004 (N = 4243), and 2015 (N = 4268) Pelotas birth cohorts were analyzed. Unplanned pregnancy was investigated in the perinatal period, with tests to assess changes over time among different sociodemographic and reproductive history subgroups and inequalities as a function of family income and skin color. RESULTS: The prevalence of unplanned pregnancy was 62.7% (3299/ 5264), 65.9% (2794/ 4243), and 52.2% (2226/ 4268) in the 1993, 2004, and 2015 cohorts, respectively. Black or brown women and women of lower socioeconomic status had a higher prevalence of unplanned pregnancy in all cohorts. The overall rate of unplanned pregnancy decreased over time in most subgroups. Inequality as a function of family income and skin color increased during the time frame of assessment. CONCLUSIONS: The prevalence of unplanned pregnancies decreased in the period analyzed, but it is still unjustifiably high. Efforts aimed at reducing unplanned pregnancy are vital and will require special attention to the most vulnerable groups.

Maternal depression symptoms and use of child health-care services at The Pelotas 2004 Birth Cohort.

OBJECTIVE: To investigate the influence of maternal depression on child health-care services utilization. METHODOLOGY: Data from The Pelotas 2004 Birth Cohort collected at birth and at 12- and 24-month follow-ups were used. Four outcomes occurring in the second year of life were investigated: number of well-baby visits, number of medical appointments, number of visits to emergency rooms, and number of hospitalizations. The main exposure was maternal depression symptoms at 12-month post-partum as assessed by the Edinburgh Postpartum Depression Scale (EPDS). Adjusted prevalence ratios (PR) with 95% confidence intervals (95% CI) were calculated by Poisson regression. RESULTS: The prevalence of mothers with depressive symptoms was 27.6% (95% CI: 26.2-29.0%). These mothers showed a 10% lower probability of taking their children to well-baby visits (0.90; 0.85-0.95; p = 0.001); 16% higher probability to seek medical consultations (1.16; 1.09-1.25, p = 0.001); and they sought emergency services for their children more often (1.30; 1.17-1.45, p < 0.001) as compared to mothers who did not present depressive symptoms. Although the PR for hospitalizations was 26% higher for children from mothers with depressive symptoms, the association did not achieve statistical significance (1.26; 0.98-1.63; p = 0.072). CONCLUSION: Children from mothers with depressive symptoms attend fewer number of preventive consultations. In contrast, they are taken to medical and emergency care more often, suggesting that these children are given healthcare when they are at more advanced stages of their illnesses.

Reasons for direct restoration failure from childhood to adolescence: A birth cohort study.

OBJECTIVES: The aim of this study was to assess the prevalence of direct restorations in posterior teeth in children aged 12, from a birth cohort, and to test the association between the quality of the restorations and individual variables experienced in the life cycle. METHODS: All live-born children in Pelotas, in 2004, were prospectively investigated and a representative sample was assessed for oral conditions at ages 5 and 12. The outcome was the quality of the restoration (satisfactory/unsatisfactory). Independent variables included socioeconomic, behavioral and oral health characteristics at the individual level and the size of cavity and material at the tooth level. Associations were tested using multilevel logistic regression models. RESULTS: A total of 1,000 participants and 249 restorations in the permanent dentition were examined. Most of the restorations were composites (73.5%), while only 6.8% were amalgam. After adjusted analyses, children whose parents received information on how to prevent their child from developing caries before reaching 5 years of age had 91.0% less chance of having an unsatisfactory restoration compared to children whose parents never received information (OR = 0.09; 95% CI 0.01-0.59). Also, the chances of presenting unsatisfactory restorations were 5.3 higher in children at high-risk for untreated dental caries in the permanent dentition, in comparison with children at low risk (OR = 5.32; 95% CI 1.07-26.6). CONCLUSIONS: Low-risk for untreated dental caries and having received information on preventing dental caries, reduced the chance of presenting failed restorations, showing that factors related to individuals play an important role in the quality of restorations. CLINICAL SIGNIFICANCE: Our findings highlight the role that individual-related factors play in restoration longevity in children, reinforcing the need for a patient-centered approach in restorative dentistry.

Validation and reliability of visual assessment with a shade guide for tooth-color classification.

This study evaluated the validity and reliability of the visual assessment of tooth color using a commercial shade guide. Ninety-two individuals were randomly selected from subjects enrolled in a randomized controlled trial comparing two formulations of carbamide peroxide. Initially, each individual had the color of his or her six maxillary anterior teeth (n=552) determined by one examiner using a digital spectrophotometer (Vita Easyshade). Then, a visual assessment was made by two calibrated examiners using a shade guide (Vitapan Classical). Reliability was evaluated either by kappa coefficient when all the colors were grouped into two categories (dark and light) or by weighted kappa when all 16 colors of the shade guide were considered. The digital spectrophotometer (Vita Easyshade) was used as the gold standard to calculate sensitivity and specificity of the visual assessment. The reliability of the visual assessment using two color categories was "substantial" (k=0.69). When all colors of the shade guide were considered, the reliability was "mild" (kw=0.33). Sensitivity and specificity of the visual assessment with respect to the gold standard was 86.9% and 81.9%, respectively. Despite its subjectivity, visual assessment of tooth color using the Vitapan Classical shade guide is a valid method, with good reliability for differentiating between dark and light colors.

Efficacy and safety of 10% and 16% carbamide peroxide tooth-whitening gels: a randomized clinical trial.

This double-blind randomized clinical trial evaluated the efficacy and safety of two carbamide peroxide concentrations used in at-home vital bleaching. Ninety-two volunteers with a shade mean of C1 or darker for the six maxillary anterior teeth were randomized into two balanced groups (n=46) according to bleaching agent concentration: 10% (CP10) or 16% (CP16) carbamide peroxide. The patients were instructed to use the whitening agent in a tray for two hours once a day for three weeks. Shade evaluations were done with a value-oriented shade guide and a spectrophotometer at baseline and one week post-bleaching (four-week evaluation). Tooth sensitivity was measured daily using a scale ranging from 0 (no sensitivity) to 4 (severe sensitivity). At the end of the study, the volunteers filled out a questionnaire with seven questions aimed to give their opinion about the adopted treatment regimen. Both carbamide peroxide concentrations resulted in significantly lighter teeth at the four-week evaluation compared to the baseline for all color parameters (p < 0.0001) and shade median (p < 0.001). There was no significant difference between the two groups in terms of shade change difference with either the spectrophotometer (p = 0.1) or the shade guide (p = 0.7). Also, no statistically significant difference was found in relation to deltaL* (p = 0.7), delta a* and deltaE* (p = 0.5). A significant reduction in yellowness (delta b*) was observed for CP16 compared to CP10 (p = 0.05) in crude analysis, which disappeared after controlling for b* parameter at baseline. The group treated with CP16 experienced more tooth sensitivity during the first (p = 0.02) and third (p = 0.01) weeks of treatment compared to the CP10 group. However, no major difference was observed (p = 0.09) when the degree of tooth sensitivity between groups was compared. Both 10% and 16% carbamide peroxide concentrations were equally effective and safe for a three-week at-home tooth-bleaching treatment.

Impact of an educational intervention to promote condom use among the male partners of HIV positive women.

RATIONALE AIMS AND OBJECTIVES: Promoting the secondary prevention of HIV transmission is essential. METHOD: An intervention. aimed at increasing condom use by partners. was delivered to HIV positive women attending a Brazilian clinic. It included educational advice delivered by doctors. and unlimited access to free condoms. A pre-post design was used: 170 control group women were recruited. the intervention was implemented. and 170 intervention group women were then enrolled. All were interviewed at baseline. 30 and 60 days. RESULTS: After training. doctors were more likely to provide advice on condom use. Reported use increased by 8.8% points (a 14.2% increase) in the intervention group after 30 days. and by 5.7 points (9.5%) in the control group (P = 0.52). CONCLUSION: The reasons why the intervention failed to reach a significant effect are discussed. as are the possible Public Health impact of a 14.2% increase in condom use among HIV positive women.

[Individual factors associated with medical consultation by adults]. / Fatores individuais associados à utilização de consultas médicas por adultos.

OBJECTIVE: To identify individual characteristics associated with a higher likelihood of consulting a physician and excess physician appointments. METHODS: We carried out a population-based study including 3,100 adults (> 20 years) living in the city of Pelotas, Southern Brazil between October and December 2003, using a multi-stage cluster sampling strategy. Subjects were interviewed to obtain socioeconomic, demographic, and health-related data, as well as information on the number of medical appointments in the past three months. Overusage was defined as > 4 appointments. Multivariate analysis was carried out using Poisson regression based on a conceptual model, and results are presented as prevalence ratios and their respective 95% confidence intervals. RESULTS: The prevalence of medical appointments was 55.1%. Higher likelihood of consulting a physician was associated with female sex, hospital admission in the past year, former smoking, diabetes, and arterial hypertension. We found an increasing trend in the number of appointments with increasing age (p < 0.001) and decreasing self-perceived health status (p < 0.001). Prevalence of over utilization was 9%, and showed positive association with increased body mass index, (p = 0.01), increasing age (p = 0.006), and decreasing self-perceived health status (p < 0.001). CONCLUSIONS: Presence and over utilization of physician appointments were associated with female sex, hypertension, and hospital admission in past year, as well as with increasing age and decreasing self-perceived health status.

[Prevalence of dyspepsia and associated sociodemographic factors]. / Prevalência de dispepsia e fatores sociodemográficos.

OBJECTIVE: To assess prevalence of dyspepsia and distribution of dyspepsia and frequent dyspepsia in subgroups of adults (20 years and older) according to their demographic and socioeconomic characteristics. METHODS: A cross-sectional population-based study was carried out comprising 3,934 subjects living in Pelotas, Southern Brazil, from October 1999 to January 2000. Data was collected through household interviews. Dyspepsia was defined as epigastric pain or discomfort associated or not with nausea in the previous year, according to Rome I and Rome II criteria. Frequent dyspepsia was defined as more than six dyspepsia episodes in the previous year and/or nausea, at least once a month. These outcomes were analyzed according to age, gender, skin color, educational level, per capita income and marital status. Data analysis was carried out through Pearson Chi-square test for categorical variables and linear trend test, when applicable. RESULTS: The prevalence of dyspepsia was 44.4% and frequent dyspepsia, 27.4%. The prevalences of reflux-like, ulcer-like, dysmotility-like and unspecific dyspepsia subtypes were 19.4%, 6.3%, 13.9%, and 16.6%, respectively. The prevalences of these subtypes of frequent dyspepsia were 14.7%, 4.9%, 11.2% and 6.8%, respectively. Prevalences among women were 50% higher. Low-income young people seemed to be more affected by dyspeptic symptoms. The analysis according to Rome II criteria showed prevalences of 15.9% and 7.5% for dyspepsia and frequent dyspepsia, respectively. CONCLUSIONS: Dyspepsia and frequent dyspepsia were prevalent problems in the studied population. Most people could be classified in more than one subgroup of dyspepsia.

[The 2004 Pelotas birth cohort: methods and description]. / Coorte de nascimentos de Pelotas, 2004: metodologia e descrição.

OBJECTIVE: To describe a birth cohort which started in 2004, aiming to assess pre and perinatal conditions of the newborns, infant morbimortality, early life characteristics and outcomes, and access, use and financing of health care. METHODS: All children born in the urban area of Pelotas and Capão do Leão municipalities (Southern Brazil) in 2004 were identified and their mothers invited to join the study. In the first year of the study the children were seen at birth, at three and 12 months of age. These visits involved the application of a questionnaire to the mothers including questions on health; life style; use of health services; socioeconomic situation; estimation of gestational age; anthropometric measurements on the newborn (weight, length, head, chest and abdominal circumferences); anthropometric measurements on the mother (weight and height) and assessment of infant development. RESULTS: Out of the eligible infants (4,558), more than 99% were recruited to the study at birth. Follow-up rates were 96% at three months and 94% at 12 months of age. Among the initial results we highlight the following. Infant mortality rate was 19.7 per thousand, with 66% of infant deaths occurring in the neonatal period. There were frequencies of 15% premature babies and 10% low birthweight. Cesarean sections represented 45% of deliveries. CONCLUSIONS: The third Pelotas birth cohort showed an infant mortality rate similar to that of 11 years ago, with most deaths occurring in the neonatal period. The rates of prematurity and cesarean sections increased substantially.

Intellectual Disability in a Birth Cohort: Prevalence, Etiology, and Determinants at the Age of 4 Years.

BACKGROUND: Intellectual disability (ID), characterized by impairments in intellectual function and adaptive behavior, affects 1-3% of the population. Many studies investigated its etiology, but few are cohort studies in middle-income countries. AIMS: To estimate prevalence, etiology, and factors related to ID among children prospectively followed since birth in a Southern Brazilian city (Pelotas). METHODS: In 2004, maternity hospitals were visited daily and births were identified. Live-born infants (n = 4,231) whose family lived in the urban area have been followed for several years. At the age of 2 and 4 years, performances in development and intelligence tests were evaluated using the Battelle Developmental Inventory and Wechsler Intelligence Scale, respectively. Children considered as having developmental delay were invited to attend a genetic evaluation. RESULTS: At 4 years of age, the prevalence of ID was 4.5%, and the etiology was classified into 5 groups: environmental (44.4%), genetic (20.5%), idiopathic (12.6%), neonatal sequelae (13.2%), other diseases (9.3%). Most children presented impairment in two or more areas of adaptive behavior. There was no difference in prenatal care attendance or maternal schooling among the groups. CONCLUSION: For about 40% of children, ID was attributed to nonbiological factors, suggesting that the rate may be reduced with appropriate interventions early in life.