Validity of partial protocols to assess the prevalence of periodontal outcomes and associated sociodemographic and behavior factors in adolescents and young adults

BACKGROUND

Most studies comparing prevalence of periodontal disease and risk factors by using partial protocols were performed in adult populations, with several studies being conducted in clinical settings. The aim of this study is to assess the accuracy of partial protocols in estimating the prevalence of periodontal outcomes in adolescents and young adults from two population-based birth cohorts from Pelotas, Brazil, and to assess differences in the estimation and strength of the effect measures when partial protocols are adopted compared to full-mouth examination.

METHODS

Gingival bleeding at probing among adolescents (n = 339) and young adults (n = 720) and dental calculus and periodontal probing depth among young adults were assessed using full-mouth examinations and four partial protocols: Ramfjord teeth (RT), community periodontal index (CPI), and two random diagonal quadrants (1 and 3, 2 and 4). Socioeconomic, demographic, and periodontal health-related variables were also collected. Sensitivity, absolute and relative bias, and inflation factors were calculated. Prevalence ratio for each periodontal outcome for the risk factors was estimated.

RESULTS

Two diagonal quadrants showed better accuracy; RT had the worst, whereas CPI presented an intermediate pattern when compared to full-mouth examination. For bleeding assessment in adolescence, RT and CPI underestimated by 18.4% and 16.2%, respectively, the true outcome prevalence, whereas among young adults, all partial protocols underestimated the prevalence. All partial protocols presented similar magnitude of association measures for all investigated periodontal potential risk factors.

CONCLUSION

Two diagonal quadrants protocol may be effective in identifying the risk factors for the most relevant periodontal outcomes in adolescence and in young adulthood.

Cesarean section and risk of obesity in childhood, adolescence, and early adulthood: evidence from 3 Brazilian birth cohorts

BACKGROUND

The number of cesarean sections (CSs) is increasing in many countries, and there are concerns about their short- and long-term effects. A recent Brazilian study showed a 58% higher prevalence of obesity in young adults born by CS than in young adults born vaginally. Because CS-born individuals do not make contact at birth with maternal vaginal and intestinal bacteria, the authors proposed that this could lead to long-term changes in the gut microbiota that could contribute to obesity.

OBJECTIVE

We assessed whether CS births lead to increased obesity during childhood, adolescence, and early adulthood in 3 birth cohorts.

DESIGN

We analyzed data from 3 birth-cohort studies started in 1982, 1993, and 2004 in Southern Brazil. Subjects were assessed at different ages until 23 y of age. Poisson regression was used to estimate prevalence ratios with adjustment for ≤15 socioeconomic, demographic, maternal, anthropometric, and behavioral covariates.

RESULTS

In the crude analyses, subjects born by CS had ∼50% higher prevalence of obesity at 4, 11, and 15 y of age but not at 23 y of age. After adjustment for covariates, prevalence ratios were markedly reduced and no longer significant for men or women. The only exception was an association for 4-y-old boys in the 1993 cohort, which was not observed in the other 2 cohorts or for girls.

CONCLUSION

In these 3 birth cohorts, CSs do not seem to lead to an important increased risk of obesity during childhood, adolescence, or early adulthood.

Oral health studies in the 1982 Pelotas (Brazil) birth cohort: methodology and principal results at 15 and 24 years of age

The aim of this study was to describe the methodology and results of oral health studies nested in a birth cohort in Pelotas, Southern Brazil. For the oral health studies a sub-sample (n = 900) was selected from the cohort and dental examinations and interviews were performed at ages 15 (n = 888) and 24 years (n = 720; 81.1%). Data collection included dental outcomes, dental care, oral health behaviors, and use of dental services. Mean DMF-T varied from 5.1 (SD = 3.8) to 5.6 (SD = 4.1) in the study period. The proportion of individuals with at least one filled tooth increased from 51.9% to more than 70%. Individuals who had always been poor used dental services less and had fewer healthy teeth on average than those who had never been poor. Individuals with decreasing or increasing family income trajectories showed intermediate values. An increase was seen in the number of healthy teeth from age 15 to 24 only among those who had never been poor. A history of at least one experience with poverty had a negative impact on oral health in adulthood.

The case for launch of an international DNA-based birth cohort study

The global health agenda beyond 2015 will inevitably need to broaden its focus from mortality reduction to the social determinants of deaths, growing inequities among children and mothers, and ensuring the sustainability of the progress made against the infectious diseases. New research tools, including technologies that enable high-throughput genetic and '-omics' research, could be deployed for better understanding of the aetiology of maternal and child health problems. The research needed to address those challenges will require conceptually different studies than those used in the past. It should be guided by stringent ethical frameworks related to the emerging collections of biological specimens and other health related information. We will aim to establish an international birth cohort which should assist low- and middle-income countries to use emerging genomic research technologies to address the main problems in maternal and child health, which are still major contributors to the burden of disease globally.

Metabolic syndrome in the 1982 Pelotas cohort: effect of contemporary lifestyle and socioeconomic status

OBJECTIVES

Describe the prevalence of metabolic syndrome, and its association with contemporary lifestyle factors.

SUBJECTS AND METHODS

In 2004-2005, 4,296 subjects of the 1982 Pelotas Birth Cohort were evaluated, and metabolic syndrome (MetS) was assessed in 3,599 according to the NCEP-ATP III and IDF criteria.

RESULTS

Prevalence of MetS was 5.9% and 6.7% for NCEP-ATPIII and IDF, respectively. Smoking, alcohol intake, and physical activity were not associated with MetS. Among men, the body mass index (BMI) was associated with MetS - overweight [RR: 3.14 (95% CI, 1.97-5.00)] and obese subjects [RR: 17.41 (95% CI, 11.85-25.60)]. In women, family income and schooling were inversely associated with MetS, overweight increased the risk of MetS 7.73 (95% CI, 3.65-16.38) times and obesity 40.67 (95% CI, 20.85-79.33) times.

CONCLUSIONS

MetS was more prevalent among men according to NCEP-ATP III criteria, and obesity was the main risk factor.

First-borns carry a higher metabolic risk in early adulthood: evidence from a prospective cohort study

BACKGROUND

Birth order has been associated with early growth variability and subsequent increased adiposity, but the consequent effects of increased fat mass on metabolic risk during adulthood have not been assessed. We aimed to quantify the metabolic risk in young adulthood of being first-born relative to those born second or subsequently.

METHODOLOGY AND PRINCIPAL FINDINGS

Body composition and metabolic risk were assessed in 2,249 men, aged 17-19 years, from a birth cohort in southern Brazil. Metabolic risk was assessed using a composite z-score integrating standardized measurements of blood pressure, total cholesterol, high density lipoprotein, triglycerides and fat mass. First-borns had lower birth weight z-score (Δ = -0.25, 95%CI -0.35, -0.15,p<0.001) but showed greater weight gain during infancy (change in weight z-score from birth to 20 months: Δ = 0.39, 95%CI 0.28-0.50, p<0.0001) and had greater mean height (Δ = 1.2 cm, 95%CI: 0.7-1.6, p<0.0001) and weight (Δ = 0.34 kg, 95%CI: 0.13-0.55, p<0.002) at 43 months. This greater weight and height tracked into early adulthood, with first-borns being significantly taller, heavier and with significantly higher fat mass than later-borns. The metabolic risk z-score was significantly higher in first-borns.

CONCLUSIONS/SIGNIFICANCE

First-born status is associated with significantly elevated adiposity and metabolic risk in young adult men in Brazil. Our results, linking cardiovascular risk with life history variables, suggest that metabolic risk may be associated with the worldwide trend to smaller family size and it may interact with changes in behavioural or environmental risk factors.

Caesarean sections and risk of wheezing in childhood and adolescence: data from two birth cohort studies in Brazil

Background

There is evidence from two meta-analyses that children born through caesarean section (C-section) may have an increased risk of developing asthma compared with those born through vaginal delivery.

Objective

To evaluate the association between mode of delivery and wheezing (current and persistent) in childhood and adolescence, in two birth cohort studies in Brazil.

Methods

The outcome variable was based on the International Study of Allergy and Asthma questionnaire, which collects information about wheezing within the 12 months before the interview. Persistent wheezing was defined when it was present in more than one follow-up at different ages, in the 1993 cohort. The questions were asked to mothers when children were aged 4 years (1993 and 2004 cohorts) and directly to cohort participants at 11 and 15 years (1993 cohort). Mode of delivery was collected by the research team of each cohort when children were born.

Results

Response rates in the last follow-up visit of the 1993 and 2004 cohorts were 85% and 92%, respectively. The prevalence of current wheezing increased from 20% to 28% at 4 years from 1993 to 2004; at 11 and 15 years, the prevalence was around 14% and 12%, in the 1993 cohort. The proportion of C-sections increased from 30.5% to 45% between 1993 and 2004. In each cohort, the prevalence of current wheezing was similar among children born through vaginal and C-section. The risk for persistent wheezing in the 1993 cohort was higher among girls born through C-section than boys.

Conclusion

Despite the increase in the proportion of C-section in two cohorts in Southern Brazil, we found no evidence of an association between mode of delivery and the subsequent risk of wheezing. Among girls, although there was no statistical significance, the risk was higher for those born by C-section, especially regarding persistent wheezing.

Prevalence of angina pectoris in Pelotas, south of Brazil

BACKGROUND

Ischemic heart disease is the leading cause of death in the world and angina is its cardinal manifestation.

OBJECTIVE

To determine the prevalence of angina and possible angina and its distribution by main demographic and socioeconomic characteristics among adults 40 years of age or older.

METHODS

This is a population-based, cross-sectional study featuring residents of the urban area in Pelotas, a city located in the south of Brazil, from October through December 2007. A two-stage cluster sampling--census tracts and households--was used. The prevalence of angina and possible angina was defined according to the Rose questionnaire. These conditions were assessed by demographic and socioeconomic characteristics: age, sex, skin color, economic status, and schooling. Data were collected using standardized questionnaires in interviews with the individuals in their homes. The non-respondent rate was 6.8%.

RESULTS

The prevalence of angina among the 1,680 individuals taking part in the study was 8.2% (95% CI: 6.7 - 9.6), while that of possible angina came to 12.3% (95% CI: 10.6 - 14.0). The prevalence of angina and possible angina was higher among women, black/brown-skinned individuals, low economic class individuals and subjects with the low schooling. The prevalence of angina was higher among older individuals, while possible angina was found not to be associated with age.

CONCLUSION

The prevalence of angina and possible angina was found to be high, affecting approximately 20% of the population in Pelotas.

The influence of family income trajectories from birth to adulthood on adult oral health: findings from the 1982 Pelotas birth cohort

OBJECTIVES

We assessed whether 3 models of life course socioeconomic status (critical period, accumulation of risk, and social mobility) predicted unsound teeth in adulthood among a Brazilian cohort.

METHODS

Life course data were collected on the 5914 live-born infants in the 1982 Pelotas Birth Cohort study. Participants' oral health was assessed at 15 (n = 888) and 24 (n = 720) years of age. We assessed family income trajectories and number of episodes of poverty in the life course through Poisson regressions, yielding unadjusted and adjusted prevalence ratios for number of unsound teeth at age 24 years.

RESULTS

The adjusted prevalence ratio for participants born into poverty was 30% higher than for those who were not. Participants who were always poor had the highest prevalence of unsound teeth; those who were downwardly or upwardly mobile also had more unsound teeth than did other participants, after adjustment for confounders. More episodes of poverty were associated with greater prevalence of unsound teeth in adulthood.

CONCLUSIONS

Poverty at birth and during the life course was correlated with the number of unsound teeth at 24 years of age.

'Kangaroo mother care' to prevent neonatal deaths due to preterm birth complications

Background ‘Kangaroo mother care’ (KMC) includes thermal care through continuous skin-to-skin contact, support for exclusive breastfeeding or other appropriate feeding, and early recognition/response to illness. Whilst increasingly accepted in both high- and low-income countries, a Cochrane review (2003) did not find evidence of KMC’s mortality benefit, and did not report neonatal-specific data.

Objectives The objectives of this study were to review the evidence, and estimate the effect of KMC on neonatal mortality due to complications of preterm birth.

Methods We conducted systematic reviews. Standardized abstraction tables were used and study quality assessed by adapted GRADE methodology. Meta-analyses were undertaken.

Results We identified 15 studies reporting mortality and/or morbidity outcomes including nine randomized controlled trials (RCTs) and six observational studies all from low- or middle-income settings. Except one, all were hospital-based and included only babies of birth-weight <2000 g (assumed preterm). The one community-based trial had missing birthweight data, as well as other limitations and was excluded. Neonatal-specific data were supplied by two authors. Meta-analysis of three RCTs commencing KMC in the first week of life showed a significant reduction in neonatal mortality [relative risk (RR) 0.49, 95% confidence interval (CI) 0.29–0.82] compared with standard care. A meta-analysis of three observational studies also suggested significant mortality benefit (RR 0.68, 95% CI 0.58–0.79). Five RCTs suggested significant reductions in serious morbidity for babies <2000 g (RR 0.34, 95% CI 0.17–0.65).

Conclusion This is the first published meta-analysis showing that KMC substantially reduces neonatal mortality amongst preterm babies (birth weight <2000 g) in hospital, and is highly effective in reducing severe morbidity, particularly from infection. However, KMC remains unavailable at-scale in most low-income countries.

Lifecourse socioeconomic trajectories and C-reactive protein levels in young adults: findings from a Brazilian birth cohort

Socioeconomic factors are associated with cardiovascular disease. C-reactive protein (CRP) is increasingly implicated as a candidate linking conventional risk factors and atherosclerosis. The impact of early- and later-life socioeconomic status (SES) on CRP levels has not been widely investigated and a handful of studies from high-income countries are inconsistent. We set out to examine the associations between lifecourse socioeconomic indicators (family income at birth, maternal education, family income at age 23 and own education) on CRP levels in young adults belonging to the 1982 Pelotas (Brazil) Birth Cohort Study (n = 5914). Early-life SES showed significant and graded associations with CRP levels at age 23 independently of later SES. For example, men with higher family income at birth showed higher CRP levels at age 23 (p = 0.001 for trend) and women with less educated mothers showed higher CRP levels (p = 0.01 for trend). Notably, differential directions of association between SES indicators and CRP levels between men and women were found. When adjusted for SES at age 23, men with the lowest family income at birth showed 42% lower CRP levels when compared to men in the highest family income group (−42; 95% CI: -60,-16). In contrast women born to the least educated mothers had the highest CRP levels (35; 95% CI -2, 86). In both sexes, adiposity accounted for the overwhelming majority of the associations between SES and CRP levels. Sex and gender roles specific to middle-income countries, socio-cultural and environmental conditions that may impact adiposity, and the level of epidemiological transition may be key factors that are linked to the associations between lifecourse SES and CRP levels. Public health strategies aimed at decreasing the burden of cardiovascular disease in middle-income settings, in addition to highlighting the risks associated with adult obesity, should not overlook the wide-ranging impacts of lifecourse social determinants.

Weight gain in the first two years of life is an important predictor of schooling outcomes in pooled analyses from five birth cohorts from low- and middle-income countries

Schooling predicts better reproductive outcomes, better long-term health, and increased lifetime earnings. We used data from 5 cohorts (Brazil, Guatemala, India, the Philippines, and South Africa) to explore the relative importance of birthweight and postnatal weight gain for schooling in pooled analyses (n = 7945) that used appropriate statistical methods [conditional weight (CW) gain measures that are uncorrelated with prior weights] and controlled for confounding. One SD increase in birthweight, approximately 0.5 kg, was associated with 0.21 y more schooling and 8% decreased risk of grade failure. One SD increase in CW gain between 0 and 2 y, approximately 0.7 kg, was associated with higher estimates, 0.43 y more schooling, and 12% decreased risk of failure. One SD increase of CW gain between 2 and 4 y, approximately 0.9 kg, was associated with only 0.07 y more schooling but not with failure. Also, in children born in the lowest tertile of birthweight, 1 SD increase of CW between 0 and 2 y was associated with 0.52 y more schooling compared with 0.30 y in those in the upper tertile. Relationships with age at school entry were inconsistent. In conclusion, weight gain during the first 2 y of life had the strongest associations with schooling followed by birthweight; weight gain between 2 and 4 y had little relationship to schooling. Catch-up growth in smaller babies benefited schooling. Nutrition interventions aimed at women and children under 2 y are among the key strategies for achieving the millennium development goal of universal primary education by 2015.

[Maternity and paternity in the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil]

OBJECTIVE

To describe the prevalence of maternity and paternity among subjects and its association with perinatal, socioeconomic and demographic variables.

METHODS

The participants were youth, aged 23, on the average, accompanied in a cohort study since they were born, in 1982, in Pelotas (Southern Brazil) and interviewed in 2004-5. Those who were considered eligible referred having had one or more children, whether these were liveborns or stillborns. Data was collected on reproductive health as well as socioeconomic and demographic information, by means of two different instruments. The independent variables were sex and skin color, family income in 1982 and in 2004-5, changes in income, birth weight and educational level when aged 23 years old. Crude and adjusted analysis were conducted by means of Poisson regression so as to investigate the effects of the independent variables on maternity/paternity during adolescence.

RESULTS

Among the 4,297 youth interviewed, 1,373 (32%) were parents and 842 (19.6%) of these had experienced maternity/paternity during their adolescence. Planned pregnancy of the first child was directly related to the youth's age. Socioeconomic variables were inversely related to the occurrence of maternity/paternity during adolescence. The probability of being an adolescent mother was higher among black and mixed skin colored women, but skin color was not associated to adolescent paternity.

CONCLUSIONS

There was a strong relation between adolescent maternity/paternity and socioeconomic conditions, which should be taken into consideration when delineating preventive actions in the field of public health.

[Prevalence and early determinants of common mental disorders in the 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To estimate the prevalence of common mental disorders and assess its association with risk factors in a cohort of young adults.

METHODS

Cross-sectional study nested in a 1982 birth cohort study conducted in Pelotas, Southern Brazil. In 2004-5, 4,297 subjects were interviewed during home visits. Common mental disorders were assessed using the Self-Report Questionnaire. Risk factors included socioeconomic, demographic, perinatal, and environmental variables. The analysis was stratified by gender and crude and adjusted prevalence ratios were estimated by Poisson regression.

RESULTS

The overall prevalence of common mental disorders was 28.0%; 32.8% and 23.5% in women and men, respectively. Men and women who were poor in 2004-5, regardless of their poor status in 1982, had nearly 1.5-fold increased risk for common mental disorders (p<0.001) when compared to those who have never been poor. Among women, being poor during childhood (p<0.001) and black/mixed skin color (p=0.002) increased the risk for mental disorders. Low birth weight and duration of breastfeeding were not associated to the risk of these disorders.

CONCLUSIONS

Higher prevalence of common mental disorders among low-income groups and race-ethnic minorities suggests that social inequalities present at birth have a major impact on mental health, especially common mental disorders.

[Methodology of the Pelotas birth cohort study from 1982 to 2004-5, Southern Brazil]

OBJECTIVE

To describe the methods employed in the longitudinal and follow-up studies of children born in Pelotas (Southern Brazil) in 1982.

METHODS

The cohort began with a perinatal health survey that included all 6,011 children born in maternity wards in Pelotas in 1982. The 5,914 children born alive in the city were included in the follow-up studies. By 2004-5, we had conducted eight follow-ups, which consisted of the administration of questionnaires to mothers and/or cohort members, depending on age, in addition to anthropometric and clinical examination. Cohort subjects are described in terms of demographic, socioeconomic, and health-related variables collected during early follow-up studies, which are used as exposure variables.

RESULTS

The majority of subjects in the cohort were followed for 23 years and on multiple occasions. The most successful follow-ups were those preceded by a city census. Using this method, we were able to locate 87.2% of subjects in 1984 (mean age 19 months), 84.1% in 1986 (mean age 43 months), and 77.4% in 2004-5, and 77.4% in 2004-5 (mean age 23 years).

CONCLUSIONS

Birth cohort studies can be carried out successfully in developing countries, and the methods employed in this life-cycle study have allowed us to investigate the influence of early exposures in determining disease outcomes in adult life.

[Pattern of health services utilization by adults of the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil]

OBJECTIVE

To describe the pattern of health services utilization by young adults.

METHODS

Longitudinal study in Pelotas (Southern Brazil), in which the individuals were identified at birth in 1982 and followed up until 23 years of age. The outcome was defined by information collected about visits to health professionals that were attended in the year before the interview, between 2004 and 2005. The places where the visits occurred were categorized as public, private or belonging to health plan systems. Descriptive analyses were carried out for utilization and type of health service. Poisson Regression was employed in the adjusted analysis.

RESULTS

Of the interviewees, 72.0% visited health professionals in the year before the interview; 86.2% (95% CI 84.7;87.7) of the women and 59.3% (95% CI 57.3;61.3) of the men. Even when gynecological visits were excluded, the women still attended more visits than the men, 68.4% (95% CI 66.4;70.4). Health services utilization was more frequent among interviewees of better socioeconomic level. A difference of lower use in relation to non-white skin color was observed only among male youths. There were differences regarding the type of professional visited by men and women and also according to family income. Men and women used more frequently the public system, the health plan system and, in a smaller proportion, the private system.

CONCLUSIONS

The socioeconomic situation influenced the utilization and the type of health service, with men and women classified as 'poor at the moment', which indicates lower utilization of services. Such socioeconomic differences may indicate difficulties in the access to the health system.

[Determinants of early sexual initiation in the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil]

OBJECTIVE

To analyze social determinants of early sexual initiation among young adults from a birth cohort.

METHODS

Individuals from the 1982 birth cohort (N=4,297) were interviewed in 2004-5, city of Pelotas, Southern Brazil. Early sexual initiation (<13 years of age) was the outcome. Descriptive and stratified analyses were performed according to sex. Variables analyzed were family income in 1982, ethnicity, young adult's level of education and change in income (between 1982 and 2004-5). Ethnographic data were used to complement result analysis.

RESULTS

Prevalence of early sexual initiation was higher among black and mixed men, and those with low level of education and low family income in 1982 and 2004-5. More traditional male sexual role requirements, such as virility and sexual initiative, showed more repercussion and adherence from an early age among men. Young family women with higher income and level of education tended to delay their sexual initiation. Imposition of traditional values was found to influence early sexual initiation among men and women with lower level of education and income.

CONCLUSIONS

Results found re-established the economic factor as a determinant of behavior or uses of sexuality for both sexes. To focus on political efforts that help the economically disadvantaged to have opportunities and egalitarian future perspectives is an important strategy for health outcomes.

[Factors associated to leisure-time sedentary lifestyle in adults of 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To assess factors associated to leisure-time physical activity and sedentary lifestyle.

METHODS

Prospective cohort study of people born in 1982 in the city of Pelotas, southern Brazil. Data were collected at birth and during in a visit in 2004-5 when 77.4% of the cohort were evaluated, making a total of 4,297 people studied. Information about leisure-time physical activity was collected using the International Physical Activity Questionnaire. Sedentary people were defined as those with weekly physical activity below 150 minutes. The following independent variables were studied: gender, skin color, birth weight, family income at birth and income change between birth and 23 years of age. Poisson's regression with robust adjustment of variance was used for the assessment of risk factors of sedentary lifestyle.

RESULTS

Men reported 334 min of weekly leisure-time physical activity compared to 112 min among women. The prevalence of sedentary lifestyle was 80.6% in women and 49.2% in men. Scores of physical activity increased as income at birth increased. Those who were currently poor or who became poor during adult life were more sedentary.

CONCLUSIONS

Leisure-time sedentary lifestyle in young adults was high especially among women. Physical activity during leisure time is determined by current socioeconomic conditions.

[Nutritional evaluation follow-up of the 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To estimate the prevalence of over/underweight and its association with demographic and socioeconomic factors.

METHODS

Longitudinal cohort study of youths born in 1982 in Pelotas, Southern Brazil. In 2004-5 we interviewed 4,198 of the 5,914 cohort subjects, obtaining weight and stature measurements that were used to calculate body mass index (BMI). Underweight was defined as BMI lower than 18,5 kg/m(2); overweight as BMI between 25 and 30kg/m(2); and obesity as BMI IMC > 30kg/m(2). The effects of socioeconomic (family income and schooling) and demographic (skin color) variables, birthweight, and breastfeeding on underweight, overweight, and obesity were analyzed separately for men and women using Poisson regression.

RESULTS

Prevalence of underweight, obesity, and overweight were 6.0%, 8.2%, and 28.9%, respectively. In adjusted analysis, only birthweight remained associated with underweight among men and women. Poor men showed higher risk of underweight, but were protected from obesity and overweight. By contrast, risk of obesity and overweight was higher among poor women.

CONCLUSIONS

The present results underscore the importance of socioeconomic determinants on nutritional status, with special emphasis on the distinct effects these factors have among men and women in different nutritional conditions.

[Early determinants of blood pressure among adults of the 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To evaluate the effects of exposure occurring during pregnancy or the first years of life on blood pressure.

METHODS

Cohort study on all children born in 1982 in maternity hospitals in the city of Pelotas, Southern Brazil. The mothers living in the urban area were interviewed and the children were followed up on different occasions. In 2004-5, all the individuals in the cohort were sought for monitoring. Their blood pressure was measured twice, at the start and end of the interview, using a digital wrist sphygmomanometer. Associations between blood pressure and the following variables were evaluated: skin color; maternal schooling level; family income at birth; change in income between birth and 23 years of age; birth weight; and duration of breastfeeding. Analysis of variance was used to compare the means and a generalized linear model was used in the adjusted analysis.

RESULTS

Blood pressure measurements were obtained from 4,291 individuals: 2,208 males and 2,083 females. The mean systolic blood pressure was 117.5 +/- 15.0 mmHg and the mean diastolic was 73.6 +/- 11.5 mmHg. Among the men, systolic blood pressure was higher among those of black or brown skin color and among those who were never considered poor. Diastolic pressure was only associated with birth weight. Among the women, systolic blood pressure was greater among those of black or brown skin color whose mothers' schooling level was greater than or equal to 12 years or whose birth weight was less than 4,000 g.

CONCLUSIONS

For both sexes, only skin color was associated with blood pressure. Breastfeeding did not have any long-term effect on blood pressure and the associations for birth weight and socioeconomic level were inconsistent.

[Prevalence of wheezing in the chest among adults from the 1982 Pelotas birth cohort, Southern Brazil]

OBJECTIVE

To estimate the prevalence of wheezing in the chest among adults, and to explore the effect of some variables on the prevalence of this condition.

METHODS

This was a prospective cohort study on individuals born in the city of Pelotas (Southern Brazil) in 1982. A total of 4,297 subjects was traced in 2004-5, representing 77.4% of the original cohort. Data were collected by means of interviews using the ISAAC (International Study of Asthma and Allergies in Childhood Steering Committee) questionnaire. Associations between the outcome 'occurrence of wheezing in the chest within the 12 months prior to the interview' and the variables of socioeconomic, demographic and birth characteristics were tested by means of multivariable analyses, using Poisson regression.

RESULTS

The prevalence of wheezing over the preceding year was 24.9%. Among the individuals reporting wheezing, 54.6% reported difficulty in sleeping, and 12.9% reported difficulty in speaking due to wheezing. The prevalence of wheezing in the chest was significantly higher among women. This association was maintained in analyses adjusted for non-white skin color, family history of asthma and low socioeconomic level. Among men, there was no significant association in the analyses adjusted for skin color and family income at birth. Family histories of asthma and poverty throughout life presented significant associations with wheezing in the chest. For both sexes, there were no associations with the variables of birth weight and breastfeeding duration.

CONCLUSIONS

The prevalence of wheezing in the chest was high, and subjects with low family income at birth were more likely to have had wheezing in the chest over the preceding year.

[Monitoring mortality in Pelotas birth cohort from 1982 to 2006, Southern Brazil]

OBJECTIVE

To assess mortality in a birth cohort followed between 1982 and 2006 and its associated factors.

METHODS

In 1982, all of the 5914 children born in hospitals in the city of Pelotas, Southern Brazil, were identified and followed up prospectively. Between 1982 and 1987, deaths were identified through regular visits to hospitals, cemeteries and death registries. As of 1987, death data were obtained through the Mortality Information System. The studied variables were: gender, color of mother, mother's schooling rate, family income, weight at birth, weight and height per age. Poisson regression was used to estimate the relative mortality risk.

RESULTS

Between 1982 and 2006 there were 288 deaths. The infant mortality coefficient was 36 deaths/1 000 live births; and in the age brackets 1-4, years, 5-14 years and 15-24 years the mortality rates were, respectively, 14.4, 4.1 and 5.4 deaths for every 1 000 live births at the beginning of the period. In all age brackets, mortality was higher for individuals from low-income families, with a relative risk of 2.89 (95% CI: 2.08; 4.03) when comparing the first and third terciles after control for gender and skin color. Low weight at birth and height-for-age and weigh-for-height deficits were found to be associated to a higher mortality rate until age 4, but not after that age.

CONCLUSIONS

The effects of social inequalities during childhood can be felt until the beginning of adult life, but birth weight and childhood nutritional status do not have a long-lasting effect on mortality rates for adolescents or young adults.

Life course weight gain and C-reactive protein levels in young adults: findings from a Brazilian birth cohort

Rapid weight gain in childhood is associated with increased risk of chronic diseases in adults. C-reactive protein (CRP) is a mediator of atherosclerosis and chronically elevated levels predict cardiovascular outcomes. The effects of life course weight gain on CRP levels are not clear. The 1982 Pelotas (Brazil) birth cohort study (n = 5,914) has prospectively collected weight and health data at several follow-ups since birth. The most recent was in 2004-05, when 77.4% of the cohort was traced and CRP levels were measured in 89% of those interviewed (n = 3827). Geometric mean (SE) C-reactive protein levels were 0.89 mg/l (0.03) and 1.66 mg/l (0.04) in men and women, respectively. In analyses adjusted for confounding variables, weight gain in infancy showed a weak negative association among males, but from the second year onwards, weight gain was positively associated with CRP levels. In females, weight gain was associated with higher CRP at every period tested. The strongest associations were observed in the most recent (18-23 years) period; CRP ratios (95% CI) per z score increase in weight gain were 1.78 (1.57-2.00) and 1.52 (1.30-1.78) for men and women, respectively. Males who were stunted at 2 years and centrally obese at 23 years had the highest CRP levels (P = 0.002 for interaction). In summary, rapid weight gain throughout life predicted higher CRP levels. Public health efforts need to tackle chronic under-nutrition in infancy, together with rapid weight gain in later childhood and adolescence, especially in countries undergoing the nutritional transition.

Weight gain in childhood and blood lipids in adolescence

Aim:

To assess the effect of weight gain in childhood on blood lipid levels in adolescence.

Methods:

A population-based birth cohort carried out in Pelotas, Southern Brazil. All newborns in the city's hospitals were enrolled in 1982. The subjects have been followed up for several times in childhood. At age 18, 79% of all males were followed, and 2083 blood samples were available. Adjusted analyses controlled for household assets index, family income, parental schooling at birth, maternal smoking during pregnancy and breastfeeding duration.

Results:

Birth weight for gestational age and weight gain in the first 20 months was not associated with blood lipid levels in adolescence. On the other hand, those subjects whose weight gain from 20 to 42 months of age was faster than that predicted from birth weight and weight-for-age z-score at the mean age of 20 months had lower high-density lipoprotein cholesterol (HDL) cholesterol [−0.78 (95% confidence interval: −1.28; −0.29)] and higher very low-density lipoprotein cholesterol (VLDL) and low-density lipoprotein cholesterol (LDL)/HDL ratio in adolescence. After controlling for current body mass index (BMI), the regression coefficient for HDL cholesterol decreased from −0.78 mg/dL to −0.29 mg/dL (95% confidence interval: −1.00 to 0.05).

Conclusion:

Weight gain from 2 to 4 years is related to an atherogenic lipid profile in adolescence and this association is mediated by current BMI.

Intergenerational effect of weight gain in childhood on offspring birthweight

Background Some studies suggest that weight gain in childhood may increase the risk of chronic diseases in adulthood, and recent studies have noticed that the timing of weight gain may be related to its long-term consequence. However, weight gain in childhood has clear short-term benefits, and the literature on the pro and cons of weight gain in childhood is limited.

Methods In 1982, all 5914 hospital births (over 99% of all deliveries) occurring in Pelotas, Southern Brazil, were identified and studied prospectively on several occasions. In 2004–05, we attempted to trace the whole cohort and information on offspring birthweight was collected. Conditional growth modelling was used to assess the association between offspring birthweight and weight gain from birth to 20 months, and from 20 to 42 months.

Results In 2004–05, we interviewed 4297 subjects, with a follow-up rate of 77.4%. This manuscript includes data from 848 women who had already delivered a child and 525 men who were fathers at the mean age of 23 years. Maternal birthweight, weight and length for age Z-score at 20 months of age were positively associated with next-generation birthweight, whereas paternal variables were not related to the outcome. Conditional growth modelling analyses showed that women whose weight gain in the first 20 months of life was faster than predicted had heavier babies, whereas paternal weight gain was not associated. The association was strongest for mothers whose birthweight for gestational age was in the lowest tertile.

Conclusion Maternal, but not paternal birthweight and weight gain in early childhood are positively associated with next-generation birthweight.

Prepregnancy BMI and the risk of gestational diabetes: a systematic review of the literature with meta-analysis

The objective of this study is to assess and quantify the risk for gestational diabetes mellitus (GDM) according to prepregnancy maternal body mass index (BMI). The design is a systematic review of observational studies published in the last 30 years. Four electronic databases were searched for publications (1977-2007). BMI was elected as the only measure of obesity, and all diagnostic criteria for GDM were accepted. Studies with selective screening for GDM were excluded. There were no language restrictions. The methodological quality of primary studies was assessed. Some 1745 citations were screened, and 70 studies (two unpublished) involving 671 945 women were included (59 cohorts and 11 case-controls). Most studies were of high or medium quality. Compared with women with a normal BMI, the unadjusted pooled odds ratio (OR) of an underweight woman developing GDM was 0.75 (95% confidence interval [CI] 0.69 to 0.82). The OR for overweight, moderately obese and morbidly obese women were 1.97 (95% CI 1.77 to 2.19), 3.01 (95% CI 2.34 to 3.87) and 5.55 (95% CI 4.27 to 7.21) respectively. For every 1 kg m(-2) increase in BMI, the prevalence of GDM increased by 0.92% (95% CI 0.73 to 1.10). The risk of GDM is positively associated with prepregnancy BMI. This information is important when counselling women planning a pregnancy.

Preterm births, low birth weight, and intrauterine growth restriction in three birth cohorts in Southern Brazil: 1982, 1993 and 2004

Three birth cohort studies from 1982, 1993 and 2004, in Pelotas, Southern Brazil provided the data for this study of trends in preterm births, low birth weight, and intrauterine growth restriction. We found a slight increase in the period in the low birth weight prevalence from 9% to 10%. Intrauterine growth restriction decreased from 14.8% in 1982 to 9.4% in 1993, and subsequently increased to 12% in 2004, whereas preterm births increased markedly, from 6.3% in 1982 to 14.7% in 2004. This striking increment could not be explained by changes in maternal characteristics, as mothers in 2004 were heavier, smoked less during pregnancy and attended antenatal clinics more often and earlier than those of previous cohorts. However, pregnancy interruptions due either to caesarean sections or to inductions significantly increased. Caesareans increased from 28% in 1982 to 45% in 2004, and inductions were 2.5% in 1982 but 11.1% in 2004. The increase in preterms could be partially explained by the growing number of pregnancy interruptions, but there must be other causes since this increase was also observed among babies born by non-induced vaginal deliveries.

[Education and work in the Pelotas birth cohort from 1982 to 2004-5, Southern Brazil]

OBJECTIVE

To analyze the influence of biological and socioeconomic factors throughout life on entry into the university and insertion in the work force of young adults from the 1982 birth cohort.

METHODS

Longitudinal study of 5,914 births that took place in the city of Pelotas, Southern Brazil, in 1982. Data was collected by means of questionnaires applied on young adults when accompanying the 1982 cohort in 2004-5. Information was gathered concerning educational level and insertion in the labor market. Poisson Regression was utilized to study the effect of demographic and socioeconomic variables, as well as birth weight and maternal breastfeeding, on the outcomes.

RESULTS

On the average, these young adults had 9.4 (+/- 3.1) years of schooling and 42% of them were attending school in 2004-5. One in five young adults had entered a university and approximately two thirds were working during the month prior to the interview. Entry in the university was determined by economic conditions. Furthermore, women's birth weight and breastfeeding among men influenced this outcome. Insertion in the labor market was more frequent among the poorer men, but this did not affect women's outcomes in this respect.

CONCLUSIONS

The low inclusion in the university and the need to enter the labor market among the poor families maintains a vicious circle that reproduces the dominant social hierarchy.

[Smoking prevalence in the 1982 birth cohort: from adolescence to adult life, Pelotas, Southern Brazil]

OBJECTIVE

To assess smoking prevalence in adolescents and young adults of a population-based birth cohort.

METHODS

Prospective birth cohort study of infants born in 1982, in the city of Pelotas, Southern Brazil, and interviewed in 1997, 2000-2001 and 2005. In the 1997 and 2000-2001 follow-up visits, the outcome studied was smoking, defined as the consumption of at least one cigarette in the previous week. In the 2005 follow-up visit, the dependent variable was current smoking. Adjusted analysis was performed using Poisson regression.

RESULTS

Smoking prevalences among males were 5.9%, 20.2% and 27.6% in the 1997, 2000-2001 and 2005 follow-up visits, respectively. Among females, respective values were 9.3%, 27.5% and 23.6%. Mean age of smoking onset was 15.1 years (SD=2.5). In the multivariate analysis, lower maternal level of education, low income level in 1982, poverty during the follow-up period and maternal smoking were significantly associated with higher smoking prevalences in both sexes. Being non-white was associated with higher risk of smoking among females exclusively. Breastfeeding was not associated with smoking. Among females, smoking was inversely associated with birth weight in the crude analysis, but lost its significance in the adjusted analysis.

CONCLUSIONS

Higher incidence of smoking in poorer groups suggests that behavior such as avoiding smoking during pregnancy and increasing cigarette prices can have an important population impact.

[Early determinants of random blood glucose among adults of the 1982 birth cohort, Pelotas, Southern Brazil]

OBJECTIVE

To evaluate the effects of socioeconomic variables, birth weight, duration of breastfeeding and income changes on random blood glucose levels among young adults.

METHODS

This was a study on the birth cohort from 1982, when the 5,914 hospital births that occurred in the city of Pelotas (Southern Brazil) were identified and the mothers were interviewed. The children whose families lived in the urban area of the city were followed up several times. In 2004-5, 4,927 individuals of the cohort were interviewed and blood was collected from the fingertips of 3,730 of them for random blood glucose measurements. Associations between random blood glucose levels and skin color, family income at birth, maternal schooling, income change between 1982 and 2004-5, birth weight and duration of breastfeeding were evaluated.

RESULTS

The mean blood glucose level was 97.3 +/- 15.1mg/dL, and it was greater among the men. None of the variables studied was associated with the men's blood glucose level. Among the women, maternal schooling, family income at 23 years of age and birth weight were inversely associated with blood glucose levels. However, birth weight lost its statistical significance in the multivariable analysis.

CONCLUSIONS

Birth weight and duration of breastfeeding did not present any long-term effect on random blood glucose levels. Only maternal schooling level and present income presented associations with random blood glucose levels among the women.

Early life diarrhoea and later blood pressure in a developing country: the 1982 Pelotas (Brazil) birth cohort study

BACKGROUND

It has recently been hypothesised that acute dehydration in early childhood may "programme" increased blood pressure via salt retention. We examined whether there was an association between episodes of diarrhoea (a proxy for acute dehydration) and later measured blood pressure.

METHODS

In the 1982 Pelotas birth cohort study (Brazil), parents/carers reported hospital admissions for diarrhoea in the first 12 and 20 months of study members' lives. Blood pressure was subsequently measured directly in adolescence (aged 15, 18, 19 years) and early adulthood (aged 23 years).

RESULTS

We found no evidence of an association between diarrhoea in the first 12 months of life and blood pressure measured at any point in adolescence or early adulthood. These findings were unchanged after adjustment for a range of covariates. Equally null results were apparent when diarrhoea admissions in the first 20 months of life, access to home sanitation and use of piped water were the exposures of interest.

CONCLUSIONS

Early life proxies for dehydration and diarrhoea were unrelated to later blood pressure in this examination, the most comprehensive to date, of the potential association.

Two studies on suicidality in the postpartum

OBJECTIVE

Research in the prevalence of and risk factors for suicidality in the postpartum is extremely limited. We present here data on the prevalence of and factors associated with suicidality from two postpartum samples.

METHOD

The first sample (SC) comprised 317 women consecutively screened for a trial of psychotherapy for postpartum depression. The second sample was a population-based (PB) sample of 386 women. We used the Mini-International Neuropsychiatric Interview (MINI) to assess suicidality in the SC sample and the self-harm question of the Beck Depression Inventory (BDI9) in the PB sample.

RESULTS

According to the MINI and the BDI9, prevalence of high suicide risk was 5.7% and 11.1%, respectively, in the SC sample. Previous suicide attempts and a positive BDI were retained as predictors of suicidality. The BDI9 indicated suicidality in 8.3% of the 386 women in the PB sample; a positive BDI was retained in the multivariate analysis as a risk of suicidality.

CONCLUSION

Clinicians should enquire vigorously about suicidality in women presenting with depressive symptoms or previous suicide attempts in the postpartum.

Methods used in the 1982, 1993, and 2004 birth cohort studies from Pelotas, Rio Grande do Sul State, Brazil, and a description of the socioeconomic conditions of participants' families

Three birth cohorts are currently being followed in Pelotas, Southern Brazil, in order to assess changes in birth conditions, growth, development, morbidity, and infant mortality, as well as the influence of pre- and perinatal factors on the subsequent morbidity of participants in their adult lives. We provide a description of the methodology used for the cohort studies that began in 1982, 1993, and 2004 in Pelotas, and a description of the economic conditions of the families involved. For the three cohorts, similar strategies were used to recruit babies born to mothers living in the municipality's urban area. These included daily visits to maternity hospitals where births were identified, mothers interviewed, and newborns examined. Over this time frame, there has been a significant reduction in the number of births due to declining fertility rates amongst the target population. Salaries (measured as a multiple of the minimum wage) were stable across cohorts, but quality of life indicators - such as the availability of piped water, flushing toilets and refrigerators - showed clear improvements. Mothers' levels of education improved markedly. Important changes in the demographic profile of risk factors and health outcomes are being recorded by the Pelotas cohorts.

Breastfeeding and feeding patterns in three birth cohorts in Southern Brazil: trends and differentials

Breastfeeding is fundamental for child health. Changes in the duration of breastfeeding are compared for three population-based cohorts of children born in 1982, 1993 and 2004 in the city of Pelotas, Southern Brazil. Samples of the 1982 and 1993 children and all of the children from the 2004 cohort study were sought at home when they were aged around 12 months. Both the duration of breastfeeding and the stage at which different kind of foods were regularly introduced were investigated. The median duration of breastfeeding increased from 3.1 to 6.8 months in this period. Exclusive breastfeeding at three months was practically non-existent in 1982 and had reached one third of infants by 2004. The increase was faster after 1993, suggesting an important impact made by promotion activities. Up to about 6-9 months, breastfeeding was more prevalent in high-income families, but after this age it became more common among the poor. Low birth weight babies were breastfeed for shorter durations. The duration of breastfeeding is still far short of international recommendations, justifying further campaigns. Special attention should be given to low birth weight babies and those from low-income families.

Use of contraceptive methods by sexually active teenagers in Pelotas, Rio Grande do Sul State, Brazil

This study aimed to assess the prevalence of contraceptive use by adolescents. A cross-sectional study was performed from March to September 2002 in a representative sample of adolescents 15 to 18 years of age in the urban area of Pelotas, Rio Grande do Sul State, Brazil. Multiple-stage sampling was used, and in the 448 census tracts located in the urban area, 90 were sampled and households were visited in each tract. Information was collected on sexual initiation and use of contraceptive methods. Chi-square test was used to compare proportions. The sample included 960 adolescents. 88% of subjects reported the use of any contraceptive method. Condoms were the most commonly used method (63.2%). Low adolescent schooling was the only variable associated with increased risk of non-use of contraceptives. Condom use was higher among males, adolescents whose mothers had 9 or more years of schooling, and those reporting several sexual partners in the previous year. Condoms were the most commonly used contraceptive method.

Undernutrition in early life and body composition of adolescent males from a birth cohort study

The evidence for an association between poor nutrition in early life and subsequent obesity is inconclusive. In the present study, we investigated the associations between stunting, wasting and underweight at 2 and 4 years of age, and body composition in adolescence in male subjects studied since birth. The 1982 Pelotas Birth Cohort Study included all children born in maternity hospitals and living in the urban area of the city of Pelotas, Southern Brazil. All males born in 1982 were legally required to enlist in the army between January and April 2000. We were thus able to track 2250 subjects in 2000 (78.9% of the original cohort). Anthropometric measurements were collected in 1984 and 1986, and body composition was assessed in 2000. In the present analysis, we used as predictors the nutritional indices height-for-age, weight-for-height and weight-for-age presented in six categories. Outcomes included fat, lean and body mass indices and fat:lean mass ratio, derived from anthropometric and bioimpedance measurements. ANOVA and linear regression were used in the analyses to adjust for confounding. All predictors were positively associated with fat and body mass indices. Height-for-age Z score at age 2 or 4 years was not associated with lean mass index, but all other predictors were associated. Fat:lean mass ratio was associated only with weight-for-height Z score. Our results suggest that undernutrition is not a risk factor for overweight and obesity in our population and may partially protect against fatness in adolescence.

Prevalência de níveis pressóricos elevados em escolares de Cuiabá, Mato Grosso

OBJETIVO: As formas de obtenção dos níveis pressóricos basais podem levar a diferentes estimativas de prevalência. O objetivo do estudo foi estimar a prevalência de níveis pressóricos elevados em escolares e comparar médias sistólicas e diastólicas obtidas após três aferições da pressão arterial. MÉTODOS: Estudo transversal, com escolares entre sete e dez anos (N=601), de escolas públicas e privadas da zona urbana de Cuiabá-MT, Brasil, em 2005. A pressão arterial foi aferida três vezes, com intervalo de dez minutos, em visita única. Consideraram-se crianças com níveis pressóricos elevados as que, segundo sexo, idade e percentil de estatura, atingiram pressão sistólica e/ou diastólica maiores ou iguais ao percentil 95 da tabela de referência. Para o cálculo de prevalência, foram considerados separadamente os níveis pressóricos da primeira e terceira medidas. RESULTADOS: Houve diferença estatisticamente significante entre as médias sistólicas e diastólicas nas três medidas do estudo. A pressão sistólica e diastólica média, utilizando a terceira medida do estudo foi de 97,2 (DP=8,68) mmHg e 63,1 (DP=6,66) mmHg, respectivamente. A prevalência de níveis pressóricos elevados foi de 8,7% (IC 95%: 6,4;10,9) na primeira medida e 2,3% (IC 95%: 1,1;3,5) na 3ª medida. Não houve diferença estatística entre as prevalências com relação à idade, sexo, cor da pele e tipo de escola. CONCLUSÕES: A pressão arterial, em estudos de visita única, diminui significativamente entre a primeira e terceira aferição. A terceira medida parece revelar níveis pressóricos mais próximos dos basais.

Size at birth and blood pressure in early adolescence: a prospective birth cohort study

Previous studies have suggested that birth size may influence blood pressure in later life. Most of these reported inverse associations only became evident after weight or body mass index at some later age was included in the regression model. In a prospective birth cohort study in Brazil, the effect of birth size on blood pressure at age 11 years was explored. Of the 5,249 cohort members, 4,452 were interviewed. Mean systolic and diastolic blood pressures were 101.9 mmHg (standard deviation, 12.3) and 63.4 mmHg (standard deviation, 9.9), respectively. Birth weight was positively associated with blood pressure in the crude analysis, but this effect was no longer significant after adjustment for confounders. When current body mass index-a possible mediating variable-was added to the model, the association between birth weight and blood pressure tended to become negative, though not quite significant. Birth length showed a positive effect on later blood pressure regardless of the adjustments made. Head circumference, gestational age, and ponderal index were not associated with blood pressure. Children born small for gestational age had lower blood pressure values. The postulated inverse association between birth weight and later blood pressure was not confirmed in this cohort. Instead, a positive effect of birth length was detected.

Breast feeding and blood lipid concentrations in male Brazilian adolescents

OBJECTIVE

To assess the association between breast feeding and blood lipid levels in adolescence.

DESIGN

Population based prospective birth cohort study.

SETTING

City of Pelotas, Brazil.

SUBJECTS

All hospital births taking place in 1982; 79% of all males (n = 2250) were followed up for 18 years, and 2089 blood samples were available.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Total cholesterol and fractions (very low density lipoprotein cholesterol (VLDL), low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL)), LDL/HDL ratio, serum triglycerides.

RESULTS

Three breast feeding variables were studied: total duration of breast feeding, duration of exclusive or predominant breast feeding, and ever compared with never breast fed. Adjusted analyses were controlled for family income, household assets index, maternal education, maternal pre-pregnancy body mass index (BMI), skin colour, birth weight, gestational age, maternal smoking during pregnancy, and adolescent BMI, and behavioural variables (fat content of diet, physical activity, smoking, and alcohol drinking). Only one association reached borderline significance (p = 0.05): LDL cholesterol was slightly higher among never (mean 41.0 mg/dl; 95% CI 39.4 to 42.7) than among ever breast fed men (38.6 mg/dl; 95% CI 38.6 to 40.3), in the adjusted analyses. All other associations were not significant (p> or =0.09). There was no evidence of effect modification according to preterm status, intrauterine growth retardation, socioeconomic level, growth velocity in the first two years of life, or nutritional status at 2 years of age.

CONCLUSIONS

There was no clear association between breast feeding duration and serum lipid concentrations at the age of 18 years in this sample of Brazilian men.

[Breastfeeding duration in two generations]

OBJECTIVE

To assess the intergenerational repetition of breastfeeding duration in a cohort of adolescent mothers who had been prospectively followed up since birth.

METHODS

All hospital births occurred in Pelotas (N=5,914), a Southern Brazilian city, in 1982 were studied prospectively. The cohort was visited in 1984 and 1986, and information on feeding practices was gathered. In 2001, a search was conducted in the Live Birth Information System and adolescents born in 1982 who gave birth between January 1995 and March 2001 were identified. Parous adolescents answered a detailed questionnaire on pregnancy-related variables and breastfeeding duration for each child. For multiparous adolescents, the information from the first live born child was used. Poisson regression with robust adjustment of the variance was used in the univariate and multivariable analysis.

RESULTS

A total of 446 parous adolescents belonging to the 1982 cohort were identified, of which 420 (94.2%) were interviewed. After adjustment for confounding variables, mothers who had not been breastfed presented a relative risk of 1.34 (95% CI: 0.35; 5.18) of not breastfeeding their children, compared to mothers who were ever breastfed. Similarly, adolescents who were breastfed for less than one month were slightly - but not significantly - more likely to fail to breastfeed their own infants (RR=1.64; 95% CI: 0.70; 4.03). The proportion of adolescent mothers who breastfed for less than six months was higher among those who were themselves breastfed for less than one month (PR=1.29; 95% CI: 1.02; 1.62)].

CONCLUSIONS

Duration of breastfeeding is slightly higher among infants whose mother was breastfed.

Weight gain in childhood and body composition at 18 years of age in Brazilian males

AIM

To assess the association between weight gain at different time periods during childhood and measures of adiposity in late adolescence.

METHODS

A population-based birth cohort carried out in Pelotas, a 320 000-inhabitant city in a relatively developed area in Southern Brazil. All newborns in the city's hospitals were enrolled in 1982. Weight gain from 0-1, 1-2, 2-4 and 4-15 years were expressed as changes in weight-for-age Z-scores relative to the NCHS/WHO reference. In 2000, 79% (2250) of all males were located when enrolling at the national Army. Weight and height were assessed. Body composition indicators (fat mass/height(2), lean mass/height(2), fat mass/lean mass(2.3)) were estimated through bioimpedance. Analyses were adjusted for maternal and social factors, as well as for gestational age.

RESULTS

In the adjusted analyses, birthweight and weight gain in the first year of life were positively associated with attained height at age 18 years. Except for the fat mass/lean mass(2.3) ratio, all weight-related outcomes were positively associated with weight gain in different periods of life. Children who gained weight rapidly in more than one time period became fatter at age 18 years, independently of when fast growth took place.

CONCLUSIONS

Height was primarily determined by fetal and infant growth. Weight-related indices, including the fat/lean mass ratio, were more strongly influenced by later growth. No clear critical windows of growth during which absolute tissue masses are programmed could be identified.

Early determinants of smoking in adolescence: a prospective birth cohort study

In a prospective birth cohort study in Brazil, the prevalence and early risk factors for smoking in adolescence were investigated. All 1982 hospital-born children in Pelotas, Rio Grande do Sul, Brazil, were enrolled in a birth cohort study (N = 5,914; boys: 3,037; girls: 2,877). All male participants were searched in 2000 when enrolling in the national army, and 78.8% were traced. In 2001, a systematic sample of 473 girls was interviewed, representing a follow-up rate of 69.1%. Among males, 48.6% (95%CI: 46.6-50.7) had ever tried smoking and 15.8% (95%CI: 14.3-17.3) were daily smokers. Among females, 53.1% (95%CI: 48.6-57.6) had ever tried smoking and 15.4% (95%CI: 12.1-18.7) were daily smokers. Boys born to single mothers and those with fathers with low schooling were more likely to smoke in adolescence. Girls from low-income families, with mothers who smoked during pregnancy, and fathers with alcohol-related problems were more likely to smoke. Although the smoking prevalence was similar in boys and girls, risk factors for smoking were different between the sexes. Social environment appears to be the strongest predictor of tobacco use in adolescence.

Basic indicators of child health in an urban area in southern Brazil: estimating prevalence rates and evaluating differentials

OBJECTIVE

To evaluate and compare basic indicators of the health of children under 5 years old in the urban area of Rio Grande, RS, Brazil, for 1995 and 2004.

METHODS

Two cross-sectional population studies were carried out in the city. Interviewers were previously trained and applied standardized questionnaires during visits to families with children under 5 years old. The following variables were investigated: family income, maternal education, type of construction of home (wooden/masonry etc.), availability of toilet, running water, sewage system and domestic appliances. Data collected on the children themselves included number of antenatal consultations and age at first antenatal, type of delivery and medical care received during delivery, breastfeeding and dietary patterns, morbidity and health services utilization. Children were weighed and measured for height/length. Comparisons of frequencies between the two datasets were made using the chi-square test.

RESULTS

In 1995, 395 children were studied and in 2004 there were 384. During the intervening period improvements had taken place in type of construction, number of homes with flush toilet, the availability of running water and in breastfeeding pattern and duration. The frequency of diarrhea reduced, while rates of basic vaccination coverage, growth monitoring, patients in possession of their own medical cards and reporting of birth weights all increased. There was a deterioration in families' purchasing power and in the mean number of antenatal consultations. The prevalence of childhood obesity increased by 92%, while the incidence of malnutrition remained practically unchanged.

CONCLUSIONS

Comparing health indicators from the two periods revealed that, in addition to improvements in the majority of the indicators assessed, there had been a substantial increase in the prevalence of childhood obesity.

Effects of socioeconomic change from birth to early adulthood on height and overweight

BACKGROUND

In this work we explored the association of height and overweight with change in socioeconomic position between birth and 19 years of age.

METHODS

A birth cohort has been followed-up in Pelotas, Brazil, since 1982. All 5914 hospital births were enrolled in the study just after delivery. In 2001, 27% of the cohort subjects were sought, and 1031 (69% of the survivors) were interviewed. Weight and height were obtained for women; men had been examined 6 months earlier. Information on family income in 1982 and 2001 was used to classify the sample into tertiles, the lowest classified as 'poor' and the other two as 'non-poor'. Four trajectories resulted: always poor, never poor, poor at birth/non-poor at 19, and non-poor at birth/poor at 19-which were compared in terms of mean height and prevalence of overweight.

RESULTS

Height showed a similar behaviour for men and women, with the never poor presenting the highest mean, followed by those who were non-poor at birth and later became poor. Those who were poor at birth, regardless of later status, were shortest. Overweight was approximately twice as common among men who were never poor in relation to the others. Among women, those who were always poor presented the highest prevalence of overweight. In this case, social determination seems to be complex and may involve aspects of lifestyle and behaviour acting differently for each gender.

CONCLUSION

Socioeconomic trajectories affected both height and overweight, the effect on the latter being different for each gender.

Breastfeeding duration and blood pressure among Brazilian adolescents

OBJECTIVE

To assess the relationship between breastfeeding duration and blood pressure in a large birth cohort of Brazilians followed from birth to adolescence.

METHODS

All 5914 hospital births occurring in Pelotas in 1982 (over 99% of all deliveries) were studied prospectively. Detailed information on feeding practices was prospectively collected during childhood. In 1997 and 2001 we attempted to trace a sample of the cohort, whereas in 2000 we identified the male subjects when presenting for the army recruitment exam. Blood pressure measurements were taken in 1997 for both sexes, males in 2000 and females in 2001.

RESULTS

Information on breastfeeding collected between 1983 and 1986 was available for 90.8% of the 5914 original cohort subjects. We managed to follow 1076, 2250 and 1031 subjects in 1997, 2000 and 2001, respectively. Total breastfeeding duration was not associated with systolic and diastolic blood pressure in adolescence. Diastolic blood pressure at the age of 15 y (1997) was higher among girls who had been predominantly breastfed for at least 4 mo. After controlling for confounding variables (family income, maternal education at birth and maternal BMI at birth, skin colour, birthweight, gestational age, maternal smoking during pregnancy, adolescent smoking and alcohol drinking), the strength of the association was reduced and the 95% confidence interval encompassed the other blood pressure estimates. Furthermore, such association was not replicated in the 2001 follow-up visit.

CONCLUSION

Breastfeeding duration was not related to blood pressure in adolescence.

Is paternal postpartum depression associated with maternal postpartum depression? Population-based study in Brazil

OBJECTIVE

To describe the prevalence of paternal postpartum depression (PPD) as well as its association with maternal PPD.

METHOD

A population-based random sample of 386 couples was assessed from the sixth to the 12th week postpartum for demographic characteristics, alcohol misuse (AUDIT) and depressive symptoms [Beck Depression Inventory (BDI)]. Logistic regression was employed to control for potential confounders.

RESULTS

In the BDI, 26.3% of mothers and 11.9% of fathers scored above the selected threshold of 10. Mild maternal depression [odds ratio (OR) 3.31, 95% CI 1.52-7.20] and moderate to severe maternal depression (OR 8.44, 95% CI 3.53-20.21) were associated with paternal PPD.

CONCLUSION

Paternal PPD is a clinically meaningful phenomenon. Fathers should be evaluated for mood disorders in the postpartum, especially when their partner is depressed.

Early life factors are determinants of female height at age 19 years in a population-based birth cohort (Pelotas, Brazil)

The purpose of this study was to investigate the influence of biological and social background on height of adolescent girls at age 19 y in the city of Pelotas, Southern Brazil. In 2001, a sample of the urban census tracts was visited and adolescent girls who were part of the Pelotas 1982 Birth Cohort Study were located. Standardized questionnaires were administered to the adolescents and their mothers. Height was measured using locally manufactured stadiometers; standardized protocols were employed. The information obtained in 2001 was combined with data collected in earlier phases of the study. The follow-up rate was 69% and 473 girls were studied in 2001. Multiple linear regressions were used to analyze the determinants of height. The height of the 19-y-old adolescents was 161.2+/-6.3 cm. The significant determinants of height were family income, maternal pre-gestational weight, maternal height, smoking during pregnancy, birth weight, height gain, and age at menarche. Birth weight was a more important predictor than weight gain during infancy or height gain between the ages of 2 and 4 y. Each 100 g in birth weight was associated with an increase of approximately 0.2 cm in the adolescent's height (P=0.001). The current findings reinforce the importance of early life factors in the determination of adult height.

Breastfeeding and school achievement in Brazilian adolescents

AIM

To assess the effect of breastfeeding duration on school achievement in a Brazilian cohort.

METHODS

In a population-based birth cohort, we analysed the highest grade achieved in school of over 2,000 male 18-y-olds relative to breastfeeding information collected in early life. Analyses were adjusted for birthweight, family income, maternal and paternal schooling, household assets, number of siblings, social class, maternal smoking during pregnancy, and ethnicity.

RESULTS

After adjustment for confounding variables, there was a highly significant trend in school achievement with increasing breastfeeding duration. Those breastfed for 9 mo or more were ahead by 0.5-0.8 school grades, relative to those breastfed for less than 1 mo. Data from a cross-sectional survey in the same population suggest that such a difference corresponds to a 10-15% difference in adult income levels. The duration of exclusive or predominant breastfeeding was also positively associated with schooling.

CONCLUSION

Unlike studies from developed countries, there was no clear association between breastfeeding duration and either the family's socio-economic level or parental schooling in our sample and therefore residual confounding is improbable. These results suggest that the impact of breastfeeding on intellectual development may lead to sizeable differences in adult education and wage-earning performance.