Bernardo Lessa Horta

What are the causal effects of breastfeeding on IQ, obesity and blood pressure? Evidence from comparing high-income with middle-income cohorts

Background A novel approach is explored for improving causal inference in observational studies by comparing cohorts from high-income with low- or middle-income countries (LMIC), where confounding structures differ. This is applied to assessing causal effects of breastfeeding on child blood pressure (BP), body mass index (BMI) and intelligence quotient (IQ). Methods Standardized approaches for assessing the confounding structure of breastfeeding by socio-economic position were applied to the British Avon Longitudinal Study of Parents and Children (ALSPAC) (Nu2009≃u20095000) and Brazilian Pelotas 1993 cohorts (Nu2009≃u20091000). This was used to improve causal inference regarding associations of breastfeeding with child BP, BMI and IQ. Analyses were extended to include results from a meta-analysis of five LMICs (Nu2009≃u200910u2009000) and compared with a randomized trial of breastfeeding promotion. Findings Although higher socio-economic position was strongly associated with breastfeeding in ALSPAC, there was little such patterning in Pelotas. In ALSPAC, breastfeeding was associated with lower BP, lower BMI and higher IQ, adjusted for confounders, but in the directions expected if due to socioeconomic patterning. In contrast, in Pelotas, breastfeeding was not strongly associated with BP or BMI but was associated with higher IQ. Differences in associations observed between ALSPAC and the LMIC meta-analysis were in line with those observed between ALSPAC and Pelotas, but with robust evidence of heterogeneity detected between ALSPAC and the LMIC meta-analysis associations. Trial data supported the conclusions inferred by the cross-cohort comparisons, which provided evidence for causal effects on IQ but not for BP or BMI. Conclusion While reported associations of breastfeeding with child BP and BMI are likely to reflect residual confounding, breastfeeding may have causal effects on IQ. Comparing associations between populations with differing confounding structures can be used to improve causal inference in observational studies.

Anthropometry and body composition of 18 year old men according to duration of breast feeding: birth cohort study from Brazil

Abstract Objective To assess the association between duration of breast feeding and measures of adiposity in adolescence. Design Population based birth cohort study. Setting Pelotas, a city of 320 000 inhabitants in a relatively developed area in southern Brazil. Participants All newborn infants in the citys hospitals were enrolled in 1982; 78.8% (2250) of all male participants were located at age 18 years when enrolling in the national army. Main outcome measures Weight, height, sitting height, subscapular and triceps skinfolds, and body composition (body fat, lean mass). Results Neither the duration of total breast feeding nor that of predominant breast feeding (breast milk plus non-nutritive fluids) showed consistent associations with anthropometric or body composition indices. After adjustment for confounding factors, the only significant associations were a greater than 50% reduction in obesity among participants breast fed for three to five months compared with all other breastfeeding categories (P = 0.007) and a linear decreasing trend in obesity with increasing duration of predominant breast feeding (P = 0.03). Similar significant effects were not observed for other measures of adiposity. Borderline direct associations also occurred between total duration of breast feeding and adult height (P = 0.06). Conclusions The significant reduction in obesity among children breast fed for three to five months is difficult to interpret, as no a priori hypothesis existed regarding a protective effect of intermediate duration of breast feeding. The findings indicate that, in this population, breast feeding has no marked protective effect against adolescent adiposity.

Prevalência da depressão pós-parto e fatores associados

OBJETIVO: Avaliar a prevalencia e os fatores associados a depressao pos-parto. METODOS: O estudo foi realizado na cidade de Pelotas, entre outubro e novembro de 2000. As maes (n=410) foram entrevistadas no hospital, utilizando dois questionarios sobre informacoes obstetricas e psicossociais. Posteriormente, as puerperas foram visitadas em casa, entre 30 a 45 dias depois do parto, quando foi aplicada a Escala de Hamilton com o objetivo de medir e caracterizar a presenca de sintomas depressivos. O teste do qui-quadrado foi utilizado na comparacao entre proporcoes e a regressao logistica nao condicional, na analise multivariada. Os dados foram analisados hierarquicamente: no primeiro nivel as variaveis socioeconomicas, no segundo, as variaveis demograficas, no terceiro, estavam as variaveis obstetricas e no ultimo nivel, as variaveis psicossociais. RESULTADOS: A prevalencia de depressao pos-parto encontrada foi de 19,1%. As variaveis renda familiar (OR=5,24; IC 95%: 2,00-13,69), preferencia pelo sexo da crianca (meninos: OR=3,49; IC 95%: 1,76-6,93) e pensar em interromper a gestacao (OR=2,52; IC 95%: 1,33-4,76), apresentaram associacao com a ocorrencia de depressao. CONCLUSOES: Os achados sugerem que baixas condicoes socioeconomicas de vida da puerpera e a nao aceitacao da gravidez sao elementos-chave no desenvolvimento da depressao pos-parto.

Prevalência e fatores associados ao sedentarismo em adolescentes de área urbana

OBJETIVO: Determinar a prevalencia e fatores associados ao sedentarismo em adolescentes residentes em uma area urbana. METODOS: Realizou-se estudo transversal em uma amostra representativa de 960 adolescentes com idades entre 15 e 18 anos, em 2002, em Pelotas, Estado do Rio Grande do Sul. Os dados foram coletados por meio de um questionario anonimo e auto-aplicado. Foi definindo como sedentario o adolescente que participava de atividades fisicas por um tempo menor do que 20 minutos diarios e uma frequencia menor do que tres vezes por semana. Variaveis sociodemograficas e comportamentais foram avaliadas. Para as comparacoes entre proporcoes, utilizou-se o teste do qui-quadrado, e para a analise multivariada, a regressao de Poisson com ajuste robusto para as variâncias. Foi feito controle para efeito de delineamento. RESULTADOS: Foram entrevistados 960 adolescentes, dos quais 39% foram considerados sedentarios. As meninas foram mais sedentarias do que os meninos, 2,45 (IC 95% 2,06-2,92). Os adolescentes das classes sociais mais baixas foram mais sedentarios, 1,35 (IC 95% 1,06-1,72). Escolaridade inferior a quatro anos de estudo do adolescente 1,30 (IC 95% 1,01-1,68) e da mae 1,75 (IC 95% 1,31-2,23) apresentaram maior risco para o sedentarismo. Apos controle para possiveis fatores de confusao, mostrou-se tambem positiva a associacao entre o sedentarismo e a presenca de transtornos psiquiatricos menores e relacao inversa, fator de protecao para os sexualmente ativos 0,84 (IC 95% 0,71-0,99). CONCLUSOES: Ser do sexo feminino, pertencer a classe social baixa, ter uma baixa escolaridade e ser filho de mae com baixa escolaridade sao fatores associados ao sedentarismo.

Prevalência e fatores associados ao sobrepeso e à obesidade em adolescentes

OBJETIVO: Determinar a prevalencia e os fatores associados ao sobrepeso e a obesidade em adolescentes de zona urbana. METODOS: Estudo transversal de base populacional, realizado no municipio de Pelotas, Rio Grande do Sul, de 2001 a 2002. Adolescentes entre 15 e 18 anos de idade foram medidos, pesados e responderam a questionario auto-aplicavel. De 90 setores sorteados, foram visitados 86 domicilios em cada setor, totalizando 960 adolescentes. A prevalencia de sobrepeso e obesidade foi definida a partir do indice de massa corporal, mediante a utilizacao dos pontos de corte, ajustados a idade e ao sexo. Realizou-se analise multivariada com regressao de Poisson, considerando um modelo hierarquico das variaveis associadas ao sobrepeso e a obesidade. RESULTADOS: A prevalencia de sobrepeso e de obesidade foi 20,9% e 5%, respectivamente. A relacao entre a obesidade e idade e escolaridade do adolescente foi inversa. Verificou-se associacao de sobrepeso e obesidade com o relato de obesidade dos pais (p=0,03) e maturacao sexual do adolescente (p=0,01). Os habitos de fazer dieta e omitir refeicoes foram associados a obesidade, com riscos de 3,98 (IC 95%: 1,83-8,67) e 2,54 (IC 95%: 1,22-5,29), respectivamente. CONCLUSOES: A prevalencia de sobrepeso e obesidade na regiao sao preocupantes a despeito do comportamento dos adolescentes para prevenir a obesidade. E necessaria a implantacao de campanhas mais eficazes, direcionadas a orientar melhor os adolescentes.OBJECTIVEnTo assess the prevalence and factors associated to overweight and obesity in urban area adolescents.nnnMETHODSnA cross-sectional population-based study was carried out in the municipality of Pelotas, Southern Brazil, between 2001 and 2002. Adolescents between 15 and 18 years old were weighed, measured and asked to complete a self-administered questionnaire. Of 90 areas drawn, 86 dwellings were visited in each area, comprising a total of 960 adolescents interviewed. Overweight and obesity prevalences were defined based on the body mass index, according to cutoff values and adjusted to age and sex. Multivariate analysis with Poisson regression was performed using a hierarchical model of variables associated to overweight and obesity.nnnRESULTSnOverweight and obesity prevalences were 20.94% and 5% respectively. There was found an inverse relationship between obesity and age and schooling. An association of overweight and obesity with reporting parents obesity (p=0.03) and adolescents sexual maturation (p=0.01) was seen. Dieting and skipping meals were associated to obesity with a risk of 3.98 (95% CI: 1.83-8.67) and 2.54 (95% CI: 1.22-5.29) respectively.nnnCONCLUSIONSnOverweight and obesity prevalences in the area studied are of concern despite adolescents behaviors to prevent to obesity. There is a need to implement more effective campaigns to provide better guidance to adolescents.

Early and late growth and blood pressure in adolescence

Objective: To assess the effect of growth during infancy and childhood on blood pressure in adolescence. Design: Birth cohort study. Setting: Pelotas, southern Brazil. Participants: 749 adolescents with complete information on birth weight and gestational age, as well as on anthropometric data at all three follow up visits (mean age 20 months, 42 months, and 15 years). Main outcome measurements: Systolic and diastolic blood pressure at adolescence. Results: After controlling for possible confounding variables, birth weight was negatively associated with systolic blood pressure, one unit increase in standard deviation score of birth weight for gestational age was associated with a decrease of 1.23 mm Hg (95% confidence intervals −2.03 to −0.43) in systolic blood pressure. Weight for age z score at the age of 15 years showed a strong positive association with systolic blood pressure, one unit increase in standard deviation score of birth weight for gestational age was associated with an increase of 4.4 mm Hg (95% confidence intervals 3.50 to 5.3). Diastolic blood pressure was not associated with birth weight. For adequate for gestational age infants, the positive association between weight in adolescence and blood pressure became stronger when previous weights were added to the model. Conclusion: This study showed that early—as well as—late catch up growth is associated with increased systolic blood pressure in adolescence, whereas only late catch up is related with diastolic blood pressure. These findings suggest that catch up growth, irrespective of age, is associated with increased blood pressure in adolescence.

Relação entre bem-estar espiritual e transtornos psiquiátricos menores: estudo transversal

OBJECTIVEnTo assess the influence of spiritual well-being in mental health of college students.nnnMETHODSnIt was interviewed 464 medical and law students of Pelotas, Brazil. Data collection was carried out in groups in the school classroom, 43 absent students were not interviewed and represented a loss of 9.3% of the sample. It was used a self-reported questionnaire with three instruments: 1) Spiritual Well-Being Scale (SWBS), 2) SRQ-20, and 3) a precoded questionnaire with questions on sociodemographic data, religious/spiritual practices, and stressful life events. Statistical analysis was performed using Chi-square test and logistic regression.nnnRESULTSnMost of the students (80%) declared that they had a spiritual belief and/or religious denomination. The mean score of spiritual well-being was 90.4 with scores 45.6 and 45.1 in the existential and religious subscales, respectively. SWBS showed an association with religious practices, but it was not influenced by sociodemographic and cultural variables. Subjects presenting low and moderate spiritual well-being showed a doubled risk of presenting minor psychiatric disorders (MPD) (OR=0.42; 95%CI: 0.22-0.85). Subjects presenting low or moderate existential well-being showed almost five times more MPD (OR=0.19; 95%CI: 0.08-0.45).nnnCONCLUSIONSnThe study reveals spiritual well-being as a protection factor for minor psychiatric disorders, and that the results were mostly due to the Existential Well-Being subscale.

Tabagismo em adolescentes de área urbana na região Sul do Brasil

OBJECTIVE: To evaluate the prevalence of tobacco smoking and its determinants among adolescents. METHODS: A cross-sectional study, using a multiple stage sampling, was carried out in 1997 and a sample of adolescents aged between 12 and 18 years who were living in the urban area of Pelotas, Brazil, was studied. Those who reported having smoked at least one cigarette per week during the last month were considered smokers. Chi-square test was used to compare proportions and conditional logistic regression was applied in the multivariate analysis. RESULTS/ CONCLUSIONS: Six hundred and thirty-two adolescents were interviewed, among which 38 were non-respondents. Of those interviewed, 11.1% were smokers at time of the study, 6.8% were former smokers and 82.1% had never smoked. Prevalence of tobacco smoking was directly related to the age. Even after adjusting for confounding factors, those who had left or failed at school, their parents were divorced or reported alcohol abuse in the last month showed a higher odds ratio for smoking.OBJECTIVEnTo evaluate the prevalence of tobacco smoking and its determinants among adolescents.nnnMETHODSnA cross-sectional study, using a multiple stage sampling, was carried out in 1997 and a sample of adolescents aged between 12 and 18 years who were living in the urban area of Pelotas, Brazil, was studied. Those who reported having smoked at least one cigarette per week during the last month were considered smokers. Chi-square test was used to compare proportions and conditional logistic regression was applied in the multivariate analysis. RESULTS/ CONCLUSIONS: Six hundred and thirty-two adolescents were interviewed, among which 38 were non-respondents. Of those interviewed, 11.1% were smokers at time of the study, 6.8% were former smokers and 82.1% had never smoked. Prevalence of tobacco smoking was directly related to the age. Even after adjusting for confounding factors, those who had left or failed at school, their parents were divorced or reported alcohol abuse in the last month showed a higher odds ratio for smoking.

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.

Fatores associados à não realização de exame citopatológico de colo uterino no extremo Sul do Brasil

Early detection of cervical cancer substantially increases the probability of cure. The aim of this study was to determine the prevalence and factors associated with non-participation in cervical cancer screening among women 15 to 49 years of age in Rio Grande, Southern Brazil. A representative survey was carried out using a systematic sample based on a census tract. Trained interviewers used standard, individualized, household questionnaires to interview the women. Data analysis used logistic regression according to a previously determined hierarchical framework. Among 1,302 women interviewed, 57% had never had a Pap smear. The risk factors most closely associated with non-participation in screening were black or brown skin color, young age, low family income, low schooling, living alone, and first childbirth after 25 years of age. Coverage for early detection of cervical cancer was very low. In addition, women at high risk of developing cervical cancer were shown to have a significantly higher risk of non-participation in this type of screening.A identificacao precoce do câncer de colo uterino aumenta substancialmente a sua probabilidade de cura. Este estudo mediu a prevalencia e identificou alguns fatores associados a nao realizacao de exame citopatologico de colo uterino entre mulheres em idade fertil, no Municipio de Rio Grande, Rio Grande do Sul, Brasil. Utilizou-se delineamento transversal, de base populacional com amostragem sistematica por conglomerados. Aplicou-se questionario individual, padronizado mediante visita domiciliar, por entrevistadores previamente treinados. Os dados foram analisados por regressao logistica obedecendo a modelo hierarquico previamente determinado. Dentre as 1.302 mulheres entrevistadas, 57% nunca se submeteram ao exame citopatologico para deteccao de câncer uterino. Mulheres de cor parda ou preta, de menor idade, renda familiar e escolaridade, que estavam vivendo sem companheiros e que tiveram o primeiro parto com 25 anos ou mais de idade foram as que apresentaram as maiores razoes de prevalencias para a nao realizacao deste tipo de exame. A cobertura para deteccao precoce de câncer de colo uterino por meio de exame citopatologico foi muito baixa em Rio Grande. Alem disso, mulheres com maior probabilidade de ter esta doenca foram as que apresentaram maiores razoes de prevalencias a sua nao realizacao.