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Introduction: Web-based epidemiologic surveys are being widely used, but still present lower response rates compared to traditional methods. Their design can influence survey response rates. Objective: Analyse the influence of questionnaire length, frequency of reminders, and the interaction between them, on the response rates of five web-based questionnaires. Methods: This is a 2×2 factorial study. Participants registered into the "coortesnaweb" platform (n=1,277) were randomly assigned to respond to short or long questionnaires, and to receive high or low frequency of reminders. We analysed the influence of these factors on the response rates of five web-based questionnaires applied in a longitudinal manner. The relative risk of responding to an additional questionnaire was also analysed. Results: The mean response rate was 54.3%. Sending reminders more frequently was positively associated with the response rates for the first questionnaires. Questionnaire length did not influence response rates. We found no interaction between questionnaire length and frequency of reminders. Women and highly educated participants had, respectively, 13.0% and 28.0% increased probability of responding an additional questionnaire. Conclusions: We obtained high response rates for the first questionnaires. Sending reminders more frequently and providing conditional incentives should be employed. Long questionnaires did not jeopardize response rates of web-based questionnaires.

Background: Many low- and middle-income countries have high levels of violence. Research in high-income countries shows that risk factors in the perinatal period are significant precursors of conduct problems which can develop into violence. It is not known whether the same early influences are important in lower income settings with higher rates of violence. This study compared perinatal and sociodemographic risk factors between Brazil and Britain, and their role in explaining higher rates of conduct problems and violence in Brazil. Methods: Prospective population-based birth cohort studies were conducted in Pelotas, Brazil (N = 3,618) and Avon, Britain (N = 4,103). Eleven perinatal and sociodemographic risk factors were measured in questionnaires completed by mothers during the perinatal period. Conduct problems were measured in questionnaires completed by mothers at age 11, and violence in self-report questionnaires completed by adolescents at age 18. Results: Conduct problems were predicted by similar risk factors in Brazil and Britain. Female violence was predicted by several of the same risk factors in both countries. However, male violence in Brazil was associated with only one risk factor, and several risk factor associations were weaker in Brazil than in Britain for both females and males. Almost 20% of the higher risk for conduct problems in Brazil compared to Britain was explained by differential exposure to risk factors. The percentage of the cross-national difference in violence explained by early risk factors was 15% for females and 8% for males. Conclusions: A nontrivial proportion of cross-national differences in antisocial behaviour are related to perinatal and sociodemographic conditions at the start of life. However, risk factor associations are weaker in Brazil than in Britain, and influences in other developmental periods are probably of particular importance for understanding male youth violence in Brazil.

The objective of this study is to examine the association between preterm infants' size at 1 year and attention-deficit/hyperactivity disorder (ADHD) assessed categorically and dimensionally in childhood and adolescence. We studied infants born < 37 weeks' gestation from two Brazilian birth cohorts (n = 653). ADHD was evaluated using the Development and Well-Being Assessment (DAWBA) interview at the age of 6 years in one cohort and by a structured interview according to DSM-5 criteria at 18 years in the other one. The presence of child attention difficulties was measured by the Strengths and Difficulties Questionnaire (SDQ) at 6 and 11 years in the 2004 and 1993 cohorts, respectively. We estimated associations of weight, length, head circumference, and BMI z-scores at 1-year chronological age with ADHD using Poisson Regression Model; and with attention difficulties using Linear Regression, adjusting for covariates. Mean birth weight was 2500 g and gestational age was 34.5 weeks. The aggregated ADHD prevalence in the two cohorts was 2.7%, and the median score for attention difficulties was 3.0. We found that increased head circumference at 1 year was associated with a lower risk of ADHD diagnosis (RR = 0.7, 95% CI 0.4, 0.9; p = 0.04 per standard deviation difference) and with fewer dimensional attention symptoms. In sensitivity analysis with other mental disorders, head circumference was associated with depression, but not with anxiety. Our findings emphasize poor head growth in the first year of life as a potential determinant of attentional difficulties in the preterm infant population. [ABSTRACT FROM AUTHOR]

Background: The study of gene-environment interactions (G by E) is one of the most promising strategies to uncover the origins of mental disorders. Replication of initial findings, however, is essential because there is a strong possibility of publication bias in the literature. In addition, there is a scarcity of research on the topic originated from low- and middle-income countries (LMIC). The aim of this study was to replicate G by E hypotheses for externalizing problems among adolescents in a middle-income country. Methods: As part of the Pelotas 1993 Birth Cohort Study, 5,249 children were enrolled at birth and followed up to the age of 15 years, with an 85.7% retention rate. We sought an interaction between the homozygosity of the 10-repeat allele at the dopamine transporter ("DAT1") gene and prenatal maternal smoking in the development of hyperactivity problems during adolescence assessed by the Strengths and Difficulties Questionnaire. We also tested for an interaction between the uVNTR polymorphism at the monoamine oxidase A ("MAOA") and the experience of childhood maltreatment in the occurrence of conduct problems among adolescent boys. Results: Although there was a clear association between prenatal maternal smoking and hyperactivity scores in adolescence ("p" less than 0.001), no main genetic or interaction effects for the "DAT1" gene were detected. Similarly, childhood maltreatment showed to be associated with conduct problems among boys ("p" less than 0.001), with no observable main genetic or interaction effects for the "MAOA" gene. Conclusions: In the largest mental health G by E study performed in a LMIC to date, we did not replicate previous positive findings from the literature. Despite the presence of main environmental effects, there was no evidence of effect modification by genotype status. Additional replication efforts to measure G by E are needed to better understand the origins of mental health and illness, especially in LMIC. (Contains 1 table and 2 figures.)

Estudo transversal de base populacional na Cidade de Pelotas, Sul do Brasil, entre 1999 e 2000, para descrever a distribuição de adiposidade abdominal na população de acordo com os níveis de interven��ão e identificar fatores de risco. O estudo incluiu uma amostra de 1.935 adultos (20-69 anos) residentes na zona urbana do município. Obesidade abdominal foi classificada como nível I para circunferência da cintura (CCnI) de 80-88cm em mulheres e de 94-102cm em homens; e nível II (CCnII) > 88cm para mulheres e > 102cm para homens. Apresentavam obesidade abdominal 62% das mulheres e 37% dos homens. Os valores de CCnI foram 23% e 19% e de CCnII 39% e 19%, para mulheres e homens, respectivamente. Após ajuste para fatores de confusão, o aumento da idade e estar casado ou vivendo em união, em homens e mulheres, mantiveram-se fortemente associadas com CCnII. Escolaridade manteve-se como fator de risco apenas para homens e renda familiar apenas para mulheres, nas quais, o efeito da renda manteve-se inversamente associado com a obesidade abdominal. A utilização da medida da CC deveria ser incorporada às ações de promoção à saúde, principalmente, no acompanhamento e monitoramento da população.

OBJETIVO: O melanoma tem incidência crescente, sendo que a prevalência dos tumores malignos epiteliais é alta, e o diagnóstico precoce contribui significativamente para a redução da morbimortalidade dessas doenças. O objetivo da pesquisa é medir a prevalência das lesões cutâneas pré-malignas e malignas e determinar a sensibilidade e a especificidade de um rastreamento para essas lesões. MÉTODOS: Foi realizado um estudo transversal de base populacional com escolha aleatória de 48 setores censitários da zona urbana de Pelotas, RS, Brasil. Um total de 2.112 domicílios foram visitados, sendo entrevistadas 1.292 pessoas de 50 anos de idade ou mais. O rastreamento possuía questões específicas sobre o surgimento de lesões de pele nos últimos seis meses e/ou a presença de lesões em áreas expostas. Os que responderam afirmativamente foram encaminhados ao exame médico. Também foi examinada uma subamostra daqueles que haviam respondido negativamente às questões do rastreamento. RESULTADOS: A prevalência corrigida das lesões cutâneas pré-malignas e malignas foi de 20,7%. A sensibilidade do rastreamento foi de 20,1%, a especificidade, de 86,9%, o valor preditivo positivo, de 29%, o valor preditivo negativo, de 80,4%, e acurácia, de 72,9%. Com diferentes pontos de corte, o valor máximo da sensibilidade atingiu 38,8%, e a especificidade não se alterou significativamente. CONCLUSÕES: O estudo demonstrou alta prevalência de lesões cutâneas pré-malignas e malignas em adultos. O rastreamento para essas lesões mostrou baixa sensibilidade e especificidade inferior ao desejado, independentemente dos pontos de corte.

INTRODUCTION: Although there was a considerable reduction in infant mortality in Pelotas, Rio Grande do Sul in the last decade, its perinatal causes were reduced only by 28%. The associated factors of these causes were analised. MATERIAL AND METHOD: All hospital births and perinatal deaths were assessed by daily visits to all the maternity hospitals in the city, throughout 1993 and including the first week of 1994. RESULTS: The perinatal mortality rate was 22.1 per thousand births. The multivariate analysis showed the following risk factors: low socioeconomic level, male sex and maternal age above 35 years . Among multigravidae women, the fetal mortality rate was significantly increased for mothers with a previously low birthweight and a previous stillbirth. For early neonatal mortality the risk was significantly increased by a smaller number of antenatal visits than 5 and low birthweight. CONCLUSIONS: Main risk factors for perinatal mortality: low socioeconomic level, maternal age above 35 years and male sex. For early neonatal mortality the risk was significantly increased by a smaller number of antenatal visits than 5 and low birthweight.

OBJETIVO: Avaliar as mudanças na prevalência de tabagismo durante a gravidez na cidade de Pelotas, RS, Brasil, com base nos estudos da população materno-infantil realizados nos anos de 1982 e 1993. METODOLOGIA: Estudo transversal, tendo sido identificados 6.011 e 5.304 recém-nascidos, cujas famílias residiam na área urbana da cidade de Pelotas, respectivamente em 1982 e 1993. RESULTADOS: O tabagismo materno durante a gestação apresentou uma discreta redução de 35,7%, em 1982, para 33,5% em 1993 (p < 0,05). O hábito de fumar esteve inversamente relacionado com a renda e o número de consultas no pré-natal.

A evolução da mortalidade perinatal foi estudada em Pelotas, Rio Grande do Sul, através de dois estudos de coorte realizados em 1982 e 1993. Todos os nascimentos hospitalares e os óbitos foram monitorizados com visitas diárias aos hospitais. A causa da morte foi determinada através de informações do prontuário, entrevista com o pediatra e de necrópsias. O coeficiente de mortalidade perinatal sofreu uma redução de 31% na década. O sub-registro que era de 42,1% em 1982, foi de apenas 6,8% em 1993. Dentre as causas de mortalidade perinatal, houve uma redução em 1993 de 58% para óbitos fetais antepartum, 47% para imaturidade e 62% para outras causas. Os coeficientes para asfixia sofreram um aumento de 4,5/1.000 para 8,3/1.000. As meninas apresentaram um coeficiente de mortalidade perinatal menor do que os meninos. Os coeficientes de mortalidade perinatal conforme peso ao nascer e renda familiar sofreram importantes reduções, sendo que a mais notável foi para crianças de baixo peso e de famílias de renda alta, com uma queda de 68%. Assim como em 1982, os recém-nascidos pré-termo tiveram coeficientes três vezes mais elevados do que crianças pequenas para a idade gestacional. Apesar da queda dos índices de mortalidade na década, as diferenças entre os grupos sociais mantiveram-se grandes.

Estudou-se a tendência temporal da mortalidade infantil através de dois estudos de coorte realizados em Pelotas, Rio Grande do Sul, em 1982 e 1993. Ambas coortes incluíram todos os nascimentos hospitalares e óbitos verificados através de visitas regulares aos hospitais, cartórios e cemitérios. As informações sobre a causa de morte foram obtidas através de entrevistas com pediatras, revisão do prontuário, necrópsias e entrevista com os pais das crianças. O coeficiente de mortalidade infantil caiu de 36,4 por mil nascidos vivos para 21,1 na década. As principais causas de mortalidade infantil em 1993 foram as perinatais, malformações congênitas, diarréia e infecções respiratórias. Crianças com baixo peso ao nascer apresentaram mortalidade 12 vezes maior do que crianças com peso adequado, e crianças pré-termo, duas vezes mais do que crianças com retardo de crescimento intra-uterino. Crianças de famílias com renda baixa (um salário mínimo) apresentaram mortalidade sete vezes superior àquelas com renda alta (10 salários mínimos). A mortalidade de crianças de baixo peso ao nascer e alta renda familiar decresceu em 67%, contra apenas 36% para as de baixa renda. Conclui-se que, mesmo com uma queda expressiva da mortalidade infantil na década, persistem importantes desigualdades sociais.