Cora Luiza Araújo

Gender differences in leisure-time physical activity

Summary.Objectives:To explore the association between gender and leisure-time physical activity in a population-based sample of adults living in Brazil. To study a variety of variables possibly associated with physical activity levels.Methods:A multistage sampling of households was undertaken in Pelotas, a medium-sized Southern Brazilian city. Leisure-time physical activity was measured using the long version of the International Physical Activity Questionnaire. Data on potential predictors of leisure-time physical activity behavior were collected using a standardized questionnaire. 1 344 men and 1 756 women were interviewed. Several definitions of moderate and vigorous-intensity physical activity were used.Results:Regardless of the guideline used, males were more active than women. Socioeconomic level was positively associated with leisure-time physical activity in both genders. A positive dose-response between age and inactivity was found in men, but not among women.Conclusions:Because men and women have different levels of physical activity, and the variables associated with activity levels are not consistent across the genders, interventions promoting physical activity should take these differences into account.Zusammenfassung.Geschlechterbedingte Unterschiede bei körperlichen Aktivitäten in der FreizeitZiel:Die Beziehung zwischen Geschlecht und körperlichen Freizeitktivitäten in einer bevölkerungsbasierten Stichprobe von in Brasilien lebenden Erwachsenen zu untersuchen.Methoden:Ein mehrstufiges Sampling von Haushalten wurde in Pelotas durchgeführt, einer mittelgrossen südbrasilianischen Stadt. Körperliche Freizeitaktivitäten wurden anhand der Langversion des Fragebogens zur Erhebung gesundheitsrelevanter körperlicher Aktivität (IPAC) gemessen. Daten zu potentiellen Prädiktoren des Verhaltens im Bereich der körperlichen Freizeitaktivitäten wurden mittels eines standardisierten Frage-bogens erhoben. Es wurden 1 344 Männer und 1 756 Frauen befragt. Verschiedene Definitionen körperlicher Aktivität von moderater bzw. starker Intensität kamen zur Anwendung.Ergebnisse:Unabhängig der verwendeten Richtlinien waren Männer aktiver als Frauen. Der sozioökonomische Status war negativ assoziiert mit körperlichen Freizeitaktivitäten bei beiden Geschlechtern. Eine positive Dosis-Wirkungs-Beziehung zwischen Alter und Inaktivität konnte bei Männern festgestellt werden, jedoch nicht bei Frauen.Schlussfolgerungen:Da Männer und Frauen ein unterschiedliches Mass an körperlicher Aktivität aufweisen und die Variablen, die mit körperlicher Betätigung assoziiert sind, zwischen den Geschlechtern nicht einheitlich sind, sollten Interventionen zur Förderung körperlicher Aktivität diese Unterschiede berücksichtigen.Résumé.Pratique de l’activité physique durant les loisirsdifférences entre les sexesObjectifs:Etudier l’association entre le genre et la pratique de l’activité physique durant les loisirs dans un échantillon populationnel d’adultes vivant au Brésil. Etudier différentes variables qui pourraient être associées avec les niveaux d’activité physique.Méthodes:Un échantillonnage en grappe des ménages a été effectué à Pelotas, un ville de taille moyenne au sud du Brésil. L’activité physique pratiquée durant les loisirs a été mesurée au moyen de la version longue du «Questionnaire International d’Activité Physique». Les variables prédictrices de la pratique de l’activité physique durant les loisirs ont été collectées au moyen d’un questionnaire standardisé. 1 344 hommes et 1 756 femmes ont été interviewés. Diverses définitions actuelles des niveaux d’activité physique recommandés (modérée/intense) ont été utilisées.Résultats:Indépendamment des recommandations utilisées comme critères, les hommes étaient plus actifs que les femmes. Le niveau socio-économique était associé négativement avec la pratique d’une activité physique pendant les loisirs pour les deux sexes. Une dose-réponse positive entre l’âge et la sédentarité a été identifiée chez les hommes mais pas chez les femmes.Conclusions:Les hommes et les femmes ont des niveaux de pratique de l’activité physique différents. Les variables associées à cette pratique varient également entre les sexes. Les interventions de promotion de l’activité physique devraient donc tenir compte de ces spécificités.

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) (N ≃ 5000) and Brazilian Pelotas 1993 cohorts (N ≃ 1000). 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 (N ≃ 10 000) 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.

Sleep patterns and television viewing in relation to obesity and blood pressure: evidence from an adolescent Brazilian birth cohort.

Background:Disruption of circadian rhythms has been associated with obesity in children and adolescents, and with hypertension in adults, in industrialized populations.Objective:We examined cross-sectional associations between sleep duration or television viewing and obesity and blood pressure in Brazilian adolescents.Design:The sample consisted of 4452 adolescents aged 10–12 years participating in a prospective birth cohort study in Pelotas, Brazil. Sleep duration and television viewing were determined through questionnaires. Obesity was assessed using international cut-offs for body mass index (BMI), and body fatness by skinfold thicknesses. Blood pressure was measured using a validated monitor.Results:Short sleep duration was associated with increased BMI, skinfolds, systolic blood pressure, activity levels and television viewing. Each hour of sleep reduced BMI by 0.16 kg/m2 (s.e. 0.04), and was associated with odds ratio for obesity of 0.86 (s.e. 0.04), both P<0.001. Television viewing was associated with increased BMI and skinfolds, and increased blood pressure. The effects of sleep duration and television viewing on obesity were independent of one another. Their associations with blood pressure were mediated by body fatness.Conclusions:Both short sleep duration and increased television viewing were associated with greater body fatness, obesity and higher blood pressure, independently of physical activity level. These associations were independent of maternal BMI, identified in other studies as the strongest predictor of childhood obesity. Our study shows that behavioural factors associated with metabolic risk in industrialized populations exert similar deleterious effects in a population undergoing nutritional transition and suggest options for public health interventions.

Methodological aspects of the 1993 Pelotas (Brazil) birth cohort study

This paper describes the main methodological aspects of a cohort study, with emphasis on its recent phases, which may be relevant to investigators planning to carry out similar studies. In 1993, a population based study was launched in Pelotas, Southern Brazil. All 5,249 newborns delivered in the citys hospitals were enrolled, and sub-samples were visited at the ages of one, three and six months and of one and four years. In 2004-5 it was possible to trace 87.5% of the cohort at the age of 10-12 years. Sub-studies are addressing issues related to oral health, psychological development and mental health, body composition, and ethnography. Birth cohort studies are essential for investigating the early determinants of adult disease and nutritional status, yet few such studies are available from low and middle-income countries where these determinants may differ from those documented in more developed settings.

Fatores socioculturais e nível de atividade física no início da adolescência

OBJETIVO: Descrever o nivel de atividade fisica de adolescentes nascidos em 1993 em Pelotas (Brasil) e avaliar o efeito de variaveis socioculturais sobre o nivel de atividade fisica. METODOS: Utilizamos uma combinacao de duas abordagens metodologicas, a epidemiologica e a etnografica. No estudo epidemiologico, 4 452 adolescentes nascidos em 1993 foram entrevistados. O nivel de atividade fisica foi avaliado atraves de questionario. Foram classificados como sedentarios os adolescentes com menos de 300 minutos por semana de atividade fisica. O estudo etnografico incluiu 69 adolescentes, selecionados aleatoriamente entre todos os participantes da coorte. Foram realizadas, em media, tres entrevistas aprofundadas (uma a cada 6 meses), separadamente com as maes e os adolescentes. RESULTADOS: A prevalencia de sedentarismo foi de 48,7% (IC95%: 46,5 a 50,8) nos meninos e 67,5% (IC95%: 65,6 a 69,5) nas meninas (P < 0,001). A variavel independente que apresentou a associacao mais forte com o nivel de atividade fisica foi o numero de vezes por semana que o adolescente encontrava amigos fora do ambiente escolar. O estudo etnografico mostrou que os meninos tem mais apoio social e familiar para a realizacao de atividades fisicas na adolescencia e que muitos pais atribuem o mau desempenho escolar ao tempo gasto na rua. CONCLUSOES: Este estudo sugere que a atividade fisica e muitas vezes considerada como concorrente dos valores familiares na adolescencia. E importante que essa nocao seja foco de estudos adicionais e que seja trabalhada junto as familias para que a atividade fisica possa ser adotada como um habito cultural.

Prevalência de sobrepeso em adolescentes: um estudo de base populacional em uma cidade no Sul do Brasil

The prevalence of overweight and its association with demographic, socioeconomic, behavioral, and biological variables were evaluated. The sample included 810 adolescents (10-19 years of age) living in the urban area of Pelotas, a southern Brazilian city. Overweight was defined as a body mass index >= the 85th percentile, according to sex and age, and compared to the First National Health and Nutrition Examination Survey, following the WHO recommendation for adolescents. A clustering sampling strategy was used, and both the crude and adjusted analyses (Poisson Regression) took this strategy into account. The prevalence of overweight was 19.3% (95%CI: 16.6-22.0) and there was no difference between the sexes. The following groups presented a greater probability of being overweight: those classified in the wealthiest socioeconomic groups, those who had dieted to lose weight within the previous 3 months, those who watch 4 or more hours of television per day, and those who have less than 3 regular meals per day. After stratification by gender, high socioeconomic level was associated with greatest risk of overweight among boys. Dieting to lose weight during the previous 3 months, 4 or more hours of television viewing per day, and less than 3 formal meals per day were risk factors for overweight among girls.

Breastfeeding and overweight in childhood: evidence from the Pelotas 1993 birth cohort study.

Objectives:The effect of breastfeeding duration on the prevalence of overweight and on mean weight for height z-score (WHZ) was evaluated in Brazilian children.Design:Prospective population-based birth cohort study.Subjects:In total, 1273 children aged 4 years, corresponding to a follow-up rate of 87.2%.Measurements:Three explanatory variables were studied: duration of any breastfeeding, duration of exclusive or predominant breastfeeding, and ever breastfeeding. Weight and height were measured using a digital electronic scale and a portable stadiometer. Overweight was defined as WHZ >2 using the National Center for Health Statistics reference curve.Results:Overweight prevalence at the age of 4 years was 10.2% (95% CI 8.4; 11.8). The lowest prevalence (6.5%) was observed among children breastfed for >11 months. Among those breastfed for less than 3 months, the prevalence of overweight was approximately 9.5%. Mean WHZ ranged from 0.38 among children breastfed for less than 1 month to 0.62 among those breastfed for 9–11.9 months. No linear trends were detected in the association between breastfeeding and anthropometric indicators. None of the three breastfeeding variables was significantly associated with the prevalence of overweight or mean WHZ in multivariable analyses. No interactions were detected between breastfeeding and the variables sex, birth weight, socioeconomic status, skin color and pregestational in body mass index.Conclusion:Our results do not support the hypothesis that breastfeeding promotion would reduce overweight or obesity in this population. Existing evidence on many other benefits of breastfeeding for the mother and the child supports its continued promotion, protection and support.

Conhecimento e percepção sobre exercício físico em uma população adulta urbana do sul do Brasil

This study evaluates perception and knowledge of physical exercise in an urban adult population and relates knowledge level to behavioral, demographic, and socioeconomic factors, using a cross-sectional, population-based approach with 3,182 participants aged 20 or older. The questionnaire originated a score (range 0-25 points). Mean score for the sample was 17.1 (SD=4.0). After adjustment, female gender, age 30 to 40 years, higher social strata, and schooling were strongly associated (p<0.001) with the outcome (knowledge). Weaker associations (p< or =0.01) were observed between the score and higher body mass index, level of physical activity, and white skin color. Based on the results, specific benefits from exercising are still unknown to some population groups. Counseling by teachers on the advantages of an active lifestyle is still not common practice.

Toothache prevalence and associated factors: a life course study from birth to age 12 yr

This study estimated the lifetime prevalence of toothache at ages 6 and 12 yr, the prevalence of toothache during the last month, and their association with social, behavioural and clinical exposures in the course of life of 339 12-yr-old children from a birth cohort in Pelotas, Brazil. Exploratory variables were collected in the perinatal study and during several follow-up studies. Prevalence ratios were calculated using Poisson regression, following a hierarchical conceptual model. The lifetime prevalence of toothache at ages 6 and 12 yr were 39% [95% confidence interval (CI) = (34;45)] and 63% [95% CI = (58;69)], respectively. Toothache during the last month was reported by 11% [95% CI = (8;15)]. Children who did not live with their biological father at birth, and children with higher dmf-t counts, reported a higher lifetime prevalence of toothache at age 6 yr. Children experiencing poverty between ages 0 and 4 yr, with higher dmf-t and DMF-T indexes presented a greater lifetime prevalence of toothache at 12 yr. Toothache within the last month was more likely to be reported by girls and by children who did not live with their biological father at birth. Preventive strategies should be implemented in early stages of the life cycle, taking into account the socio-economic and family context in which pain mostly occurs.

O Mestrado do Programa de Pós-graduação em Epidemiologia da UFPel baseado em consórcio de pesquisa: uma experiência inovadora

O Programa de Pos-graduacao em Epidemiologia da UFPel realizou um intenso trabalho de auto-avaliacao para resolver problemas identificados com seu curso de mestrado. O resultado foi a introducao de uma estrutura curricular baseada em dois pilares. De um lado, disciplinas de cunho teorico, fornecendo a base da formacao do mestrando; de outro, disciplinas de cunho pratico, onde os alunos trabalham coletivamente a construcao de seu projeto de pesquisa, passando pela escolha de um tema, revisao da literatura, definicao de objetivos e da metodologia. Esse esforco conjunto culmina na realizacao de um trabalho de campo unico, na forma de um estudo transversal de base populacional, em que todos os mestrandos participam de maneira integral, obtendo dados para sua dissertacao. Essa estrategia tem garantido a formacao de mestres em epidemiologia com forte base teorica e com experiencia de preparacao e conducao de um trabalho de campo. Alem disso, tem sido possivel manter um tempo de titulacao abaixo de 24 meses. Cerca de 80% dos egressos tem publicado pelo menos um artigo baseado em seu mestrado. Destas publicacoes, quase 90% tem se dado em periodicos classificados como Internacional-A no Qualis da Capes.