Pedro Hallal

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.

Cohort profile update: The 1993 Pelotas (Brazil) Birth Cohort follow-up visits in adolescence.

In this paper we update the profile of the 1993 Pelotas (Brazil) Birth Cohort Study, with emphasis on a shift of priority from maternal and child health research topics to four main categories of outcome variables, collected throughout adolescence: (i) mental health; (ii) body composition; (iii) risk factors for non-communicable diseases (NCDs); (iv) human capital. We were able to trace 81.3% (n = 4106) of the original cohort at 18 years of age. For the first time, the 18-years visit took place entirely on the university premises, in a clinic equipped with state-of-the-art equipment for the assessment of body composition. We welcome requests for data analyses from outside scientists. For more information, refer to our website (http://www.epidemio-ufpel.org.projetos_de_pesquisas/estudos/coorte_1993) or e-mail the corresponding author.

Deciduous-dentition malocclusion predicts orthodontic treatment needs later: findings from a population-based birth cohort study.

INTRODUCTIONnEstimating orthodontic treatment need in the permanent dentition using information from the deciduous-dentition malocclusion may assist in defining the time for appropriate orthodontic intervention. Our objective was to investigate whether malocclusion in the deciduous teeth predicts orthodontic treatment need in the permanent dentition.nnnMETHODSnTwo oral health studies nested in a birth cohort were carried out at ages 6 (n = 359) and 12 (n = 339) years. Open bite, crossbite, and canine malocclusion were assessed in the deciduous teeth. Orthodontic treatment need was determined in the permanent dentition using the dental esthetic index. Prevalence ratios were estimated using 2 dental esthetic index cutoff points: highly desirable/mandatory orthodontic treatment and only mandatory orthodontic treatment. We tested all combinations of the deciduous malocclusion and the outcomes, controlling for confounders.nnnRESULTSnChildren with only open bite and those with concurrent open bite and canine malocclusion were more likely to have either highly desirable/mandatory orthodontic treatment or only mandatory orthodontic treatment needs by age 12. The combination of crossbite and open bite in the deciduous teeth was associated with the highest risk of need for mandatory orthodontic treatment.nnnCONCLUSIONSnMalocclusion in the deciduous teeth is a risk factor for orthodontic treatment need in the permanent dentition. Children with malocclusion at a young age should be monitored regularly, and caregivers may be able to better prepare for possible orthodontic treatment.

ASSOCIAÇÃO DE CARACTERÍSTICAS ANTROPOMÉTRICAS, FUNCIONAIS E DE RISCO CARDIOVASCULAR COM O CONSUMO MÁXIMO DE OXIGÊNIO EM UNIVERSITÁRIOS

A aptidao fisica esta associada com menor incidencia de doenca cardiovascular e de mortalidade. O objetivo do estudo foi estimar o consumo maximo de oxigenio (VO2max) e investigar fatores associados em universitarios. Para tal, realizou-se um estudo transversal com 52 adultos jovens saudaveis. O VO2max foi estimado indiretamente por meio de teste progressivo maximo em cicloergometro. Dentre as variaveis independentes, foram coletadas caracteristicas antropometricas, funcionais e de risco cardiovascular dos participantes. A media de idade foi de 21,9 anos (DP=3,6), variando de 17 a 33 anos. A media de VO2max para os homens foi 47,7 mL/kg.min e para as mulheres foi 38,0 mL/kg.min. Houve associacao inversa significativa entre o VO2max e circunferencia da cintura, razao cintura-quadril, percentual de gordura e componente endomorfico para ambos os sexos. O estudo reforca a evidencia de que o VO2max esta fortemente associado a uma composicao corporal mais favoravel.