Cesarean section is associated with increased peripheral and central adiposity in young adulthood : cohort study

Background: Cesarean section (CS) has been associated with obesity, measured by body mass index (BMI), in some studies. It has been hypothesized that this association, if causal, might be explained by changes in gut microbiota. However, little is known about whether CS is also associated with increased adiposity as measured by indicators other than BMI. Objective: To assess the association between CS and indicators of peripheral and central adiposity in young adults. Methods: The study was conducted on 2,063 young adults aged 23 to 25 years from the 1978/79Ribeira˜o Preto birth cohort, Sa˜o Paulo, Brazil. CS was the independent variable. The anthropometric indicators of adiposity were: waist circumference (WC), waist-height ratio (WHtR), waist-hip ratio (WHR), tricipital skinfold (TSF), and subscapular skinfold (SSF). The association between CS and indicators of adiposity was investigated using a Poisson model, with robust adjustment of variance and calculation of incidence rate ratio (IRR) with 95% confidence interval (95%CI), and adjustment for birth variables. Results: Follow-up rate was 31.8%. The CS rate was 32%. Prevalences of increased WC, WHtR, WHR were 32.1%, 33.0% and 15.2%, respectively. After adjustment for birth variables, CS was associated with increased risk of adiposity when compared to vaginal delivery: 1.22 (95%CI 1.07; 1.39) for WC, 1.25 (95%CI 1.10;1.42) for WHtR, 1.45 (95%CI 1.18;1.79) for WHR, 1.36 (95%CI 1.04;1.78) for TSF, and 1.43 (95%CI 1.08;1.91) for SSF. Conclusion: Subjects born by CS had a higher risk for increased peripheral and central adiposity during young adult age compared to those born by vaginal delivery. The association of CS with adiposity was consistently observed for all indicators and was robust after adjustment for a variety of early life confounders

Cesarean section and increased body mass index in school children: two cohort studies from distinct socioeconomic background areas in Brazil

Abstract\ud \ud \ud \ud Background\ud Recent studies have raised controversy regarding the association between cesarean section and later obesity in the offspring. The purpose of this study was to assess the association of cesarean section with increased body mass index (BMI) and obesity in school children from two Brazilian cities with distinct socioeconomic backgrounds.\ud \ud \ud \ud Methods\ud Two birth cohorts respectively born in 1994 in Ribeirao Preto, a wealthy city in Southeast, and in 1997/98 in Sao Luis, a less wealthy city in Northeast of Brasil, were evaluated. After birth, 2,846 pairs of mothers-newborns were evaluated in Ribeirao Preto and 2,542 in Sao Luis. In 2004/05, 790 children aged 10/11 years were randomly reassessed in Ribeirao Preto and 673 at 7/9 years in Sao Luis. Information on type of delivery, maternal and child characteristics, socioeconomic position and anthropometric measurements were collected after birth and at school age. Obesity was defined as BMI ≥ 95th percentile at school age.\ud \ud \ud \ud Results\ud Obesity rate was 13.0% in Ribeirao Preto and 2.1% in Sao Luis. Cesarean section was associated with obesity and remained significant after adjustment only in Ribeirao Preto [OR = 1.74 (95% CI: 1.04; 2.92)]. The association between cesarean section and BMI remained significant after adjustment for maternal schooling, maternal smoking during pregnancy, duration of breastfeeding, gender, birth weight and gestational age, type of school and, only in Sao Luis, pre-pregnancy maternal weight. In Ribeirao Preto children born by cesarean section had BMI 0.31 kg/m2 (95%CI: 0.11; 0.51) higher than those born by vaginal delivery. In Sao Luis BMI of children born by cesarean section was 0.28 kg/m2 higher (95%CI: 0.08; 0.49) than those born by vaginal delivery.\ud \ud \ud \ud Conclusion\ud A positive association between cesarean section and increased BMI z-score was demonstrated in areas with different socioeconomic status in a middle-income country.This study was supported by Fundaçao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP) – No. 93/05250, 97/095171, 00/095087 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – No. 523474/962 and 520664/981, Brazil.This study was supported by Fundaçao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP) – No. 93/0525-0, 97/09517-1, 00/09508-7 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – No. 523474/96-2 and 520664/98-1, Brazil

O paradoxo epidemiológico do baixo peso ao nascer no Brasil

OBJECTIVE: To examine whether the low birth weight (LBW) paradox exists in Brazil. METHODS: LBW and cesarean section rates between 1995 and 2007 were estimated based on data from SINASC (Brazilian Live Births Database). Infant mortality rates (IMRs) were obtained using an indirect method that correct for underreporting. Schooling information was obtained from census data. Trends in LBW rate were assessed using joinpoint regression models. The correlations between LBW rate and other indicators were graphically assessed by lowess regression and tested using Spearman's rank correlation. RESULTS: In Brazil, LBW rate trends were non-linear and non-significant: the rate dropped from 7.9% in 1995 to 7.7% in 2000, then increased to 8.2% in 2003 and remained nearly steady thereafter at 8.2% in 2007. However, trends varied among Brazilian regions: there were significant increases in the North from 1999 to 2003 (2.7% per year), and in the South (1.0% per year) and Central-West regions (0.6% per year) from 1995 to 2007. For the entire period studied, higher LBW and lower IMRs were seen in more developed compared to less developed regions. In Brazilian States, in 2005, the higher the IMR rate, the lower the LBW rate (p=0.009); the lower the low schooling rate, the lower the LBW rate (p=0.007); the higher the number of neonatal intensive care beds per 1,000 live births, the higher the LBW rate (p=0.036). CONCLUSIONS: The low birth weight paradox was seen in Brazil. LBW rate is increasing in some Brazilian regions. Regional differences in LBW rate seem to be more associated to availability of perinatal care services than underlying social conditions.OBJETIVO: Identificar la presencia de la paradoja de bajo peso al nacer (BPN) en Brasil. MÉTODOS: Las tasas de BPN y de cesárea, de 1995 a 2007, fueron estimadas a partir del Sistema de Informaciones sobre Nacidos Vivos. Las tasas de mortalidad infantil fueron calculadas por métodos indirectos, con corrección para subregistro. La tasa de escolaridad fue obtenida de datos de censos. Las tendencias de la tasa de bajo peso al nacer fueron evaluadas utilizándose modelos de regresión joinpoint. Las asociaciones entre la tasa de bajo peso al nacer con otros indicadores fueron evaluadas por regresión lowess y correlación de Spearman. RESULTADOS: En Brasil, las tendencias en la tasa de BPN fueron no lineares y no significativas: la tasa disminuyó de 7,9% en 1995 a 7,7% en 2000, aumentando a 8,2% en 2003, y permaneciendo estable en 8,2% en 2007. Mientras, las tendencias variaron en las regiones brasileras: hubo aumentos significativos en el Norte (2,7% por año), de 1999 a 2003, y en el Sur (1,0% por año) y Centro-Oeste (0,6% por año), de 1995 a 2007. Las tasas de BPN fueron más altas y las tasas de mortalidad infantil más bajas en las regiones más desarrolladas en comparación con las menos desarrolladas. En 2005, cuanto más elevada la tasa de mortalidad infantil, menor fue la tasa de BPN (p=0,009); cuanto más alta la tasa de baja escolaridad, menor la tasa de BPN (p=0,007); cuanto mayor el número de lechos de terapia intensiva neonatal por 1000 nacidos vivos, más elevada la tasa de BPN (p=0,036). CONCLUSIONES: La paradoja del BPN fue detectado en Brasil. La tasa de BPN está aumentando en algunas regiones brasileras. Diferencias regionales en la tasa de BPN parecen estar más relacionadas con la disponibilidad de asistencia perinatal que con las condiciones sociales.OBJETIVO: Identificar a presença do paradoxo do baixo peso ao nascer (BPN) no Brasil. MÉTODOS: As taxas de BPN e de cesárea, de 1995 a 2007, foram estimadas a partir do Sistema de Informações sobre Nascidos Vivos. As taxas de mortalidade infantil, foram calculadas por métodos indiretos, com correção para sub-registro. A taxa de escolaridade foi obtida de dados censitários. As tendências da taxa de BPN foram avaliadas utilizando-se modelos de regressão joinpoint. As associações entre a taxa de BPN com outros indicadores foram avaliadas por regressão lowess e correlação de Spearman. RESULTADOS: No Brasil, as tendências da taxa de BPN foram não lineares e não significantes: a taxa caiu de 7,9% em 1995 para 7,7% em 2000, aumentando para 8,2% em 2003 e permanecendo estável em 8,2% em 2007. Entretanto, as tendências variaram nas regiões brasileiras: houve aumentos significantes no Norte (2,7% por ano), de 1999 a 2003, e no Sul (1,0% por ano) e Centro-Oeste (0,6% por ano), de 1995 a 2007. As taxas de BPN foram mais altas e as taxas de mortalidade infantil mais baixas nas regiões mais desenvolvidas do que nas menos desenvolvidas. Em 2005, quanto mais elevada a taxa de mortalidade infantil, menor foi a taxa de BPN (p = 0,009); quanto mais alta a taxa de baixa escolaridade, menor foi a taxa de BPN (p = 0,007); quanto maior o número de leitos de terapia intensiva neonatal por 1.000 nascidos vivos, mais elevada foi a taxa de BPN (p = 0,036). CONCLUSÕES: O paradoxo do BPN foi detectado no Brasil. A taxa de BPN está aumentando em algumas regiões brasileiras. Diferenças regionais na taxa de BPN parecem estar mais relacionadas à disponibilidade de assistência perinatal do que às condições sociais

Normal weight obesity is associated with metabolic syndrome and insulin resistance in young adults from a middle-income country

Objective: This population-based birth cohort study examined whether normal weight obesity is associated with metabolic disorders in young adults in a middle-income country undergoing rapid nutrition transition. Design and Methods: The sample involved 1,222 males and females from the 1978/79 Ribeira˜o Preto birth cohort, Brazil, aged 23–25 years. NWO was defined as body mass index (BMI) within the normal range (18.5–24.9 kg/m2) and the sum of subscapular and triceps skinfolds above the sex-specific 90th percentiles of the study sample. It was also defined as normal BMI and % BF (body fat) .23% in men and .30% in women. Insulin resistance (IR), insulin sensitivity and secretion were based on the Homeostasis Model Assessment (HOMA) model. Results: In logistic models, after adjusting for age, sex and skin colour, NWO was significantly associated with Metabolic Syndrome (MS) according to the Joint Interim Statement (JIS) definition (Odds Ratio OR = 6.83; 95% Confidence Interval CI 2.84–16.47). NWO was also associated with HOMA2-IR (OR = 3.81; 95%CI 1.57–9.28), low insulin sensitivity (OR = 3.89; 95%CI 2.39–6.33), and high insulin secretion (OR = 2.17; 95%CI 1.24–3.80). Significant associations between NWO and some components of the MS were also detected: high waist circumference (OR = 8.46; 95%CI 5.09–14.04), low High Density Lipoprotein cholesterol (OR = 1.65; 95%CI 1.11–2.47) and high triglyceride levels (OR = 1.93; 95%CI 1.02–3.64). Most estimates changed little after further adjustment for early and adult life variables. Conclusions: NWO was associated with MS and IR, suggesting that clinical assessment of excess body fat in normal-BMI individuals should begin early in life even in middle-income countries

Peso medio al nacer entre recién nacidos a término : tendencia, magnitud y factores asociados

A trend towards increasing birth weight has been shown, but factors that explain these trends have not been elucidated. The objectives of this study were to evaluate changes in mean birth weight of term newborns and to identify factors associated with them. All cohorts are population-based studies in which random samples of births (Ribeirão Preto, São Paulo State in 1978/1979, 1994 and 2010; Pelotas, Rio Grande do Sul State in 1982, 1993 and 2004; and São Luís, Maranhão State in 1997/1998 and 2010, Brazil). A total of 32,147 full-term, singleton live births were included. Mean birth weight reduced in the first study period (-89.1g in Ribeirão Preto from 1978/1979 to 1994, and -27.7g in Pelotas from 1982 to 1993) and increased +30.2g in Ribeirão Preto from 1994 to 2010 and +24.7g in São Luís from 1997 to 2010. In the first period, in Ribeirão Preto, mean birth weight reduction was steeper among mothers with high school education and among those born 39-41 weeks. In the second period, the increase in mean birth weight was steeper among mothers with low schooling in Ribeirão Preto and São Luís, females and those born 37-38 weeks in Ribeirão Preto and cesarean section in São Luís. Birth weight decreased in the first study period then increased thereafter. The variables that seem to have been able to explain these changes varied over time.Existem evidências de uma tendência de aumento do peso ao nascer, mas pouco se sabe sobre os fatores que explicam essa tendência. Avaliar as mudanças na média de peso ao nascer e identificar os fatores associados. Foram incluídas todas as coortes de base populacional com amostras aleatórias de nascimentos (Ribeirão Preto, São Paulo em 1978/1979, 1994 e 2010; Pelotas, Rio Grande do Sul em 1982, 1993 e 2004; São Luís, Maranhão em 1997/1998 e 2010, Brasil). Foi incluído um total de 32.147 nascidos vivos a termo, de feto único. A média de peso ao nascer diminuiu no primeiro período estudado (-89,1g entre 1978/1979 e 1994 em Ribeirão Preto e -27,7g entre 1982 e 1993 em Pelotas) e aumentou no segundo período, +30,2g entre 1994 e 2010 em Ribeirão Preto e +24,7g entre 1997 e 2010 em São Luís. No primeiro período, em Ribeirão Preto, a redução na média de peso ao nascer foi maior entre mães com escolaridade mais alta e crianças nascidas com 39-41 semanas de idade gestacional. No segundo período, o aumento na média de peso ao nascer foi maior entre mães com escolaridade mais baixa em Ribeirão Preto e São Luís, crianças do sexo feminino e nascidas com 37-38 semanas em Ribeirão Preto e crianças nascidas de cesárea em São Luís. O peso ao nascer diminuiu no primeiro período e aumentou desde então. As variáveis que parecem explicar essas mudanças variaram ao longo do tempo.Se ha mostrado una tendencia de aumento de peso al nacer, pero los factores que explican esta tendencia todavía no han sido elucidados. Evaluar los cambios en el peso medio al nacer de los recién nacidos a término e identificar factores asociados. Se trata de un estudio de todas las cohortes basadas en población, donde existe una muestra aleatoria simple de nacimientos (Ribeirão Preto, São Paulo en 1978/1979, 1994 y 2010; Pelotas, Rio Grande do Sul en 1982, 1993 y 2004; y São Luís, Maranhão en 1997/1998 y 2010, Brasil). Se incluyeron un total de 32.147 de nacimientos a término completo con embarazo de un único feto. El peso medio al nacer se redujo en el primer estudio del período (-89,1g en Ribeirão Preto desde 1978/1979 a 1994 y -27,7g en Pelotas desde 1982 a 1993) y se incrementó +30,2g en Ribeirão Preto desde 1994 a 2010 y +24.7g en São Luís desde 1997 a 2010. En el primer periodo, en Ribeirão Preto, la reducción del peso medio al nacer fue más pronunciada entre madres con una escolarización más alta y entre aquellos nacidos con 39-41 semanas. En el segundo período, el incremento en el peso medio al nacer fue más pronunciado entre las madres con una escolarización más baja en Ribeirão Preto y São Luís, mujeres y aquellos que nacieron con 37-38 semanas en Ribeirão Preto y en el área de cesáreas en São Luís. Disminuyó el peso al nacer durante el primer período de estudio y se vio incrementado después. Las variables que parecen capaces de explicar estos cambios varían a lo largo del tiempo

Secular trends in the rate of low birth weight in Brazilian State Capitals in the period 1996 to 2010

Secular trends in rates of low birth weight in Brazilian state capital cities were evaluated for the period 1996 to 2010 using joinpoint regression models. The rates were calculated using data from the Live Births Information System. Newborns weighing less than 500g were excluded. Only data for capital cities was included since under-registration of births in these cities is lower and new trends can be detected earlier. There was a significant increase in the rate of low birth weight in the Brazilian capitals of the North Region, Northeast Region, South Region and Southeast Region up to 2003/2004, stabilizing thereafter. In the capitals of the Center-west Region the rate increased throughout the whole study period. The rate of low birth weight was higher in the capitals of the more developed regions. The rate of multiple births increased significantly in all Brazilian capitals, while the stillbirth rate decreased and showed a negative correlation with the rate of low birth weight. The increase in the rate of low birth weight may be partially explained by the increase in multiple births, an increase in the birth of infants weighing 500 to 999g and by the reduction in the stillbirth rate

Changes in infant and neonatal mortality and associated factors in eight cohorts from three Brazilian cities

Stillbirth (SBR), perinatal (PMR), neonatal (NMR) and infant mortality rates (IMR) are declining in Brazil and the factors associated with these falls are still being investigated. The objective of the present study was to assess changes in SBR, PMR, NMR and IMR over time and to determine the factors associated with changes in NMR and IMR in eight Brazilian cohorts. All cohorts are population-based (Ribeirão Preto in 1978/79, 1994 and 2010; Pelotas in 1982, 1993 and 2004; and São Luís in 1997/98 and 2010). Were included data on 41440 children. All indicators were decreased, except in the city of Pelotas, from 1993 to 2004, and except SBR in São Luís. Sociodemographic variables seem to be able to explain reductions of NMR and IMR in Ribeirão Preto, from 1978/79 to 1994, and in São Luís. In Ribeirão Preto, from 1994 to 2010 declines in NMR and IMR seem to be explained by reductions in intrauterine growth restriction (IUGR). Newborn’s gestational age had diminished in all cohorts, preventing even greater reductions of NMR and IMR. Improved sociodemographic variables and reduction of IUGR, seem to be able to explain part of the decrease observed. NMR and IMR could have been reduced even more, were it not for the worsening in gestational age distribution