Obesity-induced hypoadiponectinaemia: the opposite influences of central and peripheral fat compartments.

Background and Aims: The substantial reduction in adiponectin concentration among obese individuals seems to depend on fat distribution and is a marker of metabolic and adipose tissue dysfunction. We aimed to: (i) address whether abdominal fat from different compartments (visceral, deep subcutaneous abdominal and superficial subcutaneous abdominal) and gluteofemoral fat are independently associated with blood adiponectin concentration; and (ii) investigate whether abdominal (proxied by waist circumference) and gluteofemoral fat (proxied by hip circumference) accumulation causally determine blood adiponectin concentration. Methods: To investigate the independent association of abdominal and gluteofemoral fat with adiponectin concentration, we used multivariable regression and data from 30-year-old adults from the 1982 Pelotas Birth Cohort (n = 2,743). To assess the causal role of abdominal and gluteofemoral fat accumulation on adiponectin concentration, we used Mendelian randomization and data from two consortia of genome-wide association studies-the GIANT (n > 210 000) and ADIPOGen consortia (n = 29 347). Results: In the multivariable regression analysis, all abdominal fat depots were negatively associated with adiponectin concentration, specially visceral abdominal fat [men: ß = -0.24 standard unit of log adiponectin per standard unit increase in abdominal fat; 95% confidence interval (CI) = -0.31, -0.18; P = 8*10-13; women: ß = -0.31; 95% CI = -0.36, -0.25; P = 7*10-27), whereas gluteofemoral fat was positively associated with adiponectin concentration (men: ß = 0.13 standard unit of log adiponectin per standard unit increase in gluteofemoral fat; 95% CI = 0.03, 0.22; P = 0.008; women: ß = 0.24; 95% CI = 0.17, 0.31; P = 7*10-11). In the Mendelian randomization analysis, genetically-predicted waist circumference was inversely related to blood adiponectin concentration (ß = -0.27 standard unit of log adiponectin per standard unit increase in waist circumference; 95% CI = -0.36, -0.19; P = 2*10-11), whereas genetically-predicted hip circumference was positively associated with blood adiponectin concentration (ß = 0.17 standard unit of log adiponectin per standard unit increase in hip circumference; 95% CI = 0.11, 0.24; P = 1*10-7). Conclusions: These results support the hypotheses that there is a complex interplay between body fat distribution and circulating adiponectin concentration, and that whereas obesity-induced hypoadiponectinaemia seems to be primarily attributed to abdominal fat accumulation, gluteofemoral fat accumulation is likely to exert a protective effect.

Body shape and size in 6-year old children: assessment by three-dimensional photonic scanning.

BACKGROUND: Body shape and size are typically described using measures such as body mass index (BMI) and waist circumference, which predict disease risks in adults. However, this approach may underestimate the true variability in childhood body shape and size. OBJECTIVE: To use a comprehensive three-dimensional photonic scan approach to describe variation in childhood body shape and size. SUBJECTS/METHODS: At age 6 years, 3350 children from the population-based 2004 Pelotas birth cohort study were assessed by three-dimensional photonic scanner, traditional anthropometry and dual X-ray absorptiometry. Principal component analysis (PCA) was performed on height and 24 photonic scan variables (circumferences, lengths/widths, volumes and surface areas). RESULTS: PCA identified four independent components of children's body shape and size, which we termed: Corpulence, Central:peripheral ratio, Height and arm lengths, and Shoulder diameter. Corpulence showed strong correlations with traditional anthropometric and body composition measures (r>0.90 with weight, BMI, waist circumference and fat mass; r>0.70 with height, lean mass and bone mass); in contrast, the other three components showed weak or moderate correlations with those measures (all r<0.45). There was no sex difference in Corpulence, but boys had higher Central:peripheral ratio, Height and arm lengths and Shoulder diameter values than girls. Furthermore, children with low birth weight had lower Corpulence and Height and arm lengths but higher Central:peripheral ratio and Shoulder diameter than other children. Children from high socio-economic position (SEP) families had higher Corpulence and Height and arm lengths than other children. Finally, white children had higher Corpulence and Central:peripheral ratio than mixed or black children. CONCLUSIONS: Comprehensive assessment by three-dimensional photonic scanning identified components of childhood body shape and size not captured by traditional anthropometry or body composition measures. Differences in these novel components by sex, birth weight, SEP and skin colour may indicate their potential relevance to disease risks.

The influence of birth order and number of siblings on adolescent body composition: evidence from a Brazilian birth cohort study.

The aim of this study was to estimate the association between birth order and number of siblings with body composition in adolescents. Data are from a birth cohort study conducted in Pelotas, Brazil. At the age of 18 years, 4563 adolescents were located, of whom 4106 were interviewed (follow-up rate 81.3 %). Of these, 3974 had complete data and were thus included in our analysis. The variables used in the analysis were measured during the perinatal period, or at 11, 15 and/or 18 years of age. Body composition at 18 years was collected by air displacement plethysmography (BOD POD®). Crude and adjusted analyses of the association between birth order and number of siblings with body composition were performed using linear regression. All analyses were stratified by the adolescent sex. The means of BMI, fat mass index and fat-free mass index among adolescents were 23.4 (sd 4.5) kg/m², 6.1 (sd 3.9) kg/m² and 17.3 (sd 2.5) kg/m², respectively. In adjusted models, the total siblings remained inversely associated with fat mass index (ß = - 0.37 z-scores, 95 % CI - 0.52, - 0.23) and BMI in boys (ß = - 0.39 z-scores, 95 % CI - 0.55, - 0.22). Fat-free mass index was related to the total siblings in girls (ß = 0.06 z-scores, 95 % CI - 0.04, 0.17). This research has found that number of total siblings, and not birth order, is related to the fat mass index, fat-free mass index and BMI in adolescents. It suggests the need for early prevention of obesity or fat mass accumulation in only children.

The association of birth order with later body mass index and blood pressure: a comparison between prospective cohort studies from the United Kingdom and Brazil.

BACKGROUND: Previous studies have found greater adiposity and cardiovascular risk in first born children. The causality of this association is not clear. Examining the association in diverse populations may lead to improved insight. METHODS: We examine the association between birth order and body mass index (BMI), systolic and diastolic blood pressure (SBP/DBP) in the 2004 Pelotas cohort from southern Brazil and the Avon Longitudinal Study of Parents and Children (ALSPAC) from Bristol, south-west England, restricting analysis to families with two children in order to remove confounding by family size. RESULTS: No consistent differences in BMI, SBP or DBP were observed comparing first and second born children. Within the Pelotas 2004 cohort, first born females were thinner, with lower SBP and DBP; for example, mean difference in SBP comparing first with second born was -0.979 (95% confidence interval -2.901 to 0.943). In ALSPAC, first born females had higher BMI, SBP and DBP. In both cohorts, associations tended to be in the opposite direction in males, although no statistical evidence for gender interactions was found. CONCLUSIONS: The findings do not support an association between birth order and BMI or blood pressure. Differences to previous studies may be explained by differences in populations and/or confounding by family size in previous studies.

Caries is the main cause for dental pain in childhood: findings from a birth cohort.

AIM: The aim of the study was to evaluate the prevalence of dental pain in preschool children and its association with socioeconomic, demographic, clinical, and behavior variables. SUBJECTS AND METHODS: The study was nested in a population-based birth cohort from Pelotas, Brazil, started in 2004. A sample of 1,129 children aged 5 years was dentally examined, and their mothers were interviewed. Exploratory variables included demographics, socioeconomic status, mothers' oral health status and associated behaviors, and caries in primary teeth. Data were analyzed using multivariable Poisson regression. RESULTS: The prevalence of dental pain was 16.5% (95% CI: 14.4-18.8). Multivariate analysis showed that dark-skinned children (prevalence ratio, PR = 1.6, 95% CI: 1.1-2.4) from low socioeconomic level (PR 1.9, 1.2-3.0) whose mothers had less than 4 years of education (PR 1.9, 1.0-3.6), from mothers with less than 10 teeth in at least one arch (PR 1.7, 1.2-2.5) and less than 10 in two arches (PR 1.6, 1.0-2.6), and those with high caries prevalence at the age of 5 years (PR 4.8, 3.3-7.1) were more likely to experience dental pain. CONCLUSIONS: Unrestored caries is the main factor associated with dental pain in childhood. Socioeconomic aspects and family context in which dental pain occurs should also be taken into account when dental pain preventive measures are implemented.

Association between black stains and dental caries in primary teeth: findings from a Brazilian population-based birth cohort.

Lower dental caries experience has been observed in children and teenagers with the presence of black stains on dental structures. However, none of the previous investigations were population-based studies or adjusted the analysis for potential confounders. This study assessed the prevalence of black stains at the age of 5 in a population-based birth cohort from Pelotas, Brazil and investigated the association between black stains and dental caries. A total of 1,129 children from the 2004 Pelotas birth cohort were examined at age 5, and their mothers were interviewed at their households. Dental examinations included a search for black stains and dental caries on the primary dentition through the dmf-s index. The mothers' questionnaire comprised data on demographic, social, and behavior aspects. Prevalence of black stains was 3.5% (95% CI 2.5-4.7) and the prevalence of dental caries was 48.4% (95% CI 45.4-51.4). Multivariable logistic regression analysis was performed to assess the association between black stains and dental caries. Adjusted analysis revealed that the presence of black stains was associated with lower levels of dental caries (OR = 0.51; 95% CI 0.26-0.99). The results of the present study suggest that black stains are a protective factor for dental caries development.

Association of socioeconomic position with maternal pregnancy and infant health outcomes in birth cohort studies from Brazil and the UK.

BACKGROUND: Socioeconomic inequalities in health outcomes are dynamic and vary over time. Differences between countries can provide useful insights into the causes of health inequalities. The study aims to compare the associations between two measures of socioeconomic position (SEP)-maternal education and family income-and maternal and infant health outcomes between ALSPAC and Pelotas cohorts. METHODS: Birth cohort studies were started in Avon, UK, in 1991 (ALSPAC) and in the city of Pelotas, Brazil, in 1982, 1993 and 2004. Maternal outcomes included smoking during pregnancy, caesarean section and delivery not attended by a doctor. Infant outcomes were preterm birth, intra-uterine growth restriction (IUGR) and breast feeding for <3 months. The relative index of inequality was used for each measure of SEP so that results were comparable between cohorts. RESULTS: An inverse association (higher prevalence among the poorest and less educated) was observed for almost all outcomes, with the exception of caesarean sections where a positive association was found. Stronger income-related inequalities for smoking and education-related inequalities for breast feeding were found in the ALSPAC study. However, greater inequalities in caesarean section and education-related inequalities in preterm birth were observed in the Pelotas cohorts. CONCLUSIONS: Mothers and infants have more adverse health outcomes if they are from poorer and less well-educated socioeconomic backgrounds in both Brazil and the UK. However, our findings demonstrate the dynamic nature of the association between SEP and health outcomes. Examining differential socioeconomic patterning of maternal and infant health outcomes might help understanding of mechanisms underlying such inequalities.

Caesarean sections and risk of wheezing in childhood and adolescence: data from two birth cohort studies in Brazil.

BACKGROUND: There is evidence from two meta-analyses that children born through caesarean section (C-section) may have an increased risk of developing asthma compared with those born through vaginal delivery. Objective To evaluate the association between mode of delivery and wheezing (current and persistent) in childhood and adolescence, in two birth cohort studies in Brazil. METHODS: The outcome variable was based on the International Study of Allergy and Asthma questionnaire, which collects information about wheezing within the 12 months before the interview. Persistent wheezing was defined when it was present in more than one follow-up at different ages, in the 1993 cohort. The questions were asked to mothers when children were aged 4 years (1993 and 2004 cohorts) and directly to cohort participants at 11 and 15 years (1993 cohort). Mode of delivery was collected by the research team of each cohort when children were born. RESULTS: Response rates in the last follow-up visit of the 1993 and 2004 cohorts were 85% and 92%, respectively. The prevalence of current wheezing increased from 20% to 28% at 4 years from 1993 to 2004; at 11 and 15 years, the prevalence was around 14% and 12%, in the 1993 cohort. The proportion of C-sections increased from 30.5% to 45% between 1993 and 2004. In each cohort, the prevalence of current wheezing was similar among children born through vaginal and C-section. The risk for persistent wheezing in the 1993 cohort was higher among girls born through C-section than boys. CONCLUSION: Despite the increase in the proportion of C-section in two cohorts in Southern Brazil, we found no evidence of an association between mode of delivery and the subsequent risk of wheezing. Among girls, although there was no statistical significance, the risk was higher for those born by C-section, especially regarding persistent wheezing.

Socio-economic and ethnic group inequities in antenatal care quality in the public and private sector in Brazil.

BACKGROUND: Socio-economic inequalities in maternal and child health are ubiquitous, but limited information is available on how much the quality of care varies according to wealth or ethnicity in low- and middle-income countries. Also, little information exists on quality differences between public and private providers. METHODS: Quality of care for women giving birth in 2004 in Pelotas, Brazil, was assessed by measuring how many of 11 procedures recommended by the Ministry of Health were performed. Information on family income, self-assessed skin colour, parity and type of provider were collected. RESULTS: Antenatal care was used by 98% of the 4244 women studied (mean number of visits 8.3), but the number of consultations was higher among better-off and white women, who were also more likely to start antenatal care in the first trimester. The quality of antenatal care score ranged from 0 to 11, with an overall mean of 8.3 (SD 1.7). Mean scores were 8.9 (SD 1.5) in the wealthiest and 7.9 (SD 1.8) in the poorest quintiles (P < 0.001), 8.4 (SD 1.6) in white and 8.1 (SD 1.9) in black women (P < 0.001). Adjusted analyses showed that these differences seemed to be due to attendance patterns rather than discrimination. Mean quality scores were higher in the private 9.3 (SD 1.3) than in the public sector 8.1 (SD 1.6) (P < 0.001); these differences were not explained by maternal characteristics or by attendance patterns. CONCLUSIONS: Special efforts must be made to improve quality of care in the public sector. Poor and black women should be actively encouraged to start antenatal care early in pregnancy so that they can fully benefit from it. There is a need for regular monitoring of antenatal attendances and quality of care with an equity lens, in order to assess how different social groups are benefiting from progress in health care.

Effects of socioeconomic change from birth to early adulthood on height and overweight.

BACKGROUND: In this work we explored the association of height and overweight with change in socioeconomic position between birth and 19 years of age. METHODS: A birth cohort has been followed-up in Pelotas, Brazil, since 1982. All 5914 hospital births were enrolled in the study just after delivery. In 2001, 27% of the cohort subjects were sought, and 1031 (69% of the survivors) were interviewed. Weight and height were obtained for women; men had been examined 6 months earlier. Information on family income in 1982 and 2001 was used to classify the sample into tertiles, the lowest classified as 'poor' and the other two as 'non-poor'. Four trajectories resulted: always poor, never poor, poor at birth/non-poor at 19, and non-poor at birth/poor at 19-which were compared in terms of mean height and prevalence of overweight. RESULTS: Height showed a similar behaviour for men and women, with the never poor presenting the highest mean, followed by those who were non-poor at birth and later became poor. Those who were poor at birth, regardless of later status, were shortest. Overweight was approximately twice as common among men who were never poor in relation to the others. Among women, those who were always poor presented the highest prevalence of overweight. In this case, social determination seems to be complex and may involve aspects of lifestyle and behaviour acting differently for each gender. CONCLUSION: Socioeconomic trajectories affected both height and overweight, the effect on the latter being different for each gender.