Isabel O. Oliveira

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.

Cohort Profile Update: The 1982 Pelotas (Brazil) Birth Cohort Study

In this manuscript, we update the profile of the 1982 Pelotas Birth Cohort Study.In 1982, 5914 live births whose families lived in the urban are of Pelotas were enrolled in the cohort. In 2012–13, we tried to locate the whole original cohort; 3701 participants were interviewed who, added to the 325 known deaths, represented a follow-up rate of 68.1%. In contrast to the previous home interviews, in this wave all participants were invited to visit the research clinic to be interviewed and examined. The visit was carried out at a mean age of 30.2 years and mainly focused on four categories of outcomes: (i) mental health; (ii) body composition; (iii) precursors of complex chronic diseases; and (iv) human capital. Requests for collaboration by outside researchers are welcome.

Major dietary patterns and cardiovascular risk factors among young Brazilian adults

PurposeDiet is one of the most important modifiable risk factors for cardiovascular diseases. The scientific literature has consistently shown the effects of certain diets on health; however, given the variety of cultures and dietary habits across the world, it is likely that much remains to be learned about dietary patterns and health outcomes. We assessed the associations between main dietary patterns and cardiovascular risk factors among 4,202 young Brazilian adults in a cross-sectional analysis.MethodsIn a principle components analysis, two main dietary patterns were identified: common Brazilian and processed food. As outcomes, we examined body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol, HDL cholesterol (HDL-c), and LDL cholesterol (LDL-c). Means, crude, and adjusted β coefficients and 95% CIs were estimated according to quintiles of dietary patterns.ResultsCommon Brazilian scores were inversely associated with BMI, WC, LDL-c, HDL-c, and total cholesterol values among men. Among women, inverse association trends were observed with SBP, DBP, LDL-c, HDL-c, and total cholesterol. The processed food pattern was positively associated with LDL-c, HDL-c, total cholesterol, BMI, and WC values among the men. Among the women, the processed food pattern was not significantly associated with cardiovascular risk factors.ConclusionsIn conclusion, our findings confirm that diet has an important role on health during early adulthood. The common Brazilian pattern showed generally healthier trends regarding CVD risk factors, but the ultimate effects on risk of risk of disease are unclear because of the inverse relation with HDL-c levels.

Cohort Profile Update: 2004 Pelotas (Brazil) Birth Cohort Study. Body composition, mental health and genetic assessment at the 6 years follow-up

This is an update of the 2004 Pelotas Birth Cohort profile, originally published in 2011. In view of the high prevalence of overweight and mental health problems among Brazilian children, together with the availability of state-of-the-art equipment to assess body composition and diagnostic tests for mental health in childhood, the main outcomes measured in the fifth follow-up (mean age 6.8 years) included child body composition, mental health and cognitive ability. A total of 3722 (90.2%) of the original mothers/carers were interviewed and their children examined in a clinic where they underwent whole-body dual X-ray absorptiometry (DXA), air displacement plethysmography and a 3D photonic scan. Saliva samples for DNA were obtained. Clinical psychologists applied the Development and Well-Being Assessment questionnaire and the Wechsler Intelligence Scale for Children to all children. Results are being compared with those of the two earlier cohorts to assess the health effects of economic growth and full implementation of public policies aimed at reducing social inequalities in the past 30 years. For further information visit the programme website at [http://www.epidemio-ufpel.org.br/site/content/coorte_2004/questionarios.php]. Applications to use the data should be made by contacting 2004 cohort researchers and filling in the application form available at [http://www.epidemio-ufpel.org.br/site/content/estudos/formularios.php].

Quality of DNA extracted from saliva samples collected with the Oragene™ DNA self-collection kit

BackgroundLarge epidemiological studies in DNA biobanks have increasingly used less invasive methods for obtaining DNA samples, such as saliva collection. Although lower amounts of DNA are obtained as compared with blood collection, this method has been widely used because of its more simple logistics and increased response rate. The present study aimed to verify whether a storage time of 8 months decreases the quality of DNA from collected samples.MethodsSaliva samples were collected with an OrageneTM DNA Self-Collection Kit from 4,110 subjects aged 14–15 years. The samples were processed in two aliquots with an 8-month interval between them. Quantitative and qualitative evaluations were carried out in 20% of the samples by spectrophotometry and genotyping. Descriptive analyses and paired t-tests were performed.ResultsThe mean volume of saliva collected was 2.2 mL per subject, yielding on average 184.8 μg DNA per kit. Most samples showed a Ratio of OD differences (RAT) between 1.6 and 1.8 in the qualitative evaluation. The evaluation of DNA quality by TaqMan®, High Resolution Melting (HRM), and restriction fragment length polymorphism-PCR (RFLP-PCR) showed a rate of success of up to 98% of the samples. The sample store time did not reduce either the quantity or quality of DNA extracted with the Oragene kit.ConclusionThe study results showed that a storage period of 8 months at room temperature did not reduce the quality of the DNA obtained. In addition, the use of the Oragene kit during fieldwork in large population-based studies allows for DNA of high quantity and high quality.

Correlates of C-reactive protein levels in young adults: a population-based cohort study of 3827 subjects in Brazil

The socio-demographic, behavioral and anthropometric correlates of C-reactive protein levels were examined in a representative young adult Brazilian population. The 1982 Pelotas Birth Cohort Study (Brazil) recruited over 99% of births in the city of Pelotas that year (N = 5914). Individuals belonging to the cohort have been prospectively followed up. In 2004-2005, 77.4% of the cohort was traced, members were interviewed and 3827 individuals donated blood. Analyses of the outcome were based on a conceptual model that differentiated confounders from potential mediators. The following independent variables were studied in relation to levels of C-reactive protein in sex-stratified analyses: skin color, age, family income, education, parity, body mass index, waist circumference, smoking, fat/fiber/alcohol intake, physical activity, and minor psychiatric disorder. Geometric mean (95% confidence interval) C-reactive protein levels for the 1919 males and 1908 females were 0.89 (0.84-0.94) and 1.96 mg/L (1.85-2.09), respectively. Pregnant women and those using oral contraceptive therapies presented the highest C-reactive protein levels and all sub-groups of women had higher levels than men (P < 0.001). Significant associations between C-reactive protein levels were observed with age, socioeconomic indicators, obesity status, smoking, fat and alcohol intake, and minor psychiatric disorder. Associations were stronger at higher levels of C-reactive protein and some associations were sex-specific. We conclude that both distal (socio-demographic) and proximal (anthropometric and behavioral) factors exert strong effects on C-reactive protein levels and that the former are mediated to some degree by the latter.

Life course weight gain and C-reactive protein levels in young adults: findings from a Brazilian birth cohort.

Rapid weight gain in childhood is associated with increased risk of chronic diseases in adults. C‐reactive protein (CRP) is a mediator of atherosclerosis and chronically elevated levels predict cardiovascular outcomes. The effects of life course weight gain on CRP levels are not clear. The 1982 Pelotas (Brazil) birth cohort study (n = 5,914) has prospectively collected weight and health data at several follow‐ups since birth. The most recent was in 2004–05, when 77.4% of the cohort was traced and CRP levels were measured in 89% of those interviewed (n = 3827). Geometric mean (SE) C‐reactive protein levels were 0.89 mg/l (0.03) and 1.66 mg/l (0.04) in men and women, respectively. In analyses adjusted for confounding variables, weight gain in infancy showed a weak negative association among males, but from the second year onwards, weight gain was positively associated with CRP levels. In females, weight gain was associated with higher CRP at every period tested. The strongest associations were observed in the most recent (18–23 years) period; CRP ratios (95% CI) per z score increase in weight gain were 1.78 (1.57–2.00) and 1.52 (1.30–1.78) for men and women, respectively. Males who were stunted at 2 years and centrally obese at 23 years had the highest CRP levels (P = 0.002 for interaction). In summary, rapid weight gain throughout life predicted higher CRP levels. Public health efforts need to tackle chronic under‐nutrition in infancy, together with rapid weight gain in later childhood and adolescence, especially in countries undergoing the nutritional transition. Am. J. Hum. Biol. 2009.

Lifecourse socioeconomic trajectories and C-reactive protein levels in young adults: findings from a Brazilian birth cohort.

Socioeconomic factors are associated with cardiovascular disease. C-reactive protein (CRP) is increasingly implicated as a candidate linking conventional risk factors and atherosclerosis. The impact of early- and later-life socioeconomic status (SES) on CRP levels has not been widely investigated and a handful of studies from high-income countries are inconsistent. We set out to examine the associations between lifecourse socioeconomic indicators (family income at birth, maternal education, family income at age 23 and own education) on CRP levels in young adults belonging to the 1982 Pelotas (Brazil) Birth Cohort Study (n = 5914). Early-life SES showed significant and graded associations with CRP levels at age 23 independently of later SES. For example, men with higher family income at birth showed higher CRP levels at age 23 (p = 0.001 for trend) and women with less educated mothers showed higher CRP levels (p = 0.01 for trend). Notably, differential directions of association between SES indicators and CRP levels between men and women were found. When adjusted for SES at age 23, men with the lowest family income at birth showed 42% lower CRP levels when compared to men in the highest family income group (−42; 95% CI: -60,-16). In contrast women born to the least educated mothers had the highest CRP levels (35; 95% CI -2, 86). In both sexes, adiposity accounted for the overwhelming majority of the associations between SES and CRP levels. Sex and gender roles specific to middle-income countries, socio-cultural and environmental conditions that may impact adiposity, and the level of epidemiological transition may be key factors that are linked to the associations between lifecourse SES and CRP levels. Public health strategies aimed at decreasing the burden of cardiovascular disease in middle-income settings, in addition to highlighting the risks associated with adult obesity, should not overlook the wide-ranging impacts of lifecourse social determinants.

Maternal smoking during pregnancy and risk factors for cardiovascular disease in adulthood

Objective This study was aimed at assessing the effect of maternal smoking during pregnancy on metabolic cardiovascular risk factors in early adulthood in a Brazilian birth cohort, after controlling for possible confounding variables and health behaviors in early adulthood. Methods In 1982, the maternity hospitals in Pelotas, southern Brazil, were visited and all births were identified. Those livebirths whose family lived in the urban area of the city were studied prospectively. In 2004–2005, we attempted to follow the whole cohort, the subjects were interviewed, examined and blood sample was collected. The following outcomes were studied: blood pressure; HDL cholesterol; triglycerides; random blood glucose and C-reactive protein. To explore the effect of maternal smoking, we adjusted the coefficients for the following possible mediators: perinatal factors (low birthweight and preterm births); adult behavioral factors (physical activity, dietary pattern, intake of fat and fiber, and tobacco smoking) and adult anthropometry (body mass index and waist circumference). Results In 2004–2005, we interviewed 4297 subjects, with a follow-up rate of 77.4%. The only significant finding in the unadjusted analyses was lower HDL cholesterol among females. After adjustment for lifestyle variables in early adulthood, birthweight and waist circumference, the difference in HDL levels between offspring of smokers and non-smokers reduced from −2.10 mg/dL (95% confidence interval: −3.39; −0.80) to −1.03 mg/dL (−2.35; 0.30). Conclusion Evidence that maternal smoking during pregnancy programs offspring metabolic cardiovascular risk factors are scarce, and reported associations are likely due to postnatal exposure to lifestyle patterns.

African ancestry, lung function and the effect of genetics

African-Americans have smaller lung function compared with European-Americans. The aim of this study was to disentangle the contribution of genetics from other variables on lung function. A cohort was followed from birth to 30 years of age in Brazil. Several variables were collected: genomic analysis based on DNA; forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) obtained by spirometry; height measured by anthropometrists; and thorax circumference evaluated by photonic scanner. Crude and adjusted linear regression models were calculated according to African ancestry. The sample comprised 2869 participants out of 3701 members of the cohort. Males with higher African ancestry by DNA analysis had a smaller FEV1 (−0.13 L, 95% CI −0.23– −0.03 L) and FVC (−0.21 L, 95% CI −0.32– −0.09 L) compared with those with less African ancestry, having accounted for height, sitting to standing height ratio and other confounders. Similar effects were seen in females. After adjustment, ancestry remained significantly associated with lung function, but the large effect of adjustment for confounding among males (but not females) does not allow us to exclude the possibility that residual confounding may still account for these findings. Smaller lung function is related to African ancestry but adjustments for confounders reduced the effect sizes http://ow.ly/Iq0Ve