Stability and change in fruit and vegetable intake of Brazilian adolescents over a 3-year period: 1993 Pelotas Birth Cohort.

OBJECTIVE: To assess the stability and changes in fruit and vegetable (FV) consumption over a 3-year period during adolescence in a population-based birth cohort. DESIGN: Longitudinal descriptive study. FV consumption was collected in 2008 and 2011/12 using an FFQ. We conducted descriptive analyses of medians to assess the trends in FV intake over time. Stability of FV intake was assessed by percentage of agreement and kappa coefficients. SETTING: Pelotas, Rio Grande do Sul, Brazil. SUBJECTS: Adolescents from 15 to 18 years of age (n 3915). RESULTS: We observed an overall slight decrease in FV consumption during adolescence and also a moderate stability, especially in those with higher socio-economic status (proportion of agreement 38.6% and 40.5% for boys and girls, respectively). About a half of those consuming low levels of FV at 15 years of age still consumed low levels 3 years later. CONCLUSIONS: Our results showed that FV consumption presented a moderate stability across a 3-year period during adolescence, especially in those with higher socio-economic status. Given the great proportions of non-communicable diseases such as CVD, diabetes and obesity, knowledge about the patterns of FV consumption during adolescence has implications for health promotion interventions.

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

BACKGROUND: Large 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. METHODS: Saliva 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. RESULTS: The 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. CONCLUSION: The 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.

[Self-reported discrimination by adolescents in a Brazilian birth cohort: prevalence and associations]. / Discriminação autorrelatada por adolescentes de uma coorte de nascimentos brasileira: prevalência e associações.

OBJECTIVE: To evaluate the prevalence of and factors associated with discrimination self-reported by adolescents. METHODS: Cross-sectional analysis of adolescents belonging to a cohort of live births in 1993 in the city of Pelotas, Brazil. From the 5 249 members of the cohort, information was collected from 4 452 adolescents in 2004 and 2005 regarding self-reported discrimination, sociodemographic variables, physical attributes, and nutritional status. A Poisson regression was utilized in the raw and adjusted analyses to estimate prevalence rates (RP). RESULTS: The global prevalence of self-reported discrimination was 16.4%. In the adjusted analysis, discrimination was reported more by the following groups: girls (RP = 1.27, 95%CI: 1.10-1.48), people identified by others as black (RP = 1.28, 95%CI: 1.04-1.57), poorer adolescents (RP = 1.58, 95%CI: 1.23-2.02), those who perceived themselves to be very thin or very fat (RP = 1.81 and 1.54 respectively), those whose families had financial trouble (RP = 1.76, 95%CI: 1.49-2.08), those who wore glasses (RP = 1.74, 95%CI: 1.45-2.10), those who thought their teeth looked bad (RP = 1.58, 95%CI: 1.21-2.07), those who had been reprimanded in school (RP = 1.23, 95%CI: 1.01- 1.51), and those who had been involved in fights in the past year (RP = 1.62, 95%CI: 1.36-1.94). The association between discrimination and nutritional status varied by sex (interaction P = 0.009). Thin children reported greater discrimination than those who were overweight or obese. Discrimination on the basis of obesity was higher among girls, with this effect more strongly felt among rich girls than among poor ones. CONCLUSIONS: Self-reported discrimination was prevalent and unequally distributed among the population. Actions to reduce experiences of discrimination must be implemented during the initial stages of life.

[Prevalence of grade retention and associated factors among adolescents from the 1993 Pelotas, Brazil, birth cohort]. / Prevalência de retenção escolar e fatores associados em adolescentes da coorte de nascimentos de 1993 em Pelotas, Brasil.

OBJECTIVE: To evaluate the occurrence of grade retention until 11 years of age and the factors associated with retention. METHODS: This prospective study included 4 452 adolescents from the 1993 city of Pelotas birth cohort (state of Rio Grande do Sul, Brazil). This sample represents 87.5% of the original cohort. Grade retention was defined as the repetition of at least one school grade until the date of the interview. The following independent variables were analyzed: sex, skin color, birth weight, ownership of goods, age, maternal schooling, type of school (private, state, or city), age at school entry, and employment. RESULTS: The overall frequency of grade retention was 36.3%, vs. 42.8% for boys and 30.0% for girls. The adjusted analysis showed that the lower the level of maternal schooling, ownership of goods, and birth weight, the higher the risk of grade retention for both boys and girls. Black/brown adolescents, those studying in public schools, and those who were 7 years of age or older at school entry had a higher risk of grade retention. For boys, childhood labor was associated with grade retention. CONCLUSIONS: Low socioeconomic and low maternal schooling levels were the factors most strongly associated with grade retention. Strategies to reduce this situation must take into account demographic and socioeconomic characteristics.

Socioeconomic trajectory from birth to adolescence and lung function: prospective birth cohort study.

BACKGROUND: Socioeconomic status (SES) has been shown to be an important contributor to lung function. The aim of this study was to evaluate the association between lung function in adolescence and (a) SES at birth; (b) SES in adolescence; (c) SES trajectory from birth to adolescence ('never poor', 'non poor-poor', 'poor-non poor' and 'always poor'). Additionally, we investigate the role of adolescent and parental variables at mediating these associations. METHODS: Prospective birth cohort study in Pelotas, Brazil, including 4,005 adolescents (mean age: 14.7 years) followed up from birth. Lung function was measured by spirometry. Outcome variables were forced expiratory volume in one second in liters (FEV1) and forced vital capacity also in liters (FVC). RESULTS: Mean FEV1 was 3.46 L (95%CI 3.43-3.49) among boys and 2.93 L (95%CI 2.91-2.95) among girls. Mean FVC was 4.00 L (95%CI 3.97; 4.04) among boys and 3.30 L (95%CI 3.27; 3.32) among girls. SES at birth, in adolescence and its trajectory from birth to adolescence were inversely associated with lung function in both adolescent boys and girls. After adjustment for mediating variables, coefficients were largely reduced, particularly among boys, and the main predictor of change in coefficients was the inclusion of height in the models. CONCLUSION: Low income adolescents from Brazil present impaired lung function as compared to the better off, and this is largely explained by height.

Maternal anthropometric characteristics in pregnancy and blood pressure among adolescents: 1993 live birth cohort, Pelotas, southern Brazil.

BACKGROUND: We investigated the association between maternal anthropometric measurements in prepregnancy and at the end of pregnancy and their children's systolic (SBP) and diastolic (DBP) blood pressure at 11 years of age, in a prospective cohort study. METHODS: All hospital births which took place in 1993 in the city of Pelotas-Brazil, were identified (5,249 live births). In 2004, the overall proportion of follow-up was 85% and we obtained arterial blood pressure measurements of 4,452 adolescents. RESULTS: Independent variables analyzed included maternal prepregnancy weight and body mass index (BMI) and maternal weight, and height at the end of pregnancy. Multiple linear regression analysis controlling for the following confounders were carried out: adolescent's skin color, family income at birth, smoking, alcohol intake during pregnancy, and gestational arterial hypertension. Mean SBP and DBP were 101.9 mmHg (SD 12.3) and 63.4 mmHg (SD 9.9), respectively. Maternal prepregnancy weight and BMI, and weight at the end of pregnancy were positively associated with both SBP and DBP in adolescent subjects of both sexes; maternal height was positively associated with SBP only among males. CONCLUSIONS: Adequate evaluation of maternal anthropometric characteristics during pregnancy may prevent high levels of blood pressure among adolescent children.

Prevalence of psychiatric disorders in a Brazilian birth cohort of 11-year-olds.

OBJECTIVE: To estimate the prevalence of psychiatric disorders in preadolescents aged 11-12 years from a birth cohort in a southern Brazilian city. METHODS: This is a cross-sectional investigation nested in a cohort study with a two-phase design: screening and diagnosis. In the screening phase, 4,452 preadolescents and their mothers were interviewed with the Strengths and Difficulties Questionnaire (SDQ). In the diagnostic phase, all preadolescents with a positive SDQ (n = 122) and their mothers answered the Development and Well-Being Assessment for Children and Adolescents (DAWBA). A sample randomly selected among the cohort participants with a negative SDQ served as a control group (158 subjects and their mothers) and was also assessed using the DAWBA. RESULTS: After adjustment for the performance of the screening instrument, 10.8% (95% CI 7.1-14.5) of the preadolescents showed at least one psychiatric disorder according to either the DSM-IV or the ICD-10. The most prevalent disorders were disruptive behavior (prevalence rates were 8.5% according to the DSM-IV and 7.1% according to the ICD-10) and anxiety disorders (prevalence rates were 6.0% according to the DSM-IV and 6.2% according to the ICD-10). CONCLUSION: Both overall and individual prevalence rates of psychiatric disorders found in this study are in the same range of other international studies, although slightly higher than findings from developed countries. The results corroborate previous findings from other epidemiological studies in children and adolescents suggesting the universality of psychiatric disorders across cultures.

[Measured weight, self-perceived weight, and associated factors in adolescents]. / Peso medido, peso percebido e fatores associados em adolescentes.

OBJECTIVE: To compare weight self-perception and nutritional status based on objective measurements of weight, height, and skin folds in adolescents, and to evaluate factors associated with disagreement between these measures. METHODS: The sample included the 1993 birth cohort from the city of Pelotas, Brazil, who were interviewed at home in 2004 and 2005. The study outcome resulted from the comparison between nutritional status and the weight self-perception of adolescents, and was divided into three categories: underestimation, agreement, and overestimation. The explanatory variables were sex, skin color, accumulated goods index, physical activity, eating habits, discrimination, dieting, feeling of well-being, and opinion of the adolescent concerning the perception of his/her parents regarding the adolescent's weight. Multivariate logistic regression was used for statistical analysis. RESULTS: A total of 4 452 interviews were conducted (87.5% of original cohort). Mean age was 11 years. The analysis of nutritional status revealed that 7.1% were underweight, 69.8% normal weight, 11.6% overweight, and 11.6% obese. The analysis of self-perceived weight revealed that 19% saw themselves as thin or very thin, 56% believed their weight was normal, and 25% saw themselves as fat or very fat. Global agreement between weight self-perception and nutritional status was 65% (kappa = 0.36). Weight underestimation occurred in 24.9% of boys vs. 20.3% of girls. Overestimation occurred in 15.8% of girls vs. 8.5% of boys. CONCLUSIONS: Girls tended to overestimate their weight, and boys, to underestimate it. There was a strong association between the opinion of adolescents concerning their parents' view of the adolescent's body and self-perceived weight.

Social and dental status along the life course and oral health impacts in adolescents: a population-based birth cohort.

BACKGROUND: Harmful social conditions in early life might predispose individuals to dental status which in turn may impact on adolescents' quality of life. AIMS: To estimate the prevalence of oral health impacts among 12 yr-old Brazilian adolescents (n = 359) and its association with life course socioeconomic variables, dental status and dental services utilization in a population-based birth cohort in Southern Brazil. METHODS: Exploratory variables were collected at birth, at 6 and 12 yr of age. The Oral Impacts on Daily Performances index (OIDP) was collected in adolescence and it was analyzed as a ranked outcome (OIDP from 0 to 9). Unadjusted and adjusted multivariable Poisson regression with robust variance was performed guided by a theoretical determination model. RESULTS: The response rate was of 94.4% (n = 339). The prevalence of OIDP = 1 was 30.1% (CI95%25.2;35.0) and OIDP >or= 2 was 28.0% (CI95%23.2;32.8). The most common daily activity affected was eating (44.8%), follow by cleaning the mouth and smiling (15.6%, and 15.0%, respectively). In the final model mother schooling and mother employment status in early cohort participant's life were associated with OIDP in adolescence. As higher untreated dental caries at age 6 and 12 years, and the presence of dental pain, gingival bleeding and incisal crowing in adolescence as higher the OIDP score. On the other hand, dental fluorosis was associated with low OIDP score. CONCLUSION: Our findings highlight the importance of adolescent's early life social environmental as mother schooling and mother employment status and the early and later dental status on the adolescent's quality of life regardless family income and use of dental services.

Socioeconomic position and overweight among adolescents: data from birth cohort studies in Brazil and the UK.

BACKGROUND: Developed and developing countries are facing rapid increases in overweight and obesity among children and adolescents. The patterns of overweight/obesity differ by age, sex, rural or urban residence and socioeconomic position (SEP) and vary between and within countries. METHODS: We investigated patterns of SEP--overweight status association among adolescents from the UK (ALSPAC) and Brazil (the 1982 and 1993 Pelotas birth cohort studies). All analyses were performed separately for males and females. Logistic regression analysis was used to examine the relationships between overweight status and two SEP indicators--family income and maternal education. RESULTS: A strong positive association was observed in 11-year-old boys from the 1993 Pelotas cohort, with higher prevalence of overweight among the least poor and among those whose mothers had more years of schooling (x2 for linear trend p < 0.001). In ALSPAC study higher prevalence of overweight was seen among boys whose mothers had lower educational achievement (x2 for linear trend p = 0.006). Among 11 year-old girls from 1993 Pelotas cohort study there was a positive association (higher prevalence of overweight in the higher socioeconomic and educational strata, x2 for linear trend p < 0.001 and p = 0.01, respectively) while an inverse association was found in the ALSPAC study (x2 for linear trend p < 0.001). Among males from the 1982 cohort study, overweight at 18 years of age showed a positive association with both SEP indicators while among females, the reverse association was found. CONCLUSION: The results of this study demonstrate that the social patterning of overweight varies between and within populations over time. Specific approaches should be developed within populations in order to contain the obesity epidemic and reduce disparities.

Continuity of behavioral and emotional problems from pre-school years to pre-adolescence in a developing country.

BACKGROUND: All previous longitudinal community studies assessing the continuity of child behavioral/emotional problems were conducted in developed countries. METHOD: Six hundred and one children randomly selected from a Brazilian birth cohort were evaluated for behavioral/emotional problems through mother interview at 4 and 12 years with the same standard procedure - Child Behavior Checklist (CBCL). RESULTS: CBCL Total Problem score presented a medium stability (r = .42) with externalizing problems showing higher stability and more homotypic continuity than internalizing problems. Of the children presenting deviant scores at the age of 4, only 31% remained deviant at the age of 12 (p < .001). A deviant CBCL Total Problem score at 12 years old was predicted by Rule-Breaking Behavior [OR = 7.46, 95% CI 2.76-20.19] and Social Problems [OR = 3.56, 95% CI 1.36-9.30] scores at 4 years of age. Either Rule-Breaking or Aggressive Behavior - externalizing syndromes - were part of the predictors for the three broad-band CBCL scores and six out of the eight CBCL syndromes. CONCLUSIONS: Behavioral/emotional problems in preschool children persist moderately up to pre-adolescence in a community sample. Externalizing problems at the age of 4 comprise the developmental history of most behavioral/emotional problems at pre-adolescence. Our findings concur with findings from developed countries and are quite similar for continuity, stability and predictability.

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.

Size at birth and height in early adolescence: a prospective birth cohort study.

The aim of this study was to evaluate the association between size at birth (birthweight and birth length) and height in early adolescence in a prospective birth cohort study in Pelotas, Rio Grande do Sul, Brazil. Interviews were carried out in 1993, including measurements of birthweight and length, and in 2004-2005, including measurements of weight and height. This analysis includes 4,452 individuals, with a mean age of 11.3 years (standard deviation-SD=0.3), representing a follow-up rate of 87.5%. Mean height at 11 years was 145.8 cm (SD=7.9), or 144.9 cm (SD=7.7) in boys and 146.8 cm (SD=7.9) in girls. Birthweight and birth length were positively associated with height in early adolescence in the crude analysis, but after adjustment for confounding and for each other, only the effect of birth length was still significant. A one z-score increase in birth length was associated with a 1.63 cm increase in height at 11 years. The present study shows that birth length is a strong predictor of later height, while the effect of birth weight disappears after adjustment for birth length.

Validity of maternal report on birth weight 11 years after delivery: the 1993 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil.

Birth weight has short and long-term effects on health. Some studies have used retrospective data on birth weight, reported by the subject or by the parents. This paper compares data on birth weight measured by the research team in 1993 with birth weight reported by the mother in 2004-2005, using data from the 1993 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil. We also evaluate the role of misclassification when exploring the effect of birth weight on a given outcome. Mean difference between the two variables was 20g (SD = 288.3). Agreement for detecting low birth weight was 95.2% in the sample as a whole (kappa = 0.73), but was lower among low-schooling mothers. Mothers of children weighing less than 3,500g at birth tended to overestimate the child's birth weight. Inversely, mothers of heavier children tended to underestimate the values. One out of four mothers reported a difference of at least 200g in birth weight as compared to that measured in 1993. Use of reported birth weight diluted the magnitude of the association with body mass index at 11 years in comparison with measured birth weight. Reported birth weight should be used with great caution, if at all.

Randomized clinical trial of the impact of a nutritional supplement "multimixture" on the nutritional status of children enrolled at preschools.

OBJECTIVE: To evaluate the effect of adding a nutritional supplement "multimixture" to school meals on the nutritional status of children enrolled at municipal preschools. METHODS: Longitudinal, controlled intervention study of 24 preschools which were compared before and after an intervention. The control and intervention groups were defined by drawing lots to choose schools that had previously been paired for nutritional status. The intervention consisted of the addition of 10 g of multimixture to the meals provided to children attending the 12 schools in the intervention group. Outcome measures include changes in z scores for the three nutritional indices and hemoglobin values over the 6-month period during which the supplement was added. A multilevel model was used for analyses. RESULTS: Mean z scores for weight for age at the end of follow-up were 0.40 (+/-1.34) and 0.31 (+/-1.32), for the intervention and control groups respectively. The multilevel analysis demonstrated non-significant differences in favor of the intervention in mean z scores for weight for age (beta 0.05; 95%CI -0.03 to 0.12) and height for age (beta 0.02; 95%CI -0.06 to 0.09). Mean change in hemoglobin was against the intervention, but this was also without significance (beta -0.01; 95%CI -0.36 to 0.34). CONCLUSIONS: Supplementation with 10 g of multimixture did not have a significant effect on any of the nutritional indices or measurements of the municipal preschool pupils studied here.

[Prevalence of overweight in adolescents: a population-based study in a southern Brazilian city]. / 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 > or = 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.

Who, when, and how much? Epidemiology of walking in a middle-income country.

BACKGROUND: Physical inactivity is one of the leading causes of morbidity and mortality worldwide. Walking, an inexpensive and accessible activity, is protective against unhealthy outcomes. Little data on walking practices are available outside developed countries. This study estimated the prevalence and correlates of compliance with physical activity recommendations through leisure-time and all-domain (combined leisure time, commuting, and work-related) walking in individuals aged > or =20 years in a southern Brazilian city. METHODS: Data from two population-based surveys carried out in 2002 and 2003 in Pelotas, Rio Grande do Sul, were compared and analyzed in 2004. Multistage sampling procedures were undertaken in both surveys. Compliance with physical activity recommendations was defined as > or =150 minutes/week of walking during the previous week, although other cut-off points were estimated. The International Physical Activity Questionnaire was used in both studies. RESULTS: Samples comprised 3182 (2002 study) and 3100 (2003 study) individuals. Nonresponse rates were 5.6% and 3.5%, respectively. Both prevalence and correlates of leisure-time and all-domains walking were markedly different. Compliance with physical activity guidelines (> or =150 minutes/week) through walking was 40.6% (all domains) and 15.0% (leisure time). Poor and uneducated participants had a lower likelihood of walking than higher-income and more educated people, particularly in leisure time. Walkers were also more likely to practice other vigorous and moderate-intensity activities. CONCLUSIONS: Although the results derive from a single Brazilian city, they are likely to be relevant to similar environments/locales in middle-income countries, where the obesity epidemic is rapidly increasing. Due to the low levels of walking detected, particularly during leisure time, healthcare professionals are encouraged to recommend walking to their patients.

Implementation of the WHO Multicentre Growth Reference Study in Brazil.

The World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) South American site was Pelotas, Brazil. The sample for the longitudinal component was drawn from three hospitals that account for approximately 90% of the city's deliveries. The cross-sectional sample was drawn from a community survey based on households that participated in the longitudinal sample. One of the criteria for site selection was the availability of a large, community based sample of children whose growth was unconstrained by socioeconomic conditions. Local work done in 1993 demonstrated that children of families with incomes at least six times the minimum wage had a stunting rate of 2.5%. Special public relations and implementation activities were designed to promote the acceptance of the study by the community and its successful completion. Among the major challenges of the site were serving as the MGRS pilot site, low baseline breastfeeding initiation and maintenance rates, and reluctance among pediatricians to acknowledge the relevance of current infant feeding recommendations to higher socioeconomic groups.

HIV/AIDS transmission knowledge among adolescents aged 11 years from Southern Brazil.

OBJECTIVE: To investigate the effect of demographic, socioeconomic, educational and family variables on HIV/AIDS knowledge among adolescents aged 11 years. METHODS: 3,949 adolescents born in Pelotas (Brazil). HIV/AIDS knowledge was assessed through a self-administered questionnaire and measured through five questions about HIV transmission: heterosexual intercourse, homosexual intercourse, needle sharing, open-mouth kissing and hugging someone with AIDS. All the analyses were adjusted based on a hierarchical model, using Poisson regression with robust adjustment of variance. RESULTS: Prevalence of wrong answers to the examined questions were 17.2% for heterosexual transmission, 44.1% for homosexual intercourse, 34.9% for needle sharing, 25.6% for kiss on the mouth and 16.2% for hugging someone with AIDS. In adjusted analysis, lower knowledge levels were more prevalent among boys, adolescents with lower socioeconomic status and with less maternal education level, among those who had not talked about sex with mother and without sexual education lessons at school. Knowledge was not associated with school type (public or private), skin color or talk about sex with father. CONCLUSION: Providing information to adolescents is essential to improve knowledge about HIV and other sexually transmitted infections, especially among young males, with lower socioeconomic status and with lower maternal education level. Public policies aimed to reducing HIV infection should consider maternal and school relevance to improve knowledge on adolescents.

Socioeconomic trajectories from birth to adolescence and risk factors for noncommunicable disease: prospective analyses.

PURPOSE: To evaluate the associations between family socioeconomic trajectories from 0 to 11 years of age and risk factors for noncommunicable disease at 15 years. METHODS: Individuals born in the city of Pelotas, Brazil, in 1993 are part of a birth cohort study. Socioeconomic position, collected at birth and at 11 years of age, was our main exposure. Risk factors for chronic disease were collected at 15 years. Body mass index was transformed into Z score using the World Health Organization standard. Transport and leisure-time physical activity, smoking, and alcohol consumption were assessed by self-report. Blood pressure was measured using a digital sphygmomanometer. RESULTS: Of 5,249 cohort members, 85.7% were located at the 15-year follow-up visit. Rich adolescents were more likely to be overweight, be obese, and not use active modes of transport to school. Poor adolescents were more likely to smoke. In relation to socioeconomic trajectories, the odds of obesity were 46% higher among those who were "always rich" compared with those who were "always poor"; the odds of use of an inactive mode of transportation were 326% greater among the "always rich" than the "always poor," whereas the reverse was observed for smoking (odds of 200%). The "always rich" had one-half the odds of walking or cycling to school compared with those who became wealthy in the studied period. CONCLUSIONS: Adolescent socioeconomic position is a stronger determinant of risk factors for noncommunicable diseases than socioeconomic trajectories. However, trajectories do matter, particularly in terms of use of active transportation to school.