Marlos Rodrigues Domingues

Physical activity change during adolescence: a systematic review and a pooled analysis

BACKGROUND It is presumed that physical activity (PA) level declines during the lifespan, particularly in adolescence. However, currently, there is no study that quantifies these changes and pools results for a common interpretation. Therefore, the purpose was to systematically review the international literature regarding PA change during adolescence, and to quantify that change according to a series of study variables, exploring gender-and-age differences. METHODS An electronic search was conducted in the Medline/PubMed and Web of Science databases. Longitudinal studies with, at least, two PA measures throughout adolescence (10-19 years old) or the first PA measure during childhood and the second one during adolescence were selected. From each article, study project name, country, year of the first data collection, sample size, baseline age, follow-up duration, characteristics of the instrument (type, recall time, PA intensity and PA domain), unit of PA measure and report of statistical significance were collected. RESULTS Overall, 26 studies matched the inclusion criteria. Most were carried out in the USA, assessed PA by questionnaire, and found a decline in PA levels during the adolescence. On average, the mean percentage PA change per year, across all studies, was -7.0 (95% confidence interval: -8.8 to -5.2), ranging from -18.8 to 7.8. The decline was significant according to most sub-groups of variables analysed. Although earlier studies revealed a higher PA decline in boys, the decline has been greater in girls in more recent studies (commenced after 1997). Moreover, although the decline among girls was higher in younger ages at baseline (9-12 years), it was higher in older ages (13-16 years) among boys. CONCLUSIONS The decline of PA during adolescence is a consistent finding in the literature. Differences between boys and girls were observed and should be explored in future studies. Interventions that attempt to attenuate the PA decline, even without an increase in PA levels, could be considered as effective.

Cohort Profile: The 2004 Pelotas (Brazil) Birth Cohort Study

The last decades of the 20th century witnessed a major epidemiological and nutritional transition in Latin America. Mortality due to infectious diseases and malnutrition declined in most countries and neonatal deaths now account for a growing proportion of infant deaths. In Brazil, infant mortality fell from 82.8 per 1000 live births in 1980 to 27.4 per 1000 in 2000. There were also marked improvements in undernutrition: 37.1% of Brazilian children <5 years of age were stunted in 1974 compared with 10.5% in 1996. Because of the speed of epidemiological and nutritional changes, and motivated by the successful implementation and follow-up of two previous population-based birth cohorts in 1982 and 1993, the research team decided to start a new cohort in 2004 to assess the magnitude of changes in maternal and child health status and their determinants. The existence of three prospective birth cohorts in the same population would provide a unique opportunity to study time trends over a 22-year span.

The challenge of reducing neonatal mortality in middle-income countries: findings from three Brazilian birth cohorts in 1982, 1993, and 2004

BACKGROUND Middle-income countries will need to drastically reduce neonatal deaths to achieve the Millennium Development Goal for child survival. The evolution of antenatal and perinatal care indicators in the Brazilian city of Pelotas from 1982 to 2004 provides a useful case study of potential challenges. METHODS We prospectively studied three birth cohorts representing all urban births in 1982, 1993, and from January to July, 2004. The same methods were used in all three studies. FINDINGS Despite improvements in maternal characteristics, prevalence of preterm births increased from 6.3% (294 of 4665) in 1982 to 16.2% (342 of 2112) in 2004, corresponding to a 47 g reduction in mean birthweight. Average number of antenatal visits in 2004 was 8.3 per woman, but quality of care was still inadequate--97% of women had an ultrasound scan, but only 1830 (77%) had a vaginal examination and 559 of 1748 non-immunised women did not receive tetanus toxoid. Rate of caesarean sections increased greatly, from 28% (1632 of 5914) in 1982 to 43% (1039 of 2403) in 2004, reaching 374 of 456 (82%) of all private deliveries in 2004. The increased rate of preterm births seemed to result largely from caesarean sections or inductions. Newborn care improved, and gestational-age-specific mortality rates had fallen by about 50% since 1982. As a result, neonatal mortality rates had been stable since 1990, despite the increase in preterm deliveries. INTERPRETATION Excessive medicalisation--including labour induction, caesarean sections, and inaccurate ultrasound scans--led by an unregulated private sector with spill-over effects to the public sector, might offset the gains resulting from improved maternal health and newborn survival. These challenges will have to be faced by middle-income countries striving to achieve the child survival Millennium Development Goal.

The Role of Perceived Personal Barriers to Engagement in Leisure-Time Physical Activity

OBJECTIVES We sought to identify perceived personal barriers to physical activity and examine the potential association between these barriers and sociodemographic and behavioral variables, including participation in leisure-time physical activity. METHODS In 2003, we conducted a population-based study in Pelotas, Brazil. Participants aged 20 years and older were selected according to a multistage sampling strategy. Participants responded to both the International Physical Activity Questionnaire and a standardized questionnaire investigating 8 perceived personal barriers. RESULTS Only 26.8% of participants achieved 150 minutes per week of leisure-time physical activity. Lack of money (40.3%) and feeling too tired (38.1%) were the most frequently reported barriers to physical activity. A dose-response group association was observed between number of perceived barriers and level of physical activity. In the multivariable analysis, lack of time, dislike of exercising, feeling too tired, lack of company, and lack of money were associated with physical inactivity. CONCLUSION Detection of the determinants of physical inactivity, a growing epidemic, should be a public health priority. Brazil is a middle-income (developing) country. The prevalence of most of the personal barriers studied was higher in this population than those levels observed in high-income (developed) countries. Perceiving 5 of the 8 barriers investigated was inversely associated with leisure-time physical activity level.

The 2004 Pelotas birth cohort: methods and description

OBJECTIVE To describe a birth cohort which started in 2004, aiming to assess pre and perinatal conditions of the newborns, infant morbimortality, early life characteristics and outcomes, and access, use and financing of health care. METHODS All children born in the urban area of Pelotas and Capão do Leão municipalities (Southern Brazil) in 2004 were identified and their mothers invited to join the study. In the first year of the study the children were seen at birth, at three and 12 months of age. These visits involved the application of a questionnaire to the mothers including questions on health; life style; use of health services; socioeconomic situation; estimation of gestational age; anthropometric measurements on the newborn (weight, length, head, chest and abdominal circumferences); anthropometric measurements on the mother (weight and height) and assessment of infant development. RESULTS Out of the eligible infants (4,558), more than 99% were recruited to the study at birth. Follow-up rates were 96% at three months and 94% at 12 months of age. Among the initial results we highlight the following. Infant mortality rate was 19.7 per thousand, with 66% of infant deaths occurring in the neonatal period. There were frequencies of 15% premature babies and 10% low birthweight. Cesarean sections represented 45% of deliveries. CONCLUSIONS The third Pelotas birth cohort showed an infant mortality rate similar to that of 11 years ago, with most deaths occurring in the neonatal period. The rates of prematurity and cesarean sections increased substantially.

Patterns of deliveries in a Brazilian birth cohort: almost universal cesarean sections for the better-off

OBJETIVO: Describir el padron de los partos en una cohorte de nacimientos, comparando partos normales y cesareos. METODOS: Todos los recien nacidos de moradoras de area urbana de Pelotas (Sur de Brasil) en 2004 fueron reclutados para una cohorte de nacimientos. Las madres fueron entrevistadas aun en el hospital, cuando informaciones detalladas de la gestacion, el parto y el recien nacido, junto con una historia de salud materna y caracteristicas de la familia fueron colectadas. Caracteristicas maternas y el financiamiento del parto fueron los principales factores estudiados. Tambien se hizo descripcion de la distribucion de las cesareas por hora del dia y dia de la semana. Tecnicas de padron de analisis descriptivo y pruebas chi-cuadrado para comparar proporciones y regresion Poisson para explorar el efecto independiente de predictores de la cesarea fueron los metodos utilizados. RESULTADOS: La tasa global de cesareas fue de 45%, 36% entre pacientes del servicio publico y 81% en el servicio privado, donde se relato que 35% de las cesareas fueron electivas. Las cesareas fueron mas frecuentes martes y miercoles, con una reduccion de cerca de un tercio los domingos, mientras que los partos normales presentaron distribucion uniforme a lo largo de la semana. El horario de las cesareas en el servicio publico y en el privado fue muy diferente. La escolaridad materna se asocio positivamente con la cesarea entre las madres del servicio publico, pero no del privado. CONCLUSIONES: La cesarea fue muy frecuente entre las madres mas ricas, y fuertemente asociada con la escolaridad materna entre pacientes del servicio publico. Los padrones descritos son compatibles con la hipotesis de que las cesareas son hechas, en gran parte, para atender la conveniencia de las agendas de los medicos. La situacion actual solo sera revertida con politicas radicales.OBJECTIVE To describe the patterns of deliveries in a birth cohort and to compare vaginal and cesarean section deliveries. METHODS All children born to mothers from the urban area of Pelotas, Brazil, in 2004, were recruited for a birth cohort study. Mothers were contacted and interviewed during their hospital stay when extensive information on the gestation, the birth and the newborn, along with maternal health history and family characteristics was collected. Maternal characteristics and childbirth care financing - either private or public healthcare (SUS) patients - were the main factors investigated along with a description of C-sections distribution according to day of the week and delivery time. Standard descriptive techniques, Χ² tests for comparing proportions and Poisson regression to explore the independent effect of C-section predictors were the methods used. RESULTS The overall C-section rate was 45%, 36% among SUS and 81% among private patients, where 35% of C-sections were reported elective. C-sections were more frequent on Tuesdays and Wednesdays, reducing by about a third on Sundays, while normal deliveries had a uniform distribution along the week. Delivery time for C-sections was markedly different among public and private patients. Maternal schooling was positively associated with C-section among SUS patients, but not among private patients. CONCLUSIONS C-sections were almost universal among the wealthier mothers, and strongly related to maternal education among SUS patients. The patterns we describe are compatible with the idea that C-sections are largely done to suit the doctors schedule. Drastic action is called for to change the current situation.

Leisure-time physical activity during pregnancy in the 2004 Pelotas Birth Cohort Study

OBJECTIVE Physical activity during pregnancy is a poorly investigated subject on population level. The study aimed to describe duration, type and frequency of leisure-time physical activity during pregnancy, and to explore its associated factors. METHODS A population-based study was carried out during 2004 in Southern Brazil. A total of 4,471 mothers were interviewed soon after delivery. Physical activity was measured using a questionnaire, developed for the study. Results were obtained by Poisson regression. RESULTS In the sample, 14.8% of women reported to engage in some type of physical activity prior to pregnancy and 12.9% during pregnancy. In the first trimester, 10.4% of all mothers engaged in some type of physical activity; 8.5% in the second trimester and 6.5% in the third trimester. Only 194 mothers (4.3%) were active during the whole pregnancy. In the adjusted analysis, leisure-time physical activity was positively associated with schooling, physical activity advice during prenatal care, and family income (p<0.001), being employed during pregnancy (p=0.05), and number of pregnancies (p=0.02). Walking was the most frequent activity. CONCLUSIONS The prevalence of leisure-time physical activity is low among Brazilian pregnant women. Although physical activity is not perceived as being pregnancy-threatening, and current guidelines recommend it, this populations behavior does not seem to be changing. Active lifestyle for both pregnant women and future mothers should be encouraged.

Conhecimento e percepção sobre exercício físico em uma população adulta urbana do sul do Brasil

This study evaluates perception and knowledge of physical exercise in an urban adult population and relates knowledge level to behavioral, demographic, and socioeconomic factors, using a cross-sectional, population-based approach with 3,182 participants aged 20 or older. The questionnaire originated a score (range 0-25 points). Mean score for the sample was 17.1 (SD=4.0). After adjustment, female gender, age 30 to 40 years, higher social strata, and schooling were strongly associated (p<0.001) with the outcome (knowledge). Weaker associations (p< or =0.01) were observed between the score and higher body mass index, level of physical activity, and white skin color. Based on the results, specific benefits from exercising are still unknown to some population groups. Counseling by teachers on the advantages of an active lifestyle is still not common practice.

Prevalence of food insecurity in Pelotas, Rio Grande do Sul State, Brazil, and associated nutritional status

A population-based cross-sectional study was conducted in Pelotas, Southern Brazil, to assess the prevalence of food insecurity and describe the nutritional status of family members living in this condition. The sample included 1,450 households from the urban area of Pelotas. The six questions of the Food Insecurity Scale (United States Department of Agriculture) were administered to the person in charge of preparing meals in the house. A 12-month recall period was used. If the household was considered insecure, all members were weighed and measured. Prevalence of food insecurity for all families was 11% (95%CI: 9%-13%). In families living in food insecurity, overweight and obesity were frequent; meanwhile, 21% of the children showed height deficit. The authors conclude that food insecurity results not only from quantitative limitations but also from deficient food quality.

Mothers and their pregnancies: a comparison of three population-based cohorts in Southern Brazil

Mothers from the 1982, 1993 and 2004 Pelotas birth cohorts were compared across biological, socioeconomic, demographic and reproductive characteristics. Women in the 2004 cohort had higher levels of education, gained more weight during pregnancy, and were heavier at the beginning and end of their pregnancy than mothers who gave birth in 1993 and 1982. There was an important increase in obesity rates (body mass index > 30kg/m(2)) over the 22 years of the study. Mean parity decreased from 1.3 in 1982 to 1.1 in 2004, with a growing proportion of primiparas and a decline in the proportion of women with > or = 4 children. The mean birth interval increased from 33.5 months in 1982 to 65.7 in 2004. Smoking during pregnancy decreased from 35.6% in 1982 to 25.1% in 2004. As with other characteristics, the change in smoking status differed according to income, with higher reductions among the wealthiest (from 24.9% to 8.7%) than among the poorest mothers (from 43.7% to 33.6%). In general terms, between 1993 and 2004 there was a decrease in the prevalence of maternal risk factors for unfavorable perinatal outcomes.