Breastfeeding and feeding patterns in two cohorts of children in southern Brazil: trends and differences

Breastfeeding is fundamental for infant health. However, its median duration in Brazil is very short, and national campaigns since the mid-1980s have attempted to revert this situation. In the present paper, data on breastfeeding are compared for two population-based cohorts of children born in 1982 and 1993 in the city of Pelotas in Southern Brazil. All hospital births in both years were studied and samples of these children were visited at home around 12 months of age. Median duration of breastfeeding increased from 3.1 to 4.0 months in this period. This rise suggests an impact by the national campaigns. In both cohorts, there were interactions between family income and the percentages of children breastfed at different ages. In the early months, breastfeeding was more prevalent in high-income families, but from nine months onwards it was more common among the poor. Low birthweight babies enjoyed shorter duration of breastfeeding. Despite the progress observed during the decade, duration of breastfeeding is still far short of international recommendations, justifying further campaigns prioritizing low birthweight babies and those from low-income families.     

The epidemiological transition in maternal and child health in a Brazilian city, 1982-93: a comparison of two population-based cohorts

Two studies carried out in 1982 and 1993 in the city of Pelotas, Southern Brazil, provide a unique opportunity for assessing the impact on maternal and child health of the economic and health care changes, which took place in Brazil in this period. The cohorts of mothers and infants of 1982 and 1993 were studied from the time of delivery. In both years, all mothers identified in the city's maternity hospitals answered a standardised questionnaire and their infants were examined. Over 99% of all children born in the city in each of the 2 years were included in the cohorts. Deaths occurring among these children were monitored prospectively, as well as all hospital admissions in the 1993 cohort. In the 1982 study, attempts were made to locate a 25% sample of the children at the mean age of 12 months using the addresses collected at the hospital (82% of the children were located), and all of the cohort children at the mean age of 20 months and 42 months, through a city census (87% were located in both follow-ups). In the 1993 study, 20% of all children plus all low birthweight infants were sought at 12 months of age, using the addresses collected at the hospital, and 95% were successfully traced. There was a 12% fall in the number of births occurring in 1993 (5,304 births), in comparison with 1982 (6,011 births), in spite of the increase in the population of reproductive age in the city during the decade. There was a marked difference in maternal height and weight at the beginning of pregnancy, with women giving birth in 1993 being, on average, 3.4 cm taller and 2.5 kg heavier than those who gave birth in 1982. The proportion of preterm babies (<37 weeks), measured by the date of last menstrual period, increased from 5.6% in 1982 to 7.5% in 1993. The median duration of breast feeding increased from 3.1 months in 1982 to 4.0 months in 1993. At 12 months of age, the prevalence of deficit of weight for age decreased from 5.4% in 1982 to 3.7% in 1993. The prevalence of deficit of height for age, however, increased from 5.3% to 6.1%. The perinatal mortality rate dropped 31%, from 32.2 per 1,000 births in 1982 to 22.1 deaths per 1,000 births in 1993. There was also a marked reduction in the infant mortality rate, from 36.4 per 1,000 livebirths in 1982 to 21.1 per 1,000 livebirths in 1993. The findings of the study indicate that there were improvements in the decade for most of the indicators evaluated, with the exception of birthweight and gestational age. It appears that improvements in perinatal and infant mortality rates are largely due to improvements in the health care sector.     

Infant malnutrition and obesity in two population-based birth cohort studies in southern Brazil: trends and differences

Prevalence of anthropometric deficits and of obesity were studied in two population-based birth cohort studies in the city of Pelotas in Southern Brazil, in 1982 and 1993. All hospital delivered babies in each one-year period were identified, and samples of approximately 20% were visited at home at around 12 months of age, totalling 1,449 children submitted to anthropometric examination in 1982 and 1,359 in 1993. Losses and refusals accounted for 20% of the children in 1982 and 7% in 1993. In this 11-year period, prevalence of weight/age deficits (below -2 standard deviations of the NCHS reference) fell from 5.4% to 3.8%, while that of weight/height dropped from 1.3% to 0.8%. Height/age deficits increased slightly, from 5.3% to 6.1%, while the proportion of obese children increased from 4.0% to 6.7%. The increase in weight at 12 months was due to a more rapid weight gain in the first year, since birthweights remained unchanged. About 10% of the children from the lowest income group had weight/age or height/age deficits, compared to 3% or less of those with a high family income. On the other hand, obesity showed a direct association with income, except for the wealthiest group, where the prevalence dropped, possibly due to concern among these families about the consequences of infant obesity.     

Breastfeeding and feeding patterns in three birth cohorts in Southern Brazil: trends and differentials

Breastfeeding is fundamental for child health. Changes in the duration of breastfeeding are compared for three population-based cohorts of children born in 1982, 1993 and 2004 in the city of Pelotas, Southern Brazil. Samples of the 1982 and 1993 children and all of the children from the 2004 cohort study were sought at home when they were aged around 12 months. Both the duration of breastfeeding and the stage at which different kind of foods were regularly introduced were investigated. The median duration of breastfeeding increased from 3.1 to 6.8 months in this period. Exclusive breastfeeding at three months was practically non-existent in 1982 and had reached one third of infants by 2004. The increase was faster after 1993, suggesting an important impact made by promotion activities. Up to about 6-9 months, breastfeeding was more prevalent in high-income families, but after this age it became more common among the poor. Low birth weight babies were breastfeed for shorter durations. The duration of breastfeeding is still far short of international recommendations, justifying further campaigns. Special attention should be given to low birth weight babies and those from low-income families.     

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.     

Maternal and child care in two population-based cohorts from southern Brazil: trends and differences

Two cohort studies of mothers and children (1982 and 1993) were used to document changes in health care utilization patterns. The cohorts included all hospital deliveries in the city of Pelotas, Southern Brazil, for the two years. Some 20% of the mothers and children were visited at home at a median interval of one year later. However, there was a reduction in the percentage of mothers seeking care after the fifth month of pregnancy. The mean number of prenatal consultations increased to 7.6. Prenatal care indicators were significantly worse for low-income and high-gestational-risk women. In 1993, caesarean sections accounted for 31% of deliveries. The proportions of deliveries assisted by medical doctors increased to 88%. Low-income and high-risk mothers were less likely to have a caesarean section or to be assisted by a medical doctor. Over half of the deliveries in the highest income group were caesareans. Vaccine coverage at 12 months increased over the decade. Socioeconomic differentials were also observed. The mean number of medical consultations during the first year of life decreased to 10.5, mainly due to a drop in preventive care. Although most health care indicators improved over the course of the decade, health services are still biased towards those who least need them.     

Preterm births, low birth weight, and intrauterine growth restriction in three birth cohorts in Southern Brazil: 1982, 1993 and 2004

Three birth cohort studies from 1982, 1993 and 2004, in Pelotas, Southern Brazil provided the data for this study of trends in preterm births, low birth weight, and intrauterine growth restriction. We found a slight increase in the period in the low birth weight prevalence from 9% to 10%. Intrauterine growth restriction decreased from 14.8% in 1982 to 9.4% in 1993, and subsequently increased to 12% in 2004, whereas preterm births increased markedly, from 6.3% in 1982 to 14.7% in 2004. This striking increment could not be explained by changes in maternal characteristics, as mothers in 2004 were heavier, smoked less during pregnancy and attended antenatal clinics more often and earlier than those of previous cohorts. However, pregnancy interruptions due either to caesarean sections or to inductions significantly increased. Caesareans increased from 28% in 1982 to 45% in 2004, and inductions were 2.5% in 1982 but 11.1% in 2004. The increase in preterms could be partially explained by the growing number of pregnancy interruptions, but there must be other causes since this increase was also observed among babies born by non-induced vaginal deliveries.     

Developmental status at age 12 months according to birth weight and family income: a comparison of two Brazilian birth cohorts

Two cohorts of children born in the city of Pelotas, Southern Brazil, in 1993 and 2004, were compared in terms of neuro-psychomotor development at the age of 12 months. Children were evaluated using the Denver II screening test. Analyses were performed using the Poisson regression technique. The prevalence of suspected developmental delay fell from 37.1% in 1993 to 21.4% in 2004 and was inversely proportional to family income and birth weight. Among children born weighing under 2,000 g, there was a fourfold reduction in the prevalence of developmental delay between 1993 and 2004. With regard to family income, the poorest group showed the greatest reduction between the two cohorts--a 30% reduction in risk. Our results confirm the influence of income and birth weight on child development. The decrease in the prevalence of developmental delay in the last decade reflects, among other factors, improvements in neonatal care, increased coverage of developmental monitoring in the first year of life, and longer breastfeeding duration. Despite this reduction, the prevalence of developmental delay is still high, reinforcing the need for early diagnosis and intervention.     

Infant mortality in Pelotas, Brazil: a comparison of risk factors in two birth cohorts.

OBJECTIVES: To compare two population-based birth cohorts to assess trends in infant mortality rates and the distribution of relevant risk factors, and how these changed after an 11-year period. METHODS: Data from two population-based prospective birth cohorts (1982 and 1993) were analyzed. Both studies included all children born in a hospital (> 99% of all births) in the city of Pelotas, Southern Brazil. Infant mortality was monitored through surveillance of all maternity hospitals, mortality registries and cemeteries. RESULTS: There were 5,914 live-born children in 1982 and 5,249 in 1993. The infant mortality rate decreased by 41%, from 36.0 per 1,000 live births in 1982 to 21.1 per 1,000 in 1993. Socioeconomic and maternal factors tended to become more favorable during the study period, but there were unfavorable changes in birthweight and gestational age. Poverty, high parity, low birthweight, preterm delivery, and intrauterine growth restriction were the main risk factors for infant mortality in both cohorts. The 41% reduction in infant mortality between 1982 and 1993 would have been even greater had the prevalence of risk factors remained constant during the period studied here. CONCLUSIONS: There were impressive declines in infant mortality which were not due to changes in the risk factors we studied. Because no reduction was seen in the large social inequalities documented in the 1982 cohort, it is likely that the reduction in infant mortality resulted largely from improvements in health care.     

Trends in socioeconomic inequalities in anthropometric status in a population undergoing the nutritional transition: data from 1982, 1993 and 2004 Pelotas Birth Cohort studies

ABSTRACT: BACKGROUND: Socioeconomic inequalities in child nutrition may change rapidly over time, particularly in populations undergoing the nutrition transition. Yet, the few available studies are repeated cross-sectional surveys. By studying three prospective birth cohorts in the same city over a period of more than two decades, we describe secular trends in overweight and stunting at different ages, according to socioeconomic position. METHODS: Population-based birth cohort studies were launched in the city of Pelotas (Brazil) in 1982, 1993 and 2004, with follow-up visits at twelve, 24 and 48 months. Children were weighed and measured at every visit. Z-scores of length/height-for-age and body mass index-for-age were calculated using the WHO Child Growth Standards. The slope and relative indices of inequality, based on family income quintiles, were estimated for each follow-up visit. RESULTS: Between the 1982 and 2004 cohorts, stunting among four-year-olds declined (from 10.9% to 3.6%), while overweight increased (from 7.6% to 12.3%). In every visit, stunting prevalence was inversely related to income. Both absolute and relative inequalities declined over time; among four-year-olds stunting dropped from 26.0% in the 1982 cohort to 6.7% in the 2004 cohort in the poorest group, while in the richest group stunting prevalence dropped from 2.7% in 1982 to 1.1% in the 2004 cohort study. The secular trend towards increased overweight was evident for four-year-olds, in almost all socioeconomic groups, but not among one and two-year-olds. Among four-year old children, overweight prevalence increased in all income quintiles, by 130% in the middle-income group, 64% in the poorest and 41% in the richest group. CONCLUSIONS: The decline in stunting is remarkable, but the increase in overweight among four-year olds - particularly among the poorest and the middle-income groups- requires concerted efforts to prevent the long term consequences of child overweight.     

Evolution of the association between parental and child smoking in Finland between 1977 and 2005

OBJECTIVES: To study changes in the family smoking profile and in the association between parental and child smoking from 1977 to 2005. METHODS: Data was based on biennial surveys using nationally-representative samples of 14-18-year-old Finns (n=58,279). Response rate ranged between 88% (1977) and 65% (2005). Parental smoking categories were: two smoking parents, smoking father, smoking mother, both currently non-smokers but one or both ex-smokers, and two never-smoking parents. Child smoking categories were: experimental, daily, and never. Associations between parental and child smoking were examined using multinomial logistic regression models. RESULTS: Over the study period, the proportion of never-smoking families (child and parents never-smokers) increased (9% vs. 18%). Age, sex, family structure, and survey decade adjusted odds ratios for child's daily smoking were 6.9 (95% CI: 6.4, 7.5) when both parents smoked, 4.7 (95% CI: 4.3, 5.2) when mother smoked, 3.8 (95% CI: 3.5, 4.1) when father smoked, and 2.8 (95% CI: 2.6, 2.9) when one/both were ex-smokers compared with children of never-smoking parents. Only a few non-systematic interactions between parental smoking and survey decade were found. CONCLUSIONS: The proportion of totally smoke-free families increased substantially. Association between parental and child smoking persisted strong and mainly similar over time.     

Hospitalizations during infancy in three population-based studies in Southern Brazil: trends and differentials

Three cohort studies of children born in the urban area of Pelotas, Southern Brazil, were carried out in 1982, 1993, and 2004. The aim of these studies was to measure the occurrence of hospitalization in the first year of life and to examine the association between hospitalization and the cause of admission and sex, birth weight, and family income. Cause of admission was categorized as "diarrhea" and "all other causes". The frequency of children hospitalized at least once during their first year of life was 19.6% in 1982, 18.1% in 1993, and 19.2% in 2004. There was a marked reduction in hospitalizations due to diarrhea, but the frequency of hospitalization for all causes remained constant. In all three cohorts, infants from poorer families and those born weighing under 2,000g showed the highest frequencies of hospitalization due to diarrhea and all other causes, and the latter also showed a marked increase in hospitalizations due to all causes. These findings could be explained by an epidemic of preterm births in the study population.     

Infant malnutrition and obesity in three population-based birth cohort studies in Southern Brazil: trends and differences

The aim of this study was to compare the evolution of nutritional deficits and overweight in one-year-old children from three birth cohorts started in 1982, 1993 and 2004 in Pelotas, Southern Brazil. Samples from the 1982 and 1993 cohorts and all children from 2004 were weighed and measured, and their mothers interviewed. Anthropometric deficits and overweight were assessed using both NCHS and WHO growth standards. A comparison of the existence of nutritional deficits showed that, after a decline between 1982 and 1993, its prevalence stabilized between 1993 and 2004. Across the whole period, a decrease in all deficits was observed. Obesity, on the other hand, increased. A deficit in the ratio of body length to age was found to be strongly associated with family income. The group with income below one minimum wage was the only to present a significant reduction of stunting during the study period. The most significant improvements in the reduction of nutritional deficits occurred in the first half of the study period, while social differentials remained. Fighting malnutrition is still necessary among the 40% of the population considered poor, and must be accompanied by efforts to combat overweight which is being observed in all social strata.     

Infant mortality in three population-based cohorts in Southern Brazil: trends and differentials

We studied time trends in infant mortality and associated factors between three cohort studies carried out in Pelotas, Rio Grande do Sul State, Brazil, in 1982, 1993, and 2004. All hospital births and deaths were determined by means of regular visits to hospitals, registrar's offices, and cemeteries. This data was used to calculate neonatal, post-neonatal, and infant mortality rates per thousand live births. Rates were also calculated according to cause of death, sex, birth weight, gestational age, and family income. The infant mortality rate fell from 36.4 per 1,000 live births in 1982 to 21.1 in 1993 and 19.4 in 2004. Major causes of infant mortality in 2004 were perinatal causes and respiratory infections. Mortality among low birth weight children from poor families fell 16% between 1993 and 2004; however, this rate increased by more than 100% among high-income families due to the increase in the number of preterm deliveries in this group. The stabilization of infant mortality in the last decade is likely to be due to excess medical interventions relating to pregnancies and delivery care.     

The emergence of vaccine hesitancy among upper-class Brazilians: Results from four birth cohorts, 1982–2015

Vaccine hesitancy has been increasingly reported in Brazil. We describe secular trends and socioeconomic disparities from 1982 to 2015, using data from four population-based birth cohorts carried out in the city of Pelotas. Full immunization coverage (FIC) was defined as having received four basic vaccines (one dose of BCG and measles, and three doses of polio and DTP) scheduled for the first year of life. Information on income was collected through standardized questionnaires, and the slope index of inequality (SII) was calculated to express the difference in percent points between the rich and poor extremes of the income distribution. Full immunization coverage was 80.9% (95% CI 79.8%; 82.0%) in 1982, 97.2% (96.1%; 98.0%) in 1993, 87.8% (86.7%; 88.8%) in 2004 and 77.2% (75.8%; 78.4%) in 2015. In 1982 there was a strong social gradient with higher coverage among children from wealthy families (SII = 25.0, P < 0.001); by 2015, the pattern was inverted with higher coverage among poor children (SII = −6.0; P = 0.01). Vertical immunization programs in the 1980s and creation of the National Health Services in 1980 eliminated the social gradient that had been present up to the 1980s, to reach near universal coverage. The recent decline in coverage is likely associated with the growing complexity of the vaccination schedule and underfunding of the health sector. In addition, the faster decline observed among children from wealthy families is probably due to vaccine hesitancy.     

Immunization registry accuracy: improvement with progressive clinical application

BACKGROUND: Healthcare systems have been challenged to ensure the timely administration of immunizations. Immunization registries have been proposed to improve the accuracy and completeness of immunization information and to promote effective practice. METHODS: Comparison of randomly selected samples from two birth cohorts (1993 and 1998) from Denver Health Medical Center. Chart review and immunization registry information for these groups were compared; a composite immunization was recorded and up-to-date (UTD) status established. Registry data were compared with this composite using a sensitivity measure to assess completeness and accuracy. RESULTS: Among 818 children in the 1993 cohort and 1043 children in the 1998 cohort, there were 6386 and 6886 valid immunizations, respectively. The registry recorded 71.4% and 97.7% of these for the 1993 and 1998 cohorts, respectively (p <0.001). The apparent UTD rate, as measured with registry data alone, improved from 37% to 79% between the two time frames (p <0.001). Composite UTD status was 83.1% and 78.9% (1993 vs 1998, respectively). Accurate registry-defined UTD status improved from 44.4% to 100% between the two intervals. CONCLUSIONS: Immunization registry accuracy improved dramatically for recorded immunizations and UTD status. However, after 3 years of registry use, the overall proportion of children who were UTD had not significantly improved. The mere presence of a registry does not ensure more complete vaccination coverage. Other registry-based strategies, including use of the data for reminder, recall, and audit, may further improve immunization coverage.     

Contraceptive use and pregnancy outcome in three generations of Swedish female teenagers from the same urban population

Background

The primary objective of the study was to describe contraceptive use, reasons for discontinuation of contraception and pregnancy outcome in three generations of female teenagers over a period of 20 years. The secondary objective was to describe the relationship between contraception, smoking, body mass index (BMI) and socioeconomic status (SES).

Study Design

A cross-sectional comparison of 19-year-old women born in 1962, 1972 and 1982 and living in the city of Gothenburg, Sweden, in 1981, 1991 and 2001 was conducted. Contraceptive use, pregnancy outcome, smoking and weight/height were assessed by a postal questionnaire.

Results

Current contraceptive use was unchanged between the 62 (60%) and 72 cohorts (62%) but had increased (p<.01) in the 82 cohort (78%); there was no difference in contraceptive use between SES groups at any time. Condom use alone increased over time (p<.01), and the use of oral contraception and a condom together had increased in the 72 and 82 cohorts compared to the 62 cohort (p<.01). Reasons given for using and discontinuing oral contraceptives in three generations of teenagers were studied over 20 years. In addition to contraception, oral contraception was used to reduce dysmenorrhea and heavy bleeding. Discontinuation due to bleeding disturbances decreased (p<.01) over time, whereas discontinuation due to mental side effects increased (p<.01). The percentage of women who had been pregnant at ≤19 years of age in the 82 cohort (7%) was lower (p<.01) than in the 1962 (11%) and 1972 (13%) cohorts. However, there was a successive increase (p<.001) in the percentage of women who had been pregnant more than once at ≤19 years of age (1962/1972/1982: pregnant more than once, 8%/21%/31%). Smoking decreased over time (p<.01) and was no longer related to SES in the 82 cohort. BMI increased (p<.01) over time. There was no difference in BMI between SES groups in the 62 and 72 cohorts but was higher in the low-SES group in the 82 cohort compared to the middle (p<.01) and high (p<.05) SES groups.

Conclusions

Contraceptive use was higher in the 82 cohort where there was a corresponding reduction in the percentage of women who had been pregnant at ≤19 years of age compared with the 62 and 72 cohorts. Discontinuation of oral contraception due to mental side effects increased over time. The prevalence of smoking decreased and BMI increased, and there were changes in smoking prevalence and BMI in the different SES groups over time.     

Does adolescent perception of difficulty in getting cigarettes deter experimentation?

BACKGROUND: Considerable controversy surrounds tobacco control emphasis on youth-access-to-tobacco laws, as there is limited evidence that such enforcement reduces youth smoking. In California, access-law enforcement increased substantially in 1996 compared to earlier in the decade. METHODS: Two longitudinal cohorts of adolescent never smokers from the large, population-based California Tobacco Surveys of 1993 and 1996 were followed-up 3 years later (1993-1996 [n = 1764] and 1996-1999 [n = 2119]). We examined transition to any smoking by follow-up with adolescent perception that cigarettes are easy or hard to get, during periods with less and more access law enforcement. RESULTS: Transition to any smoking by follow-up among 12- to 15-year-old never smokers was identical in the 1993-1996 cohort, regardless of whether they perceived cigarettes as hard or easy to get (about 38%), but was lower in the 1996-1999 cohort for those who perceived that cigarettes were hard (25.9%) vs. easy (36.1%) to get. This differential effect was confirmed in multivariate analyses that adjusted for demographics, cohort, and other known predictors of adolescent smoking. CONCLUSIONS: Increased enforcement of access laws may help protect young adolescents from experimenting with cigarettes by strengthening societal anti-tobacco norms. Such enforcement appears warranted as part of a comprehensive tobacco control program.     

The use of maternal and child health services in three population-based cohorts in Southern Brazil, 1982-2004

This study aimed to describe indicators of health care assistance during antenatal care, delivery and in the first year of life in Pelotas, Rio Grande do Sul State, Brazil. In 1982, 1993, and 2004, all hospital newborns from the urban area of Pelotas were enrolled in a cohort study. In this period, the number of pregnant women that did not attend antenatal care fell from 4.9% to 1.9%; the mean number of appointments increased from 6.7 to 8.1; and the number of women who began antenatal care in the third trimester of pregnancy decreased from 14.8% to 7%; caesarean sections increased from 27.7% to 45.2% and the proportion of deliveries assisted by physicians increased from 61.2% to 89.2%. Improvements in immunization rates during the first year of life mainly occurred between 1982 and 1993, while the number of preventive medical appointments improved among those born in 2004. This increase in coverage was greater for low-income mothers and children, which may reflect the implementation of universal coverage in Brazil; however, coverage levels in 1982 were already high for wealthy mothers and children, reducing the scope for further gains.