Examining the quality of record linkage process using nationwide Brazilian administrative databases to build a large birth cohort

Impact of linkage level on inferences from big data analyses in health and medical research: an empirical study

BACKGROUND

Linkage errors that occur according to linkage levels can adversely affect the accuracy and reliability of analysis results. This study aimed to identify the differences in results according to personally identifiable information linkage level, sample size, and analysis methods through empirical analysis.

METHODS

The difference between the results of linkage in directly identifiable information (DII) and indirectly identifiable information (III) linkage levels was set as III linkage based on name, date of birth, and sex and DII linkage based on resident registration number. The datasets linked at each level were named as databaseIII (DBIII) and databaseDII (DBDII), respectively. Considering the analysis results of the DII-linked dataset as the gold standard, descriptive statistics, group comparison, incidence estimation, treatment effect, and moderation effect analysis results were assessed.

RESULTS

The linkage rates for DBDII and DBIII were 71.1% and 99.7%, respectively. Regarding descriptive statistics and group comparison analysis, the difference in effect in most cases was "none" to "very little." With respect to cervical cancer that had a relatively small sample size, analysis of DBIII resulted in an underestimation of the incidence in the control group and an overestimation of the incidence in the treatment group (hazard ratio [HR] = 2.62 [95% confidence interval (CI): 1.63-4.23] in DBIII vs. 1.80 [95% CI: 1.18-2.73] in DBDII). Regarding prostate cancer, there was a conflicting tendency with the treatment effect being over or underestimated according to the surveillance, epidemiology, and end results summary staging (HR = 2.27 [95% CI: 1.91-2.70] in DBIII vs. 1.92 [95% CI: 1.70-2.17] in DBDII for the localized stage; HR = 1.80 [95% CI: 1.37-2.36] in DBIII vs. 2.05 [95% CI: 1.67-2.52] in DBDII for the regional stage).

CONCLUSIONS

To prevent distortion of the analyses results in health and medical research, it is important to check that the patient population and sample size by each factor of interest (FOI) are sufficient when different data are linked using DBDII. In cases involving a rare disease or with a small sample size for FOI, there is a high likelihood that a DII linkage is unavoidable.

The impact of primary health care on AIDS incidence and mortality: A cohort study of 3.4 million Brazilians

BACKGROUND

Primary Health Care (PHC) is essential for effective, efficient, and more equitable health systems for all people, including those living with HIV/AIDS. This study evaluated the impact of the exposure to one of the largest community-based PHC programs in the world, the Brazilian Family Health Strategy (FHS), on AIDS incidence and mortality.

METHODS AND FINDINGS

A retrospective cohort study carried out in Brazil from January 1, 2007 to December 31, 2015. We conducted an impact evaluation using a cohort of 3,435,068 ≥13 years low-income individuals who were members of the 100 Million Brazilians Cohort, linked to AIDS diagnoses and deaths registries. We evaluated the impact of FHS on AIDS incidence and mortality and compared outcomes between residents of municipalities with low or no FHS coverage (unexposed) with those in municipalities with 100% FHS coverage (exposed). We used multivariable Poisson regressions adjusted for all relevant municipal and individual-level demographic, socioeconomic, and contextual variables, and weighted with inverse probability of treatment weighting (IPTW). We also estimated the FHS impact by sex and age and performed a wide range of sensitivity and triangulation analyses; 100% FHS coverage was associated with lower AIDS incidence (rate ratio [RR]: 0.76, 95% CI: 0.68 to 0.84) and mortality (RR: 0.68, 95%CI: 0.56 to 0.82). FHS impact was similar between men and women, but was larger in people aged ≥35 years old both for incidence (RR: 0.62, 95% CI: 0.53 to 0.72) and mortality (RR: 0.56, 95% CI: 0.43 to 0.72). The absence of important confounding variables (e.g., sexual behavior) is a key limitation of this study.

CONCLUSIONS

AIDS should be an avoidable outcome for most people living with HIV today and our study shows that FHS coverage could significantly reduce AIDS incidence and mortality among low-income populations in Brazil. Universal access to comprehensive healthcare through community-based PHC programs should be promoted to achieve the Sustainable Development Goals of ending AIDS by 2030.

Recent changes in growth trajectories: a population-based cohort study of over 5 million Brazilian children born between 2001 and 2014

Background

There is limited evidence on recent trends in childhood growth trajectories in Low-/middle-income countries. We investigated how age-trajectories for height and Body Mass Index (BMI) have changed among Brazilian children born in two different time periods after 2000.

Methods

We used a population-based cohort (part of the "Cohort of 100-Million Brazilians") created by the linkage of three Brazilian administrative databases: the Cadastro Único of the Federal Government, the National System of Live Births and the National Nutritional and Food Surveillance System. We included longitudinal data on 5,750,214 children who were 3 to <10 years of age and born between 2001 and 2014 (20,209,133 observations). We applied fractional polynomial models with random-effects to estimate mean height and BMI trajectories for children.

Findings

Compared to children born in 2001-2007, the cohort born in 2008-2014 were on average taller, by a z-score of 0.15 in boys and 0.12 in girls. Their height trajectories shifted upwards, by approximately 1 cm in both sexes. Levels of BMI increased little, by a z-score of 0.06 (boys) and 0.04 (girls). Mean BMI trajectories also changed little. However, the prevalence of overweight/obesity increased between cohorts, e.g., from 26.8% to 30% in boys and 23.9%-26.6% in girls aged between 5 and <10 years.

Interpretation

An increase of 1 cm in mean height of Brazilian children during a short period indicates the improvement in maternal and child health, especially those from low-income families due to the new health and welfare policies in Brazil. Although mean BMI changed little, the prevalence of child overweight/obesity slightly increased and remained high.

Funding

This work was supported by National Council for Scientific and Technological Development - CNPq; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES; National Institute for Health Research (NIHR) Great Ormond Street Hospital Biomedical Research Centre; Society for the Study of Human Biology; Fundação de Amparo à Pesquisa do Estado de Minas Gerais - FAPEMIG; Departamento de Ciência e Tecnologia da Secretaria de Ciência, Tecnologia, Inovação e Complexo da Saúde do Ministério da Saúde - Decit/SECTICS/MS. The study also used resources from the Centre for Data and Knowledge Integration for Health (CIDACS), which receives funding from the Bill & Melinda Gates Foundation, the Wellcome Trust, the Health Surveillance Secretariat of the Ministry of Health and the Secretariat of Science and Technology of the State of Bahia (SECTI-BA).

Evaluating the relationship between conditional cash transfer programme on preterm births: a retrospective longitudinal study using the 100 million Brazilian cohort

BACKGROUND

Preterm births increase mortality and morbidity during childhood and later life, which is closely associated with poverty and the quality of prenatal care. Therefore, income redistribution and poverty reduction initiatives may be valuable in preventing this outcome. We assessed whether receipt of the Brazilian conditional cash transfer programme - Bolsa Familia Programme, the largest in the world - reduces the occurrence of preterm births, including their severity categories, and explored how this association differs according to prenatal care and the quality of Bolsa Familia Programme management.

METHODS

A retrospective cohort study was performed involving the first live singleton births to mothersenrolled in the 100 Million Brazilian Cohort from 2004 to 2015, who had at least one child before cohort enrollment. Only the first birth during the cohort period was included, but born from 2012 onward. A deterministic linkage with the Bolsa Familia Programme payroll dataset and a similarity linkage with the Brazilian Live Birth Information System were performed. The exposed group consisted of newborns to mothers who received Bolsa Familia from conception to delivery. Our outcomes were infants born with a gestational age < 37 weeks: (i) all preterm births, (ii) moderate-to-late (32-36), (iii) severe (28-31), and (iv) extreme (< 28) preterm births compared to at-term newborns. We combined propensity score-based methods and weighted logistic regressions to compare newborns to mothers who did and did not receive Bolsa Familia, controlling for socioeconomic conditions. We also estimated these effects separately, according to the adequacy of prenatal care and the index of quality of Bolsa Familia Programme management.

RESULTS

1,031,053 infants were analyzed; 65.9% of the mothers were beneficiaries. Bolsa Familia Programme was not associated with all sets of preterm births, moderate-to-late, and severe preterm births, but was associated with a reduction in extreme preterm births (weighted OR: 0.69; 95%CI: 0.63-0.76). This reduction can also be observed among mothers receiving adequate prenatal care (weighted OR: 0.66; 95%CI: 0.59-0.74) and living in better Bolsa Familia management municipalities (weighted OR: 0.56; 95%CI: 0.43-0.74).

CONCLUSIONS

An income transfer programme for pregnant women of low-socioeconomic status, conditional to attending prenatal care appointments, has been associated with a reduction in extremely preterm births. These programmes could be essential in achieving Sustainable Development Goals.

Association of interpregnancy interval with adverse pregnancy outcomes according to the outcomes of the preceding pregnancy: a longitudinal study with 4.7 million live births from Brazil

Background

Earlier studies have proposed a link between the Interpregnancy Interval (IPI) and unfavorable birth outcomes. However, it remains unclear if the outcomes of previous births could affect this relationship. We aimed to investigate whether the occurrence of adverse outcomes-small for gestational age (SGA), preterm birth (PTB), and low birth weight (LBW)-at the immediately preceding pregnancy could alter the association between IPI and the same outcomes at the subsequent pregnancy.

Methods

We used a population-based linked cohort from Brazil (2001-2015). IPI was measured as the difference, in months, between the preceding birth and subsequent conception. Outcomes included SGA (<10th birthweight percentile for gestational age and sex), LBW (<2500 g), and PTB (gestational age <37 weeks). We calculated risk ratios (RRs), using the IPI of 18-22 months as the reference IPI category, we also stratified by the number of adverse birth outcomes at the preceding pregnancy.

Findings

Among 4,788,279 births from 3,804,152 mothers, absolute risks for subsequent SGA, PTB, and LBW were higher for women with more adverse outcomes in the preceding delivery. The RR of SGA and LBW for IPIs <6 months were greater for women without previous adverse outcomes (SGA: 1.44 [95% Confidence Interval (CI): 1.41-1.46]; LBW: 1.49 [1.45-1.52]) compared to those with three previous adverse outcomes (SGA: 1.20 [1.10-1.29]; LBW: 1.24 [1.15-1.33]). IPIs ≥120 months were associated with greater increases in risk for LBW and PTB among women without previous birth outcomes (LBW: 1.59; [1.53-1.65]; PTB: 2.45 [2.39-2.52]) compared to women with three adverse outcomes at the index birth (LBW: 0.92 [0.78-1.06]; PTB: 1.66 [1.44-1.88]).

Interpretation

Our study suggests that women with prior adverse outcomes may have higher risks for adverse birth outcomes in subsequent pregnancies. However, risk changes due to differences in IPI length seem to have a lesser impact compared to women without a prior event. Considering maternal obstetric history is essential in birth spacing counseling.

Funding

Wellcome Trust225925/Z/22/Z.

Perinatal health outcomes of international migrant women in Brazil: A nationwide data linkage study of the CIDACS birth cohort (2011-2018)

BACKGROUND

We investigated perinatal outcomes among live births from international migrant and local-born mothers in a cohort of low-income individuals in Brazil.

METHODS

We linked nationwide birth registries to mortality records and socioeconomic data from the CIDACS Birth Cohort and studied singleton live births of women aged 10-49 years from 1st January 2011 to 31st December 2018. We used logistic regressions to investigate differences in antenatal care, adverse pregnancy outcomes, and neonatal (i.e., ≤28 days) mortality among international migrants compared to non-migrants in Brazil; and explored the interaction between migration, race/ethnicity and living in international border municipalities.

RESULTS

We studied 10,279,011 live births, of which 9469 (0.1 %) were born to international migrants. Migrant women were more likely than their Brazilian-born counterparts to have a previous foetal loss (ORadj: 1.16, 1.11-1.22), a delayed start of antenatal care (i.e., beyond 1st trimester) (1.22, 95%CI:1.16-1.28), a newborn who is large for gestational age (1.29, 1.22-1.36), or a newborn with congenital anomalies (1.37, 1.14-1.65). Conversely, migrant women were less likely to deliver prematurely (0.89, 0.82-0.95) or have a low birth weight infant (0.74, 0.68-0.81). There were no differences in neonatal mortality rates between migrants and non-migrants. Our analyses also showed that, when disparities in perinatal outcomes were present, disparities were mostly concentrated among indigenous mothers in international borders and among live births of Black mothers in non-borders.

CONCLUSION

Although live births of international migrants generally have lower rates of adverse birth outcomes, our results suggest that indigenous and Black migrant mothers may face disproportionate barriers to accessing antenatal care.

Establishment of a birth-to-education cohort of 1 million Palestinian refugees using electronic medical records and electronic education records

Introduction

By linking datasets, electronic records can be used to build large birth-cohorts, enabling researchers to cost-effectively answer questions relevant to populations over the life-course. Currently, around 5.8 million Palestinian refugees live in five settings: Jordan, Lebanon, Syria, West Bank, and Gaza Strip. The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides them with free primary health and elementary-school services. It maintains electronic records to do so.We aimed to establish a birth cohort of Palestinian refugees born between 1st January 2010 and 31st December 2020 living in five settings by linking mother obstetric records with child health and education records and to describe some of the cohort characteristics. In future, we plan to assess effects of size-at-birth on growth, health and educational attainment, among other questions.

Methods

We extracted all available data from 140 health centres and 702 schools across five settings, i.e. all UNRWA service users. Creating the cohort involved examining IDs and other data, preparing data, de-duplicating records, and identifying live-births, linking the mothers' and children's data using different deterministic linking algorithms, and understanding reasons for non-linkage.

Results

We established a birth cohort of Palestinian refugees using electronic records of 972,743 live births. We found high levels of linkage to health records overall (83%), which improved over time (from 73% to 86%), and variations in linkage rates by setting: these averaged 93% in Gaza, 89% in Lebanon, 75% in Jordan, 73% in West Bank and 68% in Syria. Of the 423,580 children age-eligible to go to school, 47% went to UNRWA schools and comprised of 197,479 children with both health and education records, and 2,447 children with only education records. In addition to year and setting, other factors associated with non-linkage included mortality and having a non-refugee mother. Misclassification errors were minimal.

Conclusion

This linked open birth-cohort is unique for refugees and the Arab region and forms the basis for many future studies, including to elucidate pathways for improved health and education in this vulnerable, understudied population. Our characterization of the cohort leads us to recommend using different sub-sets of the cohort depending on the research question and analytic purposes.

Maternal and child nutrition programme of investigation within the 100 Million Brazilian Cohort: study protocol

INTRODUCTION

There is a limited understanding of the early nutrition and pregnancy determinants of short-term and long-term maternal and child health in ethnically diverse and socioeconomically vulnerable populations within low-income and middle-income countries. This investigation programme aims to: (1) describe maternal weight trajectories throughout the life course; (2) describe child weight, height and body mass index (BMI) trajectories; (3) create and validate models to predict childhood obesity at 5 years of age; (4) estimate the effects of prepregnancy BMI, gestational weight gain (GWG) and maternal weight trajectories on adverse maternal and neonatal outcomes and child growth trajectories; (5) estimate the effects of prepregnancy BMI, GWG, maternal weight and interpregnancy BMI changes on maternal and child outcomes in the subsequent pregnancy; and (6) estimate the effects of maternal food consumption and infant feeding practices on child nutritional status and growth trajectories.

METHODS AND ANALYSIS

Linked data from four different Brazilian databases will be used: the 100 Million Brazilian Cohort, the Live Births Information System, the Mortality Information System and the Food and Nutrition Surveillance System. To analyse trajectories, latent-growth, superimposition by translation and rotation and broken stick models will be used. To create prediction models for childhood obesity, machine learning techniques will be applied. For the association between the selected exposure and outcomes variables, generalised linear models will be considered. Directed acyclic graphs will be constructed to identify potential confounders for each analysis investigating potential causal relationships.

ETHICS AND DISSEMINATION

This protocol was approved by the Research Ethics Committees of the authors' institutions. The linkage will be carried out in a secure environment. After the linkage, the data will be de-identified, and pre-authorised researchers will access the data set via a virtual private network connection. Results will be reported in open-access journals and disseminated to policymakers and the broader public.

Temporal trends in prevalence and infant mortality of birth defects in Brazil, from 2001 to 2018

Congenital anomalies (CA) are a relevant problem for global public health, affecting about 3% to 6% of newborns worldwide. In Brazil, these are the second main cause of infant mortality. Thus, extensive studies are needed to demonstrate the impact of these anomalies on births and deaths. The present study describes the temporal trends of prevalence and infant mortality due to CA among live births in Brazil and regions, from 2001 to 2018, using the related data between the Live Birth Information System (SINASC, acronym in Portuguese) and the Mortality Information System (SIM, acronym in Portuguese). The prevalence and infant mortality due to CA has increased in Brazil and in most regions, especially in the Northeast and North. CAs in the musculoskeletal system were the most frequent at birth (29.8/10,000 live births), followed by those in the circulatory system (12.7/10,000 live births), which represented the primary cause of death in this group. The applied linkage technique made it possible to correct the national prevalence of CA by 17.9% during the analyzed period, after retrieving the anomalies reported in SIM, thereby proving to be a good tool to improve the quality of information on anomalies in Brazil.

National data linkage assessment of live births and deaths in Mexico: Estimating under-five mortality rate ratios for vulnerable newborns and trends from 2008 to 2019

BACKGROUND

Linked datasets that enable longitudinal assessments are scarce in low and middle-income countries.

OBJECTIVES

We aimed to assess the linkage of administrative databases of live births and under-five child deaths to explore mortality and trends for preterm, small (SGA) and large for gestational age (LGA) in Mexico.

METHODS

We linked individual-level datasets collected by National statistics from 2008 to 2019. Linkage was performed based on agreement on birthday, sex, residential address. We used the Centre for Data and Knowledge Integration for Health software to identify the best candidate pairs based on similarity. Accuracy was assessed by calculating the area under the receiver operating characteristic curve. We evaluated completeness by comparing the number of linked records with reported deaths. We described the percentage of linked records by baseline characteristics to identify potential bias. Using the linked dataset, we calculated mortality rate ratios (RR) in neonatal, infants, and children under-five according to gestational age, birthweight, and size.

RESULTS

For the period 2008-2019, a total of 24,955,172 live births and 321,165 under-five deaths were available for linkage. We excluded 1,539,046 records (6.2%) with missing or implausible values. We succesfully linked 231,765 deaths (72.2%: range 57.1% in 2009 and 84.3% in 2011). The rate of neonatal mortality was higher for preterm compared with term (RR 3.83, 95% confidence interval, CI 3.78, 3.88) and for SGA compared with appropriate for gestational age (AGA) (RR 1.22 95% CI, 1.19, 1.24). Births at <28 weeks had the highest mortality (RR 35.92, 95%CI, 34.97, 36.88). LGA had no additional risk vs AGA among children under five (RR 0.92, 95%CI, 0.90, 0.93).

CONCLUSIONS

We demonstrated the utility of linked data to understand neonatal vulnerability and child mortality. We created a linked dataset that would be a valuable resource for future population-based research.

Causes of death in children with congenital Zika syndrome in Brazil, 2015 to 2018: A nationwide record linkage study

BACKGROUND

Children with congenital Zika syndrome (CZS) have severe damage to the peripheral and central nervous system (CNS), greatly increasing the risk of death. However, there is no information on the sequence of the underlying, intermediate, immediate, and contributing causes of deaths among these children. The aims of this study are describe the sequence of events leading to death of children with CZS up to 36 months of age and their probability of dying from a given cause, 2015 to 2018.

METHODS AND FINDINGS

In a population-based study, we linked administrative data on live births, deaths, and cases of children with CZS from the SINASC (Live Birth Information System), the SIM (Mortality Information System), and the RESP (Public Health Event Records), respectively. Confirmed and probable cases of CZS were those that met the criteria established by the Brazilian Ministry of Health. The information on causes of death was collected from death certificates (DCs) using the World Health Organization (WHO) DC template. We estimated proportional mortality (PM%) among children with CZS and among children with non-Zika CNS congenital anomalies (CA) by 36 months of age and proportional mortality ratio by cause (PMRc). A total of 403 children with confirmed and probable CZS who died up to 36 months of age were included in the study; 81.9% were younger than 12 months of age. Multiple congenital malformations not classified elsewhere, and septicemia unspecified, with 18 (PM = 4.5%) and 17 (PM = 4.2%) deaths, respectively, were the most attested underlying causes of death. Unspecified septicemia (29 deaths and PM = 11.2%) and newborn respiratory failure (40 deaths and PM = 12.1%) were, respectively, the predominant intermediate and immediate causes of death. Fetuses and newborns affected by the mother's infectious and parasitic diseases, unspecified cerebral palsy, and unspecified severe protein-caloric malnutrition were the underlying causes with the greatest probability of death in children with CZS (PMRc from 10.0 to 17.0) when compared to the group born with non-Zika CNS anomalies. Among the intermediate and immediate causes of death, pneumonitis due to food or vomiting and unspecified seizures (PMRc = 9.5, each) and unspecified bronchopneumonia (PMRc = 5.0) were notable. As contributing causes, fetus and newborn affected by the mother's infectious and parasitic diseases (PMRc = 7.3), unspecified cerebral palsy, and newborn seizures (PMRc = 4.5, each) were more likely to lead to death in children with CZS than in the comparison group. The main limitations of this study were the use of a secondary database without additional clinical information and potential misclassification of cases and controls.

CONCLUSION

The sequence of causes and circumstances involved in the deaths of the children with CZS highlights the greater vulnerability of these children to infectious and respiratory conditions compared to children with abnormalities of the CNS not related to Zika.

Association of Conditional Cash Transfers With Maternal Mortality Using the 100 Million Brazilian Cohort

IMPORTANCE

Conditional cash transfers (CCTs) have been consistently associated with improvements to the determinants of maternal health, but there have been insufficient investigations regarding their effects on maternal mortality.

OBJECTIVE

To evaluate the association between being a Bolsa Família program (BFP) beneficiary and maternal mortality and to examine how this association differs by duration of BFP receipt, maternal race, living in rural or urban areas, the Municipal Human Development Index (MHDI), and municipal primary health care coverage.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional analysis was nested within the 100 Million Brazilian Cohort. Girls and women aged 10 to 49 years (hereinafter referred to as women) who had at least 1 live birth were included, using data from Brazilian national health databases linked to the 100 Million Brazilian Cohort (January 1, 2004, to December 31, 2015). Propensity score kernel weighting was applied to control for sociodemographic and economic confounders in the association between BFP receipt and maternal mortality, overall and stratified by different subgroups (race, urban or rural area, and MHDI), and duration of BFP receipt. Data were analyzed from July 12, 2019, to December 31, 2022.

MAIN OUTCOME(S) AND MEASURES

Maternal death.

RESULTS

A total of 6 677 273 women aged 10 to 49 years were included in the analysis, 4056 of whom had died from pregnancy-related causes. The risk of maternal death was 18% lower in women who received BFP (weighted odds ratio [OR], 0.82 [95% CI, 0.71-0.93]). A longer duration receiving BFP was associated with an increased reduction in maternal mortality (OR for 1-4 years, 0.85 [95% CI, 0.75-0.97]; OR for 5-8 years, 0.70 [95% CI, 0.60-0.82]; OR for ≥9 years, 0.69 [95% CI, 0.53-0.88]). Receiving BFP was also associated with substantial increases in the number of prenatal appointments and interbirth intervals. The reduction was more pronounced in the most vulnerable groups.

CONCLUSIONS AND RELEVANCE

This cross-sectional analysis nested within the 100 Million Brazilian Cohort found an association between BFP receipt and maternal mortality. This association was of greater magnitude in women with longer exposure to BFP and in the most vulnerable groups. These findings reinforce evidence that programs such as BFP, which have already proven effective in poverty reduction, have great potential to improve maternal survival.

Evaluating the effect of Bolsa Familia, Brazil's conditional cash transfer programme, on maternal and child health: A study protocol

BACKGROUND

Conditional Cash Transfer Programs have been developed in Latin America in response to poverty and marked social inequalities on the continent. In Brazil, the Bolsa Familia Program (BFP) was implemented to alleviate poverty and improve living conditions, health, and education for socioeconomically vulnerable populations. However, the effect of this intervention on maternal and child health is not well understood.

METHODS

We will evaluate the effect of BFP on maternal and child outcomes: 1. Birth weight; 2. Preterm birth; 3. Maternal mortality; and 4. Child growth. Dynamic retrospective cohort data from the 100 Million Brazilian Cohort (2001 to 2015) will be linked to three different databases: Live Birth Information System (2004 to 2015); Mortality Information System (2011 to 2015); and Food and Nutritional Surveillance System (2008 to 2017). The definition of exposure to the BFP varies according to the outcome studied. Those who never received the benefit until the outcome or until the end of the follow-up will be defined as not exposed. The effects of BFP on maternal and child outcomes will be estimated by a combination of propensity score-based methods and weighted logistic regressions. The analyses will be further stratified to reflect changes in the benefit entitlement before and after 2012.

DISCUSSION

Harnessing a large linked administrative cohort allows us to assess the effect of the BFP on maternal and child health, while considering a wide range of explanatory and confounding variables.

Relationship between the Bolsa Família national cash transfer programme and suicide incidence in Brazil: A quasi-experimental study

BACKGROUND

Socioeconomic factors have been consistently associated with suicide, and economic recessions are linked to rising suicide rates. However, evidence on the impact of socioeconomic interventions to reduce suicide rates is limited. This study investigates the association of the world's largest conditional cash transfer programme with suicide rates in a cohort of half of the Brazilian population.

METHODS AND FINDINGS

We used data from the 100 Million Brazilian Cohort, covering a 12-year period (2004 to 2015). It comprises socioeconomic and demographic information on 114,008,317 individuals, linked to the "Bolsa Família" programme (BFP) payroll database, and nationwide death registration data. BFP was implemented by the Brazilian government in 2004. We estimated the association of BFP using inverse probability of treatment weighting, estimating the weights for BFP beneficiaries (weight = 1) and nonbeneficiaries by the inverse probability of receiving treatment (weight = E(ps)/(1-E(ps))). We used an average treatment effect on the treated (ATT) estimator and fitted Poisson models to estimate the incidence rate ratios (IRRs) for suicide associated with BFP experience. At the cohort baseline, BFP beneficiaries were younger (median age 27.4 versus 35.4), had higher unemployment rates (56% versus 32%), a lower level of education, resided in rural areas, and experienced worse household conditions. There were 36,742 suicide cases among the 76,532,158 individuals aged 10 years, or older, followed for 489,500,000 person-years at risk. Suicide rates among beneficiaries and nonbeneficiaries were 5.4 (95% CI = 5.32, 5.47, p < 0.001) and 10.7 (95% CI = 10.51, 10.87, p < 0.001) per 100,000 individuals, respectively. BFP beneficiaries had a lower suicide rate than nonbeneficiaries (IRR = 0.44, 95% CI = 0.42, 0.45, p < 0.001). This association was stronger among women (IRR = 0.36, 95% CI = 0.33, 0.38, p < 0.001), and individuals aged between 25 and 59 (IRR = 0.41, 95% CI = 0.40, 0.43, p < 0.001). Study limitations include a lack of control for previous mental disorders and access to means of suicide, and the possible under-registration of suicide cases due to stigma.

CONCLUSIONS

We observed that BFP was associated with lower suicide rates, with similar results in all sensitivity analyses. These findings should help to inform policymakers and health authorities to better design suicide prevention strategies. Targeting social determinants using cash transfer programmes could be important in limiting suicide, which is predicted to rise with the economic recession, consequent to the Coronavirus Disease 2019 (COVID-19) pandemic.

Differences in risk factors for incident and recurrent preterm birth: a population-based linkage of 3.5 million births from the CIDACS birth cohort

BACKGROUND

Preterm birth (PTB) is a syndrome resulting from a complex list of underlying causes and factors, and whether these risk factors differ in the context of prior PTB history is less understood. The aim of this study was to explore whether PTB risk factors in a second pregnancy were different in women with versus without previous PTB.

METHODS

We conducted a population-based cohort study using data from the birth cohort of the Center for Data and Knowledge Integration for Health (CIDACS) for the period 2001 to 2015. We used longitudinal transition models with multivariate logistic regression to investigate whether risk factors varied between incident and recurrent PTB.

RESULTS

A total of 3,528,050 live births from 1,764,025 multiparous women were analyzed. We identified different risk factors (P_difference <0.05) between incident and recurrent PTB. The following were associated with an increased chance for PTB incidence, but not recurrent: household overcrowding (OR 1.09), maternal race/ethnicity [(Black/mixed-OR 1.04) and (indigenous-OR 1.34)], young maternal age (14 to 19 years-OR 1.16), and cesarean delivery (OR 1.09). The following were associated with both incident and recurrent PTB, respectively: single marital status (OR 0.85 vs 0.90), reduced number of prenatal visits [(no visit-OR 2.56 vs OR 2.16) and (1 to 3 visits-OR 2.44 vs OR 2.24)], short interbirth interval [(12 to 23 months-OR 1.04 vs OR 1.22) and (<12 months, OR 1.89, 95 vs OR 2.58)], and advanced maternal age (35-49 years-OR 1.42 vs OR 1.45). For most risk factors, the point estimates were higher for incident PTB than recurrent PTB.

CONCLUSIONS

The risk factors for PTB in the second pregnancy differed according to women's first pregnancy PTB status. The findings give the basis for the development of specific prevention strategies for PTB in a subsequent pregnancy.

Biases arising from linked administrative data for epidemiological research: a conceptual framework from registration to analyses

Linked administrative data offer a rich source of information that can be harnessed to describe patterns of disease, understand their causes and evaluate interventions. However, administrative data are primarily collected for operational reasons such as recording vital events for legal purposes, and planning, provision and monitoring of services. The processes involved in generating and linking administrative datasets may generate sources of bias that are often not adequately considered by researchers. We provide a framework describing these biases, drawing on our experiences of using the 100 Million Brazilian Cohort (100MCohort) which contains records of more than 131 million people whose families applied for social assistance between 2001 and 2018. Datasets for epidemiological research were derived by linking the 100MCohort to health-related databases such as the Mortality Information System and the Hospital Information System. Using the framework, we demonstrate how selection and misclassification biases may be introduced in three different stages: registering and recording of people's life events and use of services, linkage across administrative databases, and cleaning and coding of variables from derived datasets. Finally, we suggest eight recommendations which may reduce biases when analysing data from administrative sources.

Recurrence of preterm births: A population-based linkage with 3.5 million live births from the CIDACS Birth Cohort

OBJECTIVE

To investigate the recurrence of preterm birth (PTB) among the poorest half of the Brazilian population.

METHODS

A population-based retrospective study was conducted in Brazil with the live births of multiparous women extracted from the CIDACS Birth Cohort between 2001 and 2015. We used multivariate logistic regression to estimate the odds of recurrent PTB in second and third births.

RESULTS

A total of 3 528 050 live births from 1 764 025 multiparous women were analyzed. The adjusted odds for the occurrence of a PTB given a previous PTB was 2.58 (95% confidence interval [CI] 2.53-2.62). Lower gestational age increased the odds of a subsequent PTB (<28 weeks: adjusted OR [aOR] 3.61, 95% CI 3.41-3.83; 28-31 weeks: aOR 3.34, 95% CI 3.19-3.49; and 32-36 weeks: aOR 2.42, 95% CI 2.38-2.47). Women who had two previous PTBs were at high risk of having a third (aOR 4.98, 95% CI 4.70-5.27). Recurrence of PTB was more likely when the inter-birth interval was less than 12 months.

CONCLUSION

In Brazil, a middle-income country, women with a previous PTB had an increased risk of a subsequent one. This association was affected by gestational age, the number of PTBs, severity of previous PTBs, and a short interval between births.

Associations between cesarean delivery and child mortality: A national record linkage longitudinal study of 17.8 million births in Brazil

BACKGROUND

There is an increasing use of cesarean delivery (CD) based on preference rather than on medical indication. However, the extent to which nonmedically indicated CD benefits or harms child survival remains unclear. Our hypothesis was that in groups with a low indication for CD, this procedure would be associated with higher child mortality and in groups with a clear medical indication CD would be associated with improved child survival chances.

METHODS AND FINDINGS

We conducted a population-based cohort study in Brazil by linking routine data on live births between January 1, 2012 and December 31, 2018 and assessing mortality up to 5 years of age. Women with a live birth who contributed records during this period were classified into one of 10 Robson groups based on their pregnancy and delivery characteristics. We used propensity scores to match CD with vaginal deliveries (1:1) and prelabor CD with unscheduled CD (1:1) and estimated associations with child mortality using Cox regressions. A total of 17,838,115 live births were analyzed. After propensity score matching (PSM), we found that live births to women in groups with low expected frequencies of CD (Robson groups 1 to 4) had a higher death rate up to age 5 years if they were born via CD compared with vaginal deliveries (HR = 1.25, 95% CI: 1.22 to 1.28; p < 0.001). The relative rate was greatest in the neonatal period (HR = 1.39, 95% CI: 1.34 to 1.45; p < 0.001). There was no difference in mortality rate when comparing offspring born by a prelabor CD to those born by unscheduled CD. For the live births to women with a CD in a prior pregnancy (Robson group 5), the relative rates for child mortality were similar for those born by CD compared with vaginal deliveries (HR = 1.05, 95% CI: 1.00 to 1.10; p = 0.024). In contrast, for live births to women in groups with high expected rates of CD (Robson groups 6 to 10), the child mortality rate was lower for CD than for vaginal deliveries (HR = 0.90, 95% CI: 0.89 to 0.91; p < 0.001), particularly in the neonatal period (HR = 0.84, 95% CI: 0.83 to 0.85; p < 0.001). Our results should be interpreted with caution in clinical practice, since relevant clinical data on CD indication were not available.

CONCLUSIONS

In this study, we observed that in Robson groups with low expected frequencies of CD, this procedure was associated with a 25% increase in child mortality. However, in groups with high expected frequencies of CD, the findings suggest that clinically indicated CD is associated with a reduction in child mortality.

Barreto F, Itaparica Carvalho MS, Oliveira WK, França GVA, Carmo EH, Andrade RFS, Rodrigues MS, Veiga RV, Oliveira JF, Fernandes QHRF, Costa LC, Coelho GE, Paixao ES. Case Fatality Rate Related to Microcephaly Congenital Zika Syndrome and Associated Factors: A Nationwide Retrospective Study in Brazil †

BACKGROUND

The clinical manifestations of microcephaly/congenital Zika syndrome (microcephaly/CZS) have harmful consequences on the child's health, increasing vulnerability to childhood morbidity and mortality. This study analyzes the case fatality rate and child-maternal characteristics of cases and deaths related to microcephaly/CZS in Brazil, 2015-2017.

METHODS

Population-based study developed by linkage of three information systems. We estimate frequencies of cases, deaths, case fatality rate related to microcephaly/CZS according to child and maternal characteristics and causes of death. Multivariate logistic regression models were applied.

RESULTS

The microcephaly/CZS case fatality rate was 10% (95% CI 9.2-10.7). Death related to microcephaly/CZS was associated to moderate (OR = 2.15; 95% CI 1.63-2.83), and very low birth weight (OR = 3.77; 95% CI 2.20-6.46); late preterm births (OR = 1.65; 95% CI 1.21-2.23), Apgar < 7 at 1st (OR = 5.98; 95% CI 4.46-8.02) and 5th minutes (OR = 4.13; 95% CI 2.78-6.13), among others.

CONCLUSIONS

A high microcephaly/CZS case fatality rate and important factors associated with deaths related to this syndrome were observed. These results can alert health teams to these problems and increase awareness about the factors that may be associated with worse outcomes.