One step further in mistreatment research: Assessing the scalability of the Explicit Discrimination Scale among Brazilian working-age adult respondents.

Though the Explicit Discrimination Scale (EDS) has been subjected to extensive psychometric evaluation in Brazil, the instrument has yet to be comprehensively assessed among working-age adult respondents in the country. This study aimed to fill this knowledge gap. Data from around 1200 diverse members of a cohort investigation were used to examine: (1) the positioning of respondents along the continuum of the EDS latent trait; (2) how well the corresponding items represent the EDS construct map; and (3) the extent to which the EDS items follow their expected levels of intensity. We assessed these properties with Loevinger's H, Guttman errors, and Item Response Theory parameters. Findings suggest that two abridged versions of the instrument-but especially the eight-item EDS-may adequately arrange respondents along the latent trait continuum. Analyses also revealed that scale items are reasonably spread over the construct map, with some discrepancy between the expected levels of intensity and their empirical positioning in the corresponding plot. The shortened versions of EDS have good psychometric properties among Brazilian working-age adult respondents. In addition to examining the invariance of the EDS across multiple groups, future psychometric evaluations should assess the external validity of the scale.

The Alcohol Use Disorders Identification Test (AUDIT) in Adolescents: Using a Model-Based Approach to Identify Patterns of Alcohol Misuse.

OBJECTIVE: To explore the latent structure of the Alcohol Use Disorders Identification Test (AUDIT) among adolescents of different school grades (age strata). Methods: Data derived from two simultaneous run cohort studies from the "Adolescent Nutritional Assessment Longitudinal Study-ELANA" conducted in private and public schools of Rio de Janeiro/Brazil. Participants comprised 564 seventh-graders and 419 ninth-graders, respectively sampled in 2011 and 2013 from cohort 1, and 730 eleventh-graders sampled in 2011 from cohort 2. Latent class factor analytical (LCFA) models were applied to the AUDIT items to identify internally homogeneous latent groups of individuals representing distinct patterns of alcohol use, and optimal group-separating cutoffs. The classification agreement was also evaluated. Results: Three and two groups (classes) were found for the eleventh and the earlier grades, respectively. These best-fitting models held a very high degree of class separation (entropy >0.9). By contrasting the AUDIT's raw scores (0-10) with the model-based latent classes, the cutoff separating the base (milder) category was found between scores 0 and 1 in all grades. The eleventh-graders differed from the others by showing a third and more intense category of alcohol use (cutoff between 4 and 5). The classification agreement was almost perfect in eleventh-graders (98.6%) and perfect in the earlier grades (100%). Conclusions: Findings show that the AUDIT may be adequately used in adolescents of different ages and school grades, although the number of homogeneous categories may differ accordingly. Besides, raw scores may be pragmatically used to identify groups with confidence by applying specific optimal cutoffs.

Suitability of the eight-item version of the Brazilian Household Food Insecurity Measurement Scale to identify risk groups: evidence from a nationwide representative sample.

OBJECTIVE: The Brazilian Household Food Insecurity Measurement Scale (EBIA) has eight general/adult items applied in all households and six additional items exclusively asked in households with children and/or adolescents (HHCA). Continuing an investigation programme on the adequacy of model-based cut-off points for EBIA, the present study aims to: (i) explore the capacity of properly stratifying HHCA according to food insecurity (FI) severity level by applying only the eight 'generic' items; and (ii) compare it against the fourteen-item scale. DESIGN: Latent class factor analysis (LCFA) models were applied to the answers to the eight general/adult items to identify latent groups corresponding to FI levels and optimal group-separating cut-off points. Analyses involved a thorough classification agreement evaluation and were performed at the national level and by macro-regions. SETTING: Data derived from the cross-sectional Brazilian National Household Sample Survey of 2013. PARTICIPANTS: A nationally representative sample of 116 543 households. RESULTS: In all households and investigated domains, LCFA detected four distinct household food (in)security groups (food security and three levels of severity of FI) and the same set of cut-off points (1/2, 4/5 and 6/7). Misclassification in the aggregate data was 0·66 % in adult-only households and 1·06 % in HHCA. Comparison of the scale reduced to eight items with the 'original' fourteen-item scale demonstrated consistency in the classification. In HHCA, the agreement between both classifications was 96·2 %. CONCLUSIONS: Results indicate the eight 'generic' items in HHCA can be reliably used when it is not possible to apply the fourteen-item scale.

Perceived discrimination south of the equator: Reassessing the Brazilian Explicit Discrimination Scale.

OBJECTIVE: To reassess the Explicit Discrimination Scale (EDS; Bastos, Faerstein, Celeste, & Barros, 2012), an instrument developed in Brazil to examine intersecting forms of discrimination, with particular attention to the number of underlying dimensions, residual correlations, share of explained item variance, and stability of the configural and metric structure in broader populations. METHOD: Data from two cross-sectional studies and one cohort investigation were used. Although the cross-sectional studies were conducted among racially diverse undergraduate students (n = 1,022, 45% women, mean age = 23 years; n = 424, 59% women, mean age = 22 years), the cohort study included a probabilistic sample of community residents with 18% racial/ethnic minority respondents (n = 1,187, 57% women, mean age = 42 years). A series of exploratory models, exploratory structural equation models, and confirmatory factor analyses models was estimated. RESULTS: The EDS items might be best represented by a 3-factor model, which includes a second-order factor. Although only 1 pair of correlated residuals emerged, at least 4 different items with a sizable share of error variance were observed. The revised scale structure had an excellent fit to the data and was consistent among both undergraduate students and community residents. CONCLUSIONS: As well as demonstrating that discrimination may be structured by proximal, medial, and distal experiences with mistreatment, we suggest that the EDS has the potential to enhance research on the intersectional health impacts of discrimination. Future studies are required to assess scalability and provide scholars with a shortened version of the instrument. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Modeling Optimal Cutoffs for the Brazilian Household Food Insecurity Measurement Scale in a Nationwide Representative Sample.

Background: This is the second part of a model-based approach to examine the suitability of the current cutoffs applied to the raw score of the Brazilian Household Food Insecurity Measurement Scale [Escala Brasileira de Insegurança Alimentar (EBIA)]. The approach allows identification of homogeneous groups who correspond to severity levels of food insecurity (FI) and, by extension, discriminant cutoffs able to accurately distinguish these groups.Objective: This study aims to examine whether the model-based approach for identifying optimal cutoffs first implemented in a local sample is replicated in a countrywide representative sample.Methods: Data were derived from the Brazilian National Household Sample Survey of 2013 (n = 116,543 households). Latent class factor analysis (LCFA) models from 2 to 5 classes were applied to the scale's items to identify the number of underlying FI latent classes. Next, identification of optimal cutoffs on the overall raw score was ascertained from these identified classes. Analyses were conducted in the aggregate data and by macroregions. Finally, model-based classifications (latent classes and groupings identified thereafter) were contrasted to the traditionally used classification.Results: LCFA identified 4 homogeneous groups with a very high degree of class separation (entropy = 0.934-0.975). The following cutoffs were identified in the aggregate data: between 1 and 2 (1/2), 5 and 6 (5/6), and 10 and 11 (10/11) in households with children and/or adolescents <18 y of age (score range: 0-14), and 1/2, between 4 and 5 (4/5), and between 6 and 7 (6/7) in adult-only households (range: 0-8). With minor variations, the same cutoffs were also identified in the macroregions. Although our findings confirm, in general, the classification currently used, the limit of 1/2 (compared with 0/1) for separating the milder from the baseline category emerged consistently in all analyses.Conclusions: Nationwide findings corroborate previous local evidence that households with an overall score of 1 are more akin to those scoring negative on all items. These results may contribute to guide experts' and policymakers' decisions on the most appropriate EBIA cutoffs.

A Model-Based Approach to Identify Classes and Respective Cutoffs of the Brazilian Household Food Insecurity Measurement Scale.

BACKGROUND: The Brazilian Household Food Insecurity Measurement Scale (EBIA) is the main tool for assessing household food insecurity (FI) in Brazil, assisting in monitoring and improving national public policies to promote food security. Based on the sum of item scores, households have been classified into 4 levels of FI, with the use of cutoffs arising from expert discussions informed by psychometric analyses and policy considerations. OBJECTIVES: This study aimed to identify homogeneous latent groups corresponding to levels of FI, examine whether such subgroups could be defined from discriminant cutoffs applied to the overall EBIA raw score, and compare these cutoffs against those currently used. METHODS: A cross-sectional population-based study with a representative sample of 1105 households from a low-income metropolitan area of Rio de Janeiro was conducted. Latent class factor analysis (LCFA) models were applied to the answers to EBIA's items to identify homogeneous groups, obtaining the number of latent classes for FI measured by the scale. Based on this and a thorough classification agreement evaluation, optimal cutoffs for discriminating between different severity levels of FI were ascertained. Model-based grouping and the official EBIA classification cutoffs were also contrasted. RESULTS: LCFA identified 4 homogeneous groups with a very high degree of class separation (entropy = 0.906), endorsing the classification of EBIA as a 4-level measure of FI. Two sets of cutoffs were identified to separate such groups according to household type: 1/2, 5/6, and 10/11 in households with children and adolescents (score range: 0-14); and 1/2, 3/4, and 5/6 in adult-only households (score range: 0-7). CONCLUSION: Although roughly classifying EBIA as in previous studies, the current approach suggests that, in terms of raw score, households endorsing only one item of the scale would be better classified by being placed in the same stratum as those remaining negative on all items.

Household food insecurity: a systematic review of the measuring instruments used in epidemiological studies.

OBJECTIVE: To conduct a systematic review aimed at identifying and characterizing the experience-based household food security scales and to synthesize their psychometric properties. DESIGN: Search in the MEDLINE, LILACS and SciELO databases, using the descriptors ('food insecurity' OR 'food security') AND ('questionnaires' OR 'scales' OR 'validity' OR 'reliability'). There was no limitation on the period of publication. All articles had their titles and abstracts analysed by two reviewers. The studies of interest were read in their entirety and the relevant information extracted using a standard form. RESULTS: The initial bibliographic search identified 299 articles. Of these, the 159 that seemed to meet the criteria for inclusion were read fully. After consultation of the bibliographic references of these articles, twenty articles and five documents were added, as they satisfied the previously determined criteria for inclusion. Twenty-four different instruments were identified; all were brief and of easy application. The majority were devised in the USA. Forty-seven references reported results of psychometric studies. The instruments that presented the highest number of psychometric studies were the Core Food Security Measurement/Household Food Security Survey Module (CFSM/HFSSM) and the Self-Perceived Household Food Security Scale. CONCLUSIONS: There are a number of structured scales available in the literature for characterization of household food insecurity. However, despite some psychometric studies already existing about the majority of the instruments, it is observed that, except for the studies of the CFSM/HFSSM, these are still restricted to appraisal of a few aspects of reliability and validity.

Gestational weight gain according to the Brazilian charts and its association with maternal and infant adverse outcomes.

BACKGROUND: The lack of gestational weight gain (GWG) recommendations for low- and middle-income countries is a significant concern. OBJECTIVES: To identify the ranges on the Brazilian GWG charts associated with lowest risks of selected adverse maternal and infant outcomes. METHODS: Data from 3 large Brazilian datasets were used. Pregnant individuals aged ≥18, without hypertensive disorders or gestational diabetes were included. Total GWG was standardized to gestational age-specific z-scores according to Brazilian GWG charts. A composite infant outcome was defined as the occurrence of any of small-for-gestationa lage (SGA), large-forgestationa lage (LGA), or preterm birth. In a separate sample, postpartum weight retention (PPWR) was measured at 6 and/or 12 mo postpartum. Multiple logistic and Poisson regressions were performed with GWG z-scores as the exposure and individual and composite outcomes. GWG ranges associated with the lowest risk of the composite infant outcome were identified using noninferiority margins. RESULTS: For the neonatal outcomes, 9500 individuals were included in the sample. For PPWR, 2602 and 7859 individuals were included at 6 and 12 mo postpartum, respectively. Overall, 7.5% of the neonates were SGA, 17.6% LGA, and 10.5% were preterm. Higher GWG z-scores were positively associated with LGA birth, whereas lower z-scores were positively associated with SGA births. The risk of the selected adverse neonatal outcomes were lowest (within 10% of lowest observed risk) when individuals with underweight, normal weight, overweight, or obesity gained between 8.8-12.6; 8.7-12.4; 7.0-8.9; and 5.0-7.2 kg, respectively. These gains correspond to probabilities of PPWR ≥5 kg at 12 mo of 30% for individuals with under and normal weight, and <20% for overweight and obesity. CONCLUSIONS: This study provided evidence to inform new GWG recommendations in Brazil.

Alcohol misuse among partners: a potential effect modifier in the relationship between physical intimate partner violence and postpartum depression.

PURPOSE: This study evaluated if the probability of postpartum depression (PPD) increases with an upward gradient of physical intimate partner violence (IPV) during pregnancy and whether substance use by any member of the couple modifies this relationship. METHODS: The sample comprised 811 randomly selected mothers of children under 5 months old attending primary health services of Rio de Janeiro, Brazil. The Revised Conflict Tactics Scale (CTS2) gauged physical IPV, and the Edinburgh Postnatal Depression Scale (EPDS) assessed PPD. A hierarchical logistic regression model was employed to deal with confounding. Specific interaction terms between physical IPV and alcohol misuse or use of illicit drugs were also tested. RESULTS: Physical IPV during pregnancy was reported by 37.8% of respondents and 24.3% were presumably depressed (EPDS score ≥ 12). Interaction between physical IPV and partners' alcohol misuse was statistically significant (p = 0.026). Although there was a significant increase in PPD with just one act of physical IPV in the absence of a partners' alcohol misuse, mounting acts did not have any further influence. Conversely, when partners misused alcohol, the probability progressively and steeply increased from two acts onwards, reaching almost sevenfold by six cumulative physical IPV events as opposed to none. CONCLUSIONS: The results reinforce the relevance of physical IPV as a risk factor to PPD. They also suggest that context matters, partners' alcohol misuse acting as an important effect modifier. These evidences justify tailored preventive, screening and intervention procedures for IPV and alcohol misuse during pregnancy and the postpartum period.

Scaling up research on discrimination and health: The abridged Explicit Discrimination Scale.

Using data from two studies conducted among diverse undergraduate students, we assessed the scalar structure of the Explicit Discrimination Scale (EDS), and developed an abridged version of the instrument. Our findings suggest that the EDS has acceptable scalability properties, including an adequate dispersion of items along the latent trait continuum. Results also support the idea that increasing raw scale scores reflect higher intensities of perceived discrimination. This shortened version of the EDS may be used in large-scale studies on the health impacts of discrimination.

Perceived Experiences of Community Violence Among Adolescents: A School Survey From Rio de Janeiro, Brazil.

Community violence (CV) is a global public health problem due to its high frequency and severe consequences. Although CV is one of the leading causes of death among adolescents, little is known about the everyday CV situations that do not lead to death. This study aimed to estimate the frequency of exposure to and involvement in CV situations among adolescent students from public and private schools in the city of Rio de Janeiro, Brazil. This was a cross-sectional study of 693 individuals in their second year of high school selected through stratified multistage random sampling. Information about their exposure to and involvement in CV was collected through a self-completed multidimensional questionnaire in the classrooms. For approximately 30% of the adolescents, someone close to them had been murdered, and 40% had already seen the corpse of a victim of homicide. Seventeen percent reported having been directly involved in CV situations. Approximately 38%, 13%, and 25% had been victims of robberies, interpersonal aggression, and death threats to either themselves or their relatives, respectively. Many of these situations occurred more than once. In general, CV was more frequently reported by boys and by those who did not live with both parents. Adolescents from higher economic classes experienced more interpersonal aggression and felt a greater need to carry a gun. Those who belonged to the lower economic classes and studied in public schools were more exposed to lethal violence than other students. The results call attention to the very high percentage of adolescent students that are involved in CV situations as well as to the differences in violence rates among population subgroups. Such findings should be considered when planning CV prevention and management actions in schools and other socialization spaces for adolescents.

National Trends and Disparities in Severe Food Insecurity in Brazil between 2004 and 2018.

Background: The Brazilian Household Food Insecurity Measurement Scale (EBIA) is the main tool for assessing household food insecurity (FI) in Brazil and facilitates the monitoring and improvement of national public policies to promote food security. Since 2004, the Brazilian government has conducted National Household Sample Surveys, and in 2018, the government carried out the last national evaluation of FI. Objectives: To describe trends in severe FI in Brazil from 2004 to 2018. Methods: Data from 3 cross-sectional Brazilian National Household Sample Surveys (sample sizes: 2004 = 112,530; 2009 = 120,910; 2013 = 116,196) and from the last Household Budget Survey (sample size = 57,920) that assessed the status of FI using the EBIA were analyzed. Changes in severe FI during 2 periods (2004-2013; 2013-2018) were estimated while considering sociodemographic factors. Results: The period between 2004 and 2013 was marked by a significant decrease in severe FI (-53.6%), but this trend reversed in 2013-2018 (+43.8%). The greatest decrease in severe FI occurred in the Northeast (-57.6%) among households where the reference person was a man (-57.6%) and self-identified as white (-58.1%) (2004-2013). In 2013-2018, households with children aged ≤4 y (+6.3%) and members aged ≥65 y (+12.5%) experienced the lowest increases in severe FI. Conclusions: After a significant reduction from 2004 to 2013, severe FI increased sharply from 2013 to 2018, likely due to disruptions in public policies aimed at reducing hunger and unemployment rates.

Comparison between the Brazilian and 3 international gestational weight gain charts.

BACKGROUND: Little is known about the ability of the recently released Brazilian gestational weight gain (GWG) charts to predict the occurrence of adverse birth outcomes. OBJECTIVES: We compared the new Brazilian weight gain charts with 3 international charts and determined their ability to predict the occurrence of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) births in Brazilian women. METHODS: A subsample of 6888 adult women (43,931 weight measurements) with singleton pregnancies from a nationwide, hospital-based cohort study conducted in 2011-2012 was analyzed. Selected percentiles from Brazilian GWG charts were compared with those from American, International Fetal and Newborn Growth Consortium for the 21st Century study, and Lifecycle consortium charts. Sensitivity, specificity, and AUROC values for SGA and LGA births were estimated with 95% CIs using the classification of GWG below or above selected percentiles of each chart. RESULTS: The weight gain corresponding to a given percentile varied among the charts, especially for women with pre-pregnancy overweight and obesity. The proportions of women with GWG classified below or above selected percentiles were closest to the expected values for all pre-pregnancy BMI categories in the Brazilian and Lifecycle charts. At the 10th percentile, the highest sensitivity for SGA births was observed for the American charts at midpregnancy (36.8%) and the highest specificity was observed using the Brazilian charts in the first trimester (93.4%). At the 90th percentile, the highest sensitivity for LGA births occurred in midpregnancy for the Lifecycle charts (26.8%) and the highest specificity occurred in the American charts using total GWG (97.1%). All the AUROCs were under 0.5 for SGA births and ranged from 0.55 (first trimester) to 0.62 (total GWG) for LGA births. CONCLUSIONS: The charts differ in GWG trajectories, especially for women with overweight and obesity. The 4 charts had low predictive ability of SGA and LGA births and should not be considered as isolated screening tools for those outcomes.

Revisiting the dimensional structure of the Edinburgh Postnatal Depression Scale (EPDS): empirical evidence for a general factor.

BACKGROUND: The Edinburgh Postnatal Depression Scale (EPDS) has been proposed as a one-dimensional instrument and used as a single 10-item scale. This might be considered questionable since repeated psychometric studies have shown multi-dimensionality, which would entail using separate component subscales. This study reappraised the dimensional structure of the EPDS, with a focus on the extent of factor correlations and related factor-based discriminant validity as a foundation for deciding how to effectively scale the component items. METHODS: The sample comprised 811 randomly selected mothers of children up to 5 months attending primary health services of Rio de Janeiro, Brazil. Strict Confirmatory Factor Analysis (CFA) and Exploratory Factor Analysis modeled within a CFA framework (E/CFA) were sequentially used to identify best fitting and parsimonious model(s), including a bifactor analysis to evaluate the existence of a general factor. Properties concerning the related 10-item raw-score scale were also investigated using non-parametric items response theory methods (scalability and monotonicity). RESULTS: An initial CFA rejected the one-dimensional structure, while an E/CFA subscribed a three-dimensional solution. Yet, factors were highly correlated (0.66, 0.75 and 0.82). The ensuing CFA showed poor discriminant validity (some square-roots of average variance extracted below the factor correlations). A general bifactor CFA was then fit. Results suggested that, although still weakly encompassing three specific factors, the EPDS might be better described by a model encompassing a general factor (loadings ranging from 0.51 to 0.81). The related 10-item raw score showed adequate scalability (Loevinger's H coefficient = 0.4208), monotonicity e partial double monotonicity (nonintersections of Item Step Response Functions). CONCLUSION: Although the EPDS indicated the presence of specific factors, they do not qualify as independent dimensions if used separately and should therefore not be used empirically as sub-scales (raw scores). An all-encompassing scale seems better suited and continuing its use in clinical practice and applied research should be encouraged.

Physical violence between intimate partners during pregnancy and postpartum: a prediction model for use in primary health care facilities.

This article offers a simple predictive model of physical intimate partner violence (PIPV) to be used by primary health care (PHC) professionals. The sample comprised 811 mothers of children <5 months old attending PHC facilities in Rio de Janeiro, Brazil. A multinomial logit model was used. Measured by the Revised Conflict Tactics Scales, PIPV was classified in three levels (absence, at least one episode during pregnancy or postpartum, and presence in both periods). Socio-economic, demographic and life style variables were considered as potential predictors. Maternal age <20 years, an education of <8 years of schooling, raising >2 children under 5, tobacco smoking, alcohol misuse and illicit drug use by the mother and/or partner, and perception of baby's ill-health were identified as predictors of PIPV. The model-projected prevalence of PIPV for pregnancy and/or postpartum was just 10.1% in the absence of these characteristics, whereas this increased to 96.4% when all the seven characteristics were present. Child, maternal and family characteristics greatly increase the likelihood of PIPV and could be used together as screening indicators.

Severe physical violence between intimate partners during pregnancy: a risk factor for early cessation of exclusive breast-feeding.

OBJECTIVE: To investigate the role of severe physical violence during pregnancy (SPVP) between intimate partners in early cessation of exclusive breast-feeding (EBF). DESIGN: A health services survey. The revised Conflict Tactics Scale was used to characterize SPVP; premature breast-feeding cessation was identified using a current status data approach, which was based on the information reported from food recall during the preceding 7 d. The cumulative hazard function was estimated by complementary log-log transformation models, which allowed the ensuing estimation of early breast-feeding cessation rates in different age groups and the ratio of rates of weaning between women exposed and not exposed to violence. SETTING: Five large public primary health-care facilities of Rio de Janeiro, Brazil. SUBJECTS: The sample comprised 811 randomly selected mothers of children under 5 months of age who were waiting to be consulted. RESULTS: SPVP is an independent risk factor of cessation of EBF since, after controlling for socio-economic, demographic, reproductive and lifestyle variables, women exposed to violence presented an incidence density that was 31% higher than those who were not exposed (hazard ratio = 1·30, 95% CI 1·01, 1·69). CONCLUSIONS: The findings corroborate the hypothesis that SPVP is an important risk factor for EBF. This indicates the need for incentives to adequately train health-care personnel in dealing with lactating women in order to gain a broader view of breast-feeding beyond the biological aspects of lactation, including the maternal psychological dimension.

Postpartum depression according to time frames and sub-groups: a survey in primary health care settings in Rio de Janeiro, Brazil.

This study aimed at estimating the prevalence of postpartum depression (PPD) according to postpartum periods and sub-groups in public primary health care settings in Rio de Janeiro, Brazil. A cross-sectional survey was carried out in five primary health care units and included 811 participants randomly selected among mothers of children up to five postpartum months. Women were classified as depressed and given scores on Edinburgh Postnatal Depression Scale (EPDS) above 11. The overall estimate of PPD was 24.3% (95% CI, 21.4-27.4). However, estimates were not homogeneous during the first 5 months postpartum (p value = 0.002). There was a peak of depressive symptoms around 3 months postpartum, when 128 women (37.5%, 95% CI, 29.1-46.5) disclosed scores above 11 on EPDS. Regarding the magnitude of PPD according to some maternal and partners' characteristics, it was consistently higher among women with low schooling, without a steady partner, and whose partners misused alcohol or used illicit drugs. The prevalence of PPD among women attending primary health care units in Rio de Janeiro seems to be higher than general estimates of 10-15%, especially among mothers with low schooling and that receive little (if any) support from partners. Also, the "burden" of PPD may be even higher around 3 months postpartum. These results are particularly relevant for public health policies. Evaluation of maternal mental health should be extended at least until 3 to 4 months postpartum, and mothers presenting a high-risk profile deserve special attention.

Gestational weight gain charts: results from the Brazilian Maternal and Child Nutrition Consortium.

BACKGROUND: Monitoring gestational weight gain (GWG) is fundamental to ensure a successful pregnancy for the mother and the offspring. There are several international GWG charts, but just a few for low- and middle-income countries. OBJECTIVES: To construct GWG charts according to pre-pregnancy BMI for Brazilian women. METHODS: This is an individual patient data analysis using the Brazilian Maternal and Child Nutrition Consortium data, comprising 21 cohort studies. External validation was performed using "Birth in Brazil," a nationwide study. We selected adult women with singleton pregnancies who were free of infectious and chronic diseases, gestational diabetes, and hypertensive disorders; who delivered a live birth at term; and whose children were adequate for gestational age, and with a birth weight between 2500-4000 g. Maternal self-reported pre-pregnancy weight and weight measured between 10-40 weeks of gestation were used to calculate GWG. Generalized Additive Models for Location, Scale and Shape were fitted to create GWG charts according to gestational age, stratified by pre-pregnancy BMI. RESULTS: The cohort included 7086 women with 29,323 weight gain measurements to construct the charts and 4711 women with 31,052 measurements in the external validation. The predicted medians for GWG at 40 weeks, according to pre-pregnancy BMI, were: underweight, 14.1 kg (IQR, 10.8-17.5 kg); normal weight, 13.8 kg (IQR, 10.7-17.2 kg); overweight, 12.1 kg (IQR, 8.5-15.7 kg); obesity, 8.9 kg (IQR, 4.8-13.2 kg). The 10th, 25th, 50th, 75th, and 90th percentiles were estimated. Results for internal and external validation showed that the percentages below the selected percentiles were close to those expected. CONCLUSIONS: The charts proposed provide a description of GWG patterns according to gestational age and pre-pregnancy BMI among healthy Brazilian women with good neonatal outcomes. The external validation indicates that this new tool can be used to monitor GWG in the primary health-care setting and to test potential recommended values.

Measures and models for causal inference in cross-sectional studies: arguments for the appropriateness of the prevalence odds ratio and related logistic regression.

BACKGROUND: Several papers have discussed which effect measures are appropriate to capture the contrast between exposure groups in cross-sectional studies, and which related multivariate models are suitable. Although some have favored the Prevalence Ratio over the Prevalence Odds Ratio -- thus suggesting the use of log-binomial or robust Poisson instead of the logistic regression models -- this debate is still far from settled and requires close scrutiny. DISCUSSION: In order to evaluate how accurately true causal parameters such as Incidence Density Ratio (IDR) or the Cumulative Incidence Ratio (CIR) are effectively estimated, this paper presents a series of scenarios in which a researcher happens to find a preset ratio of prevalences in a given cross-sectional study. Results show that, provided essential and non-waivable conditions for causal inference are met, the CIR is most often inestimable whether through the Prevalence Ratio or the Prevalence Odds Ratio, and that the latter is the measure that consistently yields an appropriate measure of the Incidence Density Ratio. SUMMARY: Multivariate regression models should be avoided when assumptions for causal inference from cross-sectional data do not hold. Nevertheless, if these assumptions are met, it is the logistic regression model that is best suited for this task as it provides a suitable estimate of the Incidence Density Ratio.

Brazilian Maternal and Child Nutrition Consortium: establishment, data harmonization and basic characteristics.

Pooled data analysis in the field of maternal and child nutrition rarely incorporates data from low- and middle-income countries and existing studies lack a description of the methods used to harmonize the data and to assess heterogeneity. We describe the creation of the Brazilian Maternal and Child Nutrition Consortium dataset, from multiple pooled longitudinal studies, having gestational weight gain (GWG) as an example. Investigators of the eligible studies published from 1990 to 2018 were invited to participate. We conducted consistency analysis, identified outliers, and assessed heterogeneity for GWG. Outliers identification considered the longitudinal nature of the data. Heterogeneity was performed adjusting multilevel models. We identified 68 studies and invited 59 for this initiative. Data from 29 studies were received, 21 were retained for analysis, resulting in a final sample of 17,344 women with 72,616 weight measurements. Fewer than 1% of all weight measurements were flagged as outliers. Women with pre-pregnancy obesity had lower values for GWG throughout pregnancy. GWG, birth length and weight were similar across the studies and remarkably similar to a Brazilian nationwide study. Pooled data analyses can increase the potential of addressing important questions regarding maternal and child health, especially in countries where research investment is limited.