Identifying biologically implausible values in big longitudinal data: an example applied to child growth data from the Brazilian food and nutrition surveillance system.

BACKGROUND: Several strategies for identifying biologically implausible values in longitudinal anthropometric data have recently been proposed, but the suitability of these strategies for large population datasets needs to be better understood. This study evaluated the impact of removing population outliers and the additional value of identifying and removing longitudinal outliers on the trajectories of length/height and weight and on the prevalence of child growth indicators in a large longitudinal dataset of child growth data. METHODS: Length/height and weight measurements of children aged 0 to 59 months from the Brazilian Food and Nutrition Surveillance System were analyzed. Population outliers were identified using z-scores from the World Health Organization (WHO) growth charts. After identifying and removing population outliers, residuals from linear mixed-effects models were used to flag longitudinal outliers. The following cutoffs for residuals were tested to flag those: -3/+3, -4/+4, -5/+5, -6/+6. The selected child growth indicators included length/height-for-age z-scores and weight-for-age z-scores, classified according to the WHO charts. RESULTS: The dataset included 50,154,738 records from 10,775,496 children. Boys and girls had 5.74% and 5.31% of length/height and 5.19% and 4.74% of weight values flagged as population outliers, respectively. After removing those, the percentage of longitudinal outliers varied from 0.02% (<-6/>+6) to 1.47% (<-3/>+3) for length/height and from 0.07 to 1.44% for weight in boys. In girls, the percentage of longitudinal outliers varied from 0.01 to 1.50% for length/height and from 0.08 to 1.45% for weight. The initial removal of population outliers played the most substantial role in the growth trajectories as it was the first step in the cleaning process, while the additional removal of longitudinal outliers had lower influence on those, regardless of the cutoff adopted. The prevalence of the selected indicators were also affected by both population and longitudinal (to a lesser extent) outliers. CONCLUSIONS: Although both population and longitudinal outliers can detect biologically implausible values in child growth data, removing population outliers seemed more relevant in this large administrative dataset, especially in calculating summary statistics. However, both types of outliers need to be identified and removed for the proper evaluation of trajectories.

Association between food environments and fetal growth in pregnant Brazilian women.

INTRODUCTION: Birth weight is described as one of the main determinants of newborns' chances of survival. Among the associated causes, or risk factors, the mother's nutritional status strongly influences fetal growth and birth weight outcomes of the concept. This study evaluates the association between food deserts, small for gestational age (SGA), large for gestational age (LGA) and low birth weight (LBW) newborns. DESIGN: This is a cross-sectional population study, resulting from individual data from the Live Birth Information System (SINASC), and commune data from mapping food deserts (CAISAN) in Brazil. The newborn's size was defined as follows: appropriate for gestational age (between 10 and 90th percentile), SGA (< 10th percentile), LGA (> 90th percentile), and low birth weight < 2,500 g. To characterize food environments, we used tertiles of the density of establishments which sell in natura and ultra-processed foods. Logistic regression modeling was conducted to investigate the associations of interest. RESULTS: We analyzed 2,632,314 live births in Brazil in 2016, after appropriate adjustments, women living in municipalities with limited availability of fresh foods had a higher chance of having newborns with SGA [OR2nd tertile: 1.06 (1.05-1.07)] and LBW [OR2nd tertile: 1.11 (1.09-1.12)]. Conversely, municipalities with greater availability of ultra-processed foods had a higher chance of having newborns with SGA [OR3rd tertile: 1.04 (1.02-1.06)] and LBW [OR2nd tertile: 1.13 (1.11-1.16)]. Stratification by race showed that Black and Mixed/Brown women had a higher chance of having newborns with SGA [OR3rd tertile: 1.09 (1.01-1.18)] and [OR3rd tertile: 1.06 (1.04-1.09)], respectively, while Mixed-race women also had a higher chance of having newborns with LBW [OR3rd tertile: 1.17 (1.14-1.20)]. Indigenous women were associated with LGA [OR3rd tertile: 1.20 (1.01-1.45)]. CONCLUSION: The study found that living in areas with limited access to healthy foods was associated with an increased risk of SGA and low birth weight among newborns, particularly among Black and Mixed/Brown women. Therefore, urgent initiatives aimed at reducing social inequalities and mitigating the impact of poor food environments are needed in Brazil.

Cross-sectional study of the anthropometric characteristics of children with congenital Zika syndrome up to 12 months of life.

BACKGROUND: Little is known about physical development of children with Congenital Zika Syndrome (CZS). This study aims to evaluate the anthropometric characteristics of children with CZS up to 12 months. METHODS: This is a cross-sectional study developed with 46 children with CZS living in Bahia. We used the Public Health Events Register, Live Births Information System and Childcare Records of Primary Health Care Services. Descriptive analysis was performed by distributing absolute and relative frequencies and median and interquartile range. The Weight/Age (W/A), Length/Age (L/A), Weight/Length (W/L) and Head Circumference/Age (HC/A) indexes were calculated for each month and expressed in z-score values, and the results were evaluated individually and by group average. Values between ≥ - 2 and ≤ 2 standard deviations were used as reference. T-Student and Spearman's Correlation Tests were applied to verify the existence of any relationship between maternal and children's variables with the anthropometric indexes weight/age and height/age at birth and at 3, 6 and 12 months of age. RESULTS: The studied children had high proportions of low birth weight (23.9%), dysphagia (56.8%) and seizures (53.5%). The mean z-score for the HC/A index at birth was - 3.20 and remained below - 3 z-scores throughout the assessed period. The analysis of the indices equivalent to every single child's anthropometric measurement showed a deficit in 20.4% of the W/A, 39.1% of the L/A, 9.2% of the W/L and 85.7% of the HC/A measurements. Distribution of the mean values of these anthropometric indices revealed a risk of delayed stature growth (L/A < -1 z-score). There was a statistically significant association between L/A at 12 months and dysphagia (p = 0.0148) and a positive correlation between breastfeeding time and W/A. No statistically significant correlation was found between any other tested variables. CONCLUSIONS: We observed a deficit in the HC/A index, which is a common feature in CZS, but also a high proportion of W/A and L/A deficit. The average group z-score highlighted the risk of delay in stature growth for age, which calls attention to the need for health interventions, as this condition exposes them to a higher risk of morbidity and mortality.

Oxidized Low-Density Lipoprotein (Ox-LDL) and Triggering Receptor-Expressed Myeloid Cell (TREM-1) Levels Are Associated with Cardiometabolic Risk in Nonobese, Clinically Healthy, and Young Adults.

Oxidative and inflammatory substances play an important role in the genesis of processes related to cardiometabolic risk. High levels of oxidized low-density lipoprotein (Ox-LDL) and of triggering receptor-expressed myeloid cells (TREM-1) are associated with cardiovascular and inflammatory diseases. In this study, we evaluate the association of the plasma concentrations of Ox-LDL and serum levels of circulating TREM-1 (sTREM-1) with the components of cardiometabolic risk (CMR) and other associated risk parameters. Although the individuals in this study were young, nonobese, and did not have signs, symptoms, and diagnosis of diseases, they already presented components of CMR. Ox-LDL lipid fraction correlated positively with CMR-related markers: body mass index (BMI), waist circumference (WC), body fat percentage, total cholesterol, LDL-c, VLDL-c, triglycerides, atherogenic cholesterol, and atherogenic index. Among these parameters, atherogenic cholesterol had a greater predictive effect for Ox-LDL alterations. Individuals with higher serum concentrations of sTREM-1 presented higher values for BMI, WC, triglycerides, VLDL-c, and atherogenic cholesterol. WC showed an effect on the association between the sTREM-1's inflammatory response and the components of CMR. The association of oxidative and inflammatory markers with anthropometric parameters and atherogenic cholesterol in nonobese, clinically healthy, and young individuals suggests the importance of early evaluation of these markers in order to prevent future cardiac events.