Categoria: Artigos científicos

We aimed to estimate latent foetal growth conditions and explore their determinants among maternal characteristics and ultrasound biometric parameters. We additionally investigated the influence of foetal growth conditions on perinatal variables. We used data from live-born singletons in the Maternal and Child Health and Nutrition in Acre, Brazil (MINA-Brazil Study) population-based birth cohort. Maternal and perinatal characteristics were assessed in medical records from the maternity hospital and interviews with participants from July 2015 to June 2016. A sub-sample went through ultrasound examinations during the antenatal period, with assessment of foetal head and abdominal circumferences, and femur length. We estimated latent foetal growth conditions with a structural equation modelling framework, informed by the child’s birth weight z-scores (BWZ) and birth length z-scores (BLZ) according to gestational age. Odds ratios and 95% confidence intervals (CIs) for the occurrence of perinatal events were estimated according to linear predictions of the latent variable. We included 1253 participants. Latent foetal growth conditions explained 88.3% of BWZ and 53.7% of BLZ variation. Maternal elevated blood pressure, primiparity, smoking, malaria, and insufficient gestational weight gain negatively impacted foetal growth conditions. In the subsample (n = 499), ultrasound biometric parameters assessed at 28 weeks were positively associated with the latent variable, with the largest contribution from foetal abdominal circumference. Each standardised unit of predicted foetal growth conditions halved the chance for preterm birth (95% CI = 0.26, 0.74) and longer hospital stay (>3 days) (95% CI = 0.28, 0.88). Conversely, BWZ and BLZ were not independently associated with these perinatal variables in separate logistic regression models. Latent foetal growth conditions jointly encompassing weight gain and linear growth during gestation were negatively influenced by a scenario of dual burden of maternal morbidities, with perinatal implications. Read the article and the supplementary document.

We aimed to assess the association of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with offspring BMI-for-age z-scores (BAZs) during the first 2 years of life. A population-based birth cohort study was conducted with 900 mother–child pairs. Pre-pregnancy weight and weight at delivery were collected from medical records, and anthropometric data were measured at birth and at 6-month, 1-year and 2-year follow-up visits. Linear regression and linear mixed-effect models assessed associations with pre-pregnancy BMI, GWG and BAZ during the first 2 years of life. Pre-pregnancy overweight and obesity and excessive GWG were positively associated with BAZ at birth and at 1- and 2-year follow-up visits. There were no significant additional BAZ changes per year based on the exposures up to age 2 years. Elevated maternal pre-pregnancy BMI and GWG were associated with a child’s higher BAZ at birth, and these differences remained constant throughout the first 2 years of life in Amazonian children. These findings highlight the importance of promoting adequate maternal weight before pregnancy and during prenatal care also in socially vulnerable populations. Read the article.

To review observational studies on the association between breastfeeding (BF) practices and head circumference (HC) of children < 2 years old. A systematic review was conducted using the following electronic databases of ​​health sciences: PubMed, Latin American and Caribbean Literature in Health Sciences (Lilacs), Web of Science and Scopus. We selected observational studies published in any language from January 01, 2010 to November 19, 2021, from different populations that investigated the association between BF practice and HC among healthy children <2 years old. Titles and abstracts were screened independently by two evaluators. From the 4229 articles identified, 24 were included in this review: 6 cross-sectional, 17 longitudinal, and 1 case-control. The studies varied in their definition of the variables for BF and in reporting its practice, frequency, duration, and feeding method. Regarding HC, the authors analyzed the mean differences, abnormal values ​​(z-score above + 2SD or below -2SD according to the World Health Organization (WHO) growth standards, 2007), and longitudinal growth parameters. The findings of this review suggest that BF may have a positive relationship with HC at the beginning of life. Our findings suggest that BF, especially exclusive BF, may play a protective role against abnormal HC values in young children. However, more robust evidence with standardized BF indicators and WHO growth standards (2007) are required. Read the article.

Authors’ Reply to the Letter to the Editor: ‘Prolonged breastfeeding, sugar consumption and dental caries at 2 years of age: a birth cohort study’, Community Dentistry and Oral Epidemiology. Read the letter.

Previous cohort studies have found a positive association between prolonged breastfeeding (≥12 months) on dental caries, but few of them analysed the mediated effect of sugar consumption on this association. This study investigated whether prolonged breastfeeding is a risk factor for caries at 2-year follow-up assessment (21–27 months of age) and whether this effect is mediated by sugar consumption. A birth cohort study was performed in the Brazilian Amazon (n = 800). Dental caries was assessed using the dmf-t index. Prolonged breastfeeding was the main exposure. Data on baseline covariables and sugar consumption at follow-up visits were analysed. We estimated the OR for total causal effect (TCE) and natural indirect effect (NIE) of prolonged breastfeeding on dental caries using the G-formula. The prevalence of caries was 22.8% (95% CI: 19.8%–25.8%). Children who were breastfed for 12–23 months (TCE = 1.13, 95% CI: 1.05–1.20) and for ≥24 months (TCE = 1.27, 95% CI: 1.14–1.40) presented a higher risk of caries at age of 2 years than those breastfed <12 months. However, this risk was slightly mediated by a decreased frequency of sugar consumption at age of 2 years only for breastfeeding from 12 to 23 months (NIE; OR = 0.95, 95% CI: 0.91–0.97). In this study, the effect of prolonged breastfeeding on the increased risk of dental caries was slightly mediated by sugar consumption. Early feeding practices for caries prevention and promoting breastfeeding while avoiding sugar consumption should be targeted in the first 2 years of life. Read the article.

Periconceptional maternal ultra-processed food (UPF) consumption impairs embryonic growth. Impacts of exposure to UPF on distinct components of fetal growth in late pregnancy are unknown. We investigated the influence of frequency of UPF consumption during pregnancy on fetal head circumference (HC), abdominal circumference (AC) and femur length (FL). This study included 417 live-born singleton pregnancies prospectively followed-up since the antenatal period in the MINA-Brazil Study, with an available ultrasound scan at >24 gestational weeks. Frequency of food groups consumption in the previous month was categorised as no/monthly, weekly or daily. Ultrasound scans were conducted at 27·8 (SD: 1·7) gestational weeks. HC, AC and FL z-scores were calculated for gestational age using the INTERGROWTH-21st Project standards. Simultaneous-quantile regression models were fitted at the 10th, 50th and 90th percentiles of the distribution of each ultrasound parameter according to UPF consumption, with adjustment for potential confounders. Participants were aged on average 24·7 (SD: 6·5) years, 44·8 % were primiparous, and 26·9 % and 24·9 %, respectively, had weekly and daily UPF consumption. Compared with no/monthly intake, daily UPF consumption impaired HC across its distribution, with significant effect sizes varying from –0·24 to –0·40 z-score. Weekly UPF consumption decreased HC at the 90th percentile by –0·39 z-score (95 % CI: –0·78, –0·01) and FL at the 50th percentile by –0·32 z-score (95 % CI: –0·60, –0·04). No association was noted with AC. Frequency of UPF consumption was negatively associated with skeletal components of fetal growth in late pregnancy. Infant body composition may benefit from healthy food practices since pregnancy. Read the article.

We measured the prevalence of malaria in pregnancy and estimated its impact on birth weight and length and maternal hemoglobin in 1,180 women from Juruá Valley, the main malaria hotspot in Brazil. Antenatal malaria episodes, 74.6% of them due to Plasmodium vivax, were microscopically diagnosed in 8.0% of the women and were associated with an average reduction in birth weight z-scores of 0.35 (95% confidence interval [CI] = 0.14–0.57) and in birth length z-scores of 0.31 (95% CI = 0.08–0.54), compared with malaria-free pregnancies. Affected mothers had a mean decrease in hemoglobin concentration at delivery of 0.33 g/100 mL (95% CI = 0.05–0.62 g/100 mL); 51.6% were anemic. The timing and frequency of antenatal infections influenced pregnancy outcomes and first- or second-trimester infections were not associated with decreased birth weight and length and maternal hemoglobin at delivery. Although repeated antenatal vivax infections were associated with poorer birth outcomes, even a single vivax malaria episode was associated with a significant reduction in birth weight and length and maternal hemoglobin. Overall, 7.5% women had the parasite’s DNA found in peripheral blood at delivery. Most (83.1%) of these 89 perinatal infections were due to P. vivax and only 7.9% of them progressed to symptomatic disease after delivery. Plasmodium vivax and Plasmodium falciparum DNA was found in 0.6% and 0.3% of 637 cord blood samples examined, respectively, but only one newborn developed clinical neonatal malaria. Our results further challenge the notion that vivax malaria is relatively benign during pregnancy and call for better strategies for its prevention. Read the article.

Vaccination coverage has been dropping in Brazil and other countries. In addition, immune responses after vaccination may not be homogeneous, varying according to sociodemographic and clinical factors. Understanding the determinants of incomplete vaccination and negative antibody test results may contribute to the development of strategies to improve vaccination effectiveness. In this study, we aimed to investigate the frequency of vaccine adherence, factors associated with incomplete vaccination for measles, mumps, rubella (MMR) and hepatitis A, and factors associated with the seronegative test results for measles, mumps and hepatitis A at 2 years of age. This was a population-based cohort that addressed health conditions and mother/infant nutrition in Cruzeiro do Sul city, Brazil. Vaccination data were obtained from official certificates of immunization. The children underwent blood collection at the two-year-old follow-up visit; the samples were analyzed using commercially available kits to measure seropositivity for measles, mumps, and hepatitis A. We used modified Poisson regression models adjusted for covariates to identify factors associated with incomplete vaccination and negative serology after vaccination. Out of the 825 children included in the study, adherence to the vaccine was 90.6% for MMR, 76.7% for the MMRV (MMR + varicella), and 74.9% for the hepatitis A vaccine. For MMR, after the adjustment for covariates, factors associated with incomplete vaccination included: white-skinned mother; paid maternity leave; raising more than one child; lower number of antenatal consultations; and attending childcare. For hepatitis A, the factors included: white-skinned mother and not having a cohabiting partner. The factors with statistically significant association with a negative antibody test result included: receiving Bolsa Familia allowance for measles and mumps; incomplete vaccination for measles; and vitamin A deficiency for mumps. Strategies to improve the efficiency of vaccine programs are urgently needed. These include improvements in communication about vaccine safety and efficacy, and amplification of access to primary care facilities, prioritizing children exposed to the sociodemographic factors identified in this study. Additionally, sociodemographic factors and vitamin A deficiency may impact the immune responses to vaccines, leading to an increased risk of potentially severe and preventable diseases. Read the article.

Excessive weight gain during childhood has been considered an early life risk factor for chronic disease in the long term. We examined the role of excessive gestational weight gain (GWG) and breastfeeding (BF) practices with the offspring’s body mass index-for-age z-score (zBMI) at 2 years. Data from 743 Amazonian young children of the MINA-Brazil population-based birth cohort study were used. Linear regression models were run to estimate the associations between excessive GWG and BF practices (exclusive breastfeeding, EBF <3 months of age and BF <1 year) with zBMI. Excessive GWG and BF <1 year were associated with an adjusted 0.24 units (95% CI: 0.08, 0.41) and 0.28 units (95% CI: 0.12, 0.44) higher zBMI at age 2 years, respectively. Gain excessive weight during pregnancy and shorter BF duration (<1y) were associated with a higher body mass index at 2 years of age among Brazilian Amazonian children. Read the article.

We examined the epidemiology of malaria in riverine populations of the country′s main hotspot – the upper Juruá Valley in Acre state, close to the Brazil-Peru border, where Plasmodium vivax accounts for > 80% of cases. Participants (n = 262) from 10 villages along the Azul River were screened for malaria parasites by microscopy and genus-specific, cytochrome b (cytb) gene-based polymerase chain reaction. Positive samples were further tested with quantitative TaqMan assays targeting P. vivax- and P. falciparum-specific cytb domains. We used multiple logistic regression analysis to identify independent correlates of P. vivax infection. Microscopy detected only one P. vivax and two P. falciparum infections. TaqMan assays detected 33 P. vivax infections (prevalence, 11.1%), 78.1% of which asymptomatic, with a median parasitaemia of 34/mL. Increasing age, male sex and use of insecticide-treated bed nets were significant predictors of elevated P. vivax malaria risk. Children and adults were similarly likely to remain asymptomatic once infected. Our findings are at odds with the hypothesis of age-related clinical immunity in native Amazonians. The low virulence of local parasites is suggested as an alternative explanation for subclinical infections in isolated populations . Read the article.