Preconception dietary glycemic index and risk for large-for-gestational age births

OBJECTIVES

Diets with a high glycemic index (GI) leading to elevated postprandial glucose levels and hyperinsulinemia during pregnancy have been inconsistently linked to an increased risk for large-for-gestational-age (LGA) births. The effects of prepregnancy dietary GI on LGA risk are, to our knowledge, unknown. We examined the association of prepregnancy dietary GI with LGA births and joint associations of GI and maternal overweight/obesity and infant sex with LGA births among 10 188 infants born without congenital anomalies from 1997 to 2011, using data from the National Birth Defects Prevention Study (NBDPS). The aim of this study was to investigate this association among infants without major congenital anomalies (controls) who participated in the NBDPS and to evaluate how prepregnancy BMI and infant sex may modify this association on the additive scale.

METHODS

Dietary intake was ascertained using a 58-item food frequency questionnaire. We dichotomized dietary GI into high and low categories using spline regression models. Infants with a birth weight at or above the 90th percentile for gestational age and sex, according to a U.S. population reference, were considered LGA. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of the infants, 859 (9%) had a high dietary GI (cut-point: 59), and 1244 infants (12%) were born LGA. Unadjusted analysis suggested an inverse association between high dietary GI and LGA (OR, 0.79; 95% CI, 0.62-0.99). No association was observed in multivariable models when comparing high dietary GI intake between LGA births and all other births (OR, 0.94; 95% CI, 0.74-1.20) or when excluding small-for-gestational-age (SGA) births (OR, 0.94; 95% CI, 0.73-1.19). No joint associations with maternal overweight/obesity or infant sex were observed.

CONCLUSION

High prepregnancy maternal GI was not associated with LGA births independently of or jointly with other factors.

Corrigendum to "Counting adolescents in: the development of an adolescent health indicator framework for population-based settings"

[This corrects the article DOI: 10.1016/j.eclinm.2023.102067.].

Inequities in COVID-19 Vaccination Coverage Among Pregnant Persons, by Disaggregated Race and Ethnicity - Massachusetts, May 2021-October 2022

National estimates suggest that COVID-19 vaccination coverage among pregnant persons is lower among those identifying as Hispanic or Latino (Hispanic) and non-Hispanic Black or African American. When examining COVID-19 vaccination coverage during pregnancy by race and ethnicity, however, data are typically limited to large, aggregate categories that might obscure within-group inequities. To address this, Massachusetts examined COVID-19 vaccination coverage among pregnant persons by combinations of 12 racial and 34 ethnic groupings. Among 102,275 persons with a live birth in Massachusetts during May 1, 2021-October 31, 2022, receipt of ≥1 dose of a COVID-19 vaccine before or during pregnancy was 41.6% overall and was highest among persons who identified as Asian (55.0%) and lowest among those who identified as Hispanic (26.7%). However, within all broad racial and ethnic groupings, disparities in COVID-19 vaccination coverage were identified when the data were disaggregated into more granular categories; for example, COVID-19 vaccination coverage ranged from 10.8%-61.1% among pregnant persons who identified as Hispanic. Disaggregated analyses reveal diverse experiences within broad racial and ethnic groupings. This information can be used to guide outreach to pregnant persons in communities with lower rates of COVID-19 vaccination coverage during pregnancy.

Suboptimal gestational weight gain and neonatal outcomes in low and middle income countries: individual participant data meta-analysis

OBJECTIVE

To estimate the associations between gestational weight gain (GWG) during pregnancy and neonatal outcomes in low and middle income countries.

DESIGN

Individual participant data meta-analysis.

SETTING

Prospective pregnancy studies from 24 low and middle income countries.

MAIN OUTCOME MEASURES

Nine neonatal outcomes related to timing (preterm birth) and anthropometry (weight, length, and head circumference) at birth, stillbirths, and neonatal death.

ANALYSIS METHODS

A systematic search was conducted in PubMed, Embase, and Web of Science which identified 53 prospective pregnancy studies published after the year 2000 with data on GWG, timing and anthropometry at birth, and neonatal mortality. GWG adequacy was defined as the ratio of the observed maternal weight gain over the recommended weight gain based on the Institute of Medicine body mass index specific guidelines, which are derived from data in high income settings, and the INTERGROWTH-21st GWG standards. Study specific estimates, adjusted for confounders, were generated and then pooled using random effects meta-analysis models. Maternal age and body mass index before pregnancy were examined as potential modifiers of the associations between GWG adequacy and neonatal outcomes.

RESULTS

Overall, 55% of participants had severely inadequate (<70%) or moderately inadequate (70% to <90%) GWG, 22% had adequate GWG (90-125%), and 23% had excessive GWG (≥125%). Severely inadequate GWG was associated with a higher risk of low birthweight (adjusted relative risk 1.62, 95% confidence interval 1.51 to 1.72; 48 studies, 93 337 participants; τ2=0.006), small for gestational age (1.44, 1.36 to 1.54; 51 studies, 93 191 participants; τ2=0.016), short for gestational age (1.47, 1.29 to 1.69; 40 studies, 83 827 participants; τ2=0.074), and microcephaly (1.57, 1.31 to 1.88; 31 studies, 80 046 participants; τ2=0.145) compared with adequate GWG. Excessive GWG was associated with a higher risk of preterm birth (1.22, 1.13 to 1.31; 48 studies, 103 762 participants; τ2=0.008), large for gestational age (1.44, 1.33 to 1.57; 47 studies, 90 044 participants; τ2=0.009), and macrosomia (1.52, 1.33 to 1.73; 29 studies, 68 138 participants; τ2=0) compared with adequate GWG. The direction and magnitude of the associations between GWG adequacy and several neonatal outcomes were modified by maternal age and body mass index before pregnancy.

CONCLUSIONS

Inadequate and excessive GWG are associated with a higher risk of adverse neonatal outcomes across settings. Interventions to promote optimal GWG during pregnancy are likely to reduce the burden of adverse neonatal outcomes, however further research is needed to assess optimal ranges of GWG based on data from low and middle income countries.

Periconceptional intakes of methyl donors and other micronutrients involved in one-carbon metabolism may further reduce the risk of neural tube defects in offspring: a United States population-based case-control study of women meeting the folic acid recommendations

BACKGROUND

Neural tube defects (NTDs) still occur among some women who consume 400 μg of folic acid for prevention. It has been hypothesized that intakes of methyl donors and other micronutrients involved in one-carbon metabolism may further protect against NTDs.

OBJECTIVES

To investigate whether intakes of vitamin B6, vitamin B12, choline, betaine, methionine, thiamine, riboflavin, and zinc, individually or in combination, were associated with NTD risk reduction in offspring of women meeting the folic acid recommendations.

METHODS

Data were from the National Birth Defects Prevention Study (United States population-based, case-control). We restricted deliveries between 1999 and 2011 with daily periconceptional folic acid supplementation or estimated dietary folate equivalents ≥400 μg. NTD cases were live births, stillbirths, or terminations affected by spina bifida, anencephaly, or encephalocele (n = 1227). Controls were live births without a major birth defect (n = 7095). We categorized intake of each micronutrient as higher or lower based on a combination of diet (estimated from a food frequency questionnaire) and periconceptional vitamin supplementation. We estimated NTD associations for higher compared with lower intake of each micronutrient, individually and in combination, expressed as odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for age, race/ethnicity, education, and study center.

RESULTS

NTD associations with each micronutrient were weak to modest. Greater NTD reductions were observed with concurrent higher-amount intakes of multiple micronutrients. For instance, NTD odds were ∼50% lower among participants with ≥4 micronutrients with higher-amount intakes than among participants with ≤1 micronutrient with higher-amount intake (adjusted OR: 0.53; 95% CI: 0.33, 0.86). The strongest reduction occurred with concurrent higher-amount intakes of vitamin B6, vitamin B12, choline, betaine, and methionine (adjusted OR: 0.26; 95% CI: 0.09, 0.77) compared with ≤1 micronutrient with higher-amount intake.

CONCLUSIONS

Our findings support that NTD prevention, in the context of folic acid fortification, could be augmented with intakes of methyl donors and other micronutrients involved in folate metabolism.

Counting adolescents in: the development of an adolescent health indicator framework for population-based settings

Changing realities in low- and middle-income countries (LMICs) in terms of inequalities, urbanization, globalization, migration, and economic adversity shape adolescent development and health, as well as successful transitions between adolescence and young adulthood. It is estimated that 90% of adolescents live in LMICs in 2019, but inadequate data exist to inform evidence-based and concerted policies and programs tailored to address the distinctive developmental and health needs of adolescents. Population-based data surveillance such as Health and Demographic Surveillance Systems (HDSS) and school-based surveys provide access to a well-defined population and provide cost-effective opportunities to fill in data gaps about adolescent health and well-being by collecting population-representative longitudinal data. The Africa Research Implementation Science and Education (ARISE) Network, therefore, systematically developed adolescent health and well-being indicators and a questionnaire for measuring these indicators that can be used in population-based LMIC settings. We conducted a multistage collaborative and iterative process led by network members alongside consultation with health-domain and adolescent health experts globally. Seven key domains emerged from this process: socio-demographics, health awareness and behaviors; nutrition; mental health; sexual and reproductive health; substance use; and healthcare utilization. For each domain, we generated a clear definition; rationale for inclusion; sub-domain descriptions, and a set of questions for measurement. The ARISE Network will implement the questionnaire longitudinally (i.e., at two time-points one year apart) at ten sites in seven countries in sub-Saharan Africa and two countries in Asia. Integrating the questionnaire within established population-based data collection platforms such as HDSS and school settings can provide measured experiences of young people to inform policy and program planning and evaluation in LMICs and improve adolescent health and well-being.

Risk factors for inadequate and excessive gestational weight gain in 25 low- and middle-income countries: An individual-level participant meta-analysis

BACKGROUND

Many women experience suboptimal gestational weight gain (GWG) in low- and middle-income countries (LMICs), but our understanding of risk factors associated with GWG in these settings is limited. We investigated the relationships between demographic, anthropometric, lifestyle, and clinical factors and GWG in prospectively collected data from LMICs.

METHODS AND FINDINGS

We conducted an individual participant-level meta-analysis of risk factors for GWG outcomes among 138,286 pregnant women with singleton pregnancies in 55 studies (27 randomized controlled trials and 28 prospective cohorts from 25 LMICs). Data sources were identified through PubMed, Embase, and Web of Science searches for articles published from January 2000 to March 2019. Titles and abstracts of articles identified in all databases were independently screened by 2 team members according to the following eligibility criteria: following inclusion criteria: (1) GWG data collection took place in an LMIC; (2) the study was a prospective cohort or randomized trial; (3) study participants were pregnant; and (4) the study was not conducted exclusively among human immunodeficiency virus (HIV)-infected women or women with other health conditions that could limit the generalizability of the results. The Institute of Medicine (IOM) body mass index (BMI)-specific guidelines were used to determine the adequacy of GWG, which we calculated as the ratio of the total observed weight gain over the mean recommended weight gain. Study outcomes included severely inadequate GWG (percent adequacy of GWG <70), inadequate GWG (percent adequacy of GWG <90, inclusive of severely inadequate), and excessive GWG (percent adequacy of GWG >125). Multivariable estimates from each study were pooled using fixed-effects meta-analysis. Study-specific regression models for each risk factor included all other demographic risk factors measured in a particular study as potential confounders, as well as BMI, maternal height, pre-pregnancy smoking, and chronic hypertension. Risk factors occurring during pregnancy were further adjusted for receipt of study intervention (if any) and 3-month calendar period. The INTERGROWTH-21st standard was used to define high and low GWG among normal weight women in a sensitivity analysis. The prevalence of inadequate GWG was 54%, while the prevalence of excessive weight gain was 22%. In multivariable models, factors that were associated with a higher risk of inadequate GWG included short maternal stature (<145 cm), tobacco smoking, and HIV infection. A mid-upper arm circumference (MUAC) of ≥28.1 cm was associated with the largest increase in risk for excessive GWG (risk ratio (RR) 3.02, 95% confidence interval (CI) [2.86, 3.19]). The estimated pooled difference in absolute risk between those with MUAC of ≥28.1 cm compared to those with a MUAC of 24 to 28.09 cm was 5.8% (95% CI 3.1% to 8.4%). Higher levels of education and age <20 years were also associated with an increased risk of excessive GWG. Results using the INTERGROWTH-21st standard among normal weight women were similar but attenuated compared to the results using the IOM guidelines among normal weight women. Limitations of the study's methodology include differences in the availability of risk factors and potential confounders measured in each individual dataset; not all risk factors or potential confounders of interest were available across datasets and data on potential confounders collected across studies.

CONCLUSIONS

Inadequate GWG is a significant public health concern in LMICs. We identified diverse nutritional, behavioral, and clinical risk factors for inadequate GWG, highlighting the need for integrated approaches to optimizing GWG in LMICs. The prevalence of excessive GWG suggests that attention to the emerging burden of excessive GWG in LMICs is also warranted.

Associations of Diet Quality, Socioeconomic Factors, and Nutritional Status with Gestational Weight Gain among Pregnant Women in Dar es Salaam, Tanzania

Background

Gestational weight gain (GWG) is a modifiable factor associated with maternal and child health outcomes, but the relationship between diet quality and GWG has not been evaluated using metrics validated for low-income and middle-income countries (LMICs).

Objective

This study aimed to investigate relationships between diet quality, socioeconomic characteristics, and GWG adequacy using the novel Global Diet Quality Score (GDQS), the first diet quality indicator validated for use across LMIC.

Methods

Weights of pregnant women enrolled between 12 and 27 wk of gestation (N = 7577) were recorded in Dar es Salaam, Tanzania, from 2001 to 2005 during a prenatal micronutrient supplementation trial. GWG adequacy was the ratio of measured GWG to Institute of Medicine-recommended GWG, categorized into severely inadequate (<70%), inadequate (70 to <90%), adequate (90 to <125%), or excessive (≥125%). Dietary data were collected using 24-h recalls. Multinomial logit models were used to estimate relationships between GDQS tercile, macronutrient intake, nutritional status, and socioeconomic characteristics and GWG.

Results

GDQS scores in the second [relative risk (RR): 0.82; 95% confidence interval (CI): 0.70, 0.97] tercile were associated with lower risk of inadequate weight gain than those in the first tercile. Increased protein intake was associated with higher risk of severely inadequate GWG (RR: 1.06; 95% CI: 1.02, 1.09). Nutritional status and socioeconomic factors were associated with GWG: underweight prepregnancy BMI (in kg/m2) with a higher risk of severely inadequate GWG (RR: 1.49; 95% CI: 1.12, 1.99), overweight or obese BMI with a higher risk of excessive GWG (RR: 6.80; 95% CI: 5.34, 8.66), and a higher education (RR: 0.61; 95% CI: 0.42, 0.89), wealth (RR: 0.68; 95% CI: 0.48, 0.80), and height (RR: 0.96; 95% CI: 0.95, 0.98) with a lower risk of severely inadequate GWG.

Conclusions

Dietary indicators showed few associations with GWG. However, stronger relationships were revealed between GWG, nutritional status, and several socioeconomic factors.This trial was registered at clinicaltrials.gov as NCT00197548.

SARS-CoV-2 infection during pregnancy and preterm birth in Massachusetts from March 2020 through March 2021

BACKGROUND

SARS-CoV-2 infection during pregnancy has been linked to preterm birth, but this association is not well understood.

OBJECTIVES

To examine the association between SARS-CoV-2 infection and spontaneous and provider-initiated preterm birth (PTB), and how timing of infection, and race/ethnicity as a marker of structural inequality, may modify this association.

METHODS

We conducted a retrospective cohort study among pregnant people who delivered singleton, liveborn infants (22-44 weeks gestation) from 1 March 2020 to 31 March 2021 (n = 68,288). We used Cox proportional hazards models to compare the hazard of PTB between pregnant people with and without laboratory-confirmed SARS-CoV-2 infection during pregnancy. We evaluated this association according to the trimester of infection, timing from infection to birth, and timing of PTB. We also examined the joint associations of SARS-CoV-2 infection and race/ethnicity with PTB using the relative excess risk due to interaction (RERI).

RESULTS

Positive SARS-CoV-2 tests were identified for 2195 pregnant people (3.2%). The prevalence of PTB was 7.2% (3.8% spontaneous, 3.6% provider-initiated). SARS-CoV-2 infection during pregnancy was associated with an increased risk of PTB overall (adjusted hazard ratio [HR] 1.53, 95% confidence interval [CI] 1.34, 1.74), and provider-initiated PTB (HR 1.79, 95% CI 1.50, 2.12) but not spontaneous PTB (HR 1.09, 95% CI 0.89, 1.36). Second trimester infections were associated with an increased risk of provider-initiated PTB, and third trimester infections were associated with an increased risk of both PTB subtypes. A joint inverse association between White non-Hispanic race/ethnicity and SARS-CoV-2 infection and spontaneous PTB (HR 0.56, 95% CI 0.34, 0.94; RERI -0.6, 95% CI -1.0, -0.2) was also observed.

CONCLUSIONS

SARS-CoV-2 infections were primarily associated with an increased risk for provider-initiated PTB in this study. These findings highlight the importance of promoting infection-prevention strategies among pregnant people.

Gestational weight gain during the second and third trimesters and adverse pregnancy outcomes, results from a prospective pregnancy cohort in urban Tanzania

Background

Appropriate gestational weight gain (GWG) is important for optimal pregnancy outcomes. This study prospectively evaluated the associations between GWG during the second and third trimesters of pregnancy and adverse pregnancy outcomes in an urban Tanzanian pregnancy cohort.

Methods

We used data from a randomized clinical trial conducted among pregnant women recruited by 27 weeks of gestation in Dar es Salaam, Tanzania (N = 1230). Women’s gestational weight was measured at baseline and at monthly antenatal visits. Weekly GWG rate during the second and third trimesters was calculated and characterized as inadequate, adequate, or excessive, in conjunction with measured or imputed early-pregnancy BMI status according to the 2009 Institute of Medicine (IOM) GWG guidelines. We used multivariable Poisson regression with a sandwich variance estimator to calculate risk ratios (RR) for associations of GWG with low birth weight, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). Degree of appropriate GWG defined using additional metrics (i.e., percentage of adequacy, z-score) and potential effect modification by maternal BMI were additionally evaluated.

Results

According to the IOM guidelines, 517 (42.0%), 270 (22.0%), and 443 (36.0%) women were characterized as having inadequate, adequate, and excessive GWG, respectively. Overall, compared to women with adequate GWG, women with inadequate GWG had a lower risk of LGA births (RR = 0.54, 95% CI: 0.36–0.80) and a higher risk of SGA births (RR = 1.32, 95% CI: 0.95–1.81). Women with inadequate GWG as defined by percentage of GWG adequacy had a higher risk of LBW (OR = 1.93, 95% CI: 1.03–3.63). In stratified analyses by early-pregnancy BMI, excessive GWG among women with normal BMI was associated with a higher risk of preterm birth (RR = 1.59, 95% CI: 1.03–2.44).

Conclusions

A comparatively high percentage of excessive GWG was observed among healthy pregnant women in Tanzania. Both inadequate and excessive GWGs were associated with elevated risks of poor pregnancy outcomes. Future studies among diverse SSA populations are warranted to confirm our findings, and clinical recommendations on optimal GWG should be developed to promote healthy GWG in SSA settings.

Trial registration: This trial was registered as “Prenatal Iron Supplements: Safety and Efficacy in Tanzania” (NCT01119612; http://clinicaltrials.gov/show/NCT01119612).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-022-01441-7.

Pregnancy is a critical lifetime event for both mother and the offspring, with implications in short-term and long-term health consequences. Gestational weight gain (GWG) is an important modifiable factor for pregnancy outcomes related to infant body size and weight and prematurity. Countries in sub-Saharan Africa (SSA) have long had poor rates of insufficient GWG and pregnancy complications associated with insufficient GWG. Nevertheless, some SSA countries are experiencing economic transitions accompanied with changes in lifestyle and nutrition, which might impact pregnancy experiences, including GWG and pregnancy outcomes. This study aimed to characterize recent GWG patterns and the associations of both inadequate and excessive GWG with adverse pregnancy outcomes, using an urban pregnancy cohort in Tanzania. This study found that 42.0%. 22.0%, and 36.0% of women had insufficient, adequate, and excessive GWG, respectively. Insufficient GWG was associated with higher risks of small infant size and low infant body weight, and excessive GWG was associated with higher risk of preterm birth, particularly among women with body mass index 18.5–25.0 kg/m². Results from the present study highlight that both insufficient and excessive GWG are of potential public health concerns in urban centers of SSA, concerning upward trends in obesity and possibly obesity-related pregnancy consequences. Local public health practitioners should continue to advocate longitudinal GWG monitoring and care among African pregnant women, and optimal GWG with feasible and effective clinical guidelines should be developed to prevent both over- and under-gaining of maternal weight during pregnancy.

Use of vasoactive medications in pregnancy and the risk of stillbirth among birth defect cases

BACKGROUND

Many previous studies have identified risk factors for stillbirth, but few examine stillbirth among pregnancies affected with birth defects. Because many hypothesized etiologies of stillbirth work through vascular pathologies of the placenta, we examined maternal use of vasoactive medications in relation to stillbirth among pregnancies affected with birth defects.

METHODS

Data were analyzed from the National Birth Defects Prevention Study (1997-2011). We examined use of nonsteroidal anti-inflammatory drugs (NSAIDs), decongestants, short- or long-acting beta-agonists (SABA/LABA), and antihypertensive medications in relation to pregnancies affected by birth defects ending in stillbirth compared to live birth. Associations were measured with odds ratios (ORs) for early pregnancy use and hazard ratios (HRs) for time-varying late pregnancy use.

RESULTS

Among all birth defects (n = 12,394), the risk of stillbirth was associated with use of antihypertensive medications in early (odds ratio [OR]: 1.8; 95% confidence interval [CI]: 1.0, 3.1) and late pregnancy (HR: 2.0; 95% CI: 1.1, 3.6). Other vasoactive medications were not associated with increased risk of stillbirth. Of 27 specific defect groups, increased risks were observed for only one medication/defect pair: early decongestant use was more common among mothers of stillbirth versus live birth cases with spina bifida (OR: 2.4; 95% CI: 0.9, 6.5).

CONCLUSION

This exploratory analysis of vasoactive medication use suggests that use of NSAIDs, decongestants, and SABA/LABA is not associated with increased risk of stillbirth among pregnancies affected with birth defects. Our finding of increased risks associated with antihypertensive medication use raises questions of confounding by indication, which we were not able to fully address.

Multivitamin Supplementation Is Associated with Greater Adequacy of Gestational Weight Gain among Pregnant Women in Tanzania

BACKGROUND

Gestational weight gain (GWG) is a modifiable risk factor associated with adverse birth outcomes. Studies have shown that the provision of multiple micronutrient supplements to pregnant women reduces the risk of low birth weight. However, the effect of multiple micronutrient supplements on GWG has been understudied.

OBJECTIVES

We examined the effect of daily supplementation of pregnant women with multivitamins on GWG in relation to the GWG recommendation by the Institute of Medicine (IOM).

METHODS

Pregnant women with gestational age between 12 and 27 wk were randomly assigned to receive daily multivitamins or placebo until delivery. Weight was measured at enrollment and every follow-up visit. Percentage adequacy of GWG was calculated as actual GWG divided by the recommended GWG according to the IOM recommendation. Binary outcomes included severely inadequate (<70%), inadequate (<90%), and excessive GWG (≥125%). The analysis included 7573 women with singleton pregnancies. Multiple linear regression models were used to examine the association between multivitamin supplementation and percentage adequacy of GWG, and log-binomial models were used for binary outcomes.

RESULTS

The mean percentage adequacy of GWG was 96.7% in the multivitamin arm and 94.4% in the placebo arm, with a mean difference of 2.3% (95% CI: 0.3%, 4.2%; P = 0.022). Compared with women in the placebo arm, those who received multivitamins had a lower risk of severely inadequate GWG (RR: 0.90; 95% CI: 0.83, 0.97; P = 0.008) and inadequate GWG (RR: 0.95; 95% CI: 0.91, 0.99; P = 0.018). No significant difference was found in excessive GWG.

CONCLUSIONS

Multivitamin supplementation increased GWG and reduced the risk of severely inadequate and inadequate GWG among pregnant women in Tanzania. Together with previously reported beneficial effects of the supplements on birth outcomes in low- and middle-income countries, our findings support scaling up the use of prenatal supplements that include multivitamins in addition to iron and folic acid.This trial was registered at clinicaltrials.gov as NCT00197548.

Associations between gestational weight gain adequacy and neonatal outcomes in Tanzania

Introduction: Gestational weight gain (GWG) is associated with fetal and newborn health; however, data from sub-Saharan Africa are limited. Methods: We used data from a prenatal micronutrient supplementation trial among a cohort of HIV-negative pregnant women in Dar es Salaam, Tanzania to estimate the relationships between GWG and newborn outcomes. GWG adequacy was defined as the ratio of the total observed weight gain over the recommended weight gain based on the Institute of Medicine body mass index (BMI)-specific guidelines. Newborn outcomes assessed were: stillbirth, perinatal death, preterm birth, low birthweight, macrosomia, small-for-gestational age (SGA), large-for-gestational age (LGA), stunting at birth, and microcephaly. Modified Poisson regressions with robust standard error were used to estimate the relative risk of newborn outcomes as a function of GWG adequacy. Results: Of 7561 women included in this study, 51% had severely inadequate (<70%) or inadequate GWG (70-90%), 31% had adequate GWG (90-125%), and 18% had excessive GWG (≥125%). Compared to adequate GWG, severely inadequate GWG was associated with a higher risk of low birthweight, SGA, stunting at birth, and microcephaly; whereas excessive GWG was associated with a higher risk of LGA and macrosomia. Conclusion: Interventions to support optimal gestational weight gain are needed and are likely to improve newborn outcomes.

The High Burden and Predictors of Anemia Among Infants Aged 6 to 12 Months in Dar es Salaam, Tanzania

BACKGROUND

Despite several interventions, the prevalence of anemia and related complications remains high among infants in Tanzania.

OBJECTIVE

We sought to determine the predictors of iron-deficiency anemia (IDA) among infants of HIV-negative women in Dar es Salaam, Tanzania.

METHODS

Cross-sectional analysis of 2826 mother-infant pairs who participated in a trial of vitamins and perinatal outcomes in Dar es Salaam, Tanzania. Hemoglobin and mean corpuscular volume were used to determine the prevalence of anemia among infants at 6 and 12 months. Multiple logistic regression was used to determine the maternal and infant risk factors for anemia during infancy.

RESULTS

We found high prevalence of anemia (90%) and IDA (44.2%) among infants. Higher maternal education (odds ratio [OR] = 0.52), maternal normal hemoglobin at enrollment (OR = 0.68) and during the early postpartum period reduced the odds of IDA at 6 months (OR = 0.56). The odds of IDA at 6 months were higher among males (OR = 1.65), wealth score below median (OR = 1.35), low birth weight (LBW; OR = 1.75), and small for gestational age (SGA) infants below the third centile (OR = 1.95) or third to less than fifth centile (OR = 2.29). Higher maternal education lowered the odds of IDA at 12 months (OR = 0.25). Wealth score below median (OR = 1.44), preterm delivery (OR = 1.94), SGA (less than third centile; OR = 2.40), and LBW (OR = 2.89) increased the odds of IDA during infancy in the study population. Dietary diversity was low for infants and women in the study sample.

CONCLUSION

Interventions to reduce the risk of infant IDA should address women's education, improvement of wealth status, and optimal care for premature, SGA, and LBW infants.

Plasma concentrations of leptin at mid-pregnancy are associated with gestational weight gain among pregnant women in Tanzania: a prospective cohort study

Background

Gestational weight gain (GWG) has critical implications for maternal and child health. Inflammation and angiogenesis are implicated in various aspects of maternal metabolism that may play a role in gestational weight gain. The associations of inflammatory, angiogenic, and metabolic pathways with GWG are yet to be elucidated. This study evaluated associations between a panel of inflammatory, angiogenic, and metabolic proteins measured in mid-pregnancy and gestational weight gain.

Methods

Pregnant women were enrolled from Dar es Salaam, Tanzania, between 2001 and 2004. The participants were enrolled at mid-pregnancy (12 to 27 weeks of gestation) and followed up until delivery. This analysis focused on a cohort of 1002 women who were primigravid, had singleton live births, had longitudinal measures of gestational weight, and whose mid-pregnancy plasma samples underwent analysis for 18 proteins.

Results

Higher plasma concentrations of leptin (mean difference in GWG percent adequacy comparing highest with lowest quartiles: 10.24; 95% CI 3.31, 17.16; p-trend = 0.003) and chitinase-3-like protein-1 (CH3L1) (mean difference in GWG percent adequacy comparing highest with lowest quartiles: 7.02; 95% CI 0.31, 13.72; p-trend = 0.007) were associated with greater GWG in a dose-response pattern. Higher leptin concentrations were associated with a lower risk of inadequate GWG (risk ratio comparing highest with lowest quartiles: 0.77; 95% CI 0.65, 0.91; p-trend = 0.001) and a higher risk of excessive GWG (risk ratio comparing highest with lowest quartiles: 1.57; 95% CI 1.03, 2.39; p-trend = 0.03). Higher CH3L1 concentrations were associated with a higher risk of excessive GWG (p-trend = 0.007). The associations of leptin and CH3L1 with inadequate GWG were stronger during the second than the third trimester. The other 16 proteins examined were not significantly associated with GWG.

Conclusions

Mid-pregnancy plasma leptin concentrations may be associated with GWG and have clinical predictive utility in identifying women at a higher risk of inadequate or excessive gestational weight gain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04146-0.

Gestational Age, Birth Weight, and Neurocognitive Development in Adolescents in Tanzania

OBJECTIVES

To investigate the association between gestational age, birthweight, and birthweight adjusted for gestational age, with domains of neurocognitive development and behavioral problems in adolescents in Tanzania.

STUDY DESIGN

Data from a long-term follow-up of adolescents aged 11-15 years born to women previously enrolled in a randomized controlled trial of prenatal multiple micronutrient supplementation in Dar es Salaam, Tanzania, were used. A battery of neurodevelopmental tests were administered to measure adolescent general intelligence, executive function, and behavioral problems. The INTERGROWTH-21st newborn anthropometric standards were used to derive birthweight for gestational age z-scores. We assessed the shape of relationships using restricted cubic splines and estimated the associations of gestational age, birthweight, and birthweight for gestational age z-score with adolescent development using multivariable linear regressions.

RESULTS

Among adolescents studied (n = 421), higher gestational age (per week), birthweight (per 100 grams), and birthweight for gestational age z-score (per SD) were linearly associated with higher intelligence score (adjusted standardized mean difference, 0.05 SD [95% CI, 0.01-0.09], 0.04 SD [95% CI, 0.02-0.06], and 0.09 SD [95% CI, 0.01-0.17], respectively). Birthweight and birthweight for gestational age z-score, but not gestational age, were also associated with improved executive function. Low birthweight (<2500 g) was associated with lower intelligence and executive function scores. Associations between birthweight and executive function were stronger among adolescents born to women with higher education.

CONCLUSIONS

The duration of gestation and birthweight were positively associated with adolescent neurodevelopment in Tanzania. These findings suggest that interventions to improve birth outcomes may also benefit adolescent cognitive function.

Gestational weight gain in low-income and middle-income countries: a modelling analysis using nationally representative data

INTRODUCTION

Gestational weight gain (GWG) has important implications for maternal and child health and is an ideal modifiable factor for preconceptional and antenatal care. However, the average levels of GWG across all low-income and middle-income countries of the world have not been characterised using nationally representative data.

METHODS

GWG estimates across time were computed using data from the Demographic and Health Surveys Program. A hierarchical model was developed to estimate the mean total GWG in the year 2015 for all countries to facilitate cross-country comparison. Year and country-level covariates were used as predictors, and variable selection was guided by the model fit. The final model included year (restricted cubic splines), geographical super-region (as defined by the Global Burden of Disease Study), mean adult female body mass index, gross domestic product per capita and total fertility rate. Uncertainty ranges (URs) were generated using non-parametric bootstrapping and a multiple imputation approach. Estimates were also computed for each super-region and region.

RESULTS

Latin America and Caribbean (11.80 kg (95% UR: 6.18, 17.41)) and Central Europe, Eastern Europe and Central Asia (11.19 kg (95% UR: 6.16, 16.21)) were the super-regions with the highest GWG estimates in 2015. Sub-Saharan Africa (6.64 kg (95% UR: 3.39, 9.88)) and North Africa and Middle East (6.80 kg (95% UR: 3.17, 10.43)) were the super-regions with the lowest estimates in 2015. With the exception of Latin America and Caribbean, all super-regions were below the minimum GWG recommendation for normal-weight women, with Sub-Saharan Africa and North Africa and Middle East estimated to meet less than 60% of the minimum recommendation.

CONCLUSION

The levels of GWG are inadequate in most low-income and middle-income countries and regions. Longitudinal monitoring systems and population-based interventions are crucial to combat inadequate GWG in low-income and middle-income countries.

Effects of prenatal and postnatal maternal multiple micronutrient supplementation on child growth and morbidity in Tanzania: a double-blind, randomized-controlled trial

BACKGROUND

Maternal micronutrient status is critical for child growth and nutrition. It is unclear whether maternal multiple micronutrient supplementation (MMS) during pregnancy and lactation improves child growth and prevents child morbidity.

METHODS

This study aimed to determine the effects of prenatal and postnatal maternal MMS on child growth and morbidity. In this double-blind, randomized-controlled trial, 8428 HIV-negative pregnant women were enrolled from Dar es Salaam, Tanzania, between 2001 and 2004. From pregnancy (12-27 weeks of gestation) through to 6 weeks postpartum, participants were randomized to receive daily oral MMS or placebo. All women received daily iron and folic acid during pregnancy. From 6 weeks postpartum through to 18 months postpartum, 3100 women were re-randomized to MMS or placebo. Child-growth measures, haemoglobin concentrations and infectious morbidities were assessed longitudinally from birth to ≤18 months.

RESULTS

Prenatal MMS led to modest increases in weight-for-age z-scores (mean difference: 0.050; 95% confidence interval: 0.002, 0.099; p = 0.04) and length-for-age z-score (mean difference: 0.062; 95% confidence interval: 0.013, 0.111; p = 0.01) during the first 6 months of life but not thereafter. Prenatal or postnatal MMS did not have benefits for other child outcomes.

CONCLUSIONS

Whereas maternal MMS is a proven strategy to prevent adverse birth outcomes, other approaches may also need to be considered to curb the high burdens of child morbidity and growth faltering.

Effects of Prenatal and Postnatal Maternal Multiple Micronutrient Supplementation on Child Growth and Morbidity in Tanzania: A Double-Blind, Randomized Controlled Trial

Objectives

Maternal micronutrient status is critical for child growth and nutrition. It is unclear whether maternal multiple micronutrient supplementation (MMS) during pregnancy and lactation improves child growth and prevents child morbidity. The aim of this study was to determine the effects of prenatal and postnatal maternal MMS on child growth and morbidity in Tanzania.

Methods

In this double-blind, randomized controlled trial, 8,379 HIV-negative pregnant women were enrolled from Dar es Salaam, Tanzania, between 2001 and 2004. From pregnancy (12 to 27 weeks of gestation) through 6 weeks postpartum, participants were randomized to receive daily oral MMS or placebo. All women received daily iron and folic acid during pregnancy. From 6 weeks postpartum through 18 months postpartum, 3,100 women were re-randomized to MMS or placebo. Child growth measures, hemoglobin concentrations, and infectious morbidities were assessed longitudinally from birth to up to 18 months. Linear mixed-effects models were used to estimate the effects of prenatal and postnatal MMS on child growth z-scores and hemoglobin concentrations. Cox proportional hazards models were used to estimate the effects on undernutrition. Generalized estimating equations were used to estimate the effects on anemia and infectious morbidities.

Results

Prenatal MMS led to modest increases in weight-for-age z-score (mean difference: 0.050; 95% CI: 0.002, 0.099; p = 0.04) and length-for-age z-score (mean difference: 0.062; 95% CI: 0.013, 0.111; p = 0.01) during the first six months of life but not thereafter. Prenatal MMS did not have significant benefits for anemia, morbidity, or other child growth outcomes. Postnatal MMS did not have significant benefits for any child outcomes.

Conclusions

While maternal MMS is a proven strategy to prevent adverse birth outcomes, other approaches may also need to be considered to curb the high burdens of child morbidity and growth faltering.

Funding Sources

This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health.

Associations Between Gestational Weight Gain Adequacy and Perinatal Outcomes in Tanzania

Objectives

Gestational weight gain (GWG) is associated with fetal and newborn health; however, data from sub-Saharan Africa are limited. We estimated the relationship between GWG and newborn outcomes in a cohort of pregnant women in Tanzania.

Methods

We used data from a prenatal multiple micronutrient supplementation trial among HIV-negative pregnant women enrolled between 12 to 27 weeks gestational age (GA) in Dar es Salaam. GWG adequacy was defined as the ratio of the total observed weight gain over the expected weight gain based on the Institute of Medicine pre-pregnancy body mass index (BMI)-specific guidelines, and categorized as follows: severely inadequate (&lt; 70%), inadequate (70–90%), adequate (90–125%) or excessive (≥125%). Newborn outcomes assessed were: stillbirth, perinatal death, preterm birth (birth &lt; 37 weeks GA), low birthweight (LBW; &lt; 2500 grams), macrosomia (birthweight &gt; 4000 grams), small- and large-for-GA (birthweight-for-GA &lt; 10th percentile and &gt; 90th percentile, respectively), short-for-GA (length-for-GA z-score &lt; -2SD), and microcephaly (head circumference-for-GA z-score &lt; -2SD). Modified Poisson regression with robust standard error was used to estimate the relative risk of newborn outcomes as a function of GWG adequacy, adjusting for confounders.

Results

Overall, 51% (n = 3866/7561) women had severely inadequate or inadequate GWG, 31% had adequate GWG, and 18% had excessive GWG by delivery. Compared to adequate GWG, severely inadequate GWG was associated with increased risk of LBW [Adjusted Relative Risk (95% CI): 1.63 (1.24, 2.14)], SGA [1.76 (1.50, 2.08)], short-for-GA [1.24 (1.04, 1.48)], and microcephaly [1.35 (1.05, 1.73)]; but a lower risk of LGA [0.72 (0.58, 0.89)] and macrosomia [0.31 (0.17, 0.56)]. Inadequate GWG was similarly associated with a higher risk of SGA, short-for-GA, and microcephaly, but lower risk of LGA. Excessive GWG was only associated with a higher risk of LGA and macrosomia. Severely inadequate GWG in the second trimester was associated with preterm birth. GWG adequacy was not associated with stillbirth or perinatal death.

Conclusions

Inadequate GWG was associated with several indicators of poor newborn size. Interventions to support maternal nutrition during pregnancy are needed and are likely to improve newborn outcomes.

Funding Sources

Bill and Melinda Gates Foundation; CIHR Fellowship.

Methodological approaches to imputing early-pregnancy weight based on weight measures collected during pregnancy

Background

Early pregnancy weights are needed to quantify gestational weight gain accurately. Different methods have been used in previous studies to impute early-pregnancy weights. However, no studies have systematically compared imputed weight accuracy across different imputation techniques. This study aimed to compare four methodological approaches to imputing early-pregnancy weight, using repeated measures of pregnancy weights collected from two pregnancy cohorts in Tanzania.

Methods

The mean gestational ages at enrollment were 17.8 weeks for Study I and 10.0 weeks for Study II. Given the gestational age distributions at enrollment, early-pregnancy weights were extrapolated for Study I and interpolated for Study II. The four imputation approaches included: (i) simple imputation based on the nearest measure, (ii) simple arithmetic imputation based on the nearest two measures, (iii) mixed-effects models, and (iv) marginal models with generalized estimating equations. For the mixed-effects model and the marginal model with generalized estimating equation methods, imputation accuracy was further compared across varying degrees of model flexibility by fitting splines and polynomial terms. Additional analyses included dropping third-trimester weights, adding covariate to the models, and log-transforming weight before imputation. Mean absolute error was used to quantify imputation accuracy.

Results

Study I included 1472 women with 6272 weight measures; Study II included 2131 individuals with 11,775 weight measures. Among the four imputation approaches, mixed-effects models had the highest accuracy (smallest mean absolute error: 1.99 kg and 1.60 kg for Studies I and II, respectively), while the other three approaches showed similar degrees of accuracy. Depending on the underlying data structure, allowing appropriate degree of model flexibility and dropping remote pregnancy weight measures may further improve the imputation performance.

Conclusions

Mixed-effects models had superior performance in imputing early-pregnancy weight compared to other commonly used strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01210-3.

Factors associated with sub-microscopic placental malaria and its association with adverse pregnancy outcomes among HIV-negative women in Dar es Salaam, Tanzania: a cohort study

BACKGROUND

Malaria infection during pregnancy has negative health consequences for both mothers and offspring. Sub-microscopic malaria infection during pregnancy is common in most African countries. We sought to identify factors associated with sub-microscopic placental malaria, and its association with adverse pregnancy outcomes among HIV-negative pregnant women in Dar es Salaam, Tanzania.

METHODS

We recruited a cohort of pregnant women during their first trimester and assessed for the occurrence of placental malaria and pregnancy outcomes. The follow-up was done monthly from recruitment until delivery. Histopathology placental malaria positive results were defined as the presence of malaria pigment or parasitized erythrocytes on the slide (histology-positive (HP)), and the sub-microscopic placental infection was defined as positive Plasmodium falciparum DNA by polymerase chain reaction (DNA PCR) amplification in a negative histopathology test. Adverse pregnancy outcomes investigated included low birth weight (birth weight below 2.5 kg), prematurity (live birth below 37 weeks), and small-for-gestational-age (SGA) (live born with a birth weight below 10th percentile for gestational age and sex). Weighted baseline category logit, log-binomial, and log-Poisson models were used to assess factors associated with placental malaria, and its association with adverse pregnancy outcomes.

RESULTS

Among 1115 women who had histopathology and DNA PCR performed, 93 (8%) had HP placental infection, and 136 (12%) had the sub-microscopic placental infection. The risk of sub-microscopic placental malaria was greater in women who did not use mosquito prevention methods such as bed nets, fumigation, or mosquito coils (odds ratio (OR) = 1.75; 95% confidence interval (CI): 1.05-2.92; P = 0.03) and in women who were anemic (OR = 1.59; 95% CI: 1.20-2.11; P = 0.001). Women who were underweight had reduced odds of sub-microscopic placental malaria infection (OR = 0.33; 95% CI: 0.17-0.62; P = 0.001). Women who were overweight/obese had 1.48 times higher the odds of HP placental malaria compared to normal weight (OR = 1.48; 95% CI: 1.03-2.11; P = 0.03). HP placental malaria infection was associated with an increased risk of SGA births (RR = 1.30, 95% CI: 0.98-1.72, P = 0.07). In contrast, the sub-microscopic infection was associated with a reduced risk of SGA births (RR = 0.61, 95% CI: 0.43-0.88, P = 0.01). Placental malaria was not associated with low birth weight or prematurity.

CONCLUSION

Malaria prevention methods and maternal nutrition status during early pregnancy were important predictors of sub-microscopic placental malaria. More research is needed to understand sub-microscopic placental malaria and the possible mechanisms mediating the association between placental malaria and SGA.

Aflatoxin exposure in utero and birth and growth outcomes in Tanzania

Some evidence suggests that aflatoxin may contribute to the high prevalence of stunting observed in low-income countries. Whereas several studies have been conducted in West Africa, fewer exist in East Africa and even fewer in nonagricultural contexts. We analyzed serum samples from 400 iron-replete, nonanemic pregnant women from a cohort in Dar es Salaam, Tanzania to determine the extent and magnitude of exposure to aflatoxin and to study the relationship between levels of aflatoxin exposure in utero and infant birth and growth outcomes. Ninety-nine percent of women had detectable concentrations of aflatoxin B1-lysine (AFB1-lysine), with a median level of 1.4-pg/mg albumin, indicating a much lower level compared to studies of rural populations in sub-Saharan Africa. Our results do not show a statistically significant relationship between AFB1-lysine levels and birth weight, small for gestational age, or prematurity. We observe a small statistically significant reduction in gestational age at delivery (0.47 weeks; 95% CI: -0.86, -0.07) as the natural log of AFB1-lysine levels increases by 1 unit of pg/mg of albumin, after controlling for potential confounders. Among a nonrandom set of infants who had measurements for placental weight, haemoglobin at delivery, and follow-up z-score measurements, we find no association between aflatoxin plasma concentrations and these variables. These findings suggest a high prevalence of chronic low-level exposure to aflatoxin, though its effect on birth outcomes in this population remains unclear. Our research adds to a growing body of literature finding mixed associations between aflatoxins on pregnancy outcomes and child growth.

Breast milk vitamin B12 concentration and incidence of diarrhea and respiratory infections among infants in urban Tanzania: a prospective cohort study

Objective

A recent trial of vitamin B12 supplementation among Indian children 6–30 months found no effect on the incidence of diarrhea and respiratory infections. These results differ with studies in adults that showed improvement of the immune response following treatment with vitamin B12. We sought to determine how the adequacy of vitamin B12 concentrations in breast milk could act as immune modulator and protect against the incidence of diarrhea and respiratory infections of children up to 18 months in urban Tanzania.

Results

A prospective cohort study was undertaken to determine the association of breast milk vitamin B12 concentration with the incidence of acute respiratory infection and diarrhea among infants in urban Tanzania. A random sample of 491 women enrolled in a trial of multivitamins provided milk for B12 analysis at or around 6 weeks postpartum. Of 491 women, 345 had breast milk vitamin B12 inadequacy (< 310 pmol/L). Using generalized estimating equations, we found no overall association of milk vitamin B12 concentration with incident diarrhea and acute respiratory infections in infants. Studies measuring longitudinal changes of breast milk B12 concentration over time are needed to clarify the role of breast milk vitamin B12 in childhood infections.

Prenatal Zinc and Vitamin A Reduce the Benefit of Iron on Maternal Hematologic and Micronutrient Status at Delivery in Tanzania

BACKGROUND

Zinc and vitamin A supplementation have both been shown to affect iron status, hemoglobin (Hb) concentration, and anemia in animal and human studies. However, evidence on their combined use in pregnancy, in the context of iron-folic acid (IFA) supplementation, remains limited.

OBJECTIVE

This study determined the effects of prenatal zinc, vitamin A, and iron supplementation on maternal hematologic and micronutrient status at delivery in Tanzania.

METHODS

We analyzed 2 large randomized controlled trials, using generalized estimating equations, and examined the effect of daily zinc (25 mg) and vitamin A (2500 IU) supplementation starting in the first trimester of pregnancy compared with placebo (n = 2500), and separately evaluated the safety and efficacy of daily iron (60 mg) supplementation among iron-replete pregnant women (n = 1500). Blood samples from baseline and delivery were tested for Hb, serum ferritin, soluble transferrin receptor, plasma zinc, and zinc protoporphyrin.

RESULTS

Zinc and vitamin A supplementation were associated with lower Hb concentrations at delivery of  -0.26 g/dL (95% CI: -0.50, -0.02 g/dL) and -0.25 g/dL (95% CI: -0.49, -0.01 g/dL), respectively. Vitamin A increased mean ferritin concentrations at delivery (14.3 μg/L, 95% CI: 1.84, 29.11 μg/L), but was associated with increased risk of severe anemia (RR: 1.41; 95% CI: 1.06, 1.88). Among women who were iron replete at baseline, iron supplementation reduced the risk of iron depletion at delivery by 47% (RR: 0.53; 95% CI: 0.43, 0.65). There was no effect of zinc or iron supplements on plasma zinc concentrations.

CONCLUSIONS

Our findings support existing WHO guidelines on prenatal iron, vitamin A, and zinc supplementation among pregnant women. In this setting, scaling uptake of prenatal iron supplements is warranted, but prenatal zinc and vitamin A supplementation did not benefit maternal hematologic status at delivery. In settings where vitamin A deficiency is endemic, the efficacy and safety of the WHO recommended prenatal vitamin A supplementation require further evaluation.

The age of opportunity: prevalence of key risk factors among adolescents 10-19 years of age in nine communities in sub-Saharan Africa

OBJECTIVE

To measure health-related behaviours and risk factors among sub-Saharan African adolescents.

METHODS

Cross-sectional study in nine communities in Burkina Faso, Ethiopia, Eswatini, Ghana, Nigeria, Tanzania and Uganda between 2015 and 2017. Community-representative samples of males and females 10-19 years of age were selected. All communities used a uniform questionnaire that was adapted from the WHO Global School-based Student Health Survey. Weighted prevalence estimates and 95% confidence intervals were calculated for each indicator and stratified by age and sex using SAS version 9.4. All prevalence estimates were pooled across communities through random-effects meta-analyses in Stata version 14.

RESULTS

A total of 8075 adolescents participated in the study. We observed a high prevalence of inadequate fruit consumption (57-63%) and low physical activity (82-90%); a moderate prevalence of inadequate vegetable consumption (21-31%), unprotected last sex (38-45%), age at first sex <15 years (21-28%) and bullying and physical fighting (12-35%); and a low prevalence of mental health risk factors (1-11%) and alcohol and substance use risk factors (0-6%). We observed a moderate to high prevalence of daily soft drink consumption (21-31%) for all adolescents. Among sexually active adolescents 15-19 years, 37% of females reported ever being pregnant and 8% of males reported to have ever made someone pregnant. Bullying (23%) and physical fighting (35%) were more common among younger male adolescents . The prevalence of low mood was generally higher among older (15-19 years) than younger adolescents (10-14 years). The proportion of adolescents reporting alcohol, drug or cigarette use was very small, with the exception of khat use in Ethiopia.

CONCLUSION

Overall, diet and physical activity, violence, sexual and reproductive health, and depression are important risk factors for these sub-Saharan African communities. These findings suggest that more evidence is needed including novel efforts for the collection of sensitive information, as well as a need to move towards community-tailored interventions to reach adolescent populations with varying needs.

Gender differences in nutritional status, diet and physical activity among adolescents in eight countries in sub-Saharan Africa

OBJECTIVE

The objective of this study was to evaluate gender differences in nutritional status, dietary intake, physical activity and hand hygiene among adolescents from diverse geographical settings in sub-Saharan Africa.

METHODS

This study utilised cross-sectional data from six countries (Burkina Faso, Ethiopia, Ghana, Nigeria, Tanzania and Uganda) within the ARISE Adolescent Health Survey (n = 7625). Body mass index (BMI) was calculated using measured heights and weights, and z-scores were calculated based on the 2007 WHO growth standards for age and sex. Information on demographics, diet and health behaviours was collected through face-to-face interviews using a standardised questionnaire. Site-specific and pooled prevalence ratios were determined.

RESULTS

The prevalence of underweight, overweight and stunting pooled across sites was 14.3%, 6.8% and 18.1%, respectively. Female sex was associated with a lower risk of being underweight (pooled prevalence ratio 0.66, 95% 0.57, 0.77) and stunted (pooled PR 0.63, 95% CI 0.55, 0.71), but a higher risk of being overweight (pooled PR 1.60, 95% CI 1.26, 2.06). Females were also less likely to exercise for 1 h or more per day (pooled PR 0.77, 95% CI 0.67, 0.88), and more likely to wash hands after using toilets or latrines and to wash hands with soap (pooled PRs 1.13, 95% CI 1.05, 1.21 and 1.35, 95% CI 1.23, 1.45, respectively).

CONCLUSION

Our results emphasise that sex is a key predictor of nutritional status among sub-Saharan African adolescents and suggest that gender-specific interventions may be required to reduce the double burden of under- and overnutrition.

Are out-of-school adolescents at higher risk of adverse health outcomes? Evidence from 9 diverse settings in sub-Saharan Africa

OBJECTIVES

We analysed mutually comparable surveys on adolescent attitudes and behaviours from nine sites in seven sub-Saharan African countries, to determine the relationship between school enrolment and adolescent health outcomes.

METHODS

Data from the Africa Research, Implementation Science, and Education Network cross-sectional adolescent health surveys were used to examine the associations of current school enrolment, self-reported general health and four major adolescent health domains: (i) sexual and reproductive health; (ii) nutrition and non-communicable diseases; (iii) mental health, violence and injury; and (iv) healthcare utilisation. We used multivariable Poisson regression models to calculate relative risk ratios with 95% confidence intervals (CI), controlling for demographic and socio-economic characteristics. We assessed heterogeneity by gender and study site.

RESULTS

Across 7829 adolescents aged 10-19, 70.5% were in school at the time of interview. In-school adolescents were 14.3% more likely (95% CI: 6-22) to report that their life is going well; 51.2% less likely (95% CI: 45-67) to report ever having had sexual intercourse; 32.6% more likely (95% CI: 9-61) to report unmet need for health care; and 30.1% less likely (95% CI: 15-43) to report having visited a traditional healer. School enrolment was not significantly associated with malnutrition, low mood, violence or injury. Substantial heterogeneity was identified between genders for sexual and reproductive health, and in-school adolescents were particularly less likely to report adverse health outcomes in settings with high average school enrolment.

CONCLUSIONS

School enrolment is strongly associated with sexual and reproductive health and healthcare utilisation outcomes across nine sites in sub-Saharan Africa. Keeping adolescents in school may improve key health outcomes, something that can be explored through future longitudinal, mixed-methods, and (quasi-)experimental studies.

Prevalence and risk factors associated with malnutrition among adolescents in rural Tanzania

OBJECTIVE

To determine the prevalence and risk factors associated with malnutrition among adolescents in a rural Tanzanian community.

METHODS

Cross-sectional survey of 1226 randomly selected adolescents from the Dodoma Health and Demographic Surveillance System (HDSS) in the Chamwino district in the Dodoma region. Anthropometric measurements for weight and height were collected. Height-for-age-z-scores (HAZs) and body mass index (BMI)-for-age-z-scores (BAZs) were computed. Descriptive estimates were documented in graphs and tables, and weighted linear regression models were used to examine predictors of malnutrition.

RESULTS

Stunting prevalence was 18%, and thinness prevalence was 14%. Overweight and obesity affected 5.23% of participants. Girls had higher HAZs (β: 0.46, 95% CI 0.33, 0.59, P < 0.0001) and BAZs (β: 0.20, 95% CI 0.05, 0.35, P = 0.0098) than boys. Age was inversely associated with HAZs (β: -0.13, 95% CI -0.17, -0.08, P < 0.0001) and BAZs (β: -0.05, 95% CI -0.10, -0.004, P = 0.0327). Wealth score (β: 0.10, 95% CI 0.04, 0.16, P = 0.0009) and dietary diversity score (β: 0.04, 95% CI 0.01, 0.07, P = 0.0080) were positively associated with HAZs and BAZs. Out-of-school adolescents had higher HAZs (β: -0.49, 95% CI -0.75, -0.23, P = 0.0003) and BAZs (β: -0.68, 95% CI -0.99, -0.37, P < 0.0001) than adolescents who attended school.

CONCLUSION

There are substantial variations of HAZs and BAZs across gender, age, education and wealth, with an emerging burden of overweight and obesity among adolescents in this rural population. Interventions are urgently required to curb both ends of the malnutrition spectrum.

Accuracy of a mixed effects model interpolation technique for the estimation of pregnancy weight values

BACKGROUND

Interpolation of missing weight values is sometimes used in studies of gestational weight gain, but the accuracy of these methods has not been established. Our objective was to assess the accuracy of estimated weight values obtained by interpolating from the nearest observed weight values and by linear and spline regression models when compared with measured weight values.

METHODS

The study population included participants enrolled in the LIFECODES cohort at Brigham and Women's Hospital. We estimated weights at 28 (n=764) and 40 (n=382) weeks of gestation using participants' two nearest observed weights and subject-specific slopes and intercepts derived from repeated measures mixed effects models. In separate models, gestational age was parameterised as a linear and restricted cubic spline variable. Mean differences, absolute error measures and correlation coefficients comparing observed and estimated weights were calculated.

RESULTS

Mean differences and mean absolute error for weights derived from the 28-week linear model (0.18 lbs (SD 6.92), 2.73 lbs (SD 6.35)) and 40-week linear model (-0.40 lbs (SD 5.43) and 2.84 lbs (SD 4.65)) were low. Mean differences were somewhat greater at 28 weeks for weight values derived from the nearest two observed values (mean difference -1.97 lbs (SD 8.74)) and from spline models (mean difference -2.25 lbs (SD 7.13)). Results were similar at 40 weeks.

CONCLUSIONS

Overall, weight values estimated using this interpolation approach showed good agreement with observed values. When repeated measures of weight are available, mixed effects models may be used to interpolate of missing weight values with minimal error.

Prenatal nutrition, stimulation, and exposure to punishment are associated with early child motor, cognitive, language, and socioemotional development in Dar es Salaam, Tanzania

BACKGROUND

Despite growing evidence that early life experiences and exposures can impact child development, there is limited research on how prenatal and early life nutrition and early life parenting practices predict specific domains of child development in resource-limited settings. This study examines the association between prenatal factors, birth outcomes, and early life characteristics with motor, cognitive/language, and socioemotional development in Tanzania.

METHODS

We assessed motor, cognitive/language, and socioemotional development among a cohort of 198 children aged 20-39 months in Dar es Salaam, Tanzania, whose mothers were previously enrolled in a randomized, placebo-controlled trial of prenatal vitamin A and zinc supplementation. Linear regression models were used to assess standardized mean differences in child development scores for randomized prenatal regimen and pregnancy, delivery, and early childhood factors.

RESULTS

Children born to mothers randomized to prenatal vitamin A had significantly lower reported motor scores in minimally adjusted and multivariate analyses, -0.29 SD, 95% CI [-0.54, -0.04], p = 0.03, as compared with children whose mothers did not receive vitamin A. There was no significant effect of randomized prenatal zinc on any development domain. Greater caregiver-child stimulation was associated with 0.38 SD, 95% CI [0.14, 0.63], p < 0.01, better cognitive/language scores, whereas children who experienced both verbal and physical punishment had 0.29 SD, 95% CI [-0.52, -0.05], p = 0.02, lower scores in socioemotional development. Maternal completion of primary school was associated with higher reported motor and cognitive/language development. Further, children of mothers who were <155 cm tall had lower cognitive and language scores.

CONCLUSION

Prenatal vitamin A supplements in a setting with low levels of vitamin A deficiency may not provide child development benefits. However, integrated environmental, educational, parenting, and stimulation interventions may have large positive effects across child development domains in resource-limited settings.

Does early vitamin B12 supplementation improve neurodevelopment and cognitive function in childhood and into school age: a study protocol for extended follow-ups from randomised controlled trials in India and Tanzania

INTRODUCTION

As many as 250 million children under the age of 5 may not be reaching their full developmental potential partly due to poor nutrition during pregnancy and the first 2 years of life. Micronutrients, including vitamin B₁₂, are important for the development of brain structure and function; however, the timing, duration and severity of deficiencies may alter the impact on functional development outcomes. Consequently, to fully explore the effect of vitamin B₁₂ on cognitive function, it is crucial to measure neurodevelopment at different ages, in different populations and with vitamin B₁₂ supplementation at different times during the critical periods of neurodevelopment.

METHODS AND ANALYSIS

In this project, we follow up children from four recently completed randomised placebo-controlled trials of oral vitamin B₁₂ supplementation, two in India and two in Tanzania, to explore the long-term effects on neurodevelopmental outcomes and growth. All the included trials provided at least two recommended dietary allowances of oral vitamin B₁₂ daily for at least 6 months. Vitamin B₁₂ was supplemented either during pregnancy, early infancy or early childhood. Primary outcomes are neurodevelopmental status, cognitive function and growth later in childhood. We apply validated and culturally appropriate instruments to identify relevant developmental outcomes. All statistical analyses will be done according to intention-to-treat principles. The project provides an excellent opportunity to examine the effect of vitamin B₁₂ supplementation in different periods during early life and measure the outcomes later in childhood.

ETHICS AND DISSEMINATION

The study has received ethical approvals from all relevant authorities in Norway, USA, Tanzania and India and complies fully with ethical principles for medical research. Results will be presented at national and international research and policy meetings and published in peer-reviewed scientific journals, preferably open access.

TRIAL REGISTRATION NUMBER

NCT00641862 (Bangalore); NCT00717730, updated CTRI/2016/11/007494 (Delhi); NCT00197548 and NCT00421668 (Dar es Salaam).

Maternal Dietary L-Arginine and Adverse Birth Outcomes in Dar es Salaam, Tanzania

The amino acid arginine is a physiological precursor to nitric oxide, which is a key mediator of embryonic survival, fetal growth, and pregnancy maintenance. We evaluated the association between consumption of the amino acid arginine and the rate of adverse birth outcomes using data from a double-blind, randomized, placebo-controlled micronutrient supplementation trial among pregnant women in Dar es Salaam, Tanzania (2001-2004). Dietary intakes of arginine were assessed using repeated 24-hour recalls that were administered throughout pregnancy. Participants (n = 7,591) were monitored by research midwives throughout follow-up to assess pregnancy outcomes. Cubic-restricted splines and multivariable log-Poisson regression with empirical standard errors were used to estimate the continuous and categorical associations between arginine intake and adverse birth outcomes. Compared with women within the lowest quintile of arginine intake, those within the highest quintile had 0.79 times the risk of preterm birth before 37 weeks (95% confidence interval: 0.63, 1.00; P = 0.03). The continuous associations of arginine intake with preterm birth before 37 weeks and with preterm birth before 34 weeks were characterized by an initial rapid decrease in risk with increasing intake (P for nonlinearity < 0.01). Arginine intake was not associated with fetal loss or giving birth to infants who were born small for their gestational ages. This data suggest that the association between dietary arginine intake and preterm birth warrants further investigation.

Vitamin A and Zinc Supplementation Among Pregnant Women to Prevent Placental Malaria: A Randomized, Double-Blind, Placebo-Controlled Trial in Tanzania

AbstractVitamin A and zinc are important for immune function and may improve host defense against malaria and reduce the risk of adverse pregnancy outcomes. Our objective was to determine whether daily oral supplementation with either or both nutrients starting in the first trimester reduces the risk of placental malaria and adverse pregnancy outcomes. We undertook a randomized, double-blind placebo-controlled trial with a factorial design among 2,500 human immunodeficiency virus-negative primigravid or secundigravid pregnant women in their first trimester of pregnancy in Dar es Salaam, Tanzania. We randomly allocated equal numbers of participants to 2,500 IU of vitamin A, 25 mg of zinc, both 2,500 IU of vitamin A and 25 mg of zinc, or a placebo until delivery. A total of 625 participants were allocated to each treatment group. Our primary outcome, placental malaria infection (past or current), was assessed in all randomized participants for whom placental samples were obtained at delivery (N = 1,404), which represents 56% of total participants and 62% of all pregnancies lasting 28 weeks or longer (N = 2,266). Birth outcomes were obtained for 2,434 of the 2,500 randomized participants. Secondary outcomes included small for gestational age (SGA) births and prematurity. All analyses were intent to treat. Those who received zinc had a lower risk of histopathology-positive placental malaria compared with those who did not receive zinc (risk ratio = 0.64, 95% confidence interval = 0.44, 0.91), but neither nutrient had an effect on polymerase chain reaction-positive malaria, SGA, or prematurity. No safety concerns were identified. We recommend additional studies in other geographic locations to confirm these findings.

Iron Supplementation Affects Hematologic Biomarker Concentrations and Pregnancy Outcomes among Iron-Deficient Tanzanian Women

BACKGROUND

Iron deficiency is a highly prevalent micronutrient abnormality and the most common cause of anemia globally, worsening the burden of adverse pregnancy and child outcomes.

OBJECTIVE

We sought to evaluate the response of hematologic biomarkers to iron supplementation and to examine the predictors of the response to iron supplementation among iron-deficient pregnant women.

METHODS

We identified 600 iron-deficient (serum ferritin ≤12 μg/L) pregnant women, aged 18-45 y, presenting to 2 antenatal clinics in Dar es Salaam, Tanzania using rapid ferritin screening tests, and prospectively followed them through delivery and postpartum. All women received 60 mg Fe and 0.25 mg folate daily from enrollment until delivery. Proportions meeting the thresholds representing deficient hematologic status including hemoglobin <110 g/L, ferritin ≤12 μg/L, serum soluble transferrin receptor (sTfR) >4.4 mg/L, zinc protoporphyrin (ZPP) >70 mmol/L, or hepcidin ≤13.3 μg/L at baseline and delivery were assessed. The prospective change in biomarker concentration and the influence of baseline hematologic status on the change in biomarker concentrations were assessed. Regression models were estimated to assess the relation of change in biomarker concentrations and pregnancy outcomes.

RESULTS

There was significant improvement in maternal biomarker concentrations between baseline and delivery, with increases in the concentrations of hemoglobin (mean difference: 15.2 g/L; 95% CI: 13.2, 17.2 g/L), serum ferritin (51.6 μg/L; 95% CI: 49.5, 58.8 μg/L), and serum hepcidin (14.0 μg/L; 95% CI: 12.4, 15.6 μg/L) and decreases in sTfR (-1.7 mg/L; 95% CI: -2.0, -1.3 mg/L) and ZPP (-17.8 mmol/L; 95% CI: -32.1, 3.5 mmol/L). The proportions of participants with low hemoglobin, ferritin, and hepcidin were 73%, 93%, and 99%, respectively, at baseline and 34%, 12%, and 46%, respectively, at delivery. The improvements in biomarker concentrations were significantly greater among participants with poor hematologic status at baseline - up to 12.1 g/L and 14.5 μg/L for hemoglobin and ferritin concentrations, respectively. For every 10-g/L increase in hemoglobin concentration, there was a 24% reduced risk of perinatal mortality (RR = 0.76; 95% CI: 0.59, 0.99) and a 23% reduced risk of early infant mortality (RR = 0.77; 95% CI: 0.60, 0.99). The risk of anemia at delivery despite supplementation was predicted by baseline anemia (RR = 2.11; 95% CI: 1.39, 3.18) and improvements in ferritin concentration were more likely to be observed in participants who took iron supplements for up to 90 d (RR = 1.41; 95% CI: 1.13, 1.76).

CONCLUSION

Iron supplementation decreases the risk of maternal anemia and increases the likelihood of infant survival among iron-deficient Tanzanian pregnant women. Interventions to promote increased duration and adherence to iron supplements may also provide greater health benefits.

Angiogenic and inflammatory biomarkers in midpregnancy and small-for-gestational-age outcomes in Tanzania

OBJECTIVE

We sought to investigate the relationship between a panel of angiogenic and inflammatory biomarkers measured in midpregnancy and small-for-gestational-age (SGA) outcomes in sub-Saharan Africa.

STUDY DESIGN

Concentrations of 18 angiogenic and inflammatory biomarkers were determined in 432 pregnant women in Dar es Salaam, Tanzania, who participated in a trial examining the effect of multivitamins on pregnancy outcomes. Infants falling below the 10th percentile of birthweight for gestational age relative to the applied growth standards were considered SGA. Multivariate binomial regression models with the log link function were used to determine the relative risk of SGA associated with increasing quartiles of each biomarker. Restricted cubic splines were used to test for nonlinearity of these associations.

RESULTS

A total of 60 participants (13.9%) gave birth to SGA infants. Compared to those in the first quartile, the risk of SGA was reduced among those in the fourth quartiles of vascular endothelial growth factor-A (adjusted risk ratio [RR], 0.38; 95% confidence interval [CI], 0.19-0.74), placental growth factor (adjusted RR, 0.28; 95% CI, 0.12-0.61), soluble fms-like tyrosine kinase-1 (adjusted RR, 0.48; 95% CI, 0.23-1.01), monocyte chemoattractant protein-1 (adjusted RR, 0.48; 95% CI, 0.25-0.92), and leptin (adjusted RR, 0.46; 95% CI, 0.22-0.96).

CONCLUSION

Our findings provide evidence of altered angiogenic and inflammatory mediators, at midpregnancy, in women who went on to deliver SGA infants.

Maternal hyperglycemia and adverse pregnancy outcomes in Dar es Salaam, Tanzania

OBJECTIVE

To evaluate maternal glucose levels during pregnancy as a predictor of adverse perinatal outcomes in Dar es Salaam, Tanzania.

METHODS

Random blood glucose measurements were analyzed from 3383 pregnant women enrolled in a randomized trial to assess the impact of multivitamins on pregnancy outcomes in Dar es Salaam between August 2001 and July 2004. Information on maternal and neonatal morbidity was recorded at monthly study visits, delivery, and 6 weeks postpartum. Binomial regression and generalized estimating equations were used to determine the relationship between elevated glucose (>7.8 mmol/L) and pregnancy outcomes.

RESULTS

In total, 25 women had elevated glucose (0.7%). Hyperglycemia was associated with an increased risk of delivery before 37 weeks [relative risk (RR), 2.11; 95% confidence interval [CI], 1.07-4.13; P=0.03), delivery before 34 weeks (RR, 4.15; 95% CI, 1.43-12.03, P=0.009), incident gestational hypertension (RR, 2.90; 95% CI, 1.24-6.76; P=0.01), low birth weight (RR, 2.87; 95% CI, 1.18-6.99; P=0.02), reduced newborn head circumference (mean difference, -1.57; 95% CI, -2.51 to -0.62; P=0.001), and fetal loss (RR, 3.38; 95% CI, 1.13-10.08; P=0.03).

CONCLUSION

Maternal hyperglycemia is uncommon among pregnant Tanzanian women, but nonetheless seems to increase the risk of several adverse perinatal outcomes.

Burden and Determinants of Severe Anemia among HIV-Infected Adults: Results from a Large Urban HIV Program in Tanzania, East Africa

BACKGROUND AND METHODS

This cross-sectional study aimed at determining the prevalence and risk factors for severe anemia, severe microcytic anemia, and severe normocytic anemia among HIV-infected individuals aged >15 years. Univariate and multivariate analyses were performed to identify the risk factors for anemia.

RESULTS

Data from 40 408 patients were analyzed, showing an overall prevalence of 22% for severe anemia. The risk of developing severe anemia increased by 49% among patients with a body mass index of <18.5 kg/m(2), by approximately 2-fold among patients with the World Health Organization (WHO) stage III, and by 3-fold among patients with WHO stage IV illness. Severe normocytic anemia was uniquely increased among patients aged ≥50 years, among those with chronic diarrhea and Kaposi's sarcoma, and those taking cotrimoxazole.

CONCLUSION

There was a high prevalence of severe anemia among adults infected with HIV. Focused identification of anemia should be based on the hemoglobin and mean corpuscular volume measurements.

Image compression and restoration incorporating prior knowledge

It is shown how to incorporate prior knowledge into the restoration of an image from a finite number of its expansion coefficients in some basis. The significant image enhancement obtained for simple prior knowledge suggests an application to image-transform coding. A computer simulation is presented that demonstrates that compression ratios greater than 13:1 are possible.