Approaches to Quantify the Contribution of Multiple Anemia Risk Factors in Children and Women From Cross-Sectional National Surveys

Objectives

Despite challenges interpreting attributable fractions (AF) from cross-sectional data, AF of anemia are often used to understand the multifactorial etiologies of anemia. However, different strategies to calculate AF are adopted, and some can be inappropriate especially in cross-sectional studies. We aim to compare statistical approaches for estimating AF for anemia due to inflammation, malaria, iron deficiency, and other micronutrient deficiencies.

Methods

AF were calculated using nationally representative survey data among preschool children (10 countries) and nonpregnant women of reproductive age (11 countries) from the Biomarkers Reflecting Inflammation and Nutrition Determinants of Anemia (BRINDA) project, using 1) Levin's formula with prevalence ratio (PR) in place of relative risk (RR), 2) Levin's formula with odds ratio (OR) in place of RR, and 3) average (sequential) AF considering all possible removal sequences of risk factors. PR was obtained by 1) modified Poisson regression with robust variance estimation, 2) Kleinman-Norton's approach, and 3) approximated by OR using Zhang-Yu's approach. Survey weighted country-specific analysis was performed with and without adjustment for age, sex, socioeconomic status, and other risk factors.

Results

About 20–70% of children and 20–50% of women suffered from anemia. Using OR yielded the highest AF, in some cases double those using PR. Adjusted AF using different PR estimations (Poisson regression, Kleinman-Norton, Zhang-Yu) were nearly identical. Average AF estimates were similar to those using PR. Inflammation, malaria, and iron deficiency were associated with 5–20% and <10%, 2–61% and 1–24%, and 10–20% and 15–30% of children and women with anemia, respectively. Unadjusted AF were substantially higher than adjusted AF in some countries.

Conclusions

This study shows the effects of not accounting for confounding and using OR instead of the RR when quantifying AF of anemia in cross-sectional studies. Using different PR estimation approaches yielded similar results.

Funding Sources

Bill & Melinda Gates Foundation, Centers for Disease Control and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and the United States Agency for International Development.

Adjusting Iron Biomarkers for Inflammation in Pregnant Women: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) Project

Objectives

Accurate assessment of iron deficiency during pregnancy is essential for program planning and interventions. We aimed to examine the relationship between serum ferritin (SF) and soluble transferrin receptor (sTfR) and inflammation and examine the impact of inflammation on the prevalence of iron deficiency in a large multi-country analysis.

Methods

Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project provided 17 pregnancy datasets (n = 14,077) from 15 countries including at least one iron (serum ferritin, SF; soluble transferrin receptor, sTfR) and inflammation biomarker (C-reactive protein, CRP or α-1-acid glycoprotein, AGP). Spearman rank correlations between CRP or AGP and iron biomarkers (SF, sTfR) were examined. We report unadjusted and adjusted prevalence of iron deficiency, using the BRINDA regression correction approach to adjust for inflammation on behalf of the BRINDA Pregnancy Workgroup.

Results

Ferritin concentrations were positively correlated with CRP in 6 out of 14 surveys (ρ from 0.65 in Mexico, P < 0.0001 to 0.06 in Vietnam, P < 0.05) and AGP in 8 out of 9 surveys (correlation coefficients (ρ) ranging from 0.41, in Guatemala to 0.19 in Pakistan, P < 0.0001). Among the 8 datasets with both CRP and AGP, adjustment for both AGP and CRP increased the estimated prevalence of iron deficiency (ferritin < 15 μg/L) by a median of 18.8 percentage points (pp) compared to 15.6 pp for AGP alone and 10.5 pp for CRP alone. sTfR concentrations were positively correlated with AGP in 4 out of 12 surveys (ρ ranging from 0.36 in Vietnam to 0.09 in Pakistan, P < 0. 01) and positively associated with CRP in 4 out of 10 surveys (ρ ranging from 0.20 in Vietnam to 0.07 in US and Ghana, P < 0.05).

Conclusions

Failing to adjust for inflammation during pregnancy appears to underestimate iron deficiency using serum ferritin during pregnancy. Given the weak and inconsistent association between sTfR and inflammation, adjustment of sTfR biomarkers during pregnancy does not appear warranted at this time.

Funding Sources

Bill & Melinda Gates Foundation, Centers for Disease Control and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and the United States Agency for International Development.

Prevalence and Predictors of Inflammation in Pregnant Women: Multi-Country Analysis From BRINDA Project

Objectives

Limited data exist on the prevalence and predictors of inflammation during pregnancy. We aimed to characterize the inflammatory pattern and predictors of subclinical inflammation across pregnancy using multi-country analysis.

Methods

The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project compiled 17 datasets of pregnant women (n = 14,077) from 15 countries in both high- and low-income settings. Datasets were included if at least one inflammation biomarker (C-reactive protein, CRP, or α-1-acid glycoprotein, AGP) were collected. We estimated the prevalence of any subclinical inflammation (defined as CRP >5 mg/L or AGP >1 g/L), examined AGP and CRP patterns throughout pregnancy, and assessed the relationship between inflammation and covariates such as maternal age, gestational age, socioeconomic, and water and sanitation factors for each dataset.

Results

The prevalence of inflammation varied from 16.6% in Afghanistan to < 1% in Vietnam using elevated AGP and from 52.9% in the US to 7.6% in Vietnam using elevated CRP. Inflammation was common but varied across datasets: >40% in 5 datasets, 20–40% in 6 datasets, 10−< 20% in 5 datasets and < 10% in one dataset. AGP decreased with increasing gestational age (P < 0.01 in all seven datasets with gestational age information); however, the magnitude of decrease in AGP varied by country. In contrast, CRP showed an inconsistent pattern by gestational age. In multivariable models, the predictors of inflammation included age, trimester, urban or rural residence, socioeconomic status, improved sanitation, improved drinking water, lactating and smoking status, although strengths of association differed by dataset.

Conclusions

Although there was considerable heterogeneity in the prevalence of inflammation, inflammation was common across pregnancy in diverse settings. AGP, a measure of long-term inflammation, decreased across pregnancy in all countries, whereas the pattern for CRP was inconsistent. The relationship between socioeconomic and health factors and inflammation varied across countries.

Funding Sources

Bill & Melinda Gates Foundation, Centers for Disease Control and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and the United States Agency for International Development.

Effect of Zinc Supplementation on Innate and Adaptive Immunity in Lao Children at Risk of Zinc Deficiency (P19-013-19)

Objectives

Determine if children (6 to 23 mo) who received daily preventive zinc (PZ; 7 mg/d), daily high-zinc, low-iron micronutrient powder (MNP; 10 mg/d zinc, 6 mg/d iron) or therapeutic zinc during episodes of diarrhea (TZ; 20 mg/d for 10 d per episode) have improved markers of innate and adaptive immune function, compared to placebo (PL).

Methods

Rural Laotian children were recruited into a double-blind, randomized, controlled intervention trial for 9 mo. Venous blood was collected at baseline (BL) and endline (EL) for analysis. Primary outcomes included T-cell subsets (naïve and memory CD4, CD8, Tregs) measured by flow cytometry and production of T-cell cytokines (IL-2, IL-10, IL-13, IL-17A, INF-γ) and LPS-induced cytokines (IL-1β, IL-6, IL-10, TNF-α by whole blood cultures. Blood leukocytes (including lymphocytes, neutrophils, monocytes and eosinophils) were measured as secondary outcome variables. Group means at EL were compared by analysis of covariance (controlling for BL values of the outcome, sex, child age, district, month of enrollment and plasma zinc concentration). If an interaction with BL plasma zinc (above/below median) was observed, group means were compared separately in children above and below the median.

Results

Mean BL plasma zinc in all children (N = 574) was 0.55 ± 0.12 mg/L. No significant group differences were seen at EL in the primary outcomes. For secondary outcomes, the counts (^103/μL) of lymphocytes from the PZ group (5.02 ± 0.16) were significantly lower than the PL group (5.64 ± 0.16; P = 0.032). The EL counts (^103/μL) of from the PZ group (0.144 ± 0.026) were significantly lower than in the PL (0.279 ± 0.048; P = 0.036) and TZ (0.285 ± 0.047; P = 0.025) groups among children with baseline zinc below the median.

Conclusions

Primary outcomes (T-cell subsets, and cytokine production) were not affected by the zinc intervention. Lymphocyte and eosinophil concentrations may be affected by zinc treatment but this result requires confirmation.

Funding Sources

ARS Project 2032-53000-001-00-D, Mathile Institute for the Advancement of Human Nutrition.

A Randomized Controlled-feeding Trial Based on the Dietary Guidelines for Americans Does Not Affect Plasma Trimethylamine N-oxide Levels in Women (P08-031-19)

Objectives

Trimethylamine N-oxide is a gut-mediated metabolite associated with cardiovascular disease. Acute diet challenges demonstrate that circulating TMAO concentrations are diet-responsive; however, long-term trials investigating how different dietary patterns affect circulating TMAO concentrations are sparse. The objective of the current study was to determine whether consumption of a diet patterned after the USDA's 2010 Dietary Guidelines for Americans (DGA), as compared to the typical American Diet (TAD), would reduce plasma TMAO levels.

Methods

A randomized, double-blind, controlled 8-wk intervention was conducted in overweight and obese women selected according to indexes of insulin resistance or dyslipidemia. Women were randomly assigned to the DGA or TAD group (n = 28 DGA and 24 TAD). The TAD diet was based on average adult intake from the NHANES 2009–2010. All foods and beverages were provided during the intervention and matched to each participant's energy requirement to ensure maintenance of initial body weight.Plasma samples were collected at baseline, 1 wk of their typical diet, and after 2 and 8 weeks of dietary intervention, in an overnight-fasted condition, and utilized to quantitate circulating TMAO concentrations using stable isotope dilution chromatography tandem mass spectrometry. Statistical analysis were performed in SAS using analysis of covariance and partial correlation.

Results

Following 2 or 8 weeks of dietary intervention, plasma TMAO concentrations were not different between the DGA and TAD diets (3.45 ± 0.41 vs 2.91 ± 0.38 μM at week 2; 3.48 ± 0.41 vs 3.00 ± 0.40 μM at week 8, Mean ± SE, respectively). Post-intervention TMAO concentration was correlated to initial TMAO concentrations and body mass index but not age. Furthermore, we did not observe significant correlations between TMAO and measures of endothelial function (Endopat) or insulin resistance (HOMA-IR) which may reflect the relative health of the overall population enrolled in the study.

Conclusions

Consumption of a diet based on the USDA's 2010 Dietary Guidelines for Americansfor 8 weeks did not reduce plasma TMAO levels in this study.

Funding Sources

Supported by National Dairy Council; Campbell Soup Co.; USDA-ARS Projects 2032-51530-022-00D and 6026-51000-010-05S.

Methylation and gene expression responses to ethanol feeding and betaine supplementation in the cystathionine beta synthase-deficient mouse

BACKGROUND

Alcoholic steatohepatitis (ASH) is caused in part by the effects of ethanol (EtOH) on hepatic methionine metabolism.

METHODS

To investigate the phenotypic and epigenetic consequences of altered methionine metabolism in this disease, we studied the effects of 4-week intragastric EtOH feeding with and without the methyl donor betaine in cystathionine beta synthase (CβS) heterozygous C57BL/6J mice.

RESULTS

The histopathology of early ASH was induced by EtOH feeding and prevented by betaine supplementation, while EtOH feeding reduced and betaine supplementation maintained the hepatic methylation ratio of the universal methyl donor S-adenosylmethionine (SAM) to the methyltransferase inhibitor S-adenosylhomocysteine (SAH). MethylC-seq genomic sequencing of heterozygous liver samples from each diet group found 2 to 4% reduced methylation in gene bodies, but not promoter regions of all autosomes of EtOH-fed mice, each of which were normalized in samples from mice fed the betaine-supplemented diet. The transcript levels of nitric oxide synthase (Nos2) and DNA methyltransferase 1 (Dnmt1) were increased, while those of peroxisome proliferator receptor-α (Pparα) were reduced in EtOH-fed mice, and each was normalized in mice fed the betaine-supplemented diet. DNA pyrosequencing of CβS heterozygous samples found reduced methylation in a gene body of Nos2 by EtOH feeding that was restored by betaine supplementation and was correlated inversely with its expression and positively with SAM/SAH ratios.

CONCLUSIONS

The present study has demonstrated relationships among EtOH induction of ASH with aberrant methionine metabolism that was associated with gene body DNA hypomethylation in all autosomes and was prevented by betaine supplementation. The data imply that EtOH-induced changes in selected gene transcript levels and hypomethylation in gene bodies during the induction of ASH are a result of altered methionine metabolism that can be reversed through dietary supplementation of methyl donors.

Efficacy and tolerability of a novel herbal formulation for weight management

OBJECTIVE

To evaluate the efficacy of an herbal blend.

DESIGN AND METHODS

A randomized, double-blind, clinical trial in 60 subjects with body mass index (BMI) between 30 and 40 kg/m(2) . Participants were randomized into two groups receiving either 400 mg herbal capsules or 400 mg placebo capsules twice daily. The herbal blend comprises of extracts from Sphaeranthus indicus and Garcinia mangostana. Participants received a standard diet (2,000 kcal per day) and walked 30 min 5 days per week.

RESULTS

After 8 weeks, significant net reductions in body weight (3.74 kg; P < 0.0001), BMI (1.61 kg/m(2) ; P < 0.0001), and waist circumference (5.44 cm; P < 0.05) were observed in the herbal group compared with placebo. Additionally, a significant increase in serum adiponectin concentration was found in the herbal group versus placebo (P = 0.001). Adverse events were mild and were equally distributed between the two groups. In vitro studies in the 3T3-L1 adipocyte cell line showed that the herbal extract markedly downregulated the expression of peroxisome proliferator-activated receptor gamma, adipocyte-differentiation related protein, and cluster of differentiation 36 but increased adiponectin expression. The herbal extract also reduced the expression and the recruitment of perilipin onto the membrane of lipid droplets.

CONCLUSION

Supplementation with the herbal blend resulted in a greater degree of weight loss than placebo over 8 weeks.

Feasibility of using flash-heated breastmilk as an infant feeding option for HIV-exposed, uninfected infants after 6 months of age in urban Tanzania

OBJECTIVE

Heat-treating expressed breastmilk is recommended as an interim feeding strategy for HIV-exposed infants in resource-poor countries, but data on its feasibility are minimal. Flash-heating (FH) is a simple in-home technique for heating breastmilk that inactivates HIV although preserving its nutritional and anti-infective properties. Our primary objective was to determine, among HIV-infected mothers, the feasibility and protocol adherence of FH expressed breastmilk after 6 months of exclusive breastfeeding.

DESIGN

Prospective longitudinal.

PARTICIPANTS

One hundred one HIV-infected breastfeeding mothers.

SETTING

Dar es Salaam, Tanzania.

INTERVENTION

Peer counselors provided in-home counseling and support on infant feeding from 2 to 9 months postpartum. Mothers were encouraged to exclusively breastfeed for 6 months followed by FH expressed breastmilk if her infant was HIV negative. Clinic-based staff measured infant growth and morbidity monthly, and mothers kept daily logs of infant morbidity. FH behavior was tracked until 9 months postpartum using daily logs, in-home observations, and clinic-based and home-based surveys. Bacterial cultures of unheated and heated milk samples were performed.

RESULTS

Thirty-seven of 72 eligible mothers (51.4%) chose to flash-heat. Median (range) frequency of milk expression was 3 (1-6) times daily and duration of method use on-study was 9.7 (0.1-15.6) weeks. Mean (SD) daily milk volume was 322 (201) mL (range 25-1120). No heated and 32 (30.5%) unheated samples contained bacterial pathogens.

CONCLUSIONS

FH is a simple technology that many HIV-positive women can successfully use after exclusive breastfeeding to continue to provide the benefits of breastmilk while avoiding maternal-to-child transmission associated with nonexclusive breastfeeding. Based on these feasibility data, a clinical trial of the effects of FH breastmilk on infant health outcomes is warranted.

Food insecurity is positively related to overweight in women

Although individuals with poor food security might be expected to have reduced food intake, and thus reduced body fat and less likelihood of being overweight, these associations have not been adequately studied. The purpose of the current study was to examine the relationship between food insecurity and overweight as measured by body mass index (BMI) using data from the nationally representative 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII). Overweight was defined as BMI >27.3 kg/m(2) for women and 27.8 kg/m(2) for men. Food insecurity was related to overweight status for women (n = 4509, P < 0.0001), but not for men (n = 4970, P = 0.44). Excluding the 11 severely insecure women, the prevalence of overweight among women increased as food insecurity increased, from 34% for those who were food secure (n = 3447), to 41% for those who were mildly food insecure (n = 966) and to 52% for those who were moderately food insecure (n = 86). Food insecurity remained a significant predictor of overweight status, after adjustment for potentially confounding demographic and lifestyle variables (P < 0.01). In a logistic regression analysis, mildly insecure women were 30% more likely to be overweight than those who were food secure [odds ratio (OR) 1.3, P = 0.005]. Thus, food insecurity had an unexpected and paradoxical association with overweight status among women with a higher prevalence of overweight among the food insecure, and a resulting potential for increased incidence of obesity-related chronic diseases. Given that the rates of both overweight and food insecurity are on the rise, this research area warrants further investigation.

Changes in plasma lipoproteins during low-fat, high-carbohydrate diets: effects of energy intake

BACKGROUND

Low-fat diets can increase plasma triacylglycerol and reduce HDL cholesterol. Changes in energy intake and body weight can influence the lipoprotein response.

OBJECTIVE

We sought to prospectively examine the effects of euenergetic and ad libitum dietary fat restriction on plasma lipoproteins in healthy postmenopausal women.

DESIGN

Participants first received a controlled euenergetic diet in which dietary fat was reduced stepwise from 35% to 25% to 15% over 4 mo. Thereafter, participants followed an ad libitum 15%-fat diet for 8 mo; 54 women completed the intervention.

RESULTS

During the controlled euenergetic diet, plasma triacylglycerol increased from 1.70 +/- 0.10 to 2.30 +/- 0.16 mmol/L, total cholesterol decreased from 5.87 +/- 0.13 to 5.53 +/- 0. 13 mmol/L, LDL cholesterol decreased from 3.41 +/- 0.10 to 2.87 +/- 0.10 mmol/L, HDL cholesterol decreased from 1.76 +/- 0.08 to 1.50 +/- 0.08 mmol/L, and apolipoprotein (apo) A-I decreased from 5.11 +/- 0.14 to 4.78 +/- 0.14 mmol/L (P < 0.0001 for all changes). Hormone replacement therapy did not affect the relative change in HDL cholesterol. Plasma glucose, insulin, hemoglobin A(1C,) free fatty acid, and apo B concentrations did not change significantly. During the ad libitum 15%-fat diet, participants lost 4.6 +/- 0.4 kg. Plasma triacylglycerol and LDL cholesterol returned to baseline values (1.77 +/- 0.12 and 3.31 +/- 0.08 mmol/L, respectively), whereas HDL cholesterol and apo A-I remained low (1.40 +/- 0.08 and 4.82 +/- 0.18 mmol/L, respectively). HDL cholesterol and apo A-I concentrations stabilized in subjects who were not receiving hormone replacement therapy but continued to decline in women who were receiving hormone therapy.

CONCLUSIONS

The ad libitum 15%-fat diet resulted in significant weight loss. The euenergetic but not the ad libitum diet caused hypertriacylglycerolemia. HDL cholesterol decreased during both low-fat diets.

Human adipose alpha-tocopherol and gamma-tocopherol kinetics during and after 1 y of alpha-tocopherol supplementation

Alpha-tocopherol and gamma-tocopherol were monitored in human adipose by using needle biopsies in four subjects during a 1-y supplementation trial with 800 mg all-rac-alpha-tocopherol/d, and for 1 additional year after cessation of supplement. Some increase in adipose alpha-tocopherol (per milligram adipose cholesterol) and a more consistent decrease in gamma-tocopherol were observed during the supplementation period. The alpha-tocopherol/gamma-tocopherol ratio rose consistently during supplementation and fell only gradually after the supplement was stopped. We estimate that > or = 2 y are required for the alpha-tocopherol/gamma-tocopherol ratio to reach a new steady state after a change in alpha-tocopherol intake. In a cross-sectional measurement in five subjects who reported long-term use of alpha-tocopherol supplements (> or = 250 mg/d), and in five other subjects who reported no supplement use, the adipose alpha-tocopherol/gamma-tocopherol ratio clearly discriminated between the two groups (P < 0.002). This ratio may be of value in ranking individuals according to long-term alpha-tocopherol intake.