Comparison of four immunoassays to measure serum ferritin concentrations and iron deficiency prevalence among non-pregnant Cambodian women and Congolese children.

BACKGROUND: Global standardization of ferritin assays is lacking, which could have direct implications on the accurate measurement and comparability of ferritin concentration and iron deficiency (ID) prevalence rates in at-risk populations. METHODS: We measured serum ferritin concentrations using four immunoassays: the s-ELISA and the AxSYM™ analyzer were compared among 420 non-pregnant Cambodian women; the Centaur® XP analyzer, s-ELISA, and AxSYM™ analyzer were compared among a subset of 100 Cambodian women; and the s-ELISA and the Elecsys® 2010 analyzer were compared among 226 Congolese children aged 6-59 months. RESULTS: Median ferritin concentrations (adjusted for inflammation) ranged between 48 and 91 µg/L among Cambodian women and between 54 and 55 µg/L among Congolese children. ID prevalence ranged from 2% to 10% among Cambodian women and 5% to 7% among Congolese children. Bias between methods varied widely (-9 to 45 µg/L) among women, and was 43 µg/L among children. Bias was lower when ferritin values outside of the s-ELISA measurement range (>250 µg/L) were excluded. CONCLUSIONS: The observed differences in ferritin concentrations likely reflect different ferritin isoforms, antibodies, and calibrators used across assays and by different laboratories. However, despite differences in ferritin concentrations, ID prevalence was relatively similar and low across all methods.

Elevated levels of iron in groundwater in Prey Veng province in Cambodia: a possible factor contributing to high iron stores in women.

Iron is a natural element found in food, water and soil and is essential for human health. Our aim was to determine the levels of iron and 25 other metals and trace elements in groundwater from 22 households in Prey Veng, Cambodia. Water analyses were conducted using inductively coupled plasma-mass spectrometry and optical emission spectrometry. Compared to the 2011 World Health Organization guidelines for drinking water quality, aluminum, iron and manganese exceeded maximum levels (in 4.5, 72.7 and 40.9% of samples, respectively). Compared to the 2004 Cambodian drinking water quality standards, iron and manganese exceeded maximum levels (in 59.1 and 36.4% of samples, respectively). We found no evidence of arsenic contamination. Guidelines for iron were established primarily for esthetic reasons (e.g. taste), whereas other metals and elements have adverse effects associated with toxicity. Iron in groundwater ranged from 134 to 5,200 µg/L (mean ∼1,422 µg/L). Based on a daily consumption of 3 L groundwater, this equates to ∼0.4-15.6 mg iron (mean ∼4.3 mg/day), which may be contributing to high iron stores and the low prevalence of iron deficiency anemia in Prey Veng women. Elevated levels of manganese in groundwater are a concern and warrant further investigation.

Genetic hemoglobin disorders rather than iron deficiency are a major predictor of hemoglobin concentration in women of reproductive age in rural prey Veng, Cambodia.

BACKGROUND: Anemia is common in Cambodian women. Potential causes include micronutrient deficiencies, genetic hemoglobin disorders, inflammation, and disease. OBJECTIVES: We aimed to investigate factors associated with anemia (low hemoglobin concentration) in rural Cambodian women (18-45 y) and to investigate the relations between hemoglobin disorders and other iron biomarkers. METHODS: Blood samples were obtained from 450 women. A complete blood count was conducted, and serum and plasma were analyzed for ferritin, soluble transferrin receptor (sTfR), folate, vitamin B-12, retinol binding protein (RBP), C-reactive protein (CRP), and α1 acid glycoprotein (AGP). Hemoglobin electrophoresis and multiplex polymerase chain reaction were used to determine the prevalence and type of genetic hemoglobin disorders. RESULTS: Overall, 54% of women had a genetic hemoglobin disorder, which included 25 different genotypes (most commonly, hemoglobin E variants and α(3.7)-thalassemia). Of the 420 nonpregnant women, 29.5% had anemia (hemoglobin <120 g/L), 2% had depleted iron stores (ferritin <15 µg/L), 19% had tissue iron deficiency (sTfR >8.3 mg/L), <3% had folate deficiency (<3 µg/L), and 1% had vitamin B-12 deficiency (<150 pmol/L). Prevalences of iron deficiency anemia (IDA) were 14.2% and 1.5% in those with and without hemoglobin disorders, respectively. There was no biochemical evidence of vitamin A deficiency (RBP <0.7 µmol/L). Acute and chronic inflammation were prevalent among 8% (CRP >5 mg/L) and 26% (AGP >1 g/L) of nonpregnant women, respectively. By using an adjusted linear regression model, the strongest predictors of hemoglobin concentration were hemoglobin E homozygous disorder and pregnancy status. Other predictors were 2 other heterozygous traits (hemoglobin E and Constant Spring), parity, RBP, log ferritin, and vitamin B-12. CONCLUSIONS: Multiple biomarkers for anemia and iron deficiency were significantly influenced by the presence of hemoglobin disorders, hence reducing their diagnostic sensitivity. Further investigation of the unexpectedly low prevalence of IDA in Cambodian women is warranted.

Folate and vitamin B12 status of women of reproductive age living in Hanoi City and Hai Duong Province of Vietnam.

OBJECTIVES: To assess the folate and vitamin B12 status of a group of Vietnamese women of reproductive age and to estimate the rate of neural tube defects (NTD) based on red blood cell (RBC) folate concentrations. DESIGN AND SUBJECTS: A representative sample of non-pregnant women (15-49 years) living in Hanoi City (n 244) and Hai Duong Province (n 245). MEASURES: RBC folate, plasma vitamin B12 and plasma holo-transcobalamin (holoTC), a sensitive indicator of vitamin B12 status. RESULTS: Mean (95% CI) concentrations of RBC folate, plasma B12 and plasma holoTC were 856 (837, 876) nmol/l, 494 (475, 513) pmol/l and 78 (74, 82) pmol/l, respectively. Only 3% and 4% of women had plasma B12 and holoTC concentrations indicative of deficiency. No woman had an RBC folate concentration indicative of deficiency (<317 nmol/l). Only 47% of women had an RBC folate concentration > or = 905 nmol/l. Accordingly, we predict the NTD rate in these regions of Vietnam to be 14.7 (14.2, 15.1) per 10,000 pregnancies. CONCLUSION: There was no evidence of folate and vitamin B12 deficiency among this population of Vietnamese women. However, suboptimal folate status may be placing three out of five women at increased risk of NTD. Reductions in NTD rates are still possible and women would benefit from additional folic acid during the periconceptional period from either supplements or fortified foods.

Cognitive dietary restraint is associated with eating behaviors, lifestyle practices, personality characteristics and menstrual irregularity in college women.

This study characterized associations of restraint with selected physical, lifestyle, personality and menstrual cycle characteristics in female university students. The survey instrument, distributed to 1350 women, included standardized questionnaires (Three-Factor Eating Questionnaire, Perceived Stress Scale and Rosenberg's Self-esteem Scale), and assessed weight and dieting history, exercise, lifestyle characteristics, menstrual cycle characteristics and whether participants were following vegetarian diets. Among the 596 respondents included in the analysis (44%), women with high (n=145), medium (n=262) or low (n=189) restraint had similar ages, heights and weights. Despite this, compared to women with low scores, those with high scores exercised more (4.6+/-5.3 vs. 3.2+/-3.5 h/wk), were more likely to be vegetarian (14.5 vs. 3.7%), have a history of eating disorders (13.7 vs. 1.2%), be currently trying to lose weight (80.3 vs. 15.3%), report irregular menstrual cycles (34.7 vs. 17.0%), and have scores reflecting lower self-esteem and higher perceived stress. Menstrual irregularity was an independent predictor of restraint score, and restraint score was the only variable to differentiate women with regular and irregular menstrual cycles. We conclude that women with high restraint may use a combination of behavioral strategies for weight control, and differ from women with low restraint scores in personality characteristics and weight history. Some of these behaviors or characteristics may influence menstrual function.