Nutrition: Biochemical correlates of anemia in Cambodian women of reproductive age

Biochemical correlates of anemia in Cambodian women of reproductive age

Crystal Karakochuk1,2, Kyly Whitfield1,2, Aminuzzaman Talukder3, Suzanne Vercauteren4, Judy McLean1, Tim Green1,2

1University of British Columbia, Vancouver; 2Child and Family Research Institute, Vancouver; 3Helen Keller International, Phnom Penh; 4BC Children’s Hospital, Vancouver

International Food Security Dialogue 2014Enhancing Food Production, Gender Equity and Nutritional Security in a Changing World

The Fish on Farms project is being jointly conducted by the University of British Columbia (UBC) and Helen Keller International (HKI), with

technical assistance from World Fish, in Prey Veng Province, Cambodia.

This randomized control trial investigates an integrated Homestead Food Production models in relation to poverty, gender empowerment, and food

and nutrition security, particularly among women and children. 

This is the first project known to rigorously measure the effectiveness of different models of Homestead Food Production at reducing undernutrition

using biochemical and anthropometric measurements.

University of British Columbia Ministry of Health, CambodiaDr. Tim Green, Associate Professor, Human Nutrition Ministry of Planning,

CambodiaDr. Judy McLean, Assistant Professor, Human NutritionDr. Susan Barr, Professor, Human NutritionDr. Larry Lynd, Professor & Director, Collaboration for Outcomes Research & EvaluationDr. Tony Farrell, Professor, Centre for Aquaculture and Environmental ResearchDr. David Kitts, Professor, Food Science & Associate Dean of ResearchDr. Ian Forster, Centre for Aquaculture and Environmental ResearchJen Foley, Fish on Farms Program Coordinator

Helen Keller International - Cambodia Graduate StudentsDr. Zaman Talukder Kyly Whitfield (PhD, Nutrition)Mr. Hou Kroeun Crystal Karakochuk (PhD,

Nutrition)Ms. Ly Sokhoing Vashti Verbowski (MSc, Nutrition)Field Research Team Pardis Lakzadeh (MSc, Public

Health Jeff Tang (BSc, Science)

World Fish

Global Prevalence of Anemia

Iron and Hemoglobin

Iron: a natural metal found in the environment and in food

Primarily important for the synthesis of Hemoglobin (Hb) in red blood cells which is essential for oxygen transport

Anemia in women of reproductive age: defined as Hb <120 g/L

Image courtesy of antranik.org

Potential Causes of Anemia in Cambodia

disease

blood loss

inflammation

Anemia

micronutrient genetic hemoglobin

deficiencies disorders

iron, vitamin A, folate & vitamin B12

Potential Causes of Anemia in Cambodia

disease

blood loss

inflammation

Anemia

micronutrient genetic hemoglobin

deficiencies disorders

induces hepcidin = anemia of chronic inflammation

Potential Causes of Anemia in Cambodia

disease

blood loss

inflammation

Anemia

micronutrient genetic hemoglobin

deficiencies disorders

hookworm, parasites, malaria

Potential Causes of Anemia in Cambodia

disease

blood loss

inflammation

Anemia

micronutrient genetic hemoglobin

deficiencies disorders

menses, losses from childbirth

Potential Causes of Anemia in Cambodia

disease

blood loss

inflammation

Anemia

micronutrient genetic hemoglobin

deficiencies disorders

Inherited disorders that result in a defective hemoglobin

Autosomal Recessive Disorder

Audience Poll

What is the prevalence of genetic hemoglobin disorders in Cambodia?

a) 5%

b) 10%

c) 20%

d) >50%

Audience Poll

What is the prevalence of genetic hemoglobin disorders in Cambodia?

a) 5%

b) 10%

c) 20%

d) >50% *majority are heterozygous traits that are asymptomatic, but serious risk

of homozygous form inherited by offspring

(Carnley et al, 2006; George et al, 2012)

Structural hemoglobin variants

Thalassemias

-result from amino acid substitutions in the globin

chain of hemoglobin

-result from an amino acid deletion causing impaired

synthesis of the globin chains (α- or β)

Examples: Hb AE (heterozygous), EE

(homozygous), Constant Spring (CS)

Examples: α- or β thalassemias

(α-3.7 most common)

Diagnostic method: Hb gel electrophoresis

(% of Hb variants of total Hb)

Diagnostic method: Polymerase Chain Reaction

(PCR) for DNA typing

Genetic Hemoglobin Disorders

(Bain, 2006)

Objectives

1. To explore the correlates of anemia in Cambodian women of reproductive age

2. To estimate the proportion of anemia associated with iron deficiency using biochemical indicators

Study Design & Methods

Cross sectional survey design: Baseline data from ongoing RCT in Cambodia

Participants: 450 Cambodian women 18-45 yrs of age from poor

households in rural Prey Veng province

Data collected in June 2012: Venous blood sample collected Complete blood count (CBC) and serum analyses

Prevalence of Genetic Hemoglobin Disorders

*underestimated due to incomplete data for α-thalassemias (trait, co-inherited)

Table 1: Prevalence of genetic hemoglobin disorders (n=450)

Hemoglobin n %

Normal hemoglobin AA 249 59%

Hemoglobin variant Any variant 171 41%*

Heterozygous E trait AE 99 24%

Homozygous E EE 31 7%

Constant spring CS 17 4%

β -thalassemia trait β 11 3%

Other - 13 3%

Micronutrients & Inflammation

Table 2: Micronutrients and inflammation characteristics (n=450)

Cut off n %

Ferritin1, iron stores deficiency <15 ug/L 13 2.8

sTfR, tissue iron deficiency >8.3 mg/L 84 18.7

Vitamin B12 <150 pmol/L 7 1.6

Folate <3 ng/mL 11 2.4

RBP1 (Vitamin A) <0.7 mmol/L 0 0

CRP (acute inflammation) >5 mg/L 39 8.7

AGP (chronic inflammation) >1 g/L 113 25.1

1Ferritin and RBP corrected for inflammation by methods proposed by Thurnham et al (Lancet 2003, AJCN 2010). sTfR, serum transferrin receptor; RBP, retinol binding protein; CRP, c-reactive protein; AGP, alpha-1 acid glycoprotein

Anemia

Table 3: Anemia (n=420 non-pregnant women)

n %

Anemia total, Hb <120 g/L

Mild anemia, >110 to <120 g/L Moderate anemia, 90-110 g/L Severe anemia, <90 g/L

Microcytic anemia, MCV <80 fL Normocytic anemia, MCV 80-95 fL Macrocytic, anemia, MCV >95 fL

124

85390

78451

29.5

69310

6336<1

MCV; mean corpuscular volume

Hemoglobin, Ferritin & sTfR by Hb Variant

Table 4: Hemoglobin, ferritin and sTfR by hemoglobin variant (n=420 non-pregnant women)

AA(No variant)

AEHeterozygous

(trait)

EEHomozygous

CSConstant

spring

Total, n (%) 249 (59%) 99 (24%) 31 (7.4%) 17 (4%)

Hb, g/L 128.1 ± 9.71 123.3 ± 9.32 108.5 ± 7.32 119.6 ± 8.22

Ferritin, ug/L 93.5 ± 54.8 88.5 ± 47.7 129.0 ± 90.62 93.8 ± 36.9

sTfR, mg/L 6.4 ± 1.9 6.8 ± 2.2 9.5 ± 3.62 9.6 ± 3.02

1Mean±SD. 2pairwise comparisons showed significant differences (p<0.0001) compared to women with a normal hemoglobin (AA)

Anemia & Iron Deficiency by Hb Variant

Table 5: Anemia and iron deficiency by hemoglobin variant (n=420 non-pregnant women)

Without Hb Variantn=249

With Hb Variant n=171

Anemia prevalence, Hb <120 g/L 15.3% 50.3%

Ferritin, Iron stores deficiency, <15 ug/L 2.8% 1.2%

sTfR, Tissue iron deficiency, >8.3 mg/L 11.2% 30.4%

IDA, Hb <120g/L & Ferritin <15 ug/L <1% <1%

IDA, Hb <120g/L & sTfR >8.3 mg/L <1% 7%

Conclusions

1. Genetic Hb disorders cannot be ignored in South East Asia; more than just assessment of Hb is required for anemia

2. More research is warranted on hemoglobin disorders and anemia; low-cost methods for testing for genetic disorders

3. No biochemical evidence of B12, folate or vitamin A deficiencies in Cambodian women in our study

4. Iron deficiency? Ferritin & sTfR likely confounded in those with Hb disorders. However, even in those with no Hb disorder, anemia is only 15% and IDA is <1%

Next Steps & Future Research

1. Complete PCR analysis for α-thalassemia analysis

2. Multivariate logistic regression

3. Investigate potential deficiency of riboflavin, B6 and zinc as contributors to anemia in this population (May survey)

4. Further investigation of potential iron sources in diet• Dietary intake of iron (24-hr recalls)• Assessment of ground well water for iron content• Iron supplementation trial

Acknowledgements

Dr. Angela DevlinDr. Susan BarrDr. Suzanne VercauterenHKI Cambodia research teamGreen-McLean lab