Serum Selenium Levels and Nutritional Status of School Children from an HIV Prevention Programme in Zimbabwe

Patience Kuona, et alMBChB, MMED Paeds(UZ)

PhD Fellow (UIO)

J Trop Dis, 2014; 2: 134. doi:10.4172/2329-891X.1000134

Declare no conflict of interest

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Outline

• Introduction and Background• Methodology• Results• Summary Discussion• Conclusion• Acknowledgements

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Introduction• Global estimates of

underweight children are showing declining trends but not in sub-Saharan Africa.

• 1990 24 million children

below 5 years were underweight

• Figure expected to increase to 43 million in 2015 in Sub-Saharan Africa(De Onis et al, 2004).

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Introduction

• Nutrition programmes in resource poor settings mainly focus on children under the age of five years

• This has resulted in limited information on nutritional and micronutrient status of school children in areas with high burden of HIV infection.

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Background

• Stunting and wasting remain important problems in school going children

• Levels of mild stunting as high as 75% in some areas in Africa(Chesire , 2008; Zerfu, 2006; Jinabhai, 2003)

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Background

• A paradox- persisting high prevalence of under nutrition co-existing with over nutrition in children between 5 and 14 years (Jafar, 2008).

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Background

• Malnutrition is associated with micronutrient deficiencies: – Vit A, – Iodine, – Zinc, – iron , – selenium etc

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Selenium

• Selenium essential element for human health(Rayman, 2000)– antioxidant – selenoproteins : thyroid

synthesis, reproductive function

– harmless viruses become virulent in selenium deficient host

– Deficiency increases mortality in HIV infected individuals

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Selenium

• Deficiency presents with symptoms common in our environment: heart disease, arthritis, cancer

• Knowing levels of selenium could influence policy on supplementation of this micronutrient in our environment with a high burden of infectious diseases and malnutrition

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Background

• Malnutrition leads to short and long term effects of great consequence to the individual affected and the society

• Malnutrition in school going children– interferes with their growth and development potential.– inhibits physical and mental growth– result in muscle weakness and reduced work capacity

• Improving school children’s nutrition will improve their

cognitive function and linear growth(Best et al,2010)

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AIM

• Assessed the prevalence of, and factors associated with – Stunting– Thinness– Overweight– Underweight – Selenium deficiency

in school aged children from a high HIV burden peri-urban area in Zimbabwe, a low income country.

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Methodology

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Design

• Cross sectional study

• Sub-study in the BHAMAC cohort

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Study site

• 3 peri-urbarn clinics around Harare capital city of Zimbabwe offering maternal and child health services – Epworth– St Mary’s– Seke north

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Study population: Children

• Followed from birth up to 7 to 10 years of age.

• Inclusion criteria: first sibling born in cohort at least 6 years of age.

• Exclusion criteria: Second Siblings to the original cohort

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Sample size

• Calculated using Raosoft calculator based on the following formula: /(se)2

• Minimum sample size required for estimating the prevalence of malnutrition: 208

• Nutritional status using anthropometry 318

• Assessed Selenium status 269

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Definition of terms

• Malnutrition: under or over nutrition.• Underweight –Weight for age Z score below -2

(WHO)• Stunting – height-for-age below Z-score -2 (WHO)• Thinness –BMI Z-score below -2 (WHO)• Overweight – BMI for age Z-score >1 but <2• Obesity – BMI for age Z-score≥2• Selenium deficiency : serum selenium level <

0.89µmol/L

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Definition of Terms

• HIV unexposed: HIV negative children born to and breastfed by HIV negative mothers

• HIV exposed: HIV negative children born to and/ or breastfed by HIV Elisa antibody positive mothers

• HIV infected: HIV Elisa antibody positive after 18 months or HIV DNA Polymerase Chain Reaction positive children

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Ethics

• Written informed consent and assent• Consent to store and ship specimens• Local board approval• MRCZ• RCZ• Norwegian REK

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Data collection and Laboratory methods

• Questionnaire• Anthropometric measurements and physical

examination• Blood collection• Selenium - Inductively coupled plasma mass

spectrometry

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Statistical Analysis

• Descriptive statistics and prevalence calculations to describe the data

• Correlation for continuous data• Chi square and fisher’s exact tests to

determine associations of categorical data• One-way Anova test and the Boniferroni post-

hoc test to compare means of continuous outcome variables according to the HIV status of the children.

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Results

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The demographic characteristics of school children from a PMTCT cohort aged 7-10 years

Characteristic Frequency (%)Gender Male Male 137 (43)Female Female 181 (57)HIV status* Negative unexposed 180(57) Negative exposed 116(36) Positive 21(7)Orphan hood Double orphan 15(5) Single orphan 79(25) Not orphaned 223(70)Household monthly income US$ median(Q1;Q3)

N=268 150 (80;250)

Total number of people in household median(Q1;Q3)

N=318 5 (4;6)

Number children below 10 years in household median (Q1;Q3)

N=316 2 (1;3)

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Prevalence of stunting, underweight, thinness, overweight and selenium deficiency among school children from a PMTCT

cohortCharacteristic Indicator Frequency n (%)

Stunting Height-for-age Z score < -2 37(12)

Height-for-age Z score < -3 7(2)

Underweight Weight-for-age Z score < -2 25(8)1

Weight-for-age Z score < -3 4(1)

Thinness BMI-for-age Z score < -2 11 (4)

BMI-for-age Z score < -3 3 (1)

Overweight BMI-for-age Z score ≥ 1 and < 2 15 (5)

Selenium deficiency Serum Selenium < 0.89 µmol / L 129 (48)2

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Results

• 37 stunted children, 16 (43%) also underweight for age

• No obese children• No overweight children were stunted• 2 of the stunted children also had thinness• HIV uninfected unexposed children were 7.5cm

taller than HIV infected children (p= 0.00)• HIV uninfected exposed children were 5.4cm

taller than the HIV infected children (p=0.00)

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Results

• There was no significant difference in mean weight of the HIV uninfected (unexposed and exposed) children

• HIV uninfected unexposed children 3.5kg heavier than the HIV infected children (p=0.00)

• HIV uninfected exposed children 2.7kg heavier than HIV infected (p=0.01)

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Results

• No difference in head circumference among all three groups of children.

• HUU and HUE children had MUAC size longer by 11 mm (p=0.01) respectively.

• No statistically significant difference in selenium levels among the three groups

Factors associated with stunting and selenium deficiency

• *p value < 0.05 **p value <0.001 a N=317 b N=269

Characteristic Frequency Stunting

n (%)

bSelenium

deficiency n(%)

Clinic

Epworth 104 14(13) 45(62) *

St mary`s 104 12(12) 40(41)

Seke north 110 11(10) 44(45)

Household income / month

≤$250 205 26(13) 96(54)*

> $250 63 6(10) 15(33)

HIV status

Negative Unexposed 180 12(7)** 63(43)

Negative Exposed 116 17(15) 53(52)

Positive 21 8(38) 13(62)

Orphan hood

Not orphaned 224 20(9)* 97(50)

Orphaned 94 17(18) 32(42)

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Summary• First study to assess selenium status of children in Zimbabwe

• Prevalence of selenium deficiency (48%) high in all the children despite their HIV infection status.

• Selenium levels in different regions influenced by the soil content of the element

[Hurst et al, 2013] • Stunting prevalence of 12% is of mild public health significance

• Very few children had severe acute malnutrition

• A quarter of children orphaned

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• Stunting was associated with HIV exposure or infection and orphan hood.

• Selenium deficiency more prevalent in children from households with very limited incomes

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Limitations

• Serum selenium: short term status but long term status is red cell selenium level

• Select population from a peri-urban setting and very few HIV infected children

• Smaller sample size of HIV infected children • Didn’t assess diet of the children: could have assisted

in answering the question why selenium and nutritional status were poor in this group of children.

• Assessment of nutritional status done only once; hence study design didn’t address causality

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Conclusion

• Chronic malnutrition and selenium deficiency were prevalent in this cohort of children above 5 years who were born in a national mother-to-child prevention of HIV transmission programme.

• Health programmes to detect malnutrition are needed in this setting with a high burden of HIV infection for children above 5 years.

• Further and larger studies that will include children from rural and urban areas are recommended so as ascertaining the selenium status of our population to guide the need for supplementation of selenium

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References

• Black, R.E., S.S. Morris, and J. Bryce, Where and why are 10 million children dying every year? Lancet, 2003. 361(9376): p. 2226-34.

• de Onis, M., et al., Estimates of global prevalence of childhood underweight in 1990 and 2015. JAMA, 2004. 291(21): p. 2600-6.

• Agency, Z.Z.N.S. and I. ICF, Zimbabwe Demographic and Health Survey 2010-11, 2012, ZIMSTAT and ICF International Inc.: Calverton, Maryland.

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Acknowledgements• Supervisors:

– Professor Babill Strey-Pedersen– Professor Kusum Nathoo– Dr M Munjoma

• Sponsors– Letten foundation

• Participants and their caregivers• Department of Paediatrics and

Child Health, UZ College of Health Sciences

• UZ-UCSF laboratory• Fürst Medisinky Laboratorium,

Norway

• The research team Grace Mashavave- Master’s

student Precious Chandiwana- nurse Mufarowashe Masanganise-

sociologist Phenias Mbabvu- Driver

• The Peer councillors• Seke north, St Mary’s and

Epworth clinics Staff