Predictors of Early Infant Stunting in El Alto, Bolivia

Kaitlyn StanhopeMPH CandidateHubert Department of Global HealthRollins School of Public HealthEmory University

Photo credit: Matt Reichel

Presenter Disclosures: Kaitlyn Stanhope

The following personal financial relationships with commercial interests relevant to this presentation existed during the past 12 months:• No relationships to disclose

Outline

• Introduction• Methods• Results• Discussion• Conclusion• Acknowledgements

Background

• Globally, infant malnutrition is estimated to account for 45% of deaths in children under-5 years of age.1

• Stunting in infancy results in long-term adverse effects such as impaired cognitive function and increased risk of chronic disease

• Data on determinants of stunting is scarce in Andean Latin America and Bolivia

Background: El Alto, Bolivia

• High levels of poverty• 15.6% of Bolivians live on less than $1.25 a day2

• High levels of infant malnutrition• 9.4% of Bolivian infants (<5 months) are moderately or

severely stunted (<-2 LAZ)3

• El Alto is a large, urban indigenous city outside La Paz

Source: http://commons.wikimedia.org/wiki/File:El_Alto,_Bolivia_(4127372958).jpg

Key DefinitionsLow Birthweight: • Weighing less than 2500 grams at birth regardless of

gestational age (<2500 g ).

Pre-term Birth: • Birth before 37 weeks of gestation • Measured using last menstrual period, <37 weeks

Small for Gestational Age (SGA): • Weight less than the tenth percentile for gestational age

defined with Peru as a reference population4 • Proxy for intrauterine growth restriction (<10th%)

Stunted: • Chronic malnutrition • Measured along a standard international scale • Two or more standard deviations below the length

mean for age is considered stunted (<-2 LAZ ).

Exclusive Breastfeeding: • Giving an infant no nutrient or liquid other than breast

milk.

Image credits, top to bottom: 1. Trei Brundrett, via Wiki Commons, License at: http://creativecommons.org/licenses/by-sa/2.0/deed.en 2. Zerbey, via Wiki Commons, License at: http://commons.wikimedia.org/wiki/Commons:GNU_Free_Documentation_License3. Dogra et al., via Medscape: http://emedicine.medscape.com/article/404098-overview4. Alejandro Amabar Mamai, via El Riqueno: http://www.elariquenio.com/2012/10/12/iquique-el-16-y-17-de-octubre-se-realizara-jornada-de-actualizacion-sobre-la-lactancia-materna/5. UNICEF, via: http://www.thousanddays.org/author/unicef/

 

Goal

The objective of this study was to identify infant and perinatal characteristics associated with moderate-to-severe stunting (LAZ <-2) among Bolivian children in early infancy (<4 months)

Photo credit: Paulina Rebolledo

Outline

• Introduction• Methods• Results• Discussion• Conclusion• Acknowledgements

Data Collection

• 274 mother-infant pairs • Recruited through well-child visits June-October 2011• Convenience sample• Data collected at two visits (4-6 weeks apart)

• Clinical & perinatal characteristics • Infant weight & length • Maternal weight, height • Baseline socio-economic

Women in waiting room of Bolivian hospital Photo credit: Paulina Rebolledo

Is your child less than one month old?

Are you at least 18 years old?

Do you have a history of acute illness?

Has your baby been hospitalized in the past 7 days?

Does your child have a history of congenital malformation or

immunosuppression?

Eligible

Not eligible

Inclusion and Exclusion Criteria

Analysis

• Multivariable logistic regression• Tested for collinearity

• Exposures of interest: • Breastfeeding • Preterm birth• Small-for-gestational age• Inter-birth spacing• Birth weight

• Confounders • Male sex• Infant Age

Conceptual Framework

Distal Factors: • Short stature• BMI• SES

Intermediate Factors:

• Infant Birthweight

• SGA • Pre-term • Antenatal

care• Parity • Interbirth

spacing

Proximate Factors:

• Feeding practices Outcome:

Stunting

Confounders: infant age, sex

Outline

• Introduction• Methods• Results• Discussion• Conclusion• Acknowledgements

Overlaps in Populations of Stunted, Preterm and SGA Infants

Stuntedn=76

SGA n=37

Pre-term n=41

Pre-Term n=21SGA n=18

Pre-Term and Stunted n=20Stunted n=41

Stunted and SGA n=19

Pre-Term, Stunted and SGA n=4

High Prevalence of Early Infant Stunting (N=264)

Exclusive breastfeeding

Male sex

Stunting (LAZ < -2)

Preterm birth

Small for gestational age

Low birthweight

0 10 20 30 40 50 60 70 80 90 100

Percent

High Prevalence of Overweight and Obesity among Mothers(N=264)

Routine antenatal care

Crowding

Overweight or obese (BMI >25)

Short Inter-birth spacing

Short stature (<145 cm)

0 10 20 30 40 50 60 70 80 90 100

Percent

Perinatal Characteristics Associated with Stunting (N=185)

  Bivariate Analysis Multivariable Analysis*  OR

(95% CI)p-

ValueOR

(95% CI)p-

Value Perinatal Characteristics        Preterm birth (<37 weeks)Small-for-gestational age (<10th weight percentile)

5.69 (2.32-13.92)4.22 (1.67-10.62)

<0.0010.002

4.17 (1.04-16.70)3.95 (1.16-13.50)

0.0400.028

Parity 1 birth 2-4 births 5 or more births Inter-birth spacing < 24 monthsAntenatal Care

 0.68 (0.30-1.54)

1.000.63 (0.07-5.52)3.52 (1.43-8.66)

0.41 (0.10-1.68)

 0.36

 0.68

0.006

0.21

 ------

6.74 (1.76-25.77)--

 ------

0.005--

*Controlling for infant age, SGA, Inter-birth spacing, male sex, low birthweight, in multivariable analysis.

Infant Characteristics Associated with Stunting (N=185)

  Bivariate Analysis Multivariable Analysis*  OR

(95% CI)p-

ValueOR

(95% CI)p-

Value Infant Characteristics        MaleAge in weeks at 1st visit

1.23 (0.56-2.73)0.96 (0.86-1.08)

0.610.52

1.57 (0.55-4.49)--

0.400--

Low Birthweight 28.63 (7.17-114.31) <0.001 12.74 (2.05-79.08) 0.006

Exclusive Breastfeeding 0.42 (0.19-0.93) 0.03 0.22 (0.07-0.70) 0.010

         

*Controlling for infant age, SGA, Inter-birth spacing, male sex, low birthweight, in multivariable analysis.

Outline

• Introduction• Methods• Results• Discussion• Conclusion• Acknowledgements

Discussion

• Strengths: • Data from early infancy• Unique population

• Limitations:• Small sample size (prevented stratification of small

gestational age)• Only 2 time points• Convenience sample

• Future Directions• Longitudinal study throughout first year of life • Further measurement of socio-demographic factors

Conclusions

• In Bolivia, the prevalence of stunting is high in early infancy and early interventions are key

• Interventions to prevent SGA and pre-term birth are important to prevent infant stunting

• Birth spacing and exclusive breast feeding is also important to preventing stunting in Bolivian infants

Photo credit: Matt Reichel

Acknowledgments

• Study participants and their families• All study collaborators• Dedicated study staff in El Alto, Bolivia

References

1. Black, R. E., L. H. Allen, et al. (2008). "Maternal and child undernutrition: global and regional exposures and health consequences." Lancet 371(9608): 243-260.

2. The World Bank Group. (2014). Poverty. Retrieved September 2014, from The World Bank

3. Coa, R. O., Luis H. (2009). Bolivia-- Encuesta Nacional de Demografia y Salud 2008. DHS Final Reports. M. DHS. Calverton, Maryland, USA, Macro International Inc.

4. Mikolajczyk RT, Zhang J, Betran AP, et al. A global reference for fetal-weight and birthweight percentiles. The Lancet 2011; 377: 1855-61