1. Epidemiology and Global Health
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Effects of water, sanitation, handwashing, and nutritional interventions on telomere length among children in a cluster-randomized controlled trial in rural Bangladesh

  1. Audrie Lin  Is a corresponding author
  2. Benjamin F Arnold
  3. Andrew N Mertens
  4. Jue Lin
  5. Jade Benjamin-Chung
  6. Shahjahan Ali
  7. Alan E Hubbard
  8. Christine P Stewart
  9. Abul K Shoab
  10. Md Ziaur Rahman
  11. Md Saheen Hossen
  12. Palash Mutsuddi
  13. Syeda L Famida
  14. Salma Akther
  15. Mahbubur Rahman
  16. Leanne Unicomb
  17. Firdaus S Dhabhar
  18. Lia C H Fernald
  19. John M Colford Jr
  20. Stephen P Luby
  1. University of California, Berkeley, United States
  2. University of California, San Francisco, United States
  3. International Centre for Diarrhoeal Disease Research, Bangladesh
  4. University of California, Davis, United States
  5. Miller School of Medicine, University of Miami, United States
  6. Stanford University, United States
Research Article
Cite this article as: eLife 2017;6:e29365 doi: 10.7554/eLife.29365
3 figures, 4 tables, 1 data set and 2 additional files

Figures

Flowchart of participants’ progress through the phases of the trial.
https://doi.org/10.7554/eLife.29365.003
Kernel density plots summarize the distribution of the telomere lengths (T/S ratios) among enrolled children.

In each panel, a dashed orange line illustrates the distribution of T/S ratio among control children and a solid blue line illustrates the distribution of T/S ratio among N+WSH intervention children. Even if a child was not present at Year 1, they were included in the analysis if they provided a sample at Year 2.

https://doi.org/10.7554/eLife.29365.009
Author response image 1

Tables

Table 1
Enrollment characteristics within the Control households and the N + WSH intervention households
https://doi.org/10.7554/eLife.29365.005
 Children measured at Year 1Children measured at Year 2
No. of children:Control (N=321)N+WSH Intervention (N=338)Control (N=330)N+WSH Intervention (N=380)
% / mean (SD)% / mean (SD)% / mean (SD)% / mean (SD)
Maternal
 Age (years)23 (5)24 (5)23 (5)24 (5)
 Years of education7 (3)6 (3)7 (3)6 (3)
Paternal
 Years of education5 (4)5 (4)6 (4)5 (4)
 Works in agriculture24%29%25%29%
Household 
 Number of persons5 (2)5 (2)5 (2)5 (2)
 Has electricity60%62%62%62%
 Has a cement floor16%12%15%13%
 Acres of agricultural land owned0 (0)0 (0)0 (0)0 (0)
Drinking Water 
 Shallow tubewell primary water source72%70%72%72%
 Stored water observed at home49%53%49%52%
 Reported treating water yesterday0%0%0%0%
 Distance (mins) to primary water source1 (1)1 (2)1 (1)1 (2)
Sanitation 
 Reported daily open defecation
  Adult men4%9%4%9%
  Adult women3%5%3%5%
  Children: 8-<15 years4%11%2%11%
  Children: 3-<8 years29%35%32%37%
  Children: 0-<3 years73%88%73%88%
 Latrine
  Owned62%52%59%52%
  Concrete slab97%93%96%94%
  Functional water seal38%31%38%31%
  Visible stool on slab or floor54%48%52%46%
 Owned a potty8%4%7%5%
 Human feces observed in the
  House6%7%5%9%
  Child’s play area1%1%1%2%
Handwashing 
 Within 6 steps of latrine
  Has water18%13%21%14%
  Has soap9%6%11%7%
 Within 6 steps of kitchen
  Has water11%10%11%11%
  Has soap3%3%5%4%
Nutrition 
  *Household is food secure74%72%73%72%
  1. Enrollment characteristics of households with children who had telomere measurements. Data are percentages of binary variables or mean (SD) of continuous variables. Percentages were estimated from slightly smaller denominators than those shown at the top of the table for the following variables due to missing values: mother’s age, father’s education, father works in agriculture, acres of land owned, open defecation, latrine has a concrete slab, latrine has a functional water seal, visible stool on latrine slab or floor, ownership of child potty, observed feces in the house or child’s play area, handwashing variables.

    *Assessed by the Household Food Insecurity Access Scale

Table 2
Balance of enrollment characteristics in the WASH Benefits main trial, telomere substudy children enrolled at Year 1, and telomere substudy children lost to follow-up at Year 2
https://doi.org/10.7554/eLife.29365.007
WASH Benefits Main TrialTelomere substudy: Had telomere outcomes at Year 1Telomere substudy: Lost to follow-up at Year 2 (from those who had telomere outcomes at Year 1)
No. of children:Control (N=1779)N+WSH Intervention (N=953)Control (N=321)Control (N=338)N+WSH Intervention (N=61)N+WSH Intervention (N=44)
% / mean (SD)% / mean (SD)% / mean (SD)% / mean (SD)% / mean (SD)% / mean (SD)
Maternal
 Age (years)24 (5)24 (6)23 (5)24 (5)23 (4)23 (5)
 Years of education6 (3)6 (3)7 (3)6 (3)7 (3)6 (4)
Paternal
 Years of education5 (4)5 (4)5 (4)5 (4)5 (4) 5 (4)
 Works in agriculture30%30%24%29%20% 18%
Household 
 Number of persons5 (2)5 (2)5 (2)5 (2)5 (3) 5 (2)
 Has electricity57%60%60%62%57% 61%
 Has a cement floor10%10%16%12%20% 7%
 Acres of agricultural land owned0.15 (0.21)0.14 (0.38)0 (0)0 (0)0 (0) 0 (0)
Drinking Water 
 Shallow tubewell primary water source75%73%72%70%77% 66%
 Stored water observed at home48%48%49%53%56% 57%
 Reported treating water yesterday0%0%0%0%0% 0%
 Distance (mins) to primary water source1 (1)1 (2)1 (1)1 (2)1 (1) 1 (1)
Sanitation 
 Reported daily open defecation
  Adult men7%7%4%9%3% 7%
  Adult women4%4%3%5%2% 2%
  Children: 8-<15 years10%10%4%11%8% 13%
  Children: 3-<8 years38%37%29%35%30% 32%
  Children: 0-<3 years82%88%73%88%73% 83%
 Latrine
  Owned54%53%62%52%67% 50%
  Concrete slab95%94%97%93%100% 98%
  Functional water seal31%27%38%31%46% 38%
  Visible stool on slab or floor48%46%54%48%64% 53%
 Owned a potty4%4%8%4%16% 2%
 Human feces observed in the
  House8%7%6%7%10% 5%
  Child’s play area2%1%1%1%2% 0%
Handwashing 
 Within 6 steps of latrine
  Has water14%11%18%13%18% 8%
  Has soap7%6%9%6%11% 8%
 Within 6 steps of kitchen
  Has water9%9%11%10%9% 5%
  Has soap3%3%3%3%0% 0%
Nutrition 
 *Household is food secure 67% 71% 74% 72% 75% 68%
  1. Data are percentages of binary variables or mean (SD) of continuous variables. Percentages were estimated from slightly smaller denominators than those shown at the top of the table for the following variables due to missing values: mother’s age, father’s education, father works in agriculture, acres of land owned, open defecation, latrine has a concrete slab, latrine has a functional water seal, visible stool on latrine slab or floor, ownership of child potty, observed feces in the house or child’s play area, handwashing variables.

    *Assessed by the Household Food Insecurity Access Scale

Table 3
Effect of intervention on telomere length (T/S ratio) after 1 and 2 years of N + WSH intervention and on change in telomere length between Year 1 and Year 2.
https://doi.org/10.7554/eLife.29365.011
ArmNMeanUnadjusted difference:
Intervention vs. Control
(95% CI)
Age- and sex- adjusted
difference: Intervention vs.
Control (95% CI)
Fully adjusted difference:
Intervention vs. Control
(95% CI)
Inverse probability of
censoring difference: Intervention
vs. Control (95% CI)
After 1 year of intervention (age ~ 14 months)
 Control3211.47
 N + WSH3411.40−0.07 (−0.11,–0.03) p=0.001*−0.06 (−0.10,–0.02) p=0.005*−0.05 (−0.10,0.01) p=0.099−0.07 (−0.11,–0.03) p=0.001*
After 2 years of intervention (age ~ 28 months)
 Control3301.46
 N + WSH3831.44−0.02 (−0.06,0.02) p=0.305−0.02 (−0.06,0.02) p=0.271−0.04 (−0.09,0.01) p=0.147−0.02 (−0.06,0.02) p=0.288
Change in telomere length between Year 1 and 2
 Control260−0.01
 N + WSH2970.030.04 (0.00,0.08) p=0.050*0.04 (−0.00,0.08) p=0.0730.04 (−0.01,0.09) p=0.0810.03 (−0.01,0.07) p=0.088
  1. *P<0.05

    Confidence intervals were adjusted for clustered observations using robust standard errors. Separate weights were created for the inverse probability weighting for each of the different analyses because the probability of missing at Year 1 was different than at Year 2.

  2. † Adjusted for pre-specified covariates associated with the outcome (likelihood ratio test p-value<0.2): Field staff who collected data, month of measurement, household food insecurity, child age, child sex, mother’s age, mother’s height, mother’s education level, number of children < 18 years in the household, number of individuals living in the compound, distance in minutes to the primary water source, household floor materials, household wall materials, household electricity, and household assets (wardrobe, table, chair, clock, khat, chouki, radio, television, refrigerator, bicycle, motorcycle, sewing machine, mobile phone, cattle, goats, and chickens).

Table 4
Subgroup analysis across sex of the effect of N + WSH intervention on telomere length (T/S ratio) after 1 and 2 years of intervention and on change in telomere length between Year 1 and Year 2
https://doi.org/10.7554/eLife.29365.013
ArmFemale childrenMale childrenFemale children Unadjusted difference: Intervention vs. Control (95% CI)Male children Unadjusted difference: Intervention vs. Control (95% CI)Interaction term sex by treatment (95% CI)
NMeanNMean
After 1 year of intervention (age ~ 14 months)
 Control1621.501591.43
 N + WSH1801.421611.37−0.08 (−0.13,–0.03) p=0.001*−0.06 (−0.11,–0.00) p=0.040*0.03 (−0.04,0.09) p=0.435
After 2 years of intervention (age ~ 28 months)
 Control1671.501631.42
 N + WSH2021.451811.42−0.05 (−0.10,0.01) p=0.0820.00 (−0.05,0.05) p=0.8770.05 (−0.01,0.12) p=0.105
Change in telomere length between Year 1 and 2
 Control134–0.01126−0.01
 N + WSH1600.031370.040.04 (−0.02,0.09) p=0.2270.05 (0.00,0.09) p=0.048*0.01 (−0.06,0.08) p=0.747
  1. *P<0.05

    Confidence intervals were adjusted for clustered observations using robust standard errors.

Data availability

The following data sets were generated
  1. 1
    WASH Benefits Bangladesh Analysis of Telomere Outcomes
    1. Lin A
    2. Mertens A
    (2017)
    Publicly available at the Open Science Framework (project no. evc98).

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