Upgrading a Piped Water Supply from Intermittent to Continuous Delivery and Association with Waterborne Illness: A Matched Cohort Study in Urban India

English version České info

Background:
Intermittent delivery of piped water can lead to waterborne illness through contamination in the pipelines or during household storage, use of unsafe water sources during intermittencies, and limited water availability for hygiene. We assessed the association between continuous versus intermittent water supply and waterborne diseases, child mortality, and weight for age in Hubli-Dharwad, India.

Methods and Findings:
We conducted a matched cohort study with multivariate matching to identify intermittent and continuous supply areas with comparable characteristics in Hubli-Dharwad. We followed 3,922 households in 16 neighborhoods with children <5 y old, with four longitudinal visits over 15 mo (Nov 2010–Feb 2012) to record caregiver-reported health outcomes (diarrhea, highly credible gastrointestinal illness, bloody diarrhea, typhoid fever, cholera, hepatitis, and deaths of children <2 y old) and, at the final visit, to measure weight for age for children <5 y old. We also collected caregiver-reported data on negative control outcomes (cough/cold and scrapes/bruises) to assess potential bias from residual confounding or differential measurement error.

Continuous supply had no significant overall association with diarrhea (prevalence ratio [PR] = 0.93, 95% confidence interval [CI]: 0.83–1.04, p = 0.19), bloody diarrhea (PR = 0.78, 95% CI: 0.60–1.01, p = 0.06), or weight-for-age z-scores (Δz = 0.01, 95% CI: −0.07–0.09, p = 0.79) in children <5 y old. In prespecified subgroup analyses by socioeconomic status, children <5 y old in lower-income continuous supply households had 37% lower prevalence of bloody diarrhea (PR = 0.63, 95% CI: 0.46–0.87, p-value for interaction = 0.03) than lower-income intermittent supply households; in higher-income households, there was no significant association between continuous versus intermittent supply and child diarrheal illnesses. Continuous supply areas also had 42% fewer households with ≥1 reported case of typhoid fever (cumulative incidence ratio [CIR] = 0.58, 95% CI: 0.41–0.78, p = 0.001) than intermittent supply areas. There was no significant association with hepatitis, cholera, or mortality of children <2 y old; however, our results were indicative of lower mortality of children <2 y old (CIR = 0.51, 95% CI: 0.22–1.07, p = 0.10) in continuous supply areas. The major limitations of our study were the potential for unmeasured confounding given the observational design and measurement bias from differential reporting of health symptoms given the nonblinded treatment. However, there was no significant difference in the prevalence of the negative control outcomes between study groups that would suggest undetected confounding or measurement bias.

Conclusions:
Continuous water supply had no significant overall association with diarrheal disease or ponderal growth in children <5 y old in Hubli-Dharwad; this might be due to point-of-use water contamination from continuing household storage and exposure to diarrheagenic pathogens through nonwaterborne routes. Continuous supply was associated with lower prevalence of dysentery in children in low-income households and lower typhoid fever incidence, suggesting that intermittently operated piped water systems are a significant transmission mechanism for Salmonella typhi and dysentery-causing pathogens in this urban population, despite centralized water treatment. Continuous supply was associated with reduced transmission, especially in the poorer higher-risk segments of the population.

Vyšlo v časopise: Upgrading a Piped Water Supply from Intermittent to Continuous Delivery and Association with Waterborne Illness: A Matched Cohort Study in Urban India. PLoS Med 12(10): e32767. doi:10.1371/journal.pmed.1001892
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pmed.1001892

Souhrn

Zdroje

1. Bain R, Cronk R, Wright J, Yang H, Slaymaker T, Bartram J. Fecal Contamination of Drinking-Water in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis. Hunter PR, editor. PLoS Med. 2014;11: e1001644. doi: 10.1371/journal.pmed.1001644 24800926

2. Van den Berg C, Danilenko A. The IBNET Water Supply and Sanitation Performance Blue Book: The International Benchmarking Network for Water and Sanitation Utilities Databook. Washington DC: World Bank; 2011.

3. Huang LY, Wang YC, Liu CM, Wu TN, Chou CH, Sung FC, et al. Water outage increases the risk of gastroenteritis and eyes and skin diseases. BMC Public Health. 2011;11: 726. doi: 10.1186/1471-2458-11-726 21943080

4. Hunter PR, Chalmers RM, Hughes S, Syed Q. Self-reported diarrhea in a control group: a strong association with reporting of low-pressure events in tap water. Clin Infect Dis. 2005;40: e32–e34. 15712068

5. Nygard K, Wahl E, Krogh T, Tveit OA, Bøhleng E, Tverdal A, et al. Breaks and maintenance work in the water distribution systems and gastrointestinal illness: a cohort study. Int J Epidemiol. 2007;36: 873–880. 17389718

6. Özkan S, Tüzün H, Görer N, Ceyhan M, Aycan S, Albayrak S, et al. Water usage habits and the incidence of diarrhea in rural Ankara, Turkey. Trans R Soc Trop Med Hyg. 2007;101: 1131–1135. 17681361

7. Abu Mourad TA. Palestinian refugee conditions associated with intestinal parasites and diarrhoea: Nuseirat refugee camp as a case study. Public Health. 2004;118: 131–142. 15037044

8. Cifuentes E, Suárez L, Solano M, Santos R. Diarrheal diseases in children from a water reclamation site in Mexico city. Environ Health Perspect. 2002;110: A619–A624. 12361943

9. Abu Amr SS, Yassin MM. Microbial contamination of the drinking water distribution system and its impact on human health in Khan Yunis Governorate, Gaza Strip: seven years of monitoring (2000–2006). Public Health. 2008;122: 1275–1283. doi: 10.1016/j.puhe.2008.02.009 18539305

10. Yassin MM, Amr SSA, Al-Najar HM. Assessment of microbiological water quality and its relation to human health in Gaza Governorate, Gaza Strip. Public Health. 2006;120: 1177–1187. 17034823

11. Ercumen A, Gruber JS, Colford JM. Water distribution system deficiencies and gastrointestinal illness: a systematic review and meta-analysis. Environ Health Perspect. 2014;122: 651–660. doi: 10.1289/ehp.1306912 24659576

12. Arnold BF, Khush RS, Ramaswamy P, London AG, Rajkumar P, Ramaprabha P, et al. Causal inference methods to study nonrandomized, preexisting development interventions. Proc Natl Acad Sci. 2010;107: 22605–22610. doi: 10.1073/pnas.1008944107 21149699

13. Ho DE, Imai K, King G, Stuart EA. Matching as nonparametric preprocessing for reducing model dependence in parametric causal inference. Polit Anal. 2007;15: 199–236.

14. Registrar General of India. Census of India 2011: Karnataka: Dharwad District. Technical Report. New Delhi: Registrar General of India; 2011.

15. Kumpel E, Nelson KL. Comparing Microbial Water Quality in an Intermittent and Continuous Piped Water Supply. Water Res. 2013;47: 5176–5188. doi: 10.1016/j.watres.2013.05.058 23866140

16. Sangameswaran P, Madhav R, D’Rozario C. 24/7,’Privatisation’and Water Reform: Insights from Hubli-Dharwad. Econ Polit Wkly. 2008; 60–67.

17. Diamond A, Sekhon JS. Genetic matching for estimating causal effects: A general multivariate matching method for achieving balance in observational studies. Rev Econ Stat. 2013;95: 932–945.

18. Center for Multi-Disciplinary Development Research (CMDR). Socio-economic survey of Hubli-Dharwad city. [Internet]. Dharwad, India: CMDR (Center for Multi-Disciplinary Development Research); 2006. www.cmdr.ac.in

19. Colford JM Jr, Rees JR, Wade TJ, Khalakdina A, Hilton JF, Ergas IJ, et al. Participant blinding and gastrointestinal illness in a randomized, controlled trial of an in-home drinking water intervention. Emerg Infect Dis. 2002;8: 29–36. 11749745

20. Lipsitch M, Tchetgen E, Cohen T. Negative controls: A tool for detecting confounding and bias in observational studies. Epidemiol Camb Mass. 2010;21: 383–388.

21. Cogill B. Anthropometric indicators measurement guide. Food and Nutritional Technical Assistance Project, Academy for Educational Development. Washington DC.; 2003.

22. Katz J, Carey VJ, Zeger SL, Sommer A. Estimation of design effects and diarrhea clustering within households and villages. Am J Epidemiol. 1993;138: 994–1006. 8256785

23. Feng Z, Diehr P, Peterson A, McLerran D. Selected statistical issues in group randomized trials. Annu Rev Public Health. 2001;22: 167–187. 11274517

24. Rosenbaum PR. Covariance adjustment in randomized experiments and observational studies. Stat Sci. 2002;17: 286–327.

25. Vyas S, Kumaranayake L. Constructing socio-economic status indices: how to use principal components analysis. Health Policy Plan. 2006;21: 459. 17030551

26. Wood AM, White IR, Thompson SG. Are missing outcome data adequately handled? A review of published randomized controlled trials in major medical journals. Clin Trials. 2004;1: 368–376. 16279275

27. Hernán MA, Hernández-Díaz S, Robins JM. A Structural Approach to Selection Bias: Epidemiology. 2004;15: 615–625. 15308962

28. Austin PC. Using the Standardized Difference to Compare the Prevalence of a Binary Variable Between Two Groups in Observational Research. Commun Stat—Simul Comput. 2009;38: 1228–1234.

29. WHO. Guidelines for drinking-water quality. 4th edition. Geneva: World Health Organization; 2011.

30. Gleick PH. Basic Water Requirements for Human Activities: Meeting Basic Needs. Water Int. 1996;21: 83–92.

31. Kumpel E. Water Quality and Quantity in Intermittent and Continuous Piped Water Supplies in Hubli-Dharwad, India. Doctoral Dissertation, University of California, Berkeley. 2013.

32. Burt Z, Ray I. Storage and Non-Payment: Persistent Informalities within the Formal Water Supply of Hubli-Dharwad, India. Water Altern. 2014;7: 106–120.

33. Wright J, Gundry S, Conroy R. Household drinking water in developing countries: a systematic review of microbiological contamination between source and point-of-use. Trop Med Int Health. 2004;9: 106–117. 14728614

34. Cutler D, Miller G. The role of public health improvements in health advances: The twentieth-century United States. Demography. 2005;42: 1–22. 15782893

35. Baker S, Holt KE, Clements ACA, Karkey A, Arjyal A, Boni MF, et al. Combined high-resolution genotyping and geospatial analysis reveals modes of endemic urban typhoid fever transmission. Open Biol. 2011;1: 110008. doi: 10.1098/rsob.110008 22645647

36. Mermin JH, Villar R, Carpenter J, Roberts L, Samaridden A, Gasanova L, et al. A massive epidemic of multidrug-resistant typhoid fever in Tajikistan associated with consumption of municipal water. J Infect Dis. 1999;179: 1416–1422. 10228063

37. Lewis MD, Serichantalergs O, Pitarangsi C, Chuanak N, Mason CJ, Regmi LR, et al. Typhoid Fever: A Massive, Single-Point Source, Multidrug-Resistant Outbreak in Nepal. Clin Infect Dis. 2005;40: 554–561. 15712078

38. Ram PK, Naheed A, Brooks WA, Hossain MA, Mintz ED, Breiman RF, et al. Risk factors for typhoid fever in a slum in Dhaka, Bangladesh. Epidemiol Infect. 2007;135: 458–465. 16893490

39. Breiman RF, Cosmas L, Njuguna H, Audi A, Olack B, Ochieng JB, et al. Population-Based Incidence of Typhoid Fever in an Urban Informal Settlement and a Rural Area in Kenya: Implications for Typhoid Vaccine Use in Africa. PLoS ONE. 2012;7: e29119. doi: 10.1371/journal.pone.0029119 22276105

40. Cairncross S, Feachem R. Environmental Health Engineering in the Tropics. West Sussex, England: John Wiley & Sons; 1999.

41. Kirmeyer GJ, Friedman M, Martel K, Howie D, LeChevallier M, Abbaszadegan M, et al. Pathogen Intrusion into the Distribution System. Denver, CO: AWWARF; 2001.

42. Wood L, Egger M, Gluud LL, Schulz KF, Jüni P, Altman DG, et al. Empirical evidence of bias in treatment effect estimates in controlled trials with different interventions and outcomes: meta-epidemiological study. Bmj. 2008;336: 601–605. doi: 10.1136/bmj.39465.451748.AD 18316340

43. Fewtrell L, Kaufmann RB, Kay D, Enanoria W, Haller L, Colford JM, et al. Water, sanitation, and hygiene interventions to reduce diarrhoea in less developed countries: a systematic review and meta-analysis. Lancet Infect Dis. 2005;5: 42–52. 15620560

44. Arnold BF, Colford JM. Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: a systematic review and meta-analysis. Am J Trop Med Hyg. 2007;76: 354–364. 17297049

45. Gerba CP, Rose JB, Haas CN. Sensitive populations: who is at the greatest risk? Int J Food Microbiol. 1996;30: 113–123. 8856378

46. Totsuka N, Trifunovic N, Vairavamoorthy K. Intermittent urban water supply under water starving situations. Manuscript prepared for the 30th WEDC international conference on people centered approaches to water and environmental sanitation. 2004.

47. Andey SP, Kelkar PS. Influence of Intermittent and Continuous Modes of Water Supply on Domestic Water Consumption. Water Resour Manag. 2009;23: 2555–2566.

48. Bradley RM, Weeraratne S, Mediwake TM. International issues-Water use projections in developing countries-Careful evaluation of actual water use patterns is critical to planning efficient and well-used water delivery systems in. Am Water Works Assoc J. 2002;94: 52–63.

49. Lee EJ, Schwab KJ. Deficiencies in drinking water distribution systems in developing countries. J Water Health. 2005;3: 109–127. 16075938