Publications based on Cohort & Cross-sectional Analysis
21960
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Boiled or Bottled: Regional and Seasonal Exposures to Drinking Water Contamination and Household Air Pollution in Rural China

Authors:  Cohen, A., Pillarisetti, A., Luo, Q., Zhang, Q., Li, H., Zhong, G., Zhu, G., Colford, J. M., Smith, K. R., Ray, I., & Tao, Y.

Publication Year:  2020  |  Journal / Publisher:  Environmental Health Perspectives

JOURNAL PUBLICATION

Abstract/Summary: We assessed the regional and seasonal prevalence of HWT practices (including bottled water use) in low-income rural areas in two Chinese provinces, evaluated the microbiological safety of drinking water and associated health outcomes, and estimated the air pollution burden associated with the use of solid fuels for boiling. Methods: We conducted cross-sectional surveys and collected drinking water samples from 1,033 rural households in Guangxi and Henan provinces. Temperature sensors affixed to pots and electric kettles were used to corroborate self-reported boiling frequencies and durations, which were used to model household air pollution (HAP) in terms of estimated particulate matter 2.5μm in aerodynamic diameter (PM2.5) concentrations. Results: Based on summer data collection in both provinces, after controlling for covariates, boiling with electric kettles was associated with the largest log reduction in thermotolerant coliforms (TTCs) (0.66log10 TTC most probable number/100mL), followed by boiling with pots (0.58), and bottled water use (0.39); all were statistically significant (p<0.001). Boiling with electric kettles was associated with a reduced risk of TTC contamination [risk ratio (RR)=0.25p<0.001] and reported diarrhea (RR=0.80p=0.672). TTCs were detected in 51% (n=136) of bottled water samples. For households boiling with biomass, modeled PM2.5 concentrations averaged 79μg/m3 (standard deviation=21). Discussion: Our findings suggest that where boiling is already common and electricity access is widespread, the promotion of electricity-based boiling may represent a pragmatic stop-gap means of expanding safe water access until centralized, or decentralized, treated drinking water is available; displacing biomass use for water boiling could also reduce HAP concentrations and exposures. Our results also highlight the risks of increasing bottled water use in rural areas, and its potential to displace other sources of safe drinking water, which could in turn hamper efforts in China and other LMICs toward universal and affordable safe water access.

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Intermittent water supply management, household adaptation, & drinking water quality: A comparative study in two Chinese provinces

Authors:  Li, H., Cohen, A., Li, Z., Lu, S., He, Z., Wang, L., & Zhang, X.

Publication Year:  2020  |  Journal / Publisher:  Water

JOURNAL PUBLICATION

Abstract/Summary: Intermittent water supply (IWS) is a relatively common phenomenon across the world as well as in rural and peri-urban areas across China, though there has been little IWS-focused research from China published to date. IWS consumers typically adopt a range of strategies to cope with insufficient water supply, poor drinking water quality, and associated inconveniences. In this study, we collected a range of data from small-scale utilities and households in two IWS systems and two continuous water supply (CWS) systems, as well as from comparison groups, in Shandong and Hubei provinces. Data collection included water quality testing, interviews, and surveys on behavioral adaptations, coping strategies, water-related health perceptions, and other metrics of consumer satisfaction. Overall, we found that the IWS coping strategies employed in northern China (Shandong) were associated with generally safe, but inconvenient, water access, whereas adaptation strategies observed in southern China (Hubei) appeared to improve convenience, but not water quality. Compared to the CWS comparison groups, we did not observe significant differences in waterand sanitation-related behaviors in the IWS groups, suggesting interventions to increase adaptive and protective behaviors at the household level might further improve safe water access for households living with IWS. Overall, although the water supply infrastructure in these study areas appeared to be in relatively good condition, in contrast to reported data on IWS systems in other countries, we observed multiple risk factors associated with the water treatment and distribution processes in these IWS systems. Among policy recommendations, our results suggest that the implementation of Water Safety Plans in China would likely improve the management of drinking water treatment and, by extension, safe drinking water supply under conditions of IWS.

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间歇式供水卫生风险及对农村家庭卫生行为影响的初步研究 [Intermittent water supply & associated impacts on drinking water & health-related behaviors in rural households]

Authors:  Li, Z., Wang, L., Cohen, A., Lu, S., He, Z., & Li, H.

Publication Year:  2019  |  Journal / Publisher:  环境与健康杂志 [Journal of Environmental & Health]

JOURNAL PUBLICATION

Abstract/Summary: Objective: To understand the potential health risks associated with intermittent water supply(IWS) in rural area of China generally,and to evaluate the impact of IWS on water and sanitation-related behaviors in rural households specifically. Methods: Two villages with IWS were selected as the study group,one in Shandong province and one in Hubei province,and two neighboring villages with similar socioeconomic conditions and continuous water supply(CWS) were selected as the controls. A total of 600 households were randomly selected in the IWS and CWS groups. From August to November,2017,trained investigators conducted structured interviews to collect a variety of data related to general information of the investigated families,infrastructure of household water and environment,water and sanitation -related behaviors,etc. Data on basic information and operational situation of local drinking water treatment plants was also collected. Results: The primary reported reason for IWS was to decrease the electricity costs associated with water treatment and supply. Insufficient water production and poor clean water storage capacity were also the reasons for IWS. Under conditions of IWS,water was usually supplied one or three times per day during the peak period of water consumption,such as morning,noon and evening. The average duration of water supply in the IWS areas ranged from four hours to 15 hours. Households in the IWS group were much more likely to have water storage facilities (97.0%,194/200) compared with those in the CWS group (47.0%,188/400). Compared with the CWS group,IWS households had worse measures of personal hygiene,indoor hygiene and household courtyard hygiene,and these differences were statistically significant (P<0.01). The main types of water storage devices used in IWS households were roof mounted water tanks,water buckets and ceramic water tanks. The percentages of roof -mounted water tanks without mark of qualified quality,household water storage containers without hygienic administrative license for drinking water -related products,clean roof -mounted water tanks and storage containers were 44.6% ,41.5% ,17.9% and 29.7% respectively. Conclusion: Compared with CWS,IWS in rural areas is strongly associated with changes in water-related health behaviors,and unsafe household water storage is the most prominent problem for health risks. Additional attention should be paid to the water safety of rural residents living under conditions of IWS.

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Fuel use trends for boiling water in rural China (1992-2012) & environmental health implications: A national cross-sectional study

Authors:  Du, W., Cohen, A., Shen, G., Ru, M., Shen, H., & Shu, T.

Publication Year:  2018  |  Journal / Publisher:  Environmental Science & Technology

JOURNAL PUBLICATION

Abstract/Summary:Survey data from a comprehensive national survey of ∼34 000 households were analyzed for the mix status and transition trajectory of energy for boiling water in rural Chinese households from 1992 to 2012. In 1992, ∼6% of households reported using electricity, biogas, or liquefied petroleum gas (LPG) to boil drinking water; in 2012, the proportion was ∼60%. Income per capita appeared most strongly associated with this transition toward electricity and other clean fuels. Median annual incomes for households using biomass fuels, electric kettles, and LPG were RMB 15 000, 28 000, and 30 000, respectively. Overall, the transition was most pronounced in eastern China, a region which experienced relatively higher rates of economic growth over the same 20-year period. Energy type preferences appear to be highly dependent on fuel accessibility such that coal and straw usage was higher in provinces with higher coal and grain production. These trends suggest that electric kettle use would likely increase from ∼29% (2012) to ∼60% by 2030, at which point <5% of rural households would be expected to boil with solid fuels. Recent evidence suggests that this transition could contribute to reductions in water-related gastrointestinal illness as well as reductions in air pollutant emissions in rural China.

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广西农村家庭饮水行为现状及影响因素分析 [Status & influential factors of drinking water behavior in rural households of Guangxi]

Authors:  Luo, Q., Cohen, A., Zhong, G., & Tao, Y.

Publication Year:  2018  |  Journal / Publisher:  Chinese Journal of Public Health

JOURNAL PUBLICATION

Abstract/Summary: Objective:  To examine the status and the related factors of drinking water behavior among households in rural areas of Guangxi Zhuang Autonomous Region (Guangxi) and to explore effective drinking water treatment methods other than water-boiling in rural households. Methods:  We conducted a face-to-face questionnaire survey among 450 households selected with multi-stage stratified random sampling in two counties of Guangxi between 2013 and 2014. We collected information  on  10  aspects  related  to  drinking  water  treatment.  We  adopted  multivariate  logistic  regression  to  analyze influencing factors of drinking water behavior among the households. Results:   Of all the households surveyed, 47.5 %, 35.0 %,and 17.5 % reported taking boiled, bottled, and unboiled water as drinking water, respectively. There was a significant difference in the proportion of households taking boiled water as drinking water (χ2 = 9.547, P = 0.002). Multivariate logistic regression analyses showed that the households with higher level of relevant knowledge (odds ratio [OR] = 0.290, 95 %confidence interval[95 %CI]:0.097 – 0.865), not discharging sewage at will (OR = 0.295, 95 %CI:0.112 – 0.776), without household water storage (OR = 0.059, 95%CI:0.013 – 0.269), and not preferring to drink boiled water (OR = 0.001, 95 %CI:0.000 – 0.005) were more unlikely to take boiled water as drinking water. Conclusion:   In rural areas of Guangxi, the proportion of households using electric kettle to boil water for drinking is not high and a number of households use fuel-based method to boil drinking water or drink bottled water; some households even drink unboiled water; the over standard rate of microbial indicators is relatively high for samples of the drinking water for the households.

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Predictors of drinking water boiling & bottled water consumption in rural China: A hierarchical modeling approach

Authors:  Cohen, A., Zhang, Q., Luo, Q., Tao, Y., Colford, J. M., & Ray, I.

Publication Year:  2017  |  Journal / Publisher:  Environmental Science & Technology

JOURNAL PUBLICATION

Abstract/Summary: Approximately two billion people drink unsafe water. Boiling is the most commonly used household water treatment (HWT) method globally and in China. HWT can make water safer, but sustained adoption is rare and bottled water consumption is growing. To successfully promote HWT, an understanding of associated socioeconomic factors is critical. We collected survey data and water samples from 450 rural households in Guangxi Province, China. Covariates were grouped into blocks to hierarchically construct modified Poisson models and estimate risk ratios (RR) associated with boiling methods, bottled water, and untreated water. Female-headed households were most likely to boil (RR = 1.36, p < 0.01), and among boilers those using electric kettles rather than pots had higher income proxies (e.g., per capita TV ownership RR = 1.42, p < 0.01). Higher-income households with younger, literate, and male heads were more likely to purchase (frequently contaminated) bottled water, or use electric kettles if they boiled. Our findings show that boiling is not an undifferentiated practice, but one with different methods of varying effectiveness, environmental impact, and adoption across socioeconomic strata. Our results can inform programs to promote safer and more efficient boiling using electric kettles, and suggest that if rural China’s economy continues to grow then bottled water use will increase.

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Microbiological evaluation of household drinking water treatment in rural China shows benefits of electric kettles: A cross-sectional study

Authors:  Cohen, A., Tao, Y., Luo, Q., Zhong, G., Romm, J., Colford, J. M., & Ray, I.

Publication Year:  2015  |  Journal / Publisher:  PLoS ONE

JOURNAL PUBLICATION

Abstract: Background – In rural China ~607 million people drink boiled water, yet little is known about prevailing household water treatment (HWT) methods or their effectiveness. Boiling, the most common HWT method globally, is microbiologically effective, but household air pollution (HAP) from burning solid fuels causes cardiovascular and respiratory disease, and black carbon emissions exacerbate climate change. Boiled water is also easily re-contaminated. Our study was designed to identify the HWT methods used in rural China and to evaluate their effectiveness. Methods – We used a geographically stratified cross-sectional design in rural Guangxi Province to collect survey data from 450 households in the summer of 2013. Household drinking water samples were collected and assayed for Thermotolerant Coliforms (TTC), and physicochemical analyses were conducted for village drinking water sources. In the winter of 2013–2104, we surveyed 120 additional households and used remote sensors to corroborate selfreported boiling data. Findings – Our HWT prevalence estimates were: 27.1% boiling with electric kettles, 20.3% boiling with pots, 34.4% purchasing bottled water, and 18.2% drinking untreated water (for these analyses we treated bottled water as a HWT method). Households using electric kettles had the lowest concentrations of TTC (73% lower than households drinking untreated water). Multilevel mixed-effects regression analyses showed that electric kettles were associated with the largest Log10TTC reduction (-0.60, p<0.001), followed by bottled water (-0.45, p<0.001) and pots (-0.44, p<0.01). Compared to households drinking untreated water, electric kettle users also had the lowest risk of having TTC detected in their drinking water (risk ratio, RR = 0.49, 0.34–0.70, p<0.001), followed by bottled water users (RR = 0.70, 0.53–0.93, p<0.05) and households boiling with pots (RR = 0.74, 0.54–1.02, p = 0.06). Conclusion: As far as we are aware, this is the first HWT-focused study in China, and the first to quantify the comparative advantage of boiling with electric kettles over pots. Our results suggest that electric kettles could be used to rapidly expand safe drinking water access and reduce HAP exposure in rural China.

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