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The improvement of obsolete latrine pits in rural areas of China was proposed as early as 1960s, and campaigns were discussed in 2015 to prioritize the the improvements of latrines across the country (1）. By 2015, the Chinese government announced that farmers and other rural residents needed access to sanitary latrines and subsequently launched the Latrine Revolution in rural areas (2). Following these comments, China has been promoting the Latrine Revolution meant to continuously improve sanitary latrines that have played important roles in improving rural living conditions, decreasing the rates of fecal-oral transmitted diseases, and further progressing the civilizing of society goals. There were six different sanitary latrine types promoted in rural household to improve the disposal of feces. The coverage of sanitary latrines in rural communities rose from 55.0% in 2006 to 81.8% in 2017 and were accompanied by sharp drops in the rates of diarrheal diseases and soil-transmitted helminths (STH). A correlation analysis was conducted using data on the improving coverage of sanitary latrines and indicators of STH and diarrheal diseases caused by unsafe sanitation in China during 2006 and 2017. The human capital approach was also applied to calculate the reduction of indirect economic burden (IEB) associated with unsafe sanitation during 2006 and 2017. Both the prevalence of STH infections (R2 = 0.94) and mortality of diarrheal diseases (R2=0.95) due to unsafe or poor sanitation had negative correlations to increased coverage of sanitary latrines. Furthermore, in 2017, an estimated 7.60 billion CNY (1.12 billion USD in 2017) was saved in 2017 compared to 2006. This suggested that the increased coverage of these sanitary latrines significantly contributed to reducing intestinal infectious diseases and other related disease burdens, so continuing the Latrine Revolution should be a top priority and combined with health education and promotion to target affected populations.
In developing countries, controlling diseases related to sanitation facilities are vital to maintaining public health especially as fecal-oral disease burdens remain significant. In low- and middle-income countries in Southeast Asia, the lack of sanitation accounted for approximately 29% of the burden of diarrheal diseases (3). In 1993 in China, sanitary latrine coverage in rural China was only 7.5% and fecal-oral transmission of diseases accounted for more than 70% of infectious disease incidence as there were 490 million people infected with Ascaris, 200 million with hookworm, more than 1.13 million with schistosomiasis (4). Sanitation interventions and improvements are directly related to the protection of public health (5). This study aims at describing the health impacts from the Latrine Revolution on intestinal infectious diseases, especially diarrheal diseases, during 2006 and 2017.
Coverage of sanitary latrines in rural areas was extracted from the China Health Statistical Yearbook (6). The prevalence of STH infection was extracted from the National Surveillance System for Key Infectious Diseases and Vectors (7). Mortality and burden of diarrheal diseases attributed to unsafe sanitation were extracted from the Global Burden of Disease Study 2017 (GBD 2017) (8). Indicators of disease burden include disability-adjusted life years (DALYs), years of life lost (YLLs), and years lived with disability (YLD). The human capital approach (9) was applied to measure IEB, and gross domestic product (GDP) per capita was collected from the China Health Planning Statistical Yearbook 2018 (6).Correlation analysis was adopted to examine the correlation of the coverage of sanitary latrines and indicators of diarrheal diseases due to unsafe sanitation and STH. Human capital approach was applied to measure indirect economic burden (IEB) using the following formula.
$${\rm{IEB}} = \sum\limits_{i = 1}^n {DAL{Y_i} \times {W_i} \times GDP\;per\;capita} $$ (1) In formula (1), IEB was the sum of products of age-specified DALYi, Wi, and GDP per capita. DALYi is DALY in age group i . Wi is weights of productivity in age group i. GDP per capita in 2017 was used in IEB in 2006 and 2017.
During the period between 2006 and 2017, the coverage of sanitary latrines in rural areas of China increased from 55.0% to 81.8%, while deaths from diarrheal diseases attributable to unsafe sanitation decreased from 0.58/100,000 population to 0.17/100,000, and prevalence of STH infection from 20.88/100,000 reduced to 1.78/100,000 (Table 1). The result showed that the coverage of sanitary latrines in rural China was negatively correlated with both the mortality of diarrheal diseases attributable to unsafe sanitation (R2=0.94) and the prevalence of STH (R2=0.95). Moreover, both the infection rate of STH and the mortality rate of diarrheal diseases have decreased significantly alongside increasing coverage of sanitary latrines in rural China during the period from 2006 to 2017.
Year Coverage of sanitary latrines (%)* Mortality of diarrheal diseases attributable to unsafe sanitation
(per 100,000)†Prevalence of
STH infection
(per 100,000)§2006 55.0 0.58 20.88 2007 57.0 0.48 18.93 2008 59.7 0.41 16.59 2009 63.2 0.36 13.30 2010 67.4 0.31 11.25 2011 69.2 0.27 9.67 2012 71.7 0.24 6.90 2013 74.1 0.22 3.12 2014 76.1 0.20 4.49 2015 78.4 0.19 4.95 2016 80.4 0.18 −¶ 2017 81.8 0.17 1.78 * Data Source: China Health and Family Plan Statistical Yearbook (5).
† Data Source: Global Burden of Disease Study 2017 (GBD 2017) Results (7).
§ Data Source: National Surveillance System of Key Infectious Diseases and Vectors (6).
¶ Not available.Table 1. Coverage of sanitary latrines in Rural Areas, mortality of diarrheal diseases attributable to unsafe sanitation, and prevalence of soil-transmitted helminths (STH) infection — China, 2006−2017.
The number of deaths from diarrheal diseases attributable to unsafe sanitation decreased by 68.95% from an estimated 7,748.05 in 2006 to 2,405.46 in 2017. In the year 2017, DALYs (845,966.23 vs. 346,274.02, −59.07%), YLLs (531,449.12 vs. 115,418.89, −78.28%), and YLDs (314,517.12 vs. 230,855.13, −26.60%) of diarrheal diseases attributable to unsafe sanitation significantly decreased compared with those in 2006. Decreases in DALYs and YLLs were mainly found in children under 5 years old, and decreases in YLDs were mainly found in individuals over 5 years old (Table 2).
Item 2006 2017 Change Mortality 7,748.05 2,405.46 −5,342.59 −68.95% Mortality rate, per 100,000 Under 5 years 7.36 1.13 −6.23 −84.65% <1 year 30.78 4.20 −26.58 −86.35% 1 to 4 years 1.59 0.22 −1.37 −86.16% DALYs (person years) 845,966.23 346,274.02 −499,692.21 −59.07% Age-Standardized DALY rate, per 100,000 100.99 31.38 −69.61 −68.93% DALY rate, per 100,000 Under 5 years 731.65 185.00 −546.65 −74.71% <1 year 2,869.32 501.27 −2,368.05 −82.53% 1 to 4 years 205.55 91.01 −114.54 −55.72% YLLs (person years) 531,449.12 115,418.89 −416,030.23 −78.28% Age-Standardized YLL rate, per 100,000 72.49 11.58 −60.91 −84.03% YLL rate, per 100,000 Under 5 years 640.76 98.68 −542.08 −84.60% <1 year 2,691.17 367.48 −2,323.69 −86.34% 1 to 4 years 136.13 18.79 −117.34 −86.20% YLDs (person years) 314,517.12 230,855.13 −83,661.99 −26.60% Age-Standardized YLD rate, per 100,000 28.50 19.79 −8.71 −30.56% YLD rate, per 100,000 Under 5 years 90.89 86.33 −4.56 −5.02% <1 year 178.15 133.79 −44.36 −24.90% 1 to 4 years 69.42 72.22 2.80 4.03% * Data source: Global Burden of Disease Study 2017 (GBD 2017) results.
Abbreviations: DALYs=disability-adjusted life years, YLLs=years of life lost, YLD=years lived with disability.Table 2. Burden of diarrheal diseases attributable to unsafe sanitation — China, 2006−2017 *.
In addition, the human capital approach suggested that the weighted DALYs in 2017 decreased by 127,376.11 person-years compared with 2006, which was equivalent to a reduction of 7.60 billion CNY (1.12 billion USD in 2017) in IEB (Table 3).
Age group(years) Wi 2006 2017 DALYi* (person years) IEB† (100,000 CNY) DALYi* (person years) IEB† (100,000 CNY) ≥ 0 0.15 88,682.45 52,907.95 27,096.68 16,165.88 ≥ 15 0.75 91,918.96 54,838.85 36,219.17 21,608.36 ≥ 45 0.8 41,354.20 24,671.92 31,498.47 18,791.99 ≥ 60 0.1 8,049.85 4,802.54 7,815.03 4,662.45 Total 230,005.47 137,221.26 102,629.36 61,228.67 Note: Wi means the weights of productivity in age group.
* DALYi was collected from Global Burden of Disease Study 2017 (GBD 2017) results (7).
† GDP per capita in 2017 was used in IEB both 2006 and 2017, in order to avoid the impact of economic development.
Abbreviations: DALY=disability-adjusted life year, IEB=indirect economic burden.Table 3. The age-specified indirect economic burden of diarrheal diseases attributable to unsafe sanitation — China, 2006−2017.
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The findings showed that there were decreases in the mortality rate and burden of diarrheal diseases in relation to the use of unsafe sanitation facilities (mainly rural household latrines) in China during the period between 2006 and 2017. However, among children aged 1−4 years old, the YLD rate was 4.03% higher in 2017 than in 2006. It is indicated that it is worthy to promote the latrine revolution continuously due to its many health benefits as well as rich the economic benefits to China.
Previous studies in China (10-11) found that improving latrines as an intervention in rural areas was associated with lower incidence of diarrheal diseases with a relative risk of diarrheal diseases in relation to latrine improvement being 0.49; this study obtained consistent results.
Along with the development of social economy in China, the Latrine Revolution in rural areas played an important role in promoting public health, especially children’s health. The under-five mortality rate of diarrheal diseases attributable to unsafe sanitation in China during 2006 and 2017 dropped by 84.65%; during the same period, the overall under-five mortality rate in China declined by 56.08% (12). Diarrheal diseases have been known to cause malnutrition and affect the growth and development of children. Although the overall burden of diarrheal diseases has declined, the YLD rate in children aged 1−4 years in 2017 was higher than that in 2006. Therefore, it is necessary to take and develop comprehensive sanitation improvement policies and plans and combine them with health education, hygiene promotion, and improving socioeconomic conditions and living environments to achieve further success. Previous studies found that increasing coverage of sanitary latrines in rural areas was accompanied by enhanced health awareness of local residents, and the elimination of fecal pollution was accompanied by decreases in incidence of related intestinal infectious diseases that improved overall health and family life quality and promoted the development of the countryside to eliminate poverty. Meanwhile, the safe treatment of human excreta is an important environmental protection measure as it provides good organic fertilizer resources for farmland and is of great benefit to the development of agricultural ecology. This is a sound policy basis to benefit individual, societal, and environmental health.
Furthermore, several interventions related to sanitation and hygiene should be more targeted to children and their caregivers in rural areas in order to develop their health habits, and the financial support for such interventions should be further strengthened at the policy level by the government. In addition, universal access to sanitary latrines is gradually being introduced, which will produce significant effects for public health and environmental and economic benefits.
This study was subject to at least several limitations. First, the national prevalence of STH infection and national mortality of diarrheal diseases were used in this study as data focusing on rural areas was not available. This may have resulted in an overestimation of the reduction of the burden of diarrheal diseases related to the Latrine Revolution and underestimating the correlation between sanitary latrine coverage and indicators of STH and diarrheal diseases. Second, costs of patient healthcare were not included in the IEB due to data unavailability. The contribution of economic growth to GDP per capita also played an important role in the reduction of IEB. Third, the data sources used in this study were collected beginning in 2006 and GBD 2017 was the most updated version to be used in this study. This range limited the years in which the impact of the Latrine Revolution, having begun in 2015, could be examined, but the effects of gradual improvements are noticeable.
The findings of this study provided evidence for further developing the rural Latrine Revolution and plans for health education and hygiene promotion, which represent good practice and play a key role in advancing further rural social and economic development.
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