The burden of diarrhea, etiologies, and risk factors in India from 1990 to 2019: evidence from the global burden of disease study

Table 1 presents the number of diarrhea deaths and mortality rate (per 100,000 population) in 2019 in India for each age group and sex. The latest data in 2019 shows, the total number of deaths of all ages is 632,344 in 2019 (95% uncertainty interval; 358,561–1,056,036), and the mortality rate is 45 per 100,000 population (95% uncertainty interval; 25–75). Most deaths occurred in the older age group – 70+ years followed by 50–69 years in 2019. It has estimated that the mortality rate 682 (95% uncertainty interval: 362–1144) for 70+ years and 62 95% (uncertainty interval: 31–118) for 50–69 years in 2019. Similarly, the number of child deaths in the age group - Under 5 is 55,309 in 2019 (95% uncertainty interval: 39882–73,621), and the mortality rate is 47 per 100,000 population (95% uncertainty interval; 34–62).

Table 1 also presents gender-wise differences in diarrhea-related deaths and mortality in India in 2019. It has been shown that the number of deaths of males and females is 32.31 (95% uncertainty interval: 20.01–67.64) and 59.31 (95% uncertainty interval: 24.53–117.11) respectively of all age groups. These mortality differences between males and females are also exhibited in other age categories as well and it is clearly shown that females are more prone to diarrhea-related deaths than males. The differences in mortality are more widened in the age group 70+ years where the female mortality rate is 846.84 (95% uncertainty interval: 327.30–1683.73) and 495.20 (95% uncertainty interval: 295.49–1026.31). Similarly, child mortality is more prone due to the cause of diarrhea, and the gender difference between a male and female child is visible in Table 1.

Figure 1 shows the time-series trends in Diarrhea mortality rate (per 100,000 population) by age in India from 1990 to 2019. All ages: The mortality rate has been declined from 126 in 1990 to 45 in 2019. Under − 5: The mortality rate has been declined from 309 in 1990 to 47 in 2019. Five to fourteen years: The mortality rate has been declined from 27 in 1990 to 6 in 2019. Fifteen to forty-nine years: The mortality rate has been declined from 27 in 1990 to 6 in 2019. Fifty to sixty-nine years: The mortality rate has been declined from 236 in 1990 to 63 in 2019. 70+ years: The mortality rate has been declined from 2104 in 1990 to 682 in 2019. The overall analysis of Fig. 1 depicts that the deaths of diarrhea have been declined over the period across all age groups in India but still it plays a major communicable disease in India.

Figure 2 shows the time-series trends in Diarrhea DALYs rate (per 100,000 population) by age in India from 1990 to 2019. All ages: The DALYs rate has been declined from 6544 in 1990 to 1446 in 2019. Under − 5: The DALYs rate has been declined from 27,351 in 1990 to 4283 in 2019. Five to fourteen years: The DALYs rate has been declined from 2474 in 1990 to 705 in 2019. Fifteen to forty-nine years: The DALYs rate has been declined from 1591 in 1990 to 531 in 2019. Fifty to sixty-nine years: The DALYs rate has been declined from 7067 in 1990 to 2017 in 2019. 70+ years: The DALYs rate has been declined from 30,904 in 1990 to 9242 in 2019. The overall analysis of Fig. 2 depicts that the DALYs rate of diarrhea has been declined over the period across all age groups in India but still around 705 persons of all ages are living with disabilities in 2019. Similarly, the under-5 and older age (i.e., 70+ years) are more DALYs rate that is 4283 and 9242 persons in 2019 respectively.

Table 2 represents etiologies for the cause of diarrhea disease and the number of deaths among under-5 and all ages in India, 2019. We have found that there is 13 etiology that causes diarrhea in India. We have found that Adenovirus is the most prominent pathogen for the cause of diarrhea among children, followed by Campylobacter and Cryptosporidium. Our result shows that around 8864 deaths occurred due to Adenovirus whereas around 8435 for Campylobacter and 5074 for Cryptosporidium in 2019. Similarly, the most pertinent pathogen for the cause of diarrhea for all ages is Campylobacter followed by Cryptosporidium and Norovirus. Our results show that around 44,353 deaths occurred due to Campylobacter whereas around 36,007 for Cryptosporidium and 29,924 for Norovirus in 2019.

Table 3 shows the risk factors for the cause of diarrhea disease and mortality rate (per 100,000) among under-5 and all ages in India, 2019. We have found many environmental and behavioral risk factors that lead to diarrhea. The environmental factors include unsafe water, sanitation, and handwashing; and air pollution (i.e., ambient particulate matter pollution and household air pollution from solid fuels). The behavioral factors include suboptimal breastfeeding; malnutrition; vitamin A deficiency. Our result shows that major risk factors of diarrhea-related child mortality are unsafe water sources followed by child wasting and unsafe sanitation. It is shown that the under-5 diarrhea-specific mortality rate is 43 (95% uncertainty interval: 30–59) due to unsafe water, sanitation, and handwashing factors. Similarly, the mortality rate is 44 (95% uncertainty interval: 32–59) due to child and maternal malnutrition factors. Our result shows that major risk factors of diarrhea-specific mortality of all ages are unsafe water sources. It is shown that the all-ages diarrhea-specific mortality rate is 41 (95% uncertainty interval: 23–69) due to unsafe water, sanitation, and handwashing factors. Overall analysis shows that unsafe water, sanitation, and handwashing practices are the major risk factors for diarrhea-specific mortality in India of all ages as well as under-5 in India. But risk factors such as Suboptimal breastfeeding, Child growth failure, and low birth weight, and Vitamin A deficiency are the pertinent factors for the cause of diarrhea-specific mortality for children (i.e., Under 5) in India.

As our study suggests the overall morbidity and mortality associated with diarrheal disease has declined from 1990 till 2019, a similar pattern of diarrhea cases has been observed in India and different parts of the world by several public health researchers so far.

Troeger et al. have studied diarrhea burden in different regions of the world and found that although the disease burden associated with diarrhea has been declining over the years, it still is one of the biggest threats among children under 5 years and the elderly population specifically i.e., more than 70 years old [13]. In 2015, although children under 5 years had the highest number of deaths due to diarrhea among all age groups in Eastern Mediterranean Region, 17 out of 22 countries showed higher mortality among the elderly (70+) population than any other age group [14]. Similarly, this study also depicts the highest mortality among the elderly population, making them more vulnerable.

As the result of our study shows, childhood diarrhea has declined over the years significantly, yet contributes to a larger share of DALYs associated with the disease. In India, as most of the low-and middle- income countries, diarrheal proportional mortality has always been high among children even after a steady decline in childhood diarrhea deaths [15]. Being the 2nd largest cause of the under-5 mortality rate of Ethiopia, in 2013 since 1990, it shows diarrhea not only causes disability and discomfort in the younger population but also leads to deaths for a very long period [16].

Among all the death cases of Diarrhea, in 2019, the most prevalent disease-causing pathogen is found to be Campylobacter. But, Adenovirus is the major contributor to childhood diarrheal deaths. While most of the existing literature from all over the world suggests Rotavirus being the major cause of childhood diarrhea, the number of deaths associated with it among the children under 5 years in our study is relatively much lesser i.e., 2059.74 per 100,000 population, compared to Adenovirus i.e., 8864.36 per 100,000 populations. Even though Rotavirus does not cause the greatest number of deaths, it still is one of the major fatal pathogens. Reportedly, these deaths can be reduced by promoting and implementing the rotavirus vaccine in the country. By averting more than 28,000 deaths of young children around the globe, in 2016, the rotavirus vaccine has proved its efficiency [17].

As our study indicates that unsafe water, sanitation, and handwashing practices with child growth failure, LBW has a major role in increased morbidity and mortality associated with childhood diarrhea (or diarrhea in general), similarly, Lakshminarayanan and Jayalakshmy have also found a significant association of such risk factors with childhood diarrhea along with other types of risk factors. These include – age, socio-economic status, unhealthy breastfeeding practices, low birth weight, having younger siblings, etc. [15]. This finding is also parallel with many other existing public health literature by various researchers. In rural Mozambique, washing hands facilities with child stool disposal system has a noticeable impact on reduced risk of middle to severe diarrhea among children, and not providing fresh drinking water has contributed to a higher risk of childhood diarrhea [18]. In a study regarding diarrhea in urban slums of India, it was also seen that the incidence of diarrhea is relatively higher among children of poor (lower SES) strata [19]. While most of the discussion about the risk factor of diarrhea is concentrated around the consumption of unsafe water and poor sanitation, predisposing factors such as unsafe medium of drinking water conveyance, poor condition of water tanks at houses, water handling practices at households, improper disposal of wastewater and fecal matter, etc. are essential to look for to prevent diarrhea [20, 21]. Surprisingly, although not in our study, many studies have shown that the attack rate of diarrhea is higher among families with more than one child under 5 years of age than families with a single child [22].

Apart from these aforementioned factors, the knowledge, attitude, and behavior of mothers have also a significant impact on diarrhea among the younger population. Singh et al. have found a positive correlation between the educational status of a mother with the incidence of diarrheal disease [23]. Further, the literacy status of the mother can also be associated with the risk behaviors they practice at their households such as not washing hands before feeding the child, washing hands without soap, improper disposal of stools, etc. [24]. In our study, as well, the mortality rate associated with diarrhea among the under-5 cohort differs due to different types of breastfeeding behavior shown by mothers. As the children are not capable of taking the decision, hence, parents are needed to make healthy decisions for their children and the family, as a whole.

Child and maternal malnutrition are a well-acknowledged risk factor of diarrhea for ages and a similar result is also observed in our study. But in some studies, the frequency of diarrhea was found to be not significantly related to the nutritional status of the children [25]. Similarly, Ganguly et al. found that although malnutrition is significantly associated with diarrhea, there is no significant association with lack of breastfeeding, low literacy status of the mother, and consumption of untreated drinking water [26]. These findings suggest that although there are tons of literature in place, still there is a need for more research regarding risk factors of diarrhea as it may differ between countries, regions, populations, or age groups.