Date of Award

May 2020

Document Type


Degree Name

Master of Science (MS)


Biological Sciences

Committee Member

Lesly A Temesvari

Committee Member

Cheryl Ingram-Smith

Committee Member

Zhicheng Dou


Summary Background

The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 is the most comprehensive study ever carried out to report on the state of global public health for the previous 28 years (1990-2017). In 2017, it covered 359 diseases and injuries for 195 countries and territories.

Our study sought to provide an up-to-date analysis of the progress that has been made to eradicate diarrheal diseases using the GBD2017 data. Although significant progress has been made in reducing the number of deaths due to diarrhea, diarrheal diseases incidences and associated morbidity have not experienced the same level of decline. Using disability-adjusted life-years (DALYs), a metric that tracks impact on life expectancy, prevalence, and impact on quality of life due to a specific disease, we performed a comparative analysis of the impact of diarrheal diseases by World-Bank (WB) Income regions, age, and sex.


Using multi-year GBD data that we accessed from the Institute of Health Metrics (IHME) tool (GBD Compare | Viz Hub), we analyzed the impact of diarrheal diseases using Microsoft Office Excel 2017 (Microsoft, Redmond, WA). We compared the disability-adjusted life-year (DALY) metric due to diarrheal diseases among different demographic subsets including sex, age, country, and income level. One DALY is comparable to one lost year of “healthy” life, while the sum of DALYs across the population expresses the burden of disease caused by a gap between current health status and optimal health for the entire population impacting variables such as advanced age. All data estimates in the GDB2017 study were listed with 95% uncertainty intervals (UIs).

We also evaluated DALYs as a function of the socio-demographic index (SDI). This index, also developed by the GBD Project in 2015, is a measure of a region’s socio-demographic development and consists of data about the education levels, average income per person, and total fertility rate (TFR).


Diarrheal DALYs have decreased by approximately 54.64% from 1990 to 2017. In 1990 diarrheal diseases counts were estimated at 178,669,278.768251 (95% UI: 154,235,572.289659-203,868,117.467447) with an age-standardized DALY rate of 1,017.22180392645 per 100,000 people. On the other hand, in 2017, DALYs were estimated at 81,039,363.8553969 (95% UI: 70,120,051.7904495 - 972,33,423.453799); and an age-standardized DALY rate of 246 per 100,000 population globally. Interestingly, while DALYs have decreased, incidence and prevalence have increased by 52.16% and 47.22%, respectively. Age-standardization, otherwise known as age adjustment, makes it possible to apply observed age-specific data from multiple populations to a standard age distribution that enables comparison across countries and regions.

Regardless of World Bank (WB) Income region, infants 28-364 days were the most vulnerable to diarrheal diseases. Since 1990, global diarrheal disease DALYs do not differ markedly between the sexes. In 2017, there seems to be a slight difference in WB High-income regions, where women have higher DALY rates (3.36% more), the rates in WB Low-income regions were higher for males in 2017 (24.23%). We also observed that the rate of diarrheal diseases highly correlates to socio-demographic index (R² = 0.9937).


Considerable progress has been made globally in reducing the burden of diarrheal diseases, as many socio-economic risk factors have been reduced. However, progress has not been up to par in all locations, Low-income countries are still substantially behind in reducing diarrheal diseases DALY rates compared to High-income countries and the burden of diseases infants still requires special attention.



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