Trends in Morbidity and Mortality Attributable to Injuries and Selected Environmental Hazards

Excerpt

The effects of globalization on low- and middle-income countries (LMICs) have led to major changes in the disease burden attributable to injuries and environmental risks. On the one hand, rapidly developing regions face a rising number of road traffic injuries (RTIs) and fatalities, as well as health effects from increasingly polluted air. On the other hand, economic development has led to greater availability of water, sanitation, and hygiene (WASH) services and a reduced burden of diarrheal and helminthic illness in many settings. These trends are heterogeneous, however, and very poor countries, and regions within populous countries such as India, exhibit slower progress.

This chapter presents an overview of trends in the burden of injuries and environmental health issues in LMICs. We focus on five major groups of conditions, presented as they appear in this volume and not in order of importance:

1. Unintentional injuries, which include RTIs and those resulting from other causes

2. Interpersonal and collective violence

3. Occupational hazards

4. WASH-related illnesses

5. Health effects of air pollution.

Self-harm is not covered in detail in this chapter because it is covered in volume 4, chapter 9, of Disease Control Priorities (third edition) (Vijayakumar and others 2015). Although the conditions presented above are seemingly very different, a common feature links them: they can all be addressed through multisectoral interventions, including legal and regulatory frameworks and public works investments. These interventions are assessed further in the subsequent chapters of this volume.

This chapter presents two types of burden estimates. For injuries, we present deaths and disability-adjusted life years (DALYs). For occupational and environmental hazards, we present attributable deaths and DALYs. The distinction between these two types of estimates is that the former are related to specific causes of death, such as RTIs, whereas the latter are related to risk factors, such as unimproved water, for specific causes of death, such as diarrheal disease. Attributable deaths and DALYs are estimated using the comparative risk assessment (CRA) methodology rather than mortality analysis. They often total greater or less than 100 percent owing to multiple risk factors (or no known risk factors) for various causes of death. Hence, estimates of the burden of environmental and occupational risk factors cannot be directly compared to estimates of the burden of injuries.

This chapter presents estimates from two sources of data. Mortality and morbidity data on injuries are taken from the World Health Organization’s (WHO) Global Health Estimates database, most recently updated in 2014 (WHO 2016). Details on the methods for estimating cause-specific mortality and DALYs—including calculation of years of life lost and disability weights—are available in the relevant documentation from the WHO. Attributable mortality and morbidity data on occupational and environmental risks are taken from the Global Burden of Disease 2013 Study (GBD 2013) because similar data were not available from the WHO. Details on the methods for estimating attributable mortality and DALYs using CRA are provided in Forouzanfar and others (2015).

We compare trends in total deaths with trends in age-standardized mortality rates. For injuries, we calculated age-standardized rates based on the global population structure in 2012 and compared mortality in 2000 to mortality in 2012. For occupational and environmental risks, we used age-standardized attributable rates from GBD 2013, which based calculations on the global population structure in 2013 and compared attributable mortality in 1990 to attributable mortality in 2013.