Global perspective on environmental health

Thursday, January 11, 2018

The environment is a key determinant of human health, and exposures to toxic chemicals, physical factors, and pollutants all have a direct impact on the quality of life, the burden of disease, and the outcome of longevity. In the developing world, population growth with urban crowding, the introduction of many environmental pollutants and toxic exposures, and the lack of clear policies to control pollution have accentuated the negative impact that these environmental factors can have as causative factors of disease in humans.

Research to address environmental problems in any country, rich or poor can lead to greater understanding of the pathogenesis of disease processes caused by untoward environmental exposures and can guide research to improve diagnosis, treatment, and control. In fact, targeting the best scientific research to environmental problems, wherever they arise, can lead to breakthroughs in our understanding that can be of great benefit to all.

In the developing world, such problems of environmental health can be elusive, widespread, and disguised and sometimes appear where least expected. In the 1970s and 80s, one of us (R.I.G.) worked in Bangladesh and followed a program to install tube wells in many rural communities in an effort to control the annual outbreaks of cholera that were believed to be spread by contaminated river water. This program, which was admirable in its intent, had a tragic outcome that could never have been anticipated.

Two decades after the program was completed, high levels of arsenic were identified in water from these tubewells that had left a huge population with chronic exposure to toxic levels of arsenic. Identification of arsenic in this water has led to a national—and indeed international—effort to understand the extent of the problem, to assess the health impact of chronic arsenic poisoning in this population, to test novel methods of treatment, to seek the environmental source of the problem, and to design control programs to diminish this unforeseen hazard.

By applying quality science to this investigation, we can learn a great deal about how to diagnose chronic arsenosis earlier, understand its pathogenesis and long-term sequelae, identify more effective treatments, develop simple laboratory methods to screen water samples, and test different public health methods for prevention. The problem might well have arisen anywhere, but the opportunity to study this problem and intervene is clearly at the center of environmental health in a global arena.

A similar and complex problem has been observed with indoor air pollution, particularly in the developing world. One key indicator of the health of a society is the measure of mortality among children 5 years of age. The most common cause of death in this age group is acute respiratory disease, a syndrome usually linked to a wide variety of infectious agents and asthma. However, a key underlying condition that places these children at particularly high risk of death is indoor air pollution from cooking and heating fires in the home.

A Guest Editorial