Global health spends a lot of time focusing on people. How we transmit diseases to each other, and how illness and disease affect our bodies and our lives. What often gets left out is the context of our human lives. The places we live have a huge effect on our health – a new World Health Organization report estimates that 23% of global deaths are the result of environmental factors that could be changed. Primarily from stroke, ischemic heart disease, diarrhea and cancer, these deaths are preventable. And making the changes that would prevent them would benefit almost everyone.

“Preventing disease through healthy environments: a global assessment of the burden of disease from environmental risks,” was published by WHO this week. It looks at more than 100 disease and injury categories to identify the death and disability that results from environmental factors. It’s an update of a 2006 report on the same topic, and provides a discussion of the situation in 2012 and the trends over time since the last data collection in 2002.

According to the report, 12.6 million people died as a result of living or working in an unhealthy environment in 2012. Environmental risk factors like air, water and soil pollution, chemical exposures, climate change, and ultraviolet radiation, contribute to more than 100 different diseases and injuries. Air pollution, as you’d expect, ranks very high in terms on contributing to deaths. So do traffic accidents.

Low- and middle-income countries in the South-East Asia and Western Pacific Regions had the largest environment-related disease burden in 2012, with a total of 7.3 million deaths, most attributable to indoor and outdoor air pollution. The Americas had the fewest deaths related to environmental factors, at 847,000. Low- and middle-income countries bear the greatest environmental burden in all types of diseases and injuries. This continues to prove that we can’t look at heart disease and cancer as a rich country problem.

The report also breaks out health risks by sector. Agricultural, leads to risks of infection by parasitic diseases; occupational exposure to chemicals; and consumer exposure to chemicals. Transport leads to risks from traffic accidents, air pollution, and decreased physical activity.

Over time the distribution of deaths related to the environment has changed. Since 2002, deaths related to infectious, parasitic, neonatal and nutritional diseases made up 31% of the overall burden related to the environment. In 2012, that number had fallen to 20%. Non-communicable diseases such as cancer and heart disease, however, went from 17% to 22%. This is believed to reflect the trends of improving water and sanitation and worsening air pollution.

 

The report looks at all 100 categories of disease and injury, in impressive detail.  Did you know that 1.1% of global leukemia can be attributed to workplace risks? Or that both rheumatoid and osteoarthritis are worsened by air pollution and traffic? And living in crowded homes has been associated with a higher risk of developing pneumonia? The interactions between humans and their environment are extraordinarily complex, and that complexity is reflected in health impacts.

Like many WHO reports, this one is a big, sprawling mass of data and ideas. It ends not with a tidy conclusion, but a discussion of the links between environmental health on the sustainable development goals. Unsurprisingly, the linkages are many and strong. So strong that if environmental factors affecting health are not addressed, the SDGs are at risk.

The report does have recommendations. (Would it be a WHO report if it didn’t?) Broadly, to reduce environment-related deaths, the report calls for health stakeholders to work intersectorally. Many if not most of the environmental issues mentioned in the report are determined well outside the health sector. The health sector does not control city planning, sale of household fuels, or use of agricultural chemicals, for example.

A surprising amount of good news

Unusually for a UN report, this one points out that things are improving. Diarrheal diseases have declined since the 2006 report. So have overall deaths. Between 2002 and 2012, the number of deaths attributable to the environment decreased from 13.3 to 12.6 million per year. The fraction of deaths attributable to the environment also slightly decreased, from 23.3% to 22.7% over the same period.

The report also highlights a range of inexpensive interventions that would lead to immediate decreases in environmental burden. These include safer household water storage and better hygiene measures, the use of cleaner fuels and safer, more judicious use and management of toxic substances at home and in the workplace, and occupational safety and health measures.

What the report doesn’t say

This is a big report, and it covers almost every aspect of the data you would want to see. However, the report is based on identifying opportunities for policy and action. It does not take on unchangeable environmental factors such as geography. We don’t know if living on an island has greater environmental health risks than living on a peninsula or in a valley, because those factors were disregarded. You can’t make a policy change that removes neighboring mountains.

I was also surprised to see that the report didn’t address changes in death distribution by age over time. In 2016, 26% of child deaths are attributable to the environment. The report doesn’t offer the comparison number for 2002. Considering the increase in proportion of deaths from cancer and heart disease, we’d expect to see fewer child deaths in 2012 and more among the elderly than we saw in 2002, but the report doesn’t discuss it.

What you need to know about this report in once sentence

The takeaway: Where we live has a health impact on all of us, and there are plenty of ways to make that impact better.