Infectious and Non-infectious Diseases: The Lines Begin to Blur

written by Elise Miller, MEd

Deaths from noncommunicable diseases (NCDs) were estimated at 68% in 2012 globally, up from 60% in 2000, while deaths from infectious diseases are decreasing. This is according to the second edition of the World Health Organization’s report, “Preventing disease through healthy environments: a global assessment of the burden of disease from environmental risks“, published last month. The researchers found that environmental risk factors, including chemical exposures, pollutants in air, water and soil, climate change, and ultraviolet radiation, were primary contributors to these deaths.

What this tells us is the huge investment in preventing infectious diseases from philanthropic organizations, like the Bill and Melinda Gates Foundation, is making a real difference, particularly in low- and middle-income countries. This also suggests that we are not doing nearly enough to address far more intractable and pervasive concerns that lead to NCDs, such as ensuring people have clean drinking water. It’s easier to distribute vaccines than, say, stop the use of pesticides, take the lead out of pipes, or prevent coal-burning power plants from being built.

Enumerating the number of deaths also doesn’t account for the millions of people who suffer from chronic conditions that don’t necessarily lead to death, such as learning and developmental disabilities or reproductive health problems. Those of us working in the field of environmental health know that environmental risk factors can play a role in these as well, but the toll on individuals, communities, and societies is usually not as immediately obvious as from infectious diseases. This is because health outcomes from chronic and low-dose toxic exposures can take years or even decades to manifest.

In addition, what’s becoming increasingly clear is that deaths from infectious diseases and NCDs can’t always be divided into two neat categories. Instead, leading researchers are finding multiple contributors to disease often interact in a complex array of causal relationships. An infectious agent may be present, but other noncommunicable factors influence whether and what kind of disease may result. For example, endocrine disrupting chemicals can undermine the healthy functioning of the immune system, making a person more likely to contract an infectious disease.

Overall this means that even more deaths may be the result of exposure to environmental risk factors than is being currently calculated. If we increased funding for studies that could help us determine how multiple, interacting factors—including the chemical environment, viral agents, and socioeconomic status—result in disease and disability, we could then develop an algorithm to show the proportion of deaths that had both infectious and noninfectious contributors as well. And even more important, we could develop and invest in more effective upstream interventions that could decrease both.

To truly improve global health in the 21st century, the fact is we have to look beyond the rigidly defined categories and areas of expertise that have previously served to advance Western science. Instead, we now need to blur the lines some and explore the complexity of relationships between what we deemed earlier to be distinct and immutable. Systems approaches not only reflect the truth of our reality, but make it more likely that creative solutions will emerge that simultaneously address multiple, interacting factors to reduce disease incidence and boost resiliency and well-being. By doing so, perhaps 10 years from now when the third edition of WHO’s report is published, we could see the numbers for not only infectious diseases, but NCDs on the decline.

Which Chemicals Are Linked to Diabetes and Obesity? Perhaps More Than We Think.

written by Sarah Howard
Coordinator of the Diabetes-Obesity Spectrum Working Group

Sarah HowardResearchers from the National Institute of Environmental Health Sciences (NIEHS), EPA, research centers and universities have just published an article, Prioritizing environmental chemicals for obesity and diabetes outcomes research: a screening approach using toxcast high throughput data (Auerbach et al. 2016).

The intent of this project was to use new rapid screening methods to identify chemicals that may be able to affect biological processes linked to the development of diabetes and/or obesity. The researchers screened 1860 chemicals and found that, “the spectrum of environmental chemicals to consider in research related to diabetes and obesity is much broader than indicated from research papers and reviews published in the peer-reviewed literature.”

The chemicals screened include pharmaceutical drugs, chemicals already linked to diabetes or obesity development (as “signposts”), pesticide ingredients, chemicals found in consumer products, and some “green” chemicals. The biological processes that they tested for include insulin resistance, pancreatic islet and beta cell function, fat cell differentiation, and feeding behavior.

Overall, they found that the chemicals most highly ranked are generally not the ones being studied for potential effects on diabetes or obesity, in current laboratory or human research studies.

pillsThe “top 30” chemicals most likely to have effects on beta cells or islets include, for example, basic blue 7 dye (used to dye fabric), numerous pharmaceuticals, a few insecticides, a few herbicides, an “inert” pesticide ingredient, a flame retardant, a disinfectant, an air pollutant, a plasticizer, a few fragrances, a cosmetic ingredient, caffeine, a nitrosamine, and silica.

Now, before raising any alarms about these chemicals, please note:

  • some of the screening tests do not determine whether the effect was positive or negative—so chemicals/drugs with anti-diabetogenic effects for example, may show up high in the list of results;
  • most chemicals of the 85,000 in the marketplace were not included in this test, so we do not know how these chemicals compare to other chemicals;
  • we do not know how widespread exposures are to the chemicals listed in the “top 30”—they may be obscure and hardly ever used;
  • this study focused on obesity and type 2 diabetes, not type 1, due to a lack of  relevant biological assays in ToxCast (although chemicals that affect beta cells may be relevant for any type of diabetes); and
  • other studies have found that these screening tests may be inaccurate; results need to be tested further before any conclusions about these chemicals can be made. For example, researchers have found that ToxCast assays do not correlate well with laboratory studies on obesogens (Janesick et al. 2016).

The main point to take from this study is that numerous chemicals, largely unanalyzed for their potential effects on diabetes and obesity, have potential to play a role in these conditions. The study aimed to help develop hypotheses about which chemicals to test further, not to draw conclusions. Yet it also shows that the potential of chemicals to contribute to diabetes or obesity may be widespread.

Are the Glory Days Over for Glyphosate?

written by Elise Miller, EdM

The scientific evidence is mounting that glyphosate-based herbicides, which are the most heavily applied in the world, may not be the panacea for feeding the world’s hungry as its proponents have argued. A year ago the World Health Organization’s International Agency for Research on Cancer (IARC) concluded that glyphosate (also known by “Roundup”, one of its brand names) is “probably carcinogenic to humans.” Last month, over a dozen researchers published a Statement of Concern, asserting that regulations have not kept up with the emerging science on links between glyphosate exposure and human health concerns, particularly in light of the 100-fold increase in the use of the herbicide since the late 1970s. Just this past Monday, a new biomonitoring study was published that found the vast majority of Germans have glyphosate residues in their bodies, and a third of the population has levels 10 to 42 times higher than what is currently considered a safe threshold of exposure.

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Air Pollution and Weight Gain, Insulin Resistance and Metabolic Syndrome: Recent Findings

written by Sarah Howard
Coordinator of the Diabetes-Obesity Spectrum Working Group

Sarah HowardTwo studies published this month provided strong support for the idea that air pollution may cause weight gain, insulin resistance, and metabolic syndrome.

In the first study, pregnant rats exposed to Beijing’s air gained significantly more weight during pregnancy than those breathing filtered air. Their offspring (exposed pre- and postnatally) were also significantly heavier at 8 weeks of age.

In the second study, Mexican Americans living in Southern California exposed to ambient air pollutants had lower glucose tolerance, higher insulin resistance, and adverse blood lipid concentrations.  According to the authors, “the magnitudes of effect from a 1-[standard deviation] difference of [fine particulate matter] on metabolic outcomes were similar compared with the impact of a 1-unit change in percent body fat or [body mass index] BMI on the same metabolic outcomes.”

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Lead, Methane and Monetizing Natural Capital

written by Elise Miller, EdM
Widespread water contamination from lead in Flint, Michigan, and the huge methane leak in Aliso Canyon, California, have dominated media headlines in recent weeks. The oft-repeated response given to questions of why these situations weren’t addressed earlier has been: It would have been too costly. With this mindset, the government agencies and others responsible did not do anything, and even covered up how bad the situations were, until major health crises erupted. Of course these events are not anomalies. Sadly this is true for thousands of communities around the US and elsewhere because there is little economic incentive to invest in prevention-oriented actions.

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A Story of Health Wins CDC Communications Award

The National Center for Environmental Health (NCEH) and the Agency for Toxic Substances and Disease Registry (ATSDR) have honored A Story of Health multimedia eBook/continuing education course with an “Excellence in Communications” award.

NCEH and ATSDR are agencies of the Centers for Disease Control and Prevention (CDC). The award was given at the annual NCEH/ATSDR Honor Awards on February 3, 2016, to A Story of Health Team for excellence in communication for the development of a medical education product that highlights the importance of environmental health.

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Your Health: Lead at Home

image of a child running tap waterWith substantial media focus on the tap water situation in Flint, Michigan, and beyond in the last few weeks, many people are concerned about lead levels in their tap water. This concern is well founded, for lead has devastating impacts on our health, and especially on children’s health. There is no amount of lead exposure that is considered safe for children—even the smallest exposures can impact health.

What does lead do? From CHE’s Practice Prevention column on lead:

High levels of lead in children can lead to anemia, stomach and kidney problems, muscle weakness, brain damage and ultimately death. Even very low levels of exposure can affect a child’s mental and physical growth. Studies have linked elevated blood-lead levels in children with reduced intelligence, slowed mental development, attention deficit hyperactivity disorder, increased risk for delinquency and criminal behavior, heightened risk of obesity and delayed onset of puberty.

Lead at home can lurk in several places:

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