Diabetes and the Environment
Alex has had type 1 diabetes since age 1. Alarmingly, the incidence of type 1 diabetes is increasing fastest in children under 5 years of age. Why?
Our Children Are at Risk
Each year, an ever increasing number of children are diagnosed with type 1 diabetes. Among children under age 15, the risk of developing type 1 diabetes has been increasing since the 1950s around the world. The increase has been very rapid, particularly in the youngest children, under age 5 (Diamond Project Group 2006). Between 1989 and 2013, on average in Europe, a 3.4% annual increase continues, despite a slower rate of increase in some high-incidence countries (Patterson et al. 2018). As of 2021, over 108,000 children are diagnosed with type 1 diabetes each year worldwide (Ogle et al. 2021) (check the current International Diabetes Federation Diabetes Atlas for the most recent numbers). In the U.S., the number of children with type 1 diabetes increased by 45% between 2001 and 2017 (Lawrence et al. 2021). This rise is dwarfed by the rise in China; traditionally a low-incidence country, the incidence of type 1 diabetes in Shanghai's children increased by 14.2% per year between 1997 and 2011 (Zhao et al. 2014).
I know what it's like to take care of a child with type 1 diabetes: it's scary. No child should have to go through the constant parade of needles, or have to deal with high and low blood sugars that might appear at any time. Meanwhile I could use a full night's sleep, without wondering if my child was going to wake up in the morning.
Like type 1 diabetes in children, the incidence of type 2 diabetes in adults is also increasing rapidly (Geiss et al. 2006). Not only that, but type 2 diabetes incidence is increasing in children as well as adolescents. And, more and more children are showing signs of both type 1 and 2 diabetes (Pozzilli et al. 2007). The appearance of these diseases early in life is likely to have serious ramifications on health later in life.
And then there are the economic costs. In 2017, U.S. spending on diabetes (type 1 and type 2) was estimated to be $327 billion (ADA 2018) and the economic costs of diabetes (diagnosed and undiagnosed), prediabetes, and gestational diabetes in the U.S. was estimated to be over $400 billion (Dall et al. 2019). Rising health care expenditures are a serious problem, and a significant portion of health care spending is incurred by people with diabetes (Hogan et al. 2003). In 2010, type 1 diabetes cost the U.S. $14.4 billion in medical costs and lost income each year (Tao et al. 2010), a number which continues to increase (especially due to higher insulin prices) (Crossen et al. 2020).
But Why the Rising Rates?
The increasing incidence in type 2 diabetes is generally attributed to increasing weight gain, a poor diet, and lack of exercise, but is that really the whole story? There is growing scientific evidence that environmental chemicals can also contribute to the development of type 2 diabetes. Do chemicals contribute to the development of the autoimmune disease type 1 diabetes as well? This website is my attempt to examine the scientific evidence surrounding our exposure to chemicals and the development of diabetes. I focus on type 1, since my young son and I both have type 1, but also include information on type 2 and gestational diabetes as well.
It is clear that some environmental, not solely genetic, factors play a role in the development of type 1 diabetes. For instance, in sets of identical twins in which one twin has type 1 diabetes, the other twin does not necessarily develop the disease (Hyttinen et al. 2003). Also, people who move from a country where type 1 is rare to a country where it is more common have an increased incidence of the disease, implying that genetics alone does not tell the whole story (Feltbower et al. 2002). The incidence page has more information on type 1 diabetes incidence trends and patterns around the world.
Environmental Risk Factors for Type 1 Diabetes
Scientists have proposed a number of hypotheses to explain the rising rates of type 1, summarized on the why is diabetes increasing? page.
A number of environmental factors have been found to contribute to the development of type 1 diabetes-- even if they are not responsible for the increasing rates (type 1 diabetes, after all, is an ancient disease). Many of these factors are summarized in the graphic below. The research regarding these factors is summarized on individual pages throughout this website (e.g., vitamin D deficiency, the gut, viruses, air pollutants, persistent organic pollutants, etc.). Clicking on the arrows on the list on the sidebar will show all the pages and subpages in these sections.
References and More
I often post new studies in a variety of places, e.g., on twitter @sarhoward.
I also send out weekly summaries new studies via email, sign up for the HEEDS Research Roundup of Environmental Chemicals in Diabetes and Obesity.
There is an old listserv of older messages and archives: http://groups.google.com/group/diabetesandenvironment
Photos and Figures
All of the people in the photos on this site have diabetes, or are scientists studying diabetes or obesity. Some names have been changed.
Figures are used with permission as noted or are from Environmental Health Perspectives (EHP), which is in the public domain and is therefore without copyright.
This webpage relies solely on published studies in peer-reviewed scientific journals, available and categorized by topic on the References page.
Read the full Lancet Risk factors for type 1 diabetes series: The Lancet: Risk factors for type 1 diabetes, 2016.