About the Author

At age 32, while pregnant with my oldest child, I failed a glucose tolerance test. My blood glucose was so high that the nurse asked me, "Why aren't you in a coma?" I felt like I should have been. I had none of the risk factors for gestational diabetes, and my blood glucose level was a perfect 90 a month before the pregnancy. But I required insulin, and the nurse told me I needed to inject it into my (very pregnant, very large) abdomen. This, it turns out, was flawed advice. But I will never forget giving myself that first shot of insulin, in tears, with my husband out of town. I couldn't get all the air bubbles out of the syringe; would they kill me? How did the doctor know that 10 units wasn't too much? Would I wake up in the morning? What if the needle punctured my uterus? 

Six weeks after my (large, but healthy) baby was born, I failed another glucose tolerance test. The doctor said I had type 2 diabetes, and if I lost the weight I had gained while pregnant, it might improve. I lost weight-- I'd do anything to avoid those needles-- and my blood glucose went even higher. He tested me for autoantibodies, and the test was positive. I had type 1 diabetes. (Maybe someone will diagnose me with LADA (Latent Autoimmune Diabetes in Adults)-- then I will have been diagnosed with four different types of diabetes, quite possibly a world record).

Seven years later, for the first time, I was happy that I had diabetes, of whatever type. My second child, at 23 months of age, was showing some symptoms of diabetes. My husband suggested checking his blood sugar, but I couldn't bear to prick his little finger. After a week, we finally checked his blood sugar-- "HI." We went straight to the ER-- "critically high." It was almost 800. Thankfully I had seven years of practice dealing with this disease. He was on a pump within a month of diagnosis, and shortly after that a continuous glucose monitor. Without those tools, I might have lost my sanity by now, not to mention my child's life. I have been awoken out of a deep sleep more than once finding his blood sugar in the 40s and declining.

"Why do you hurt me Mommy? Me no want you hurt me."

- my son, at age 3, who does not like to be poked with needles.

I wondered, is there anything I can possibly do to prevent my older child from getting diabetes? He must be at some genetic risk, with two immediate family members who have type 1. I had heard that the incidence of type 1 diabetes was going up-- was it really? Why? What causes type 1 diabetes? And then I discovered PubMed, where I could read zillions of studies on type 1 diabetes. I took up a new hobby, reading scientific studies. It helped to have a husband with a PhD in biology. My background, however, was in the environmental field. I have a MS from the University of Michigan's School of Natural Resources and Environment in environmental policy and education. I had been reading about the role of environmental chemicals in various other diseases for years. I wondered, could chemicals have anything to do with type 1 diabetes? So I started reading studies on environmental health, looking for clues. This webpage summarizes what I have found, and I intend to keep it up to date with new studies as they become available.

I began this research while sitting with my dad, a noted economist, when he was dying of cancer. He told me he had once heard that his type of cancer might be due to pesticide exposure. He said, "If this is because of something in the air, I'll be pissed." It's too late for him, but the health effects of environmental chemicals are certainly not limited to their potential role in diabetes. I focused on diabetes due to self-interest, my own interests, and because hardly anyone else was.

I did not find all the answers to my questions, of course, but I learned a lot. I made this webpage to let others know who might be interested. Please let me know if you have any ideas, comments, suggestions, or questions: sarah@diabetesandenvironment.org.

Thank you to everyone who helped me by answering my questions, editing, or in other ways. Any mistakes or misinterpretations are my own responsibility. I have summarized and simplified a large amount of information here, and therefore ignored some of the details and complexities of the processes involved. Please keep in mind that biological systems are very complex and not well understood, and, different authors do not agree about how to interpret various findings. They are not all going to agree with my interpretations either, although I did make an effort to be fair, and present more than one view when appropriate.

Sarah Howard

Program Manager, Healthy Environment and Endocrine Disruption Strategies (HEEDS), a program of Environmental Health Sciences.

PS You can also read more about my son's diagnosis in the American Diabetes Association's Diabetes Forecast magazine article from Jan. 2011. Or listen to my tudiabetes interview on environmental factors and diabetes.

PPS As of November 2015, I am also now wearing an artificial pancreas! Thanks to Dana Lewis and Scott Leibrand (see http://diyps.org/ and http://openaps.org/). For more on this adventure, see my blog post, I am now a bionic woman, and also follow me on twitter, @sarhoward. You can also follow the open-source artificial pancreas efforts on twitter using #openAPS and #WeAreNotWaiting. UPDATE: I've switched over to t-slim, with some regrets, the algorithm isn't nearly as good as openAPS. But it's less work maintaining it. More work maintaining the diabetes though.

PPS my twitter account is @sarhoward


Articles in peer-reviewed journals

Heindel JJ, Lustig RH, Howard S, Corkey BE. Obesogens: a unifying theory for the global rise in obesity. Int J Obes (Lond). 2024 Jan 11. doi: 10.1038/s41366-024-01460-3. Epub ahead of print. PMID: 38212644. 

Heindel JJ, Alvarez JA, Atlas E, Cave MC, Chatzi VL, Collier D, Corkey B, Fischer D, Goran MI, Howard S, Kahan S, Kayhoe M, Koliwad S, Kotz CM, La Merrill M, Lobstein T, Lumeng C, Ludwig DS, Lustig RH, Myers P, Nadal A, Trasande L, Redman LM, Rodeheffer MS, Sargis RM, Stephens JM, Ziegler TR, Blumberg B. Obesogens and Obesity: State-of-the-Science and Future Directions Summary from a HEEDS Workshop. Am J Clin Nutr. 2023 May 23:S0002-9165(23)63923-1. doi: 10.1016/j.ajcnut.2023.05.024. Epub ahead of print. [PubMed ID: 37230178]. 

Lustig RH, Collier D, Kassotis C, Roepke TA, Ji Kim M, Blanc E, Barouki R, Bansal A, Cave MC, Chatterjee S, Choudhury M, Gilbertson M, Lagadic-Gossmann D, Howard S, Lind L, Tomlinson CR, Vondracek J, Heindel JJ. Obesity I: Overview and molecular and biochemical mechanisms. Biochem Pharmacol. 2022 Mar 30:115012. doi: 10.1016/j.bcp.2022.115012. [PubMed ID 35393120]


Heindel JJ, Howard S, Agay-Shay K, Arrebola JP, Audouze K, Babin PJ, Barouki R, Bansal A, Blanc E, Cave MC, Chatterjee S, Chevalier N, Choudhury M, Collier D, Connolly L, Coumoul X, Garruti G, Gilbertson M, Hoepner LA, Holloway AC, Howell G 3rd, Kassotis C, Kay MK, Ji Kim M, Lagadic-Gossmann D, Langouet S, Legrand A, Li Z, Le Mentec H, Lind L, Monica Lind P, Lustig RH, Martin-Chouly C, Munic Kos V, Podechard N, Roepke TA, Sargis RM, Starling A, Tomlinson CR, Touma C, Vondracek J, Vom Saal F, Blumberg B. Obesity II: Establishing Causal Links Between Chemical Exposures and Obesity. Biochem Pharmacol. 2022 Mar 24:115015. doi: 10.1016/j.bcp.2022.115015. [PubMed ID: 35395240]


Kassotis CD, Vom Saal FS, Babin PJ, Lagadic-Gossmann D, Le Mentec H, Blumberg B, Mohajer N, Legrand A, Munic Kos V, Martin-Chouly C, Podechard N, Langouët S, Touma C, Barouki R, Ji Kim M, Audouze K, Choudhury M, Shree N, Bansal A, Howard S, Heindel JJ. Obesity III: Obesogen assays: Limitations, strengths, and new directions. Biochem Pharmacol. 2022 Mar 26:115014. doi: 10.1016/j.bcp.2022.115014. [PubMed ID: 35393121]

Howard SG 2019 Exposure to environmental chemicals and type 1 diabetes: an update. J Epidemiol Community Health. 2019 Jun;73(6):483-488. doi: 10.1136/jech-2018-210627 [PubMed link]

Howard SG 2018 Developmental Exposure to Endocrine Disrupting Chemicals and Type 1 Diabetes Mellitus. Frontiers in Endocrinology. 2018 Sep 3;9:513. [PubMed link]

Russ K, Howard S 2016. Developmental exposure to environmental chemicals and metabolic changes in children. Current Problems in Pediatric and Adolescent Health Care, 46(8):255-285. 

Howard SG, Lee DH. 2012. What is the role of human contamination by environmental chemicals in the development of type 1 diabetes? J.Epidemiol.Community Health 66(6):479-481. PM:21502091.

Sargis RM, Howard SG, Newbold RR, Heindel JJ. 2012. The Diabetes Epidemic: Environmental Chemical Exposure in Etiology and Treatment. San.Franc.Med. 85(5):18-20. PM:24771962.

Book chapters

Schug TT, Howard SG, Taylor SW, Heindel JJ, Obesity and Diabetes: Role of Environmental Chemical Exposures in Aging and Vulnerability to Environmental Chemicals, 2013, pp. 201-240 (Weiss ed.).

Letters in peer-reviewed journals

Howard SG, Sargis RM. Type 1 diabetes-origins and epidemiology. Lancet Diabetes Endocrinol 2020; 8(5):367-368.

Howard S, Howard T 2016. The genes associated with a high risk of type 1 diabetes are becoming less common. BMJ Open Diabetes Research and Care, 10 June.

Howard SG, Heindel JJ, Thayer KA, Porta M. 2011. Environmental pollutants and beta cell function: relevance for type 1 and gestational diabetes. Diabetologia 54(12):3168-3169. PM:21947423. Free full text PDF.

Howard SG. 2011. Comment on: Berhan. Thirty Years of Prospective Nationwide Incidence of Childhood Type 1 Diabetes: The Accelerating Increase by Time Tends to Level Off in Sweden. Diabetes 2011;60:577-581. Diabetes 60(9):e25. PM:21868789.

Howard S, Howard TG. 2009. Association of bisphenol A with diabetes and other abnormalities. JAMA 301(7):720-722. PM:19224744.


Russ, K and Howard, S 2016. Endocrine Disrupting Compounds and Pediatric Metabolic Disease. American Public Health Association Annual Meeting and Exposition. Poster presentation.

Howard, SG 2013. Filling a "Critical Data Gap": Type 1 Diabetes and Environmental Chemicals. Environmental Health 2013: Science and Policy to Protect Future Generations. Abstract accepted for oral presentation.

Howard SG, 2012. Environmental Chemicals in the Development of Diabetes and Obesity. American Public Health Association 140th Annual Meeting and Exposition. Poster presentation.

Howard SG, Heindel JJ, Thayer KA, 2012. Resources on Chemical Exposures, Diabetes and Obesity. American Diabetes Association 72nd Scientific Sessions. Published abstract.

Blog posts

Uncovering the Mysteries of Diabetes and Vitamin D (New Study Findings) Diabetes Mine, 2017

Are there environmental causes of type 1? Insulin Nation, 2016

Environmental chemicals in diabetes and obesity: Unexplored territory, Physicians for Social Responsibility, 2013

Collaborative on Health and the Environment Blog

Can environmental contaminants contribute to the development of diabetes? 2010

BPA and type 2 diabetes: What do the human studies tell us? 2011

The effect of environmental chemicals on insulin production: Implications for all types of diabetes 2011

Gut microbiota and environmental chemicals in diabetes and obesity 2012

New report: "Review of the science linking chemical exposures to the human risk of obesity and diabetes" 2012

Phthalates and diabetes: Is there a connection? 2012

Critically high blood sugar, critical science 2012

Can air pollution contribute to diabetes or weight gain? 2012

You are what your great grandmother ate? Transmission of obesity across generations 2013

Diabetes and the environment: Arsenic 2014

Prospective evidence: BPA, phthalates, and type 2 diabetes 2014

Type 1 diabetes incidence skyrocketing in China 2014

Review of the evidence on developmental exposure to certain endocrine disrupting chemicals and obesity 2014

Recap: Institute of Medicine workshop meetings on obesity 2015

Air pollution exposure during pregnancy and the risk of type 1 diabetes in the offspring 2015

An environmental perspective of the American Diabetes Association's 75th Scientific Sessions 2015

I am now a bionic woman 2015

Type 1 still on the rise in US kids 2015

Air pollution and weight gain, insulin resistance and metabolic syndrome: Recent findings 2016

Which chemicals are linked to diabetes and obesity? Perhaps more than we think 2016

Scientific Consensus Statements on the Role of Environmental Chemicals in Diabetes, Obesity, and Metabolism 2016

Party like it's World Diabetes Day 2016