After studying the incidence of diabetes among the Pima Indian population in Arizona, Dana Dabelea wrote one of the first papers detailing the trend of rising rates of Type 2 diabetes – once called adult-onset diabetes – in youth. Her research has expanded to look at maternity and the ways in which a mother’s health and behavior can impact the incidence of diabetes in offspring and in future generations.
“From my work with the Pima Indians that has been replicated in many other populations, we know that Type 2 diabetes is no longer an adult chronic disease,” she said. “We see it in children and it’s increasing in children by about 30 percent in the last eight or nine years, which is substantial.”
Dabelea, who has studied diabetes for 20 years, is the Conrad M. Riley Endowed Professor in epidemiology at the Colorado School of Public Health at the University of Colorado Anschutz Medical Campus. She also is principal investigator in numerous studies and is the director of the LEAD (Lifecourse Epidemiology of Adiposity and Diabetes) center.
1. How did you choose this career path and what influenced your decision?
I was trained at the University of Medicine, Timisoara, in Romania where I completed my Ph.D. in clinical sciences. After my doctoral training, I spent two years doing postdoctoral studies at the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) branch in Phoenix, Arizona, where I did research on the Pima Indians.
That was a life-changing experience. It was there that I started to be interested in Type 2 diabetes in youth, and I wrote one of the first papers highlighting this trend. Until that time, Type 2 diabetes used to be called adult-onset diabetes, and so describing it in a youth population was extremely novel and interesting and concerning.
Thereafter, I did research into diabetes during pregnancy in that population because the children with Type 2 diabetes were very likely to have mothers with diabetes while the babies were in utero. And that is how I started thinking about a life-course approach. For example, we found that intrauterine exposure to maternal diabetes during pregnancy was the strongest risk factor for diabetes for children. Almost half of Type 2 diabetes in youth in the Pima Indians could be explained or attributed to this intrauterine exposure. My work with the Pima Indian community and with my mentors, including Peter Bennett, who are outstanding diabetes epidemiologists, were life-changing experiences that motivated me to refocus my career. So I went back to Romania after my postdoc training there and convinced my family to emigrate. My husband was very supportive and we now have strong careers in Colorado.
In 2001, I accepted a junior faculty position at CU in the Department of Preventive Medicine and Biometrics in the School of Medicine, which became the Colorado School of Public Health in 2008. I chose CU over other potential places in the United States because the person who was going to become my mentor here, Dick Hamman, had just gotten a grant, along with five other sites in the U.S., to study pediatric diabetes, which went right along with the work I had done in Romania and Phoenix.
Once here, Dick Hamman allowed me to take over the local leadership for the study called SEARCH for Diabetes in Youth. In 2004, I became the principal investigator for the Colorado site of SEARCH, and in 2005, I became co-chair of this multi-center study at the national level. This is still an ongoing study and is now in the 17th year.
SEARCH is one of the most comprehensive projects, and perhaps the only U.S. project to address the epidemiology and natural history of diabetes in youth encompassing both diabetes type and all major racial and ethnic groups. It has a registry component, which includes surveillance of pediatric diabetes, and a cohort component that aims to understand the development of diabetes-related health outcomes, the risk factors for complications and barriers to quality health care in individuals diagnosed with diabetes as children.
Surveillance is the systematic collection of information that permits one to study the burden of a disease in a population. Rather than just recruiting volunteers, what we do is identify everyone, all the children aged less than 20 years old who have diabetes in five U.S. locations, including Colorado, regardless of whether they will participate in the study or not. We do that to be able to count them to determine how many kids there are by race and by diabetes type so that we can estimate the prevalence, incidence and trends in incidence over time.
2. Earlier this year, you presented a lecture as the winner of the Elizabeth Gee Memorial Lectureship and award, and you also will present a lecture later this year as the 2017 recipient of the American Diabetes Association Kelly West Award, the premier award for epidemiology given by the ADA. What were/are the topics of the lectures?
The Gee Award recognizes outstanding work on women’s issues in academia. The lecture I gave in March focused on how my career unfolded, with examples of my mentoring experiences, scholarly accomplishments throughout various academic stages, as well as examples of mentoring and supporting CU women, junior faculty, students, fellows and staff.
The other one, the Kelly West Award, is the highest scientific award given annually to a person who has made a contribution to diabetes epidemiology. This lecture will be in June and will likely focus on pediatric diabetes as well as the life-course approach that I try to implement in my studies.
Children have a higher lifetime burden of diabetes than do adults. By studying younger people with diabetes, I think we increase our chances of finding risk factors for the disease progression before the complications develop. So the lecture will focus on what we’ve learned from studies like SEARCH and my work with the Pima Indians and some other studies I’m doing now about the life-course determinants of diabetes in youth and its complications as a motivation for future research and programs that will help us prevent it.
3. What is a life-course approach and how has this approach advanced research?
As we grow and develop from the womb to old age, there are multiple risk factors and exposures that happen to us over time, and these exposures – whether they are nutritional, environmental (like toxins and pollutants), physical, infectious and many others – cause us to respond in ways that we are just beginning to understand. Life course tries to integrate these multiple exposures as well as specific periods when they occur, which we call critical periods, to understand better how to reduce or prevent their long-term outcomes such as chronic diseases – obesity, diabetes, heart disease and cancer.
It seems that this is important not only during childhood, puberty or young adulthood or older age, but it appears to be especially important during pregnancies when multiple systems and organs in the offspring may be programmed about how to respond to such exposures both immediately before the baby is born, but also later in life. And there is evidence that these effects are transmitted or lasting into the next generation, and so the effect of exposures on one individual may be seen in grandchildren. This life-course approach gives us a more complete picture about disease etiology than something that we can develop by looking at one factor and one place in time.
This is a relatively new focus in epidemiology in general, and specifically, in diabetes research, but it’s growing and we’re learning more every day about how we can use this approach to prevent chronic disease such as diabetes. To relate to some of my studies, for instance, we know now from the types of studies that I and others have been doing, that focusing on achieving healthier pregnancies could result in less childhood obesity and less Type 2 diabetes in youth.
Healthier pregnancies may mean a number of things – more adequate weight gains, better diets, less sedentary lifestyles, no diabetes during pregnancy or better controlled diabetes during pregnancy if the mom happens to have diabetes. These healthier pregnancies are not just good for the mother but are actually good for the offspring and maybe for the following generation as well.
From some of these studies, we know that childhood obesity is one of the strongest risk factors for childhood Type 2 diabetes, but we also have learned that maternal obesity during pregnancy, maternal diabetes during pregnancy, unhealthy diets or sedentary lifestyles during pregnancy will lead to offspring adiposity and fatness, and obesity is the strongest risk factor for Type 2 diabetes. We’re learning, for example, that what the mother eats during pregnancy might influence taste development in the offspring and the satiety set point in the offspring. We’ve also learned from one of my studies that breast feeding has protective effects from childhood obesity and might mitigate the effects of exposure to maternal diabetes during pregnancy.
I think that this concept of looking backwards to understand what is happening now or to predict the future is what life course is all about.
4. You are the principal investigator in several ongoing studies, including the Healthy Start Study. What does the study hope to achieve?
The study involves a pre-birth cohort and explores whether and how developmental overnutrition is associated with childhood obesity and metabolic outcomes like diabetes and heart disease. In this study, we enrolled more than 1,400 mothers before the child was born and we asked them to continue to see us throughout the pregnancy and after the babies were born, until the children are ages 4 to 5 at this point. Additional funding will allow us to follow them until they are age 7 to 9.
Mothers were asked about what they ate, how much physical activity they had, whether they smoked or drank, and other questions. We looked at weight before, during and after pregnancy, measured blood fats and glucose levels, for instance. After the baby was born, we measured fat mass in a small chamber called a peapod, and that gave us an estimate of lean and fat tissues. This is important because we want to understand how maternal diet and activity changed the ratio of the amount of fat to lean tissue in the baby. Babies born at the same weight might have different amounts of fat tissues.
As we continue to study the cohort, we’re asking about the home situation, the food environment, physical activity, growth and illness. Again, at age 4 to 5, the children will be put into a small chamber called a bodpod and we’ll look at fat and lean mass, childhood diet, sleeping, physical activity, brain development, and more in-depth measures to really understand how pregnancy and early life experiences and exposures might have increased their risk or influenced their development.
We haven’t analyzed data yet but we are developing a map of where participants in the study live to access information about air quality or air pollution, and we’ll link that to these developmental measures to see what impact air pollution has. Another thing we’re doing through ancillary study is to look at what people call environmental chemicals or endocrine disrupting chemicals or obesogens (chemical compounds that disrupt normal development and can lead to obesity). We’ve measured these in maternal blood samples or urine samples from pregnancy, hypothesizing that exposure to these chemicals during pregnancies might affect the baby or the next generation. We’re measuring three classes of these widely used chemicals that are in everything from personal care products to children’s toys to flame retardants, cooking utensils and plastic bottles.
We’ve already seen that more than 95 percent of our participants have detectable levels of some of these chemicals in their bodies. We haven’t yet published any of these results, but a colleague of mine has an abstract that she presented last year in Rome and the paper has been accepted by an environmental health journal.
5. Do you have a favorite memory from your time at CU? If so what is it and why does it mean so much to you?
The development of the LEAD Center was started a couple of years ago, and that has to be a favorite memory. It’s an accomplishment, of course, but also is a point in my life that allows me to start to focus on helping others achieve their goals and build successful careers.
By creating the center, I’m hoping to create an infrastructure that supports their academic growth and development, hopefully throughout their own life course. The center focuses on researching obesity, diabetes, and chronic disease over the life course that puts together all of my studies, but also other people’s studies that are similar. That means having a cohort to study for junior people who don’t have the patients or participants they need to develop their own studies. That’s one example of what we do. We also created research teams that can help others collect data or write successful grants and study protocols and we also provide research and career mentoring.