Typical Type 1 Triggers By Sandra Gordon Type 1 diabetes, which accounts for nearly all of the diabetes in kids under age 10, is on the rise among children and adolescents almost everywhere in the world. The disease occurs when the body's immune system attacks healthy, insulin-producing beta cells in the pancreas, preventing the pancreas from producing the insulin it needs. Anyone with type 1 diabetes must have an underlying genetic susceptibility to autoimmunity (about 40 percent of the population). But DNA alone can't account for the type 1 diabetes upturn. "We know that genes don't change that quickly," says Lori Laffel, M.D., M.P.H., chief of Pediatrics at Joslin Diabetes Center in Boston, which is affiliated with Harvard Medical School. "There has to be an environmental influence present globally to have led to this increase." There's no definitive trigger to date that has been identified to cause type 1 diabetes. Currently, however, a landmark 15-year study called the Environmental Determinants of Diabetes in Youth (TEDDY) is underway at six clinical centers in the U.S. and Europe, tracking 8,000 newborns at high risk genetically for type 1 diabetes. Scientists will likely know much more about what triggers the process that ultimately leads to type 1 diabetes in children in a decade or so, when the results of this study are in. Meanwhile, more potentially definitive studies are ongoing. Here's a round-up of some of the possible environmental triggers under investigation. Possible trigger: Not enough vitamin D Having plenty of vitamin D on board can help build healthy bones and possibly reduce the risk of type 1 diabetes. The incidence of type 1 diabetes is typically highest in countries such as Finland, Sweden and Canada, which are far from the equator, where sun exposure is greatest. Almost all milk sold in the U.S. is fortified with vitamin D. The body also produces its own vitamin D when the sun's ultraviolet rays strike skin. Sun exposure may cause skin cancer, but there's little down side to giving kids a vitamin D supplement as possible health insurance, especially since many kids in the U.S. may be low in the sunshine vitamin. Still, studies to date are mixed about whether giving children vitamin D supplements protects against type 1 diabetes. To play it safe, Dr. Laffel says giving kids a multivitamin that contains vitamin D makes sense for their overall health.

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Typical Type 1 Triggers, Continued Possible trigger: Rubella Exposure to rubella, a contagious disease caused by a virus, "is the single most convincing environmental trigger for type 1 diabetes," says Michael Haller, M.D., associate professor of pediatric endocrinology at the University of Florida in Gainesville. Roughly 50 percent of those who contract rubella get type 1 diabetes. Fortunately, the MMR vaccine, which is one of your child's routine immunizations, protects against rubella as well as the measles and mumps. Since the vaccine was developed, rubella has become virtually extinct. There were just 12 reported cases of the disease in the U.S. in 2007. To protect your child against rubella and possibly type 1 diabetes, make sure he gets immunized on schedule. If you're like 90 percent of parents in the U.S., you get your baby immunized on schedule, according to U.S. Centers for Disease Control and Prevention's timetable. But a growing number of parents—about 9 percent—are creating their own immunization schedule by skipping or delaying certain vaccines, or all of them. "There's no physiologic need to create a new immunization schedule or spread out vaccinations," says Patricia Stinchfield, M.S., R.N., director of Infectious Disease, Immunology and Infection Control at Children's Hospitals and Clinics of Minnesota. Kids should get the MMR vaccine between 12 and 15 months of age and a second dose before entering school, when they're 4 to 6 years old. Possible trigger: Overweight/obesity Being overweight or obese can increase the risk of type 2 diabetes, in which the pancreas doesn't produce enough insulin and the body is resistant to the insulin it does produce. Once reserved for adults, type 2 diabetes is occurring more often in kids age 10 and older. "Obesity may also play a role in the development of type 1 diabetes," Dr. Haller says. To help lower your child's risk of both types of diabetes, encourage him/her to be physically active and to eat a balanced diet, with plenty of fruits, vegetables and whole grains. Exercise and a healthy diet without too many calories can help your child keep his/her weight in check.

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Typical Type 1 Triggers, Continued Possible trigger: Cow's milk protein When it comes to feeding infants, "breast is best" because breast milk isn't just nutrients and calories. It's a liquid immune booster that helps reduce the risk of a host of conditions, including ear and gastrointestinal infections, SIDS, allergies, childhood cancers, and celiac and inflammatory bowel diseases. It may also help reduce the risk of type 1 diabetes. Researchers postulate that cow's milk protein, which is found in regular cow's-milk-based infant formula, may set the stage for the autoimmune process that can lead to type 1 diabetes in months. But the jury's still out. If you can't breastfeed exclusively for your baby's first six months, which is the recommendation of the American Academy of Pediatrics, ask your doctor about giving your baby hydrolyzed infant formula. Although it also contains cow's milk protein, the protein fragments have been micronized into tiny fragments so they're less of a potential threat to a baby's developing immune system. Currently, TRIGR, an international, randomized, double-blinded trial is under way on three continents. The study, which involves 2159 infants from 15 countries, will test whether hydrolyzed infant formula decreases the risk of developing type 1 diabetes in children who are genetically susceptible, compared to regular cow's milk formula. Possible triggers: Viruses Studies suggest that enteroviruses, which are common bad bugs pervasive in the environment that can cause diarrhea, the common cold, or gastroenteritis (a tummy bug), may also increase the risk of type 1 diabetes indirectly by upsetting the natural protective balance of the intestinal tract. "It's speculated that enteroviruses alter the microbium of the gut to allow in different antigens that promote autoimmunity," Dr. Laffel says. Once they're in, these antigens can make a beeline for the pancreas, which can trigger the immune system to destroy insulin-producing beta calls. Studies are under way to understand which, if any, enteroviruses may be part of this lethal chain reaction. Possible Triggers: Infant cereal, gluten The AAP recommends that infants begin eating "solids" between 4 and 6 months of age. Timing could be important for type 1 diabetes risk. Studies suggest that starting infants on infant cereal before 4 months of age or after 7 months of age increases the rise of beta cell autoimmunity. Gluten, a protein found in wheat, is alsounder investigation. A German study known as BABYDIET is exploring whether delaying introducing gluten (wheat products) until after 12 months of age will reduce the risk of autoimmunity in youngsters genetically prone to type 1 diabetes. (NEXT)    

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Typical 1 Triggers, Continued "All of these potential triggers are in the to-be-determined category," Dr. Haller says. "Right now, we're still shooting in the dark." Time will tell and the answer isn't apt to be simple. "Most likely, it won't be any one thing that triggers type 1 diabetes, but a compilation of environmental exposures," he says.

SOURCES 1 - "Incidence of Childhood Type 1 Diabetes Worldwide," Marjatta Karvonen, PhD, et al, Diabetes Care, Vol 23, No. 10, October 2000 (Accessed 02/13) 2 - National Diabetes Education Program. Overview of Diabetes in Children and Adolescents. http://ndep.nih.gov/media/youth_factsheet.pdf (Accessed 02/13) 3 - Interview with Lori Laffel, M.D., Ph.D., Joslin Diabetes Center, One Joslin Place, Boston MA 02215 4 - Interview with Michael Haller, M.D., Associate professor and fellowship director of pediatric endocrinology, University of Florida, Diabetes Center of Excellence, 1600 SW Archer Road, Gainsville FL 32601 5 - Office of Dietary Supplements, National Institutes of Health. Overview of Diabetes in Children and Adolescents. http://ods.od.nih.gov/factsheets/VitaminDHealthProfessional/. (Accessed 02/13) 6 - Mikael Knip et al, Cold Spring Harbor Perspectives in Medicine, May 23, 2012. Environmental Triggers of Type 1 Diabetes. http://ods.od.nih.gov/factsheets/VitaminDHealthProfessional/. (Accessed 02/13) 7 - CDC. Vaccine-Preventable Diseases and Childhood Vaccines. (Accessed 02/13) 8 - Interview with Patricia Stinchfield, MS, RN, CPNP, Pediatric nurse practitioner, Director, Infectious disease/immunology, infection control, Rheumatology and Wound Care Services The Children's Immunization Project, Children's Hospitals and Clinics of Minnesota (NEXT)    

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Typical Type 1 Triggers, Continued 9 - U.S. Dept of Health and Human Services. Tips for Teens: Lower Your Risk for Type 2 Diabetes. http://indep.nih.gov/teens/LowerYourRisk.aspx. (Accessed 02/13) 10 - "Breastfeeding and the Use of Human Milk," Pediatrics, vol 129, No 3, March 1, 2012. (Accessed 02/13) 11 - American Academy of Pediatrics. AAP recommendation on starting solids. http://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/Starting-Solids-TooEarly-May-Increase-Obesity-Risk.aspx. (Accessed 02/13) 12 - ClinicalTrials.gov. BABYDIET-Study - Primary Prevention of Type 1 Diabetes in Relatives at Increased Genetic Risk. http://clinicaltrials.gov/show/NCT01115621%20and%20also%20%255b6. (Accessed 02/13) Reviewed by Jason C. Baker, MD 06/13.

   

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