Today, we generally think of diabetes in terms of a simple dichotomy: Type 1 is the inherited, early form of the disease, and type 2 is the kind that’s linked to obesity and develops over time. But a recent report published online by the Lancet suggests that diabetes may be far more complex than its current system of classification suggests, MedPageToday reports.

According to researchers, patients are increasingly exhibiting symptoms of two or more types of diabetes, especially adults 20 to 40 years old. Scientists say the growing obesity epidemic and increasingly sedentary lifestyles are to blame.

Until about 30 years ago, it was presumed that all diabetic children and young adults had type 1 diabetes. This form of the disease is classified by chronic high blood sugar, caused by the immune system’s destruction of insulin cells. Conversely, type 2 diabetes was thought to only affect older adults who had developed insulin resistance because of environmental factors such as poor diet or obesity.

But type 2 diabetes is an emerging pediatric disease. Between 2001 and 2009, type 2 diabetes rates increased among children by nearly 21 percent.

What’s more, scientists are discovering the phenomena of adult-onset type 1 diabetes. When this happens, patients often suffer from beta cell impairment as well as the typical insulin resistance and high blood sugar levels symptomatic of type 2 diabetes.

According to study authors, diabetes seems to result when there’s a collision between genes and environment. They also said that the rapid increase in both types of diabetes in recent years “suggests that many patients are genetically predisposed to both forms [of the disease].” This means an unhealthy lifestyle could trigger either type 1 or type 2 diabetes in a patient, or a combination of the two conditions.

Further complicating the matter, researchers recently identified subtypes of the disease, including ketosis-prone diabetes, a hybrid form, as well as latent autoimmune diabetes of adults (LADA). Patients with LADA are generally younger, produce less insulin than those with type 2 diabetes and progress faster to insulin dependence than those who have type 1 diabetes.

But the good news is that a better understanding of these subsets will help doctors better personalize diabetes care.

For more information about the causes, types and treatments for diabetes, click here.