Shocking data published by Annals of Internal Medicine. About 21 million American adults are obese and diabetic.

“Diabetes has increased dramatically. The rates have almost doubled since the late ’80s and early ’90s,” said Elizabeth Selvin, the study’s lead author and an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, in Baltimore.

“This study also highlights that the increase in diabetes really tracks closely with the epidemic of obesity. The diabetes epidemic is really a direct consequence of the rise in obesity,” Selvin said.

There are two main types of diabetes — type 1 and type 2. Type 2 diabetes is the far more prevalent type of diabetes, accounting for 90 percent to 95 percent of all diabetes, according to the National Diabetes Education Program.

Although both types of the disease result in higher-than-normal levels of blood sugar, the cause of each is different. Type 1 is an autoimmune disease, and its development is unrelated to weight. The exact cause of type 2 is unknown, but excess weight and a sedentary lifestyle are known to play a role in its development.

Poorly controlled diabetes poses serious health risks, including heart disease, kidney damage and blindness.