Lifetime Diabetes Risk More Than 70% When BMI Is Greater Than 35

Those with a body mass index (BMI) greater than 35 are almost ten times more likely to develop diabetes in their lifetimes than those with a normal BMI (18.5-24.9) according to a study published in the journal Diabetes Care in 2007.

The study involved analyzing data from the US National Health Interview Survey and involved more than 200,000 American participants aged between 18-84. Overall 15,843 (6.5%) of the study participants had been diagnosed with diabetes.

The researchers found that overall, the lifetime risk of developing diabetes was slightly higher in women than men with 39% of American women developing diabetes in their lifetime compared to 33% of American men.

At the age of 18, underweight men (those with a BMI less than 18.5) had a 7.6% chance of developing diabetes during the remainder of their lifetime. Men in the normal weight range (BMI between 18.5 and 24.9) had a lifetime diabetes risk of 19.8%. The lifetime risk of diabetes was 29.7%, 57% and 70.3% for men with BMI’s of 25-30 (overweight), 30-35 (obese) and 35+ (morbidly obese) respectively.

At the age of 18, women with a BMI less than 18.5 had a remaining lifetime risk of diabetes of 12.2% compared to 17.1% for a BMI between 18.5 and 25, 35.4% for women with a BMI between 25-30, 54.6% for women with a BMI between 30 and 35, and 74.4% for women with a BMI greater than 35.

Diabetes BMI Graph

The impact of BMI on diabetes risk appeared to decrease as age increased however even at a relatively old age, BMI was still an important risk factor of diabetes. Women who were free of diabetes at the age of 65 and had a BMI greater than 35 still had a remaining lifetime diabetes risk of 36% (34.7% for men) compared to less than 10% for individuals who were normal or under-weight.

The absolute increase in diabetes risk was greater between obese individuals (BMI 30-35) and overweight individuals (BMI 25-30) than between overweight individuals and those of a normal weight. Underweight individuals only had a slightly lower lifetime risk of type-2 diabetes compared to people of a normal weight.

The researchers concluded that “Taken as a whole, our data suggest that adult lifetime risk of diabetes is most strongly affected by a BMI greater than 30 and that the impact of BMI, expressed in terms of absolute risk of diabetes, diminishes with increasing age at risk.”

Obesity rates have exploded in the United States over the last 50 years as have the rates of diseases associated with obesity such as heart disease, diabetes, pancreatic cancer, liver cancer, and colo-rectal cancer. As of 2008, the percentage of Americans with a BMI greater than 25 is 65% while one third of Americans have a BMI greater than 30. The percentage of Americans considered morbidly obese (BMI greater than 35) has spiked from less than 5% in the early 1980s to around 15% today. The United States is currently the 9th most obese country in the world according to WHO estimates but ranks 1st among developed nations.