New research suggests that people who use marijuana may be more likely to develop prediabetes than those who have never smoked it / Getty

Adults who used marijuana were 65% more likely to have poor sugar control

People who use marijuana may be more likely to develop prediabetes than those who have never smoked it, according to new research.

A sample of more than 3,000 people in America found that adults who currently used marijuana were 65 per cent more likely to have poor sugar control which can lead to  type 2 diabetes. Those who no longer smoked the drug but had used it 100 times or more in their lifetime had a  49 per cent greater chance of developing the condition.

The link was not affected by BMI and waist circumference, the paper published in Diabetologia (the journal of the European Association for the Study of Diabetes) found.

The authors, led by the University of Minnesota School of Public Health’s Mike Bancks, said: “Marijuana use, by status or lifetime frequency, was not associated with incidence or presence of diabetes after adjustment for potential confounding factors.


“However, marijuana use was associated with the development and prevalence of prediabetes after adjustment. Specifically, occurrence of prediabetes in middle adulthood was significantly elevated for individuals who reported using marijuana in excess of 100 times by young adulthood.

“These results contrast with those previously reported on marijuana use and metabolic health. Future studies should look to objectively measure mode and quantity of marijuana use in relation to prospective metabolic health.”

Despite showing a heightened incidence of prediabetes, the study failed to establish a direct connection to type 2 diabetes itself.

The authors said: “It is unclear how marijuana use could place an individual at increased risk for prediabetes yet not diabetes.”

The data was taken from a group of more than 3,000 Americans now in their  30th year of a study called the Coronary Artery Risk Development in Young Adults. They were 18-30 when they were recruited in 1985 and 1986. The percentage who self-reported current use of marijuana declined over from 28 per cent in 1985-1986 to  12 per cent in 2010-2011.

The paper suggests the lack of a link to type 2 diabetes could be because individuals excluded from the study had higher levels of marijuana use and greater potential for development of diabetes – or that marijuana may have a greater effect on blood-sugar control in the prediabetic range than for full, type 2 diabetes.