Marijuana users are more likely to have prediabetes - the state of poor blood sugar control that can progress to type 2 diabetes - than those who have never smoked it, a new study has found.
Previous studies on marijuana use have showed conflicting results, with some suggesting marijuana can reduce the risk of diabetes, despite others showing that the drug is associated with an increased calorie consumption.
In this study, the researchers, led by Mike Bancks of University of Minnesota in US, studied the association between self-reported marijuana use and concurrent and incident prediabetes and full blown type 2 diabetes, considering both quantity used and status of current use.
They also aimed to examine the role of body mass index (BMI) and waist circumference as potential confounding and mediating factors to these associations. They also looked at the effects of sex and race.
Data from Coronary Artery Risk Development in Young Adults (CARDIA) study was used to determine marijuana use and presence of prediabetes and diabetes.
Individuals in the CARDIA study were 18-30 years of age at study recruitment in 1985-1986 and are currently in their 30th year of observation.
The association between marijuana use and prevalence of prediabetes and diabetes was examined in 3,034 participants at CARDIA exam Year 25 (2010-2011) and incidence of prediabetes and diabetes according to previous marijuana use was assessed in 3,151 individuals free from prediabetes and diabetes at Year 7 (1992-1993) who returned for at least one of the four subsequent follow-up examinations over the next 18 years.
There was a 65 per cent increased risk of having prediabetes in individuals who reported current use of marijuana, and a 49 per cent increased risk of having prediabetes in individuals who reported lifetime use of 100 times or more, researchers said.
However, there was no association between marijuana use and full blown type 2 diabetes at CARDIA exam Year 25.
The authors then did further analyses where marijuana use was assessed prior to the development or not of prediabetes.
Over 18 years follow-up, a 40 per cent greater risk for developing prediabetes (but not diabetes) was found for individuals who reported lifetime use of 100 times or more compared to individuals who reported never using marijuana.
"In conclusion, marijuana use, by status or lifetime frequency, was not associated with incidence or presence of diabetes after adjustment for potential confounding factors," the authors said.
"However, marijuana use was associated with the development and prevalence of prediabetes after adjustment," they said.
The study was published in the journal Diabetologia.
