The public should reserve judgment on studies suggesting cannabis can reduce the risk of diabetes, a doctor has urged.

Annabel Fountain, the director of endocrinology at the Bermuda Hospitals Board, spoke out after a presentation by pharmacist Marcia Williams.

As reported in The Royal Gazette yesterday, Ms Williams, who was invited to the Island by the Bermuda Pharmaceutical Association for Pharmacy Week, highlighted a 2013 study of 4,657 male subjects by the Harvard Medical School and the Beth Israel Deaconess Medical Centre, which suggested that cannabis can delay the onset of diabetes.

Dr Fountain said the issue of cannabis being used as a means for prevention remained controversial and that there was conflicting research. She referred to a study by Coronary Artery Risk Development in Young Adults (Cardia), published this year in the journal Diabetologia, that suggests those who use marijuana might be more likely to develop prediabetes in their middle adulthood than those who have never smoked it.

Prediabetes is when a person has abnormally high blood sugar levels, but they are not high enough for a diagnosis of type 2 diabetes.

The study enrolled about 3,000 young adults from the United States over a 25-year period and stated: “There were no significant links between cannabis use and full-blown diabetes.”

Dr Fountain told this newspaper: “This issue is still very controversial — the results of studies are very conflicting.

“There have been studies suggesting that current cannabis smoking is associated with lower odds of diabetes.

“Many of these studies, including that quoted in The Royal Gazette, are based on one-off points with participants providing blood work on one occasion.

“The study from 2015 aimed to analyse associations between self-reported use of marijuana and prediabetes and diabetes over time. The investigators followed 3,034 participants who were aged 18 to 30 at recruitment in 1985-86 and did blood work at two, five, seven, ten, 15, 20 and 25 years after enrolment.

“The study from 2015 showed that marijuana use in young adulthood was associated with the development of prediabetes in middle age. It did not show an increase in diabetes diagnosis.

“Compared with those who reported never using marijuana, individuals who reported using it more than 100 times had a 39 per cent increased risk of developing pre-diabetes.”

Dr Fountain pointed out that there were a large number of participants excluded from the analysis as they had already developed diabetes when recruited in the 1980s and they would have likely been at a higher risk due to certain demographic factors.

Asked what advice she would give the Bermuda public, Dr Fountain said: “Reserve judgment at this time.”