The long-running Dunedin Multidisciplinary Health and Development Study has come up with another gem in health research.
The latest information gleaned from the University of Otago’s study of 1000 individuals born in Dunedin in the 1972-73 year, has found long-term cannabis use does damage lungs, but not in the same way as tobacco.
Study co-author Prof Bob Hancox said until recently, it was assumed cannabis would have similar effects to tobacco.
“Although the effects of cannabis were detrimental, the pattern of lung function changes was not the same.
"The research found that prolonged cannabis use led to over-inflated lungs and increased the resistance to airflow to a greater extent than tobacco.
"It was also found that cannabis use may also impair the ability of the lungs to extract oxygen from the breath.
"This is a known consequence of smoking tobacco, but has not been demonstrated with cannabis until now."
He believed the Dunedin study may have the world’s most complete data on lifetime cannabis use and lung function in a large population sample.
The findings came from the Dunedin Multidisciplinary Health and Development Study, which has documented cannabis use and measured lung function throughout adult life up to age 45 in more than 1000 individuals.
"Although cannabis is one of the world’s most widely used drugs, there has been little research on the effects on the lungs," he said.
"This is because it has been difficult to study a drug that remains illegal in most parts of the world."
He said the latest findings supported observations from other research that found cannabis has different effects to tobacco.
"The Dunedin results extend these findings with more complete measures of cannabis use and a full assessment of lung function using 11 different measures."
Prof Hancox said it was not known why cannabis harmed the lungs differently than tobacco.
Given the widespread increasing use of cannabis globally, and the trend to decriminalisation, understanding its respiratory effects was a priority, he said.
