University of Otago health experts say a study showing a correlation between suicide, homicide and a lower drinking age in the US is further evidence the drinking age should be raised here.
The study, in the journal Alcoholism: Clinical & Experimental Research, looked at data gathered before 1984 when a blanket legal drinking age of 21 was applied across the US.
It showed a higher risk of suicide and homicide persisted into adulthood among women born after 1960 who came from states that had permitted under-21 drinking.
Women had a 12 per cent higher risk of suicide and a 15 per cent higher risk of homicide if they grew up where drinking was permitted at younger ages, making a new argument for keeping the legal minimum drinking age at 21, the researchers said.
The director of the University of Otago's National Addiction Centre, Prof Doug Sellman, speaking with other medical professionals for Alcohol Action New Zealand said the research was "startling" and was evidence the drinking age needed to be raised in New Zealand.
"People who begin drinking earlier in their lives are more likely to kill themselves or someone else later in their lives - not particularly surprising.
"But what was startling was the finding that raising the purchase age of alcohol was associated with a decrease in suicide and homicide rates years later," he said.
Raising the purchase age was one of the measures known to be effective in reducing harm to the wellbeing of young people and this research was a reminder that the damage from drinking at an early age continued into later life.
"We need to raise the purchase age in New Zealand even though dismantling the heavy drinking culture will require other major changes as well.
"It is for this reason that Alcohol Action has commended Hamilton West National MP Tim Macindoe on his supplementary order paper to raise the purchase age up to 20 in New Zealand, for both on-licence and off-licence premises," Prof Sellman said.
Dunedin School of Medicine head of preventive and social medicine Prof Jennie Connor said the study added considerable weight to the evidence of long-term harm from lowering legal drinking and purchasing ages.
"Heavy drinking in adolescence has been linked to poorer outcomes in later life, not only problems from alcohol use but those resulting from lost opportunities," Prof Connor said.