While the veggie patty and the superfood salad are not going to totally replace lamb, chicken or beef as Aussie staples any time soon, the number of Australians identifying as a vegetarian is rising steadily.

According to Roy Morgan Research, almost 2.1 million Australian adults now say their diet is all or almost all vegetarian. Ask someone why they are a vegetarian and you are likely to get many different answers. The reasons include environmental, animal welfare and ethical concerns, religious beliefs and, of course, health considerations.

It’s this last factor we set out to investigate. There are several existing studies on the impact of vegetarianism on health, but the results are mixed. A 2013 study, which followed more than 95,000 men and women in the United States from 2002 to 2009, found vegetarians had a 12% lower risk of death from all causes than non-vegetarians.

Given the contentious nature of discussions about vegetarianism and meat eating, these findings generated lots of coverage and vegetarianism advocates hailed the study.

We set out to test these findings, to see if being a vegetarian would translate into lower risk of early death in the Australian population. Australia is home to the largest ongoing study of healthy ageing in the southern hemisphere, the Sax Institute’s 45 and Up Study. This gives us a pool of more than 260,000 men and women aged 45 and over in New South Wales to work with.