A former friend emailed the Otago Daily Times this week "deeply distressed" by publicity over Mr Noon being denied an expensive drug, Infliximab, which is available to patients elsewhere in the country.
The story has resulted in many offers of advice and some offers of financial help.
However, the email questioned Mr Noon's suitability for public sympathy.
"What disturbs me most about this story is the fact that genuinely nice people are wanting to hand Joe money from their own pocket without knowing the person he is.
"Should these people have seen the way Joe has chosen to live his life they would certainly think twice before helping him out of a predicament he could be attempting to help himself out of."
The email described Mr Noon as a "self-confessed alcoholic and smoker by age 17".
"Had he spent his time and money on a healthy lifestyle I doubt he would be in quite the predicament he is now."
Asked to respond yesterday, Mr Noon confirmed he was a heavy drinker between the ages of 18 and 20.
"It was just probably the fact that I was 18 or 19 and didn't have a job. I was a bit at a loss, I guess. And the relationship I was in at the time was not healthy."
Asked if he considered himself an alcoholic at that stage, Mr Noon said: "Yes, I would say I was. Definitely. But not now."
Mr Noon said he had not been drinking for three years "apart from Christmas and the odd social get-together".
He said he was still a smoker - "and I hate it" - and he knew it was "terrible" for his condition.
Crohn's disease researcher Dr Richard Gearry, of the University of Otago's Canterbury School of Medicine, said yesterday that smoking doubled people's chances of getting the disease but "there aren't many other really black and white risk factors in the environment after that.
"Alcohol and diet - we don't have any data that they have any impact on your risk of getting the disease in the first place."
Dr Gearry said for those with the disease, smoking was an issue but there was no evidence that alcohol or diet worsened people's prognosis.
Although Crohn's disease patients were encouraged to give up smoking, Dr Gearry considered it "pretty unfair" to condemn a patient for being unable to give up the habit.
Much of the advice from the public to Mr Noon has centred on diet.
Dr Gearry said there was no scientifically proven evidence of diet "being effective at managing Crohn's disease" with the exception of an "exclusive elemental diet which is often given through a nasal gastric tube for months on end which we don't do, really, in New Zealand at all. And, usually, it's only effective in children."
