Study seeks to answer why patients are living 50+ years with diabetes
Endocrinologist Dr. Bruce Perkins, left, is pictured with his patient Mary Cringan at Toronto's Mount Sinai Hospital on Monday, May 12, 2014. (Chris Young / THE CANADIAN PRESS)
Sheryl Ubelacker, The Canadian Press
Published Monday, May 12, 2014 5:23PM EDT
TORONTO -- "I never expected to live this long."
That's a refrain that's become increasingly common among people with Type 1 diabetes, many of whom were told as children or teens that their lives would likely be shortened due to a complication of the disease, such like kidney failure, heart attack or a stroke.
But a growing number of diabetics have defied the odds, living with the disease for 50 years or more and often remaining otherwise healthy -- and a Canadian study is underway to find out the secrets to their longevity.
"We are now seeing that people with Type 1 diabetes can live for a lot longer than we had initially thought," says Dr. Bruce Perkins, an endocrinologist at Mount Sinai Hospital in Toronto who is heading the national study.
"It is true, what I've learned from talking to people who've had diabetes for many, many decades, that is what they were told when they were children: 'You're not going to be the one that's going to lead a full life and you are likely going to have these problems,"' Perkins says.
"And there's an amazing sort of mentality that a lot of these patients have because they went through their lives believing that or fighting that."
The Canadian Study for Longevity in Type 1 Diabetes, which began about a year ago and has so far enrolled about 300 patients, asks participants to fill out a detailed questionnaire and to provide the results of their most recent lab tests and eye exam. The researchers want to look at their insulin use; whether they self-inject or use an insulin pump; and if a family doctor or endocrinologist, a specialist in diabetes, manages their care.
The Toronto researchers are also collaborating with the Joslin Diabetes Center in Boston, which has been running a similar study and awards a 50-year medal to those who have lived with the disease for five decades or longer.
An estimated 300,000 Canadians have Type 1 diabetes, which results from the body's immune system destroying the insulin-producing cells in the pancreas. While it's not known what triggers the immune system's attack on these cells -- called islets of langerhans -- genetics may play a role, as may exposure to certain viruses. The auto-immune disease most commonly strikes in childhood and adolescence, with the peak of incidence occurring near puberty.
With little or no natural insulin, the body is unable to regulate how the body uses and stores sugar, or glucose. That means several-times-daily injections of the hormone to prevent a buildup of sugar in the bloodstream, where it can lead to life-threatening complications. (Type 1 diabetes differs from the more common Type 2 form of the disease, in which the body becomes resistant to insulin or the pancreas doesn't produce enough of the hormone.)
Type 1 diabetes was considered a death sentence until Dr. Frederick Banting and Charles Best of the University of Toronto isolated insulin in 1921, leading to its commercial production to treat patients around the world.
In the next few decades, even with the so-called miracle therapy, many diabetics died of end-stage kidney disease by the time they hit age 40, Perkins says. But with the development of more refined insulins and increased awareness of rigorous blood-sugar management over the years, life expectancy has continued to rise -- in some cases dramatically.
Mary Cringan was eight years old when she was diagnosed with Type 1 diabetes in the late 1930s and was initially treated in the Hospital for Sick Children in Toronto, along with another girl her age who had developed the dreaded disease.
"It seems to me somebody once told me I'd be lucky to live to 50," says Cringan, who will turn 85 in July. Seventy-six years after her diagnosis, she has become one of the longest-lived Type 1 diabetics in Canada.
"I think I had a very good mother -- she looked after me well," concludes the Toronto senior, who self-injected syringes she loaded with insulin until about six years ago, when Perkins switched her to an automatic pump.
Still, there have been some complications: she has high blood pressure and had a quadruple bypass to treat coronary artery disease in 2002, which Perkins says was likely related at least in part to her diabetes.
But Cringan agrees she must be doing something right. She kept in touch over the years with the girl who was her Sick Kids roommate, but learned she hadn't fared as well.
"She died of a stroke before 2000. And we were the same age."
So why do some diabetics have longer, healthier lives?
Perkins says the Mount Sinai study will include an examination of participants' genetics and physiological traits to try to tease out why some develop complications -- which also include blindness-causing diabetic retinopathy and peripheral nerve injury that can lead to amputation -- and why others don't.
"That could help us learn what are the reasons that people have success (after) 50 years of diabetes versus not, so we can then implement them as potential treatments or strategies to help people today who are young and getting diagnosed with diabetes, so they can live out their lives without complications."
One of those patients is Dr. Richard Wright, a retired dentist in Parry Sound, Ont., who was diagnosed with Type 1 diabetes when he was just a year old.
Now 68, he has spent his life with daily injections of insulin and a regimen of weighing his food to ensure he eats the proper proportion of carbohydrates and protein.
"I don't have any memories of living without diabetes, but I certainly have many memories of what I had to go through as a youngster and teenager," says Wright. It wasn't until he was in his mid-teens that his mother told him that doctors had said his life might be truncated by the disease.
"She told me 'You were given 19 years when you were diagnosed,' but she said, 'You're doing really well.' And I tip my hat to my mom -- and my dad, but to my mom in particular. She was so attentive to weighing everything that went in my mouth and to doing my urine tests."
In those days, the only way to test sugar levels was to measure it through the urine, which involved heating a sample on a Bunsen burner. Home-based blood-glucose testing by means of a finger prick was not available until the late 1970s.
Over the years, insulin has became more refined, and in the early 1980s, insulin pumps were introduced. While they do away with syringes, they must be exactly calibrated throughout the day to ensure the right dose of the hormone is injected, based on food intake, and at the correct times.
"I've been pumping for 34 years," says Wright, who attributes his lack of complications and longevity to a strict adherence to sound diabetes management, which he calls "walking a very tight tightrope and not straying off the tightrope."
"Between myself and my wife, we spend on average of 28 hours a week, every week ... just doing diabetes management, trying to maintain a target, to keep your blood sugar in that target area 24 hours a day," he says, adding that an exercise routine that includes walking three kilometres twice daily is also part of the mix.
"And that's, in my view, the only way you can do it."
His vigilance has paid off: Wright says he has no complications and he feels "wonderful."
Today, some studies estimate that patients with Type 1 diabetes may have up to 15 years knocked off their lifespan.
"I don't personally believe that to be true, now that I'm managing people and I see how healthy and well they're doing," counters Perkins, who hopes to enrol patients from across the country in the study.
"Now I have the confidence to tell them they can lead out their lives the way they would have if they hadn't developed diabetes, simply because we have so much better ways of giving insulin, better types of insulin, better ways to screen for complications," says the 43-year-old specialist, who has had Type 1 diabetes himself since age 18.
"It does require work. It requires a relentless vigilance on their part in monitoring blood sugars, thinking through insulin doses, self-managing their diabetes. But it definitely is possible and we've got beautiful examples of people living their lives to the fullest."