1242 GMT December 15, 2018
Being diagnosed with type 1 diabetes at a young age is associated with more cardiovascular complications and higher risk of premature death than being diagnosed later in life, independent of disease duration, medicalxpress.com reported.
The findings, published in The Lancet, come from a large observational study in Sweden that followed over 27,000 individuals with type 1 diabetes and more than 135,000 matched controls for an average of 10 years.
With around half of individuals with type 1 diabetes diagnosed before the age of 14, the authors stress the need to consider wider and earlier use of cardioprotective measures such as statins and blood pressure lowering drugs in this high-risk population.
"Although the relative risk of cardiovascular disease is increased after an early diabetes diagnosis, the absolute risk is low", said Dr. Araz Rawshani from the University of Gothenburg in Sweden who co-led the research.
"However, age at disease onset appears to be an important determinant of survival as well as cardiovascular outcomes in early adulthood, warranting consideration of earlier treatment with cardioprotective drugs."
The new estimates suggest that individuals diagnosed before the age of 10 have a 30-times greater risk of serious cardiovascular outcomes like heart attack (0.31 cases per 100,000 person years for participants with diabetes vs 0.02 cases in every 100,000 person-years for controls) and heart disease (0.5 vs 0.03) than those in the general population, whilst risk levels are around six times higher for people diagnosed between ages 26 and 30 (0.87 vs 0.25 and 1.80 vs 0.46 respectively).
People with younger-onset type 1 diabetes are four times as likely to die from any cause (0.61 vs 0.17), and have more than seven times the risk of dying from cardiovascular disease (0.09 vs 0.02) than their diabetes-free counterparts. In contrast, people first diagnosed between ages 26 and 30 face a lower (three-fold) risk of dying from any cause (1.9 vs 0.6) and cardiovascular disease (0.56 vs 0.15) compared to their peers without diabetes.
Professor Naveed Sattar, co-author, University of Glasgow (UK), explains: "While the absolute risk levels are higher in individuals who develop diabetes when older, simply due to age being a strong risk factor, the excess risk compared to healthy controls is much higher in those who developed diabetes when younger. If this higher excess risk persists over time in such individuals, they would be expected to have highest absolute risks at any given subsequent age. Indeed, those who develop type 1 diabetes when under 10 years of age experience the greatest losses in life expectancy, compared to healthy controls. This is something we did not fully appreciate before."
The impact of type 1 diabetes on younger people should not be underestimated, and there is a need to consider adding recommendations about age of onset in future guidelines, say the authors.
Type 1 diabetes mellitus is the second most common chronic disease in children, accounting for 85 percent of diabetes in the under 20s. But it's not unusual to develop the disease as an adult. Worldwide, the incidence of type 1 diabetes in children aged 14 years and younger has risen by three percent a year since the 1980s.
It's well known that people with type 1 diabetes are at increased risk of health problems and have shorter life expectancies, partly due to premature cardiovascular disease. But, until now, the impact of age of diagnosis on this excess mortality and cardiovascular risk was unclear.
To provide more evidence, the researchers calculated the excess risk of all-cause mortality, cardiovascular mortality, acute heart attack, stroke, cardiovascular disease, coronary heart disease, heart failure, and atrial fibrillation in 27,195 individuals from the Swedish National Diabetes Register compared to 135,178 controls matched for age, sex, and county from the general population (average age 29 years).
Individuals with diabetes, who registered between Jan 1988 and December 2012, were divided into groups by age at diagnosis — 0-10 years, 11-15 years, 16-20 years, 21-25 years, and 26-30 years — and followed up for an average of 10 years.
The researchers adjusted for a range of factors that may have influenced the results including age, sex, marital status, income, educational level, region of birth, diabetes duration, and previous history of cardiovascular complications.