Later Diagnosis Doesn’t Always Protect: Risk Seen in Adult-Onset T1D
Yuxia Wei, a PhD student at the Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, presented an analysis of data from Sweden’s national health databases comparing cardiovascular outcomes between 10,184 people diagnosed with T1D at ages 18-29 years, 30-39 years, and ≥ 40 years; another 375,523 people diagnosed with T2D at those ages; and 509,172 population controls matched for age, sex, and county.
Those diagnosed after age 40 years had higher A1c levels and were less likely to be using insulin pumps than those diagnosed at younger adult ages.
Compared with population controls, at a median of about 7 years of follow-up, people with T1D had significantly higher all-cause mortality at all diagnosis age groups, with a hazard ratio of 1.71. This rose to 2.78 for those diagnosed at age 30-39 years.
Compared with those with T2D, the mortality risks weren’t significantly different at any age, but the risks for non-cardiovascular death, including from cancer and infection, were significantly higher among those diagnosed after age 40 years (1.31 overall). Those diagnosed with T1D at any adult age had lower risks for major cardiovascular events than those diagnosed with T2D. Hazard ratios ranged from 0.27 for those diagnosed at age 18-29 years to 0.78 for those diagnosed after the age of 40 years.
Smoking and A1c above target were the greatest contributors to mortality. Those two factors, along with body mass index (BMI), were the strongest contributors to major adverse cardiovascular events (MACE).
“Adult-onset T1D carries excess risk of death and cardiovascular disease, without obvious attenuation over age at diagnosis…Smoking, A1c, and BMI are the key factors to be managed to improve prognosis in adult-onset T1D,” Ms. Wei concluded.
BMI: Often Overlooked in T1D, but a Major CVD Risk Factor
Two studies examined the link between overweight/obesity and cardiovascular risk in T1D. One, by Laurence Salle, MCU PH, of the Endocrinology, Diabetes and Metabolic Diseases Department at CHU Limoges, France, was a prospective, longitudinal cohort study of 2367 people with T1D at 68 centers in France who didn’t have a cardiovascular history at baseline.
Of those, 51% had normal BMI (18.5-24.9), 31% had overweight (25-29.9), and 18% had obesity (≥ 30). Cardiovascular risk factors, including LDL cholesterol, triglycerides, and hypertension increased with an increasing BMI. The 10-year CVD risk was significantly higher for those with overweight (9.61%) and obesity (9.93%) than for those with normal weight (7.24%), in both men and women.
However, BMI was found to be an independent predictor of 10-year high cardiovascular risk in men but not women, while waist:height ratio independently predicted risk in both men and women, Dr. Salle reported.
The second BMI study, from Enrique Soto-Pedre, MBBS, of the Division of Population Health and Genomics at the University of Dundee, Scotland, presented data on a retrospective follow-up from 1995 to 2019 of 1973 people with T1D aged > 18 years at diagnosis (42% women; mean age, 34.2 years; 18.9% had obesity.
After 10 years of follow-up, those with overweight and obesity had significantly higher odds of developing arterial hypertension, even among those taking angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, with statistically significant adjusted hazard ratios of 1.73 and 3.37 for the obese and overweight groups, respectively.
MACE were significantly more common among those with obesity, with an adjusted hazard ratio of 2.95, as was acute myocardial infarction, 3.33.
“These results emphasize the importance of incorporating weight management into the overall management of individuals with T1D. No one has doubts about weight management in T2D, but in type 1, it’s not so clear. One of the main [concerns] would be safety [in terms of hypoglycemia],” Dr. Soto-Pedre concluded.