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Type 2 Diabetes Before Age 40 Tied to Increased Risk of Serious Mental Illness

January 15, 2019

By Megan Brooks

NEW YORK—Adults who develop type 2 diabetes before age 40 have an excess of hospitalizations during their lifetime, including an "unexpectedly" large burden of serious mental illness in young adulthood, according to a population-based study from Hong Kong.

"Increased risk of distress and anxiety has been reported in young people with diabetes in other international studies but the high risk of hospitalizations due to mental illness in people with young onset diabetes in this large scale analysis involving over 0.4 million people with diabetes has not been reported before," Dr. Juliana Chan from The Chinese University of Hong Kong and Director of the Hong Kong Institute of Diabetes and Obesity told Reuters Health by email.

"Efforts to prevent young-onset diabetes (YOD) and intensify cardiometabolic risk factor control while focusing on mental health are urgently needed," she and her colleagues wrote in a paper online today in Annals of Internal Medicine.

They examined two large cohorts of Chinese adults with type 2 diabetes to determine the effects of age at onset and modifiable risk factors on hospitalization between age 20 and 75. They followed 422,908 adults (46% women) for 2.8 million person-years in The Hong Kong Diabetes Surveillance Database and 20,886 individuals (47%) women) for 0.2 million person-years in The Hong Kong Diabetes Registry.

In both cohorts, patients with YOD (before age 40) had the highest hospitalization rates by attained age, "far exceeding" age-specific rates for the general population.

In the registry cohort, roughly 37% of bed-days for patients with YOD were due to mental illness, primarily psychotic (55%) and mood (31%) disorders.

"People with diabetes from a young age are extremely vulnerable due to long disease duration (over 30-40 years). Management of young onset diabetes is complex due to the psychological burden that comes with a diagnosis of chronic disease in a young person, and the multiple demands including long term follow up, changing lifestyle and taking multiple medications," said Dr. Chan.

After multivariate adjustment, by age 60, patients with YOD had double the hospitalization rate for any cause (rate ratio 1.8), compared to those who developed diabetes after age 40 (usual-onset). YOD was also associated with nearly seven times the rate of hospitalization for renal causes (RR, 6.7), 3.7 times the rate for diabetes and 2.1 times the rate for cardiovascular causes.

"These associations were partially mediated by control of modifiable risk factors, demonstrating the importance of early intervention to reduce the adverse effects of cumulative exposure to cardiometabolic risk factors. Hospitalization rates in patients with YOD were reduced by one third with intensified management and by more than half if onset was delayed until age 40 years," the researchers said in their article.

Dr. Chan noted that YOD prevalence is increasing around the world. "Between 1990 and 2000, surveys conducted in USA, UK and Japan have reported 8-10 fold increased prevalence of young onset diabetes arbitrarily defined as age of diagnosis <35 to 45, which coincides with women's reproductive age highlighting the potential impact of maternal diabetes on the offspring, who are also at high risk of developing young onset diabetes," she said.

"We are living in a high risk environment and people, young or old, can be affected by diabetes," she told Reuters Health. "School education, professional training and government policies are called for to address this alarming issue affecting our global citizens and to formulate action plans focusing on community education, early intervention and holistic care in order to make our healthcare system sustainable, to reduce complications, premature death or hospitalization rates for enhancing our quality of life."

Funding for the study was provided by the Asia Diabetes Foundation. The authors have disclosed no relevant conflicts of interest.


Ann Intern Med 2019.

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