One in 10 of the 120,000 people over 50 in Ireland who have diabetes is unaware they have the disease, worrying research has revealed.
Prevalence of the disease - which is associated with a higher risk of heart attack, vision loss and blindness, heart failure, kidney disease and falls - is even higher among those aged 80 and over.
The problem of undiagnosed diabetes emerged from The Irish Longitudinal Study on Ageing, led by Trinity College, which tracks health trends among older age groups. It also discovered that another 5.5pc of the older population have "pre-diabetes" which leaves them at risk of developing the full-blown disease in the future.
Type 2 diabetes is on the rise due to the increase in the number of people now overweight or obese. It is also linked to age, genetics and ethnicity, and affects groups such as Chinese people and people from south Asia.
The research showed:
The research in 'Diabetes Research and Clinical Practice' is the first to provide the national prevalence of diagnosed, undiagnosed and pre-diabetes in older Irish adults and shows that Irish rates of diabetes are similar to those of other European countries.
Dr Siobhan Leahy, lead author of the research, said: "Lifestyle factors are clearly associated with diabetes and pre-diabetes.
"Public health campaigns promoting the benefits of a healthy lifestyle may help reduce the future incidence of diabetes in Ireland and lessen complications in those with diagnosed diabetes."
Principal investigator Professor Rose Anne Kenny warned: "Diabetes and its related complications account for up to 10pc of healthcare expenditure annually. Timely diagnosis and treatment of the disease are key to reducing this healthcare burden.
"However, our findings emphasise that there is still a significant proportion of Irish adults with diabetes who remain undiagnosed, and targeted screening may help to reduce this."
People can find out if they have diabetes by going to their GP for a blood glucose test. A high blood sugar can leave a person feeling thirsty, urinating frequently or feeling tired all the time.