Earlier this week Tom Hanks revealed he has Type 2 diabetes - a condition affecting approximately 2.9 million people in the UK, while a further 850,000 are thought to be undiagnosed.
Speaking on The David Letterman Show, the Oscar-winning 57-year-old said that he only received a full diagnosis recently, despite first showing signs of the disease in the early 1990s.
But why, if he first had symptoms more than 20 years ago, did diagnosis take so long?
"Type 2 diabetes can take many years to develop," explains Dr Steven Hurel, consultant physician and endocrinologist at London Bridge Hospital. "There is a slow transition from normal glucoses to raised glucoses in a pre-diabetes phase, to glucoses high enough to be considered diabetes."
Dr Hurel believes that Hanks would have had pre-diabetes signs, rather than typical Type 2 diabetes symptoms.
He adds: "His numerous roles, requiring significant weight loss, over the years may have actually slowed the progression or temporarily reversed the pre-diabetes but as he has gained weight the glucoses have risen now to such a point that he is classified (‘graduated’) as having diabetes."
Dr Kundavaram Kumar, consultant endocrinologist at London Bridge Hospital Sevenoaks Centre, adds that mild symptoms and external factors can also cause late diagnosis.
"Unlike Type 1 diabetes, symptoms for Type 2 can be sometimes very mild causing late diagnosis and by the time of diagnosis majority of patients may have complications. We also have to take into account busy work schedules, stress and socio-economic factors which can further lend into delayed diagnosis."
What symptoms should people look out for?
- Excess urination
- Recurrent infections (boils, thrush etc)
- Low energy
- Acanthosis nigricans (slight black velvety discolouration under armpits and neck folds)
Dr Kumar adds that the UK has implemented health checks for patients above the age of 40 and screening for high risk patient groups - due to ethnic population, previous pregnancy diabetes etc.
Who is at risk?
Rapid weight gain increases the risk of Type 2 diabetes, as does physical inactivity, family history of the condition, high blood pressure and some ethnicities are also prone to the condition.
Hanks linked his diagnosis with weight gain and lifestyle. "My doctor said, 'Look, if you can weigh as much as you weighed in high school, you will essentially be completely healthy and not have Type 2 diabetes,'" he said. "And I said to her, 'Well, I'm gonna have Type 2 diabetes.'"
Managing diabetes after diagnosis
Dr Hurel says: "Once diagnosed with diabetes lifestyle is really important to control the diabetes and slow the need for more medication.
"Generally speaking the longer you have diabetes the more medication you need to control it, but being sensible with your diet and exercising regularly can help a lot.
"There is also some evidence that for some a very low calorie diet may reverse diabetes."