THOUSANDS of elderly people in Bournemouth and its surrounding areas may be living with undiagnosed dementia, according to shock new NHS estimates.

Figures collected by GPs show that there are 4,822 people over 65 who have been diagnosed with some form of dementia in the Dorset authority area alone. But estimates by the NHS, based on the age profile and gender of patients, suggest that the real figure may be 8,355 – nearly double.

That means a possible 3,533 pensioners are living with a debilitating illness that has not been formally recorded by their doctor, with the attendant knock-on effects for the NHS, services and their families.

The picture in Bournemouth is little better, where figures collected by GPs show 1,942 people over 65 who have been diagnosed with some form of dementia, against NHS estimates that the real figure may be 2,739.

Poole officially has 1,443 pensioners with some form of dementia. But according to NHS estimates the real figure may be well over 2000, meaning that more than 700 people in the town could be living with the undiagnosed disease.

East Dorset’s numbers mean that a potential 724 people are living with undiagnosed dementia, on top of an official figure of 879.

The figures are being collected in response to the Prime Minister's Challenge on Dementia set up by David Cameron and the Department of Health wants GP surgeries in England to increase the rate of diagnosis.

It’s set a target for at least two thirds of the estimated number of people with dementia to be diagnosed by March 2015. The diagnosis rate for the whole of England is currently 68.3%, but area to area this ranges from 40% to over 90%. Dorset is missing the national target with a rate of 57.7%.

The Royal College of General Practitioners said doctors realised the importance of spotting the signs of dementia early but in some circumstances might delay making a formal diagnosis in the interests of patients and due to pressure on services to support them.

Chair of the RCGP Professor Helen Stokes-Lampard, said: "There may be some situations where GPs might validly consider it in the best interest of the patient to delay seeking a formal diagnosis, especially in the early stages of the condition if there is minimal adverse effect on daily living and functioning and where patients do not want to be labelled.

"This decision might also be influenced by GPs knowledge of the local availability of assessment and treatment services, which may be insufficient to meet demand."

But the Alzheimer’s Society disagreed, saying people with dementia had a ‘right to know’

Senior policy officer, Andrew Boaden, said: "Dementia diagnosis rates vary significantly from place to place, which is concerning but a diagnosis helps people by allowing them to access emotional, practical, legal and financial advice, as well as any support and treatment available.

"With the number of people with dementia set to reach 1 million by 2021, the Government and the NHS must do more to address this issue."