Scientists have published a worrying report in the journal Age and ageing that shows smoking "rots" the brain by damaging memory, learning and reasoning, according to researchers at King's College London.

Researchers were investigating links between the likelihood of a heart attack or stroke and the state of the brain. 8,800 people over 50 were tested about their health and lifestyle. As part of the study the participants had to learn new words or name as many animals as they could in a minute. They were then tested again four and then eight years later. Results showed there was a "consistent association" between smoking and lower scores in the tests. Also factored in was high blood pressure and being overweight, which also seemed to affect the brain, but to a slightly lesser degree.

Alzheimer's Research has always said that research has repeatedly linked smoking and high blood pressure to a greater risk of cognitive decline and dementia as smoking reduces blood flow into vessels to the brain thus increasing the disease, and this study adds further weight to that evidence.

Although statistically one in three people over 65 will, develop dementia. There are things people can do to reduce their risk. Such as eating a balanced diet, maintaining a healthy weight, exercising regularly, getting your blood pressure and cholesterol checked and not smoking can all make a difference.

Some early research from Finland found people taking vitamins such as B12 –were the least likely to be diagnosed with dementia. Although experts said more research is needed.

Written and presented by Ann Salter