In my forties and fifties, not a day passed without the fear of cancer present at the back of my mind. Friends died, others went through long and painful chemotherapy. My sister passed away after suffering from brain and lung cancer.

The disease operated like a lottery, not differentiating between those who led healthy lives and wore sun block, and those who smoked and drank too much. One friend died from skin cancer less than a month after diagnosis.

What can you do? Have regular check-ups and cross your fingers. I refuse to get dragged into negative thinking.

Six ways to help reduce the risk of dementia Show all 6 1 /6 Six ways to help reduce the risk of dementia Six ways to help reduce the risk of dementia Moderate, regular exercise Last year, a study found that walking briskly for 30 to 40 minutes a day, three times a week, was all it took to “re-grow” structures of the brain linked with cognitive decline in later life. Researchers have also said statins, designed to help those with heart conditions, may play an additional role in protecting the brain from dementia. Getty Images Six ways to help reduce the risk of dementia Quit smoking A review of studies relating smoking and dementia found that (when you remove studies funded by the tobacco industry) smokers have a significantly greater risk of dementia. Getty Six ways to help reduce the risk of dementia Protect your head A variety of observational studies have shown that professional boxers and war veterans are at greater risk of dementia due to repeated concussion and traumatic head injuries. Rex Six ways to help reduce the risk of dementia Puzzles and crosswords In 2010, studies suggested people who do puzzles and crosswords may stave off dementia for longer. However, the same study also found they may experience a more rapid decline once the disease sets in. Crosswords and Puzzles from The Independent can be solved here Getty Images Six ways to help reduce the risk of dementia A healthy lifestyle Dr Laura Phillips of Alzheimer’s Research UK says a healthy lifestyle is best for preventing dementia: “Eating a balanced, healthy diet, exercising regularly, not smoking, and keeping blood pressure and weight in check.” Getty Six ways to help reduce the risk of dementia A Mediterranean diet Research has suggested that a Mediterranean diet – rich in fish, fresh fruit and vegetables, whole grains, nuts and seeds – may reduce the risks of dementia. However NHS Choices has rpeviously warned some of the media coverage of this diet may overstate its benefits. Rex

But now that deep-seated, ever-present fear of cancer has been replaced by another big black cloud, equally impossible to ignore: dementia.

Every day we hear how many people are going to suffer from the disease – up to one in three – and it is already the leading cause of death, according to research published this week. Over a certain age, you wake up and do memory tests to check your brain is still OK. You reconstruct what you did the previous day, trying to remember phone numbers and names, anything to offer reassurance that the dreaded D isn’t taking hold.

A cure for dementia remains a long way off, although scientists have made a breakthrough, editing the DNA of rats to partially restore their sight. Genome editing, fixing “broken genes in the brain”, may eventually offer a cure for dementia. But how do you live with the diagnosis? Researchers also claim that computer games can be used to spot dementia earlier, by testing our map reading skills. I’m not sure I want to play the game without a cure on the horizon.