A numerical goal will be set for the first time for reducing the number of people in Japan with dementia, with an eye to cutting incidence among patients in their 70s by 6 percent over the next six years, government sources said Wednesday.

The development came a day after the Geneva-based World Health Organization published its first guidelines on the prevention and management of the disease.

The move by Tokyo is aimed at curbing an anticipated rise in social security expenses, by promoting prevention and delaying the onset of the disease. The government plans to state its goals in a new outline of policies to tackle dementia set to be released this summer, they said.

The government will hold a meeting Thursday with experts in fields related to the disease and present its plans, the sources said.

Under current policies the government emphasizes creating a society where people can live comfortably even if they develop dementia, symptoms of which can include a decline in cognition and memory loss.

But under the plan the government will also begin to focus on prevention, as a health ministry estimate predicts some 7 million people — or 1 out of 5 aged 65 or above — will suffer from dementia in 2025 as the country’s population rapidly grays.

Specific measures for disease prevention include holding exercise lessons at local community centers, as it has been found that physical activity and social engagement could help prevent the disease, the sources said.

At the same time the government will promote research into the disease, as current scientific evidence on preventing dementia is insufficient, the sources added.

In 2015, the government compiled a national strategy to support dementia patients by organizing local “dementia supporters” — people who have knowledge of the disease and are able to provide help to sufferers and their families.

Approximately 25 percent of those over 65 may have dementia by 2060 if the incidence rate for the disease remains static, according to a report published by Toshiharu Ninomiya, a professor specializing in public health at Kyushu University.

That figure would increase to 33 percent if the rate of dementia diagnoses increases over time.

In recent years Japan has seen a number of fatal car accidents caused by the elderly, as well as those with dementia.

In one case last year, an elderly woman in Chigasaki, Kanagawa Prefecture, ran over four people, killing one, when she ran her car through a red light. During her trial she claimed that she had a mild case of dementia.

Some 55,000 drivers aged over 75 were suspected to be experiencing the symptoms of dementia when they renewed their licenses in 2018, according to a report published by the National Police Agency in March. In 2017, a new law came into effect requiring elderly drivers to go through a stricter screening process.

A further 531,000 people were judged to be experiencing a decline in their cognitive functions. In total, roughly 25 percent of drivers over 75 who underwent screening last year were suspected to be experiencing some level of cognitive impairment.

The report also found that about 26,000 people didn’t renew their license after being diagnosed with dementia by a doctor.

On the other hand, 14,000 drivers renewed their licenses having not received such diagnoses.

The rate at which those over 75 have been involved in fatal car accidents has also almost doubled in recent years. Some 13.5 percent of fatal crashes were caused by drivers aged 75 or older in 2016, up from 7.4 percent in 2006.The WHO’s report on dementia puts physical activity at the top of its list of recommendations for preventing cognitive decline.

Stopping smoking, following a healthy diet and avoiding harmful use of alcohol were also among the recommendations in the report, which was titled: “Risk reduction of cognitive decline and dementia.”

Treatment for hypertension, high cholesterol and diabetes also lowers the risks, the report said.

Neerja Chowdhary, a WHO expert, said that the study had not looked at smoking marijuana and did not include environmental factors, although there was some evidence of a link to pollution. Chowdhary also said there was too little evidence of a link with poor sleep to include it in the recommendations.

Vitamins and supplements were not useful and could even be harmful if taken in high doses, she said.

But there was less evidence that cognitive training or social activity would stave off the onset of the disease, and insufficient evidence that antidepressant medicines or hearing aids could help.