TEHRAN, Young Journalists Club (YJC) - "Around 35 percent of dementia is attributable to a combination of the following nine risk factors: education to a maximum of age 11-12 years, midlife hypertension, midlife obesity, hearing loss, late-life depression, diabetes, physical inactivity, smoking, and social isolation," a study published in The Lancet medicine journal suggested on Thursday.
Breaking down the factors, the study said maintaining good hearing between the ages of 45 and 65 reduces the number of cases by 9 percent.
Attending school at least until the age of 15: The benefits of education and socialization would help reduce the cases of dementia by 8 percent, according to the study.
Stopping smoking could reduce the number of cases by 5 percent, the study said.
Other factors contributing to the risk include depression (4 percent), physical inactivity (3 percent), social isolation (2 percent), high blood pressure (2 percent), obesity (1 percent) and type 2 diabetes (1 percent).
The study said factors related to nutrition, sleep and some other determining and preventable factors other than nature had not been included in the study.
"We have not incorporated other potential risk factors, such as diet, alcohol, living near major roads, or sleep, which could be relevant. Therefore, the potentially preventable fraction of dementia might be underestimated in our figures," the study said.
A separate study by British researchers suggested that a Mediterranean-style diet might delay the risk of dementia by more than five years.
Latest estimates show nearly 50 million people around the world suffer from dementia syndrome in general.