Some 5.84 million people in Japan who are age 65 or over, or about 15% of the age group, will have dementia by 2040, up from 4.4 million in 2022, according to a projection by a health ministry team released on Wednesday.

The latest figure is significantly less than a previous projection released in 2015 that said more than 8 million people would have dementia by 2040. The lower estimate is due in part to people becoming more health conscious and better at making lifestyle changes to address conditions such as high blood pressure, diabetes and hyperlipidemia, the health ministry said. The decline in the number of smokers is also thought to have helped.

Still, the projection showed a steady growth in the number of people with dementia in the age group as Japan’s population continues to gray at one of the fastest rates. It equates to between 1 in 6.7 elderly people having dementia in 2040.