Higher blood levels of omega-3 fatty acids, the fats found in fish, are linked to a healthier old age, according to a study.

Researchers tracked 2,622 adults, average age 74 and healthy at the start of the study, from 1992 to 2015, looking to see if they continued to live without chronic diseases and without mental or physical problems.

The investigators measured blood levels of four common types of omega-3s: EPA and DHA, found in seafood; ALA, derived from plants; and DPA, which the body produces in small amounts.

They found that compared with people in the lowest one-fifth for omega-3 levels, those in the highest one-fifth had an 18 percent lower risk of unhealthy aging. The study appeared in BMJ.

Considered separately, EPA and DPA were associated with lowered risk of unhealthy aging, but DHA and ALA were not.

The lead author, Heidi T.M. Lai, a postdoctoral fellow at Tufts University, said, “In our study we found that adults with higher blood levels of omega-3s from seafood were more likely to live longer and healthier lives. So it is a great idea to eat more fish.”

DEMENTIA RISK RISES WITH PRE-ECLAMPSIA

Having pre-eclampsia — dangerously high blood pressure during pregnancy — is linked to an increased risk for dementia later in life, according to a study.

Up to 5 percent of pregnant women develop pre-eclampsia, usually after the 20th week. In addition to hypertension, the condition can include signs of diminished kidney or liver function.

Researchers followed about 1.2 million Danish women who had given birth between 1978 and 2015. More than 58,000 of them had pre-eclampsia during pregnancy. The study is in BMJ.

Having pre-eclampsia doubled the risk for vascular dementia, and quadrupled the risk for women older than 65. There was a modest association of pre-eclampsia with Alzheimer’s disease, and none with any other type of dementia.