Uncontrolled blood pressure can lead to several health complications such as heart attacks, strokes and dementia. A new study has found that patients who take medication to control blood pressure in old age have a lower risk of dementia.

According to the Centers for Disease Control and Prevention (CDC), nearly half of adults in the U.S. have hypertension, and only 25% of those with hypertension have it under control. In 2021, 691,095 people lost their lives in the U.S. directly or indirectly due to unmanaged hypertension.

In the study, published in Jama Network, researchers found that older adults on blood pressure medications have a 26% lower risk of developing dementia than those with untreated hypertension.

"Hypertension is the most prevalent risk factor for dementia, affecting more than one billion people worldwide. Midlife hypertension is associated with an approximately 60% increased risk of all-cause dementia and an approximately 25% increased risk of Alzheimer's dementia," the researchers wrote.

Vascular dementia is the most common form of dementia associated with hypertension. It happens when the brain does not receive enough oxygen due to the thickening of blood vessels caused by hypertension. The condition also leads to the buildup of amyloids, which are associated with dementia.

"Previously, studies have found variously that antihypertensive use in late life may increase dementia risk, decrease it, or have no effect at all. There have been very few large studies that have examined those older than 80 and those in developing countries," said Dr. Matthew Lennon, the lead author of the latest study.

In the latest study, researchers evaluated 17 previous studies that used data from around 34,519 community-dwelling older adults from 15 countries, including the U.S.

The participants were aged above 60 and were followed up for four years. They were grouped into three categories: those without hypertension, those with hypertension but treated with medication and those with hypertension but without medication.

The findings suggest that people with untreated hypertension have a higher risk of developing dementia.

The study's limitation is that since the participants were from different countries, the researchers did not have information on the type of blood pressure medications and dosage taken by them. Also, the definitions of hypertension change over time and vary across countries. So, there could be variations in how it is diagnosed.