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The risk of developing dementia is higher among Black and South Asian people, a study finds. Adam Kaz/Getty Images
  • The number of people with dementia is rising globally.
  • The risk of developing dementia is higher for people of some ethnicities.
  • Much of the increase is due to the aging population, but some health conditions, such as hypertension, obesity, and diabetes, also increase the risk of dementia.
  • A new study has found that these “modifiable risk factors” increase dementia risk for Black and South Asian people more than white people.
  • The authors argue that dementia prevention efforts should be targeted toward people from minority ethnic groups and tailored to risk factors of particular importance.

The number of people with dementia worldwide is expected to reach more than 150 million by 2050. An aging population is responsible for much of the increase, but modifiable risk factors, such as hypertension, high body mass index, diabetes, and smoking, could be causing up to 40% of cases.

However, these risk factors do not have the same effect on everyone. A new study carried out in the United Kingdom and published in PLOS One, suggests that they increase dementia risk more in people of color than in white people.

“This finding is not entirely surprising, as it correlates with previous research which has also concluded the differential impact of certain risk factors on dementia amongst different ethnic groups. However, this study provides valuable empirical evidence to support these previous hypotheses.”

Dr. Emer MacSweeney, Consultant Neuroradiologist at Re:Cognition Health.

Slowing down and some memory changes are a normal part of aging, but dementia is not an inevitable consequence of getting older. Around two-thirds of older adults will not develop dementia.

According to the Centers for Disease Control and Prevention, dementia is a deterioration in memory, thinking, and decision-making that interferes with normal life. There are several forms of dementia; the most common, Alzheimer’s Disease, causes an estimated 60% to 70% of dementia cases.

Several factors may increase the risk of developing dementia. These include:

Previous research has found that dementia is more common in some ethnicities than others, with higher rates found in Black and Hispanic than in white participants in a large-scale study in the United States. However, this study did not explain why the rates were higher.

This latest study could go some way toward explaining the differences, as it has found that some of these modifiable risk factors affect different ethnicities more.

The study examined data from 865,674 people from CALIBER, a database of anonymized electronic health records for 50 million people in the U.K.

All the data was for people who lived in England aged 65 and over between 1997 and 2018. None had dementia at the start of the study period, and although the records were anonymous, ethnicity was recorded in the data.

The researchers recorded dementia for anyone who had a diagnosis of dementia on their GP (primary care) records, hospital records, death records, or who had been prescribed Alzheimer’s disease medications at least once or been treated for Lewy body/Parkinson’s dementia.

Unlike previous dementia studies, the cohort contained people from diverse ethnic groups. Each person was assigned to one of the following ethnic groups, based on their records: white; South Asian (Asian Bangladeshi, Indian, Pakistani); Black (Black British, Black African or Black Caribbean), Mixed (Any mixed background), Other (Chinese, Other Asian and any category classified as “other”).

Of the 865,647 people in the study, 12.6%, or 1 in 8, developed dementia.

The researchers adjusted for variables including baseline age, sex, and deprivation, then considered many risk factors for dementia. They found that some factors had more effect on people of certain ethnicities.

Compared with the risk for white people, in South Asian people, hypertension, obesity, diabetes, low HDL (high-density lipoprotein, or ‘good’ cholesterol), and sleep disorders conferred a higher risk of dementia. In Black people, hypertension conferred a higher risk.

These risk factors are similar to those that increase the risk of cardiovascular disease in Black and South Asian people.

The researchers found that, compared with white people, hypertension had 1.57 times more impact on dementia risk in South Asian people and 1.18 times more in Black people.

Dr. MacSweeney, who was not involved in the study, told Medical News Today: “The findings provide valuable insight into the differential impact of risk factors on dementia amongst ethnic groups. The study highlights the need for targeted efforts in dementia prevention and management in diverse populations.”

“Diet, sleep and physical and mental exercise are all imperative to safeguarding against dementia.”

– Dr. MacSweeney

Although the risk of dementia increases with age, the CDC advises several lifestyle habits that will improve your brain health as you age and reduce your risk of developing the condition. These include trying to:

  • Maintain a healthy weight and keep active.
  • Manage your blood sugar levels, particularly if you have diabetes.
  • Prevent high blood pressure, and manage it if you do have high blood pressure.
  • Look after your hearing — if you have hearing loss, get it corrected.
  • Drink alcohol only in moderation, and avoid binge drinking.
  • Quit smoking — stopping smoking reduces your risk of not only dementia but also heart disease, lung cancer, and other lung diseases.

According to the Alzheimer’s Association, older Black people are twice as likely as older white people to have dementia. A complex combination of factors, such as racism, structural inequality, and socioeconomic barriers to high quality healthcare, contribute to this risk.

Dr. MacSweeney commented:

“The paper does not delve into the specific social factors or obstacles that people from ethnic minorities may face or have faced, which might elevate their risk of dementia.”

“However, it indirectly suggests that risk factors including hypertension, obesity and diabetes, which are more common in minority ethnic groups, may be linked to social determinants, such as healthcare access, lifestyle and cultural differences,” she added.

In a press release, the authors said their findings highlight the need for “tailored dementia prevention, taking into account ethnicity and risk factor profile to ensure dementia prevention is equitable.”