Dementia risk factors have greater impact on minority ethnic groups

Factors that increase the risk of dementia have a greater impact on risk for people in minority ethnic groups, finds a new study led by UCL researchers.

The new PLOS One study found that modifiable risk factors—including hypertension, obesity, diabetes, low HDL (high-density lipoprotein) cholesterol and sleep disorders—have different impacts on dementia risk for different ethnic groups.

The number of people with dementia is on the rise around the world. There has been increasing interest in potentially modifiable risk factors, as eliminating these could theoretically prevent around 40% of dementia cases, according to research led by UCL academics.

However, most risk factor studies have been conducted only in people of European descent. In the new study, researchers analyzed the relationship between risk factors and dementia onset using anonymized data from English primary care records, spanning 1997 to 2018, for 865,674 adults in diverse ethnic groups.

Overall, 12.6% of the study population developed dementia—16.0% of White people, 8.6% of South Asian people, 12.1% of Black people and 9.7% of those from other ethnic groups.

Nearly all risk factors analyzed in the study were associated with dementia, with the same risk factors often conferring a higher risk of dementia in Black and South Asian people, particularly for cardiovascular risk. After adjusting for comorbidity, age, sex and deprivation, hypertension conferred higher risk of dementia in Black people compared to White people, while hypertension, obesity, diabetes, low HDL and sleep disorders conferred a higher risk of dementia in South Asian people. Compared to the effects in White people, hypertension had 1.57 times more impact on dementia risk in South Asian people and 1.18 times more impact in Black people.

Previous research led by this study's lead author, Dr Naaheed Mukadam (UCL Psychiatry), found that dementia rates are 22% higher among Black people in the UK compared to white people, while Black and South Asian dementia patients die younger, and sooner after diagnosis.** An earlier study by Dr Mukadam found that close to one in two cases of dementia could be preventable in low- to middle-income countries.

She and her co-authors say these latest results may explain these previous findings, and they conclude that dementia prevention efforts should be targeted toward people from minority ethnic groups and tailored to risk factors of particular importance.

Dementia is a growing burden on our aging population, and this study adds to findings that this is disproportionately affecting some ethnic minority communities. Not only are some risk factors for dementia more common among ethnic minority groups, but these factors also have greater impacts on dementia risk than among the White population.

We need more prevention efforts tailored for ethnic minority communities to ensure that dementia prevention is equitable, helping health professionals become culturally sensitive and able to inform their patients about dementia risk factors."

Dr Naaheed Mukadam, Lead Author, UCL Psychiatry