Risk factors for dementia vary by ethnicity, study finds

Modifiable risk factors—including hypertension, obesity, diabetes, low HDL cholesterol and sleep disorders—confer a higher risk of dementia for people in some minority ethnic groups compared to White people, according to a new study published in the open-access journal PLOS ONE by Naaheed Mukadam of University College London, UK, and colleagues.

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. 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; 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.

The results may explain previous findings of greater susceptibility, earlier age of dementia onset, and shorter survival after dementia diagnosis in minority ethnic groups, the authors say. They conclude that dementia prevention efforts should be targeted toward people from minority ethnic groups and tailored to risk factors of particular importance.

The authors add, "We found that not only are some risk factors for dementia more common in minority ethnic groups but that the impact of some of these risk factors is even greater than in the White population. So we need tailored dementia prevention, taking into account ethnicity and risk factor profile to ensure dementia prevention is equitable."