Social Determinants of Dementia: The Causes of the Causes

There are lots of risk factors for neurodegenerative diseases like dementia – like smoking, high blood pressure and obesity – but much less attention is paid to social factors liked to these diseases. But as a recent paper points out, they are essential when it comes to preventing dementia.

Social Determinants of Health in General

A social determinant of health is a way to think about the links between people’s health and how they live, work, study and socialize.

For example, low socioeconomic status (SES) is not likely to directly cause illness. However, it would impact the quality of care you receive, the things you’re exposed in your day-to-day life and even the type of work you do.

The social determinants of a condition can be thought of as “the causes of the causes” of illness.

The Social Determinants of Dementia – Reviewing the Evidence

The recent paper [1] looked at systematic reviews on the social and environmental determinants of dementia published between 2004 and 2024. The authors found strong evidence linking pollution and other environmental exposures to dementia.

Additionally, higher SES, higher education and higher social engagement had a protective effect, while lower SES and problems accessing healthcare were linked to increased risk.

The State of the Evidence

While I can’t get full access to the new paper, a study from last year covers the same ground. They looked at 100 papers, 26 systematic reviews and 74 primary studies, and found links for:

• Physical environment: 10 reviews and 15 primary studies looked at this. They conclude that air pollution is a factor, and likely mediates racial differences in dementia risk. Specifically, research suggests that your proximity to roads, how deprived your neighbourhood is, exposure to aluminium, pesticides, and solvents are linked to higher risk. Urban green space could help, but results are mixed .

• SES and work: 16 reviews looked at these issues. They found links with lower SES in general, and specifically for income and career success. Shift work, solvents, and (oddly) magnetic field exposure also showed a link. 

• Ethnicities and identity: Being black (relative to white) in the US, being Malay or Indian (in Asia-Pacific) and being indigenous (relative to white Australian) in Australia, and being a migrant vs. a native (in Europe) were linked to greater risk.

The authors point out that most evidence comes from high income countries, and studies from other countries would help to clarify the picture in key areas.