How social connections and lifestyle can reduce dementia risk

New research has found that social environment and lifestyle factors can significantly influence dementia risk, independent of genetic predisposition

Recent data from aged care provider Dementia Australia revealed that dementia cases are expected to triple by 2050, affecting over 153 million people globally. It estimated that there are currently more than 421,000 people living with a form of dementia in Australia. This figure is projected to increase to more than 812,500 by 2054 and the illness is set to become the leading cause of death among Australians. 

These statistics put dementia on track to become the nation’s leading cause of death, according to the Australian Bureau of Statistics (ABS). In 2023, dementia accounted for 9.1 per cent of all deaths, closely following ischaemic heart disease at 9.2 per cent. Dementia remains the leading cause of death for Australian women, representing 12.2 per cent of all female deaths and 6.4 per cent of male deaths.

Dementia Australia CEO Professor Tanya Buchanan said that, given there is no cure for dementia and poor community understanding of the terminal nature of the disease, the ABS data reinforces the urgent need for a public health approach to reducing – or preventing – the risk of developing dementia.

“This call is backed by the 2024 update of The Lancet Commission on the prevention, treatment, and care of dementia, which reports that almost half of dementia cases worldwide could be prevented or delayed,” Professor Buchanan said. “As dementia edges closer to becoming the leading cause of death of Australians, it is crucial that we act now to focus on the brain health of the nation as well as provide more targeted, effective support to those impacted by dementia. Taking this dual approach will ensure we are working towards reducing the impact of dementia in the future.”

While genetic predisposition plays a role in dementia risk, new research from UNSW Business School suggests that social environment and lifestyle factors can significantly influence cognitive health outcomes for older adults. The research team examined how social determinants of health affected dementia risk among 5199 participants over a 14-year period. The research, Social Environment, Lifestyle, and Genetic Predisposition With Dementia Risk: A Long-Term Longitudinal Study Among Older Adults, published in The Journals of Gerontology: Series A, found that an unfavourable social environment increased dementia risk substantially.

The social environment impact on brain health

“We know that a healthy lifestyle – factors such as a balanced diet, regular exercise and avoiding smoking can reduce dementia risk, but our study shows that social factors are equally important,” said research paper co-author Katja Hanewald, an Associate Professor in the School of Risk and Actuarial Studies at UNSW Business School. “And while more businesses are developing programs for ageing populations, too few are considering these crucial social determinants.”

The research team developed a “polysocial risk score” to assess overall social risk. This score aggregates 19 social determinants of health across five domains. “The polysocial risk score was developed using Principal Component Analysis to aggregate social determinants across economic stability, education, healthcare access, neighbourhood environment, and social context,” said Dr Shu Chen, a UNSW Business School Scientia PhD graduate who led the research.

The score ranges from 0 to 10, with higher scores indicating greater social risk, and the research found that every 1-point increase in the polysocial risk score was associated with a 21.6% higher risk of developing dementia among older people, controlling for genetic risk and lifestyle factors.

"The findings are consistent with previous studies that underscore the significant role of social contact in protecting older people from dementia," explained Dr Chen, who said the polysocial risk assessment could help businesses and healthcare providers identify individuals or groups at higher risk and tailor interventions accordingly.

"Although it is difficult to design interventions targeting income or education, future intervention studies or government programs may consider designing prevention strategies to improve the companionship of older people, especially among those who are widowed or isolated."

How lifestyle choices impact dementia prevention

While social environment played a crucial role, the research revealed that lifestyle modifications could help offset increased social environmental risks. The study found that regular physical activity and moderate alcohol consumption were associated with lower dementia risk across all social environment categories.

"Regular exercise and moderate drinking were found to protect participants from developing dementia across all social environment risk groups," the researchers explained. Among participants with high social environmental risk, for example, regular exercise and moderate drinking were associated with a 43-60% lower risk of developing dementia.

“Being married or in a partnership provides emotional and social support, which can help reduce stress and promote mental health, thereby lowering dementia risk,” said research paper co-author Scientia Professor Henry Brodaty from the Centre for Healthy Brain Ageing at UNSW Sydney. “Similarly, those who live alone or are socially isolated may lack the social interactions that are important for cognitive health, increasing the risk of dementia,” he said.

Higher-income levels are also associated with lower dementia risk. “Higher household income is often associated with better access to healthcare, healthier living environments, and lower levels of chronic stress,” said Dr Chen. “As for education, higher education levels are linked to greater cognitive reserve, which can delay the onset of dementia symptoms by making the brain more resilient to damage.”

Practical implications for health professionals and policymakers

For healthcare providers and policymakers, the research provides evidence-based insights for developing more effective dementia prevention strategies. The study suggests that programs focusing solely on genetic risk or individual lifestyle changes may miss crucial social determinants that influence cognitive health.

Instead, companies should look beyond just promoting physical health and integrate social interventions into their wellness programs. “Reducing dementia risk can lead to significant economic benefits, including lower healthcare costs, reduced absenteeism, and increased productivity within the workforce,” said A/Prof. Hanewald.

“Companies should focus on initiatives that foster social interaction, such as teambuilding activities, social clubs, and community service projects, to improve employees' social environments. For society, these interventions can lessen the burden on healthcare systems and long-term care facilities while also enhancing the overall well-being and economic stability of older adults.”

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This study demonstrates that while we cannot control genetic predisposition to dementia, addressing social environment factors and promoting healthy lifestyle choices can significantly impact cognitive health outcomes. For healthcare professionals and policymakers, this research provides a framework for developing more comprehensive and equitable approaches to dementia prevention.

“Our research uncovers a powerful insight: your social connections and daily habits could be your brain's best defence against dementia,” said Prof. Brodaty. “By staying active and nurturing meaningful relationships, even in difficult circumstances, you can significantly reduce your risk. Designing good-quality wellness programs is an important element businesses can adopt to benefit society. That means designing them for the holistic needs of people, including their social environment, not just their physical health.”