As life expectancy increases, preserving cognitive function is crucial for promoting health among ageing populations, as it can lead to dementia. However, a concerning issue accompanying this increase is the widening gap in cognitive function between different socioeconomic groups because of age. A study by Wang and colleagues published in Scientific Reports this month assessed the extent of this gap in the US. The authors analysed data from 1,313 adults ages 60 years and older in the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014. They found that higher socioeconomic status (SES), as measured by a combination of education, occupation, income-to-poverty ratio, health insurance, and food security, was linked to better cognitive function in older adults.

To measure these differences, Wang and colleagues compared differences in four cognition test scores between high, medium, and low SES groups. They found statistically significant differences in three of these four tests (Delayed recall, Animal Fluency, and Digit Symbol Substitution), with scores increasing by higher SES across these cognitive tests. Given that the loss of cognitive function can result in dementia, these results have important implications for the US. According to GlobalData, the number of diagnosed prevalent cases of dementia is expected to increase substantially over the next five years, from 1.97 million cases in 2023 to over 2.59 million cases by 2032. This trend is likely to continue as the US population ages. While lifestyle interventions such as physical activity, healthy diets, and stress reduction may help mitigate cognitive decline, there is no cure for the disease. These trends underscore the need for interventions aimed at reducing the morbidity of dementia in the US over the next decade.

The findings of Wang and colleagues highlight the critical need to focus public health efforts on identifying vulnerable populations and enabling targeted lifestyle interventions to prevent cognitive decline and, ultimately, dementia. This is particularly important given the greater impact of SES on cognitive function compared to healthy lifestyle factors. Targeting vulnerable populations for preventative interventions is imperative for reducing disparities in health outcomes. However, this will be challenging as it may require systemic interventions such as providing access to affordable and nutritious food, creating safe recreational spaces, and offering comprehensive healthcare services to address socioeconomic disparities in population health. However, such interventions can help create an environment that supports adopting and maintaining healthy behaviours over the long term.