Low earnings and alcohol withdrawal have been linked to the early development of dementia
Scientists analyzed data from more than 350,000 participants in a British biobank and found that 15 factors were significantly associated with a higher risk of dementia at a younger age (less than 65 years). As reported in JAMA Neurology, the main risk factors were low education, low socioeconomic status, the presence of variants in the APOE4 gene and both no alcohol use and alcoholism.
Dementia that develops in people younger than 65 years of age is called early-onset dementia. Various estimates put the global incidence of early-onset dementia at 3.9 million people. And, although the prevalence of this type of dementia is low compared to the classic variant of this neurodegenerative disease, it affects people more severely because of the early development of incapacity.
The identification of risk factors (modifiable and non-modifiable) for early dementia could help in the development of preventive interventions. Early studies focused mainly on genetic risk factors, with variants of the apolipoprotein E (APOE) gene playing a leading role. However, little is known about modifiable risk factors for early dementia.
Stevie Hendriks of Maastricht University and colleagues in the UK analyzed data from 356052 participants in the UK Biobank (197036 of whom were women). The average age of the sample was 54.6 years. There were 485 deaths during 2891409 person-years (mean follow-up 8.12 years; median follow-up 9.18 years). Of 39 risk factors initially selected, 30 had a significant association with early dementia.
People with higher levels of education had a lower risk than those with lower levels of education. The risk of early dementia was increased in people with low socioeconomic status, and moderate to high alcohol consumption had a weaker association with early dementia than complete alcohol withdrawal. Moreover, alcoholism increased the risk of early dementia. In terms of social isolation, participants who socialized with friends or family once a month or less had a higher risk of developing early dementia than those who visited friends or family more often. Also, the risk of early dementia was increased with vitamin D deficiency (vitamin levels less than 10 nanograms per milliliter) and high levels of C-reactive protein (more than one milligram per deciliter).
Notably, higher carpal tunnel strength was associated with a lower risk of early dementia. But hearing impairment, orthostatic hypotension, stroke, diabetes, heart disease and depression, as well as different variants of the APOE4 gene were associated with a high risk of early dementia. In addition, some risk factors depended on gender: for example, men with diabetes had a higher risk of developing dementia than men without diabetes, while women had no statistical association with diabetes at all. Women with high levels of C-reactive protein had a higher risk of dementia than women with low protein levels, while in men protein had no effect on the risk of dementia (in all comparisons of risk factors, statistical significance reached values of p < 0.05).
Overall, this study shows that modifiable risk factors exist for early dementia. Consequently, it is possible to develop meaningful early dementia prevention programs through exposure to these risk factors.
Air pollution is known to be a risk factor for dementia, but little is known about the direct mechanism of this exposure. But this is about to change: in 2024, British scientists will conduct a clinical trial in which volunteers with a family history of dementia will inhale various air pollutants - wood smoke, exhaust fumes, cleaning products and cooking emissions.