Vision Loss and High 'Bad' Cholesterol Linked to Increased Dementia Risk

Loss of vision and elevated bad cholesterol levels have been identified as new risk factors for dementia, according to a recent Lancet Commission report. Researchers emphasised that addressing these risk factors from childhood and monitoring them throughout life could help delay or prevent the onset of dementia, even in individuals with a high genetic predisposition.

The 2024 Lancet Commission for dementia suggested that quality education for children and reduced exposure to air pollution could lower the risk of developing the disease. An international team, led by researchers at University College London, found that approximately nine per cent of global dementia cases could be linked to these newly identified risk factors. Specifically, seven per cent were attributed to high bad cholesterol starting at age 40, and two per cent to untreated vision loss in later life.

Impact of Education and Social Isolation

Lower education levels in early life and social isolation in later life were also significant risk factors, each accounting for five per cent of global dementia cases. Dementia affects thinking, memory, and decision-making, impacting daily activities. Alzheimer's disease is the most prevalent form of dementia.

The 12 previously identified risk factors for dementia by the 2020 Lancet Commission included lower education levels, air pollution, and health conditions such as high blood pressure, diabetes, obesity, and depression. These factors were linked to 40 per cent of global dementia cases.

Global Dementia Projections

Dementia cases worldwide are projected to nearly triple by 2050, increasing from 57 million in 2019 to 153 million. A study published in February in PLoS ONE estimated that about 3.4 crore older adults in India, aged 60 years and above, are living with mild cognitive impairment, affecting their daily lives.

The authors urged governments and individuals to be proactive in addressing dementia risks throughout life. "We now have stronger evidence that longer exposure to risk has a greater effect and that risks act more strongly in people who are vulnerable," said lead author Gill Livingston from University College London. "That's why it is vital that we redouble preventive efforts towards those who need them most."

Recommendations for Reducing Dementia Risk

To mitigate dementia risk throughout life, the commission recommended 13 measures for governments and individuals. These included providing good quality education for all children and encouraging cognitive activity in mid-life. Other suggestions involved managing high bad cholesterol in mid-life, effectively treating depression, and reducing air pollution through strict clean air policies.

The authors also advised governments to implement measures to reduce smoking through price control or raising the minimum age for purchasing tobacco products. Additionally, they recommended reducing salt and sugar content in foods available in stores and restaurants.

Economic Impact of Policy Interventions

A separate study published in The Lancet Healthy Longevity journal alongside the Commission modelled the economic impact of implementing some of these recommendations using England as an example. The study found that policy interventions addressing excess alcohol use, brain injury, air pollution, smoking, obesity, and high blood pressure could save more than GBP four billion.

Moreover, such interventions could potentially add about 70,000 years lived in perfect health. The authors noted that potential gains might be even greater in low- and middle-income countries where population-level interventions like public smoking bans and compulsory education are not yet widespread.

The findings underscore the importance of early intervention and continuous monitoring of risk factors to combat the rising prevalence of dementia globally.