A study published in The Lancet, on July 20th 2017, reveals that 1 out of 3 dementia cases are preventable when risk factors are targeted beginning from childhood.
The study has found that when the health of the brain is improved through the stages of life, by focusing on nine risk factors such as continuation of education during early stages of life, minimizing loss of hearing in middle life, and minimizing smoking in the later part of life, there is a possibility of preventing dementia in one out of three individuals.
The new study has modeled the effect of risk factors across various life stages and has for the first time quantified the potential role of hearing impairment and isolation from society in causing dementia.
According to the recent estimates, approximately 47 million people across the globe are diagnosed with dementia. The annual cost for treating dementia is US $818 billion. The affected population is set to increase by about 3 times and 131 million people are expected to be affected by 2050. Low- and middle-income countries contributing to the increase in dementia cases the most.
Lead author Professor Gill Livingston, University College London, UK, said that the life of dementia patients and their families will improve vastly if action is taken now and he believes that society’s future will be transformed.
He added, “Although dementia is diagnosed in later life, the brain changes usually begin to develop years before, with risk factors for developing the disease occurring throughout life, not just in old age. We believe that a broader approach to prevention of dementia which reflects these changing risk factors will benefit our ageing societies and help to prevent the rising number of dementia cases globally.”
The study report modeled the effects of health and lifestyle factors across various life stages. The nine risk factors are:
- Early life: no education or education up to primary school
- Midlife (age 45–65 years): hypertension, obesity, and hearing loss
- Later life (age above 65 years): smoking, depression, physical inactivity, social isolation, and diabetes.
The study results showed the percentage of dementia cases that can be prevented when the risk factors are eliminated completely was 35%.
- Education in early life contributes to 8%
- Midlife (age 45–65 years): high blood pressure (2%), obesity (1%), and hearing loss (9%)
- Later life (age above 65 years): smoking (5%), depression (4%), physical inactivity (3%), social isolation (2%), and diabetes (1%)
In contrast, to find a way of targeting apolipoprotein E (ApoE) ε4 allele— the main hereditary risk factor— helps in preventing 7% (less than 1 out of 10 cases).
Out of the 35% of preventable dementia cases, three major common factors of risk that should be focused on are:
- Increasing early life education, estimates report 8% reduction in dementia cases when all the people continue their schooling until over 15 years of age.
- Reducing midlife hearing losses, as it reduces the dementia cases by 9%.
- Avoiding smoking in later life, as the number of cases is reduced by 5% when all people stop smoking.
When the individuals do not complete secondary education during their early life, the risk of dementia may be increased as their cognitive reserve is reduced; in later life, the cognitive resilience is enhanced because the brain reserve is developed by education during early childhood.
In the midlife, protecting hearing will assist individuals to gain a cognitively rich environment and to create a cognitive reserve, which will not be the case when there is hearing loss. Yet, this topic is at an early stage of research and the reason for dementia may be due to other factors such as social isolation and depression that is in turn caused due to hearing loss or degeneration of the brain occurring at the same time.
Avoiding smoking in later life is important for reducing exposure to neurotoxins and improving heart health, which has an effect on the health of the brain.
Researchers recommend public health interventions such as building cognitive reserves for reducing risk of dementia:
- By making more children complete their secondary education during early life
- Involving in mental stimulation activities including combination with hobbies such as visiting cinema halls and restaurants, playing games or watching sport events, reading, and volunteering, and involving in a busy life socially during their later life
During midlife, protecting hearing ability and treatment of hearing loss are important for preventing dementia. Yet, whether hearing aids work against the cognitive damage caused earlier is not clear.
Increasing physical activity, reducing the frequency of smoking, and controlling high blood pressure and diabetes are potentially beneficial interventions. Researchers mentioned that these interventions produce other health benefits, and are safe and already available, however, they need to be used more frequently by the society to get maximum impact.
Even though the intervention for the factors of risk may not cure, prevent, or delay the onset of all cases of the disease, acting on these findings have the potential to:
- Halve the prevalence of dementia if there is a 5-year delay in the onset of the disease.
- Reduce by 10% the occurrence of the seven health and lifestyle factors and minimize the prevalence of dementia by more than a million patients globally.
The study did not consider diet and alcohol consumption and because of the difference in the quality of data, some estimates were not based on global data, cited the authors in regards to the limitations of the study. Authors mentioned that some of the risk factors, such as learning throughout one’s lifetime, may be advantageous as learning progresses through all stages of life.
“The WHO Global Action Plan, with its emphasis on the inalienable human rights of those affected, special attention to LMICs, and accountability for achieving universal coverage of health and social care, promises much for the future—if it can be delivered.”
Professor Martin Prince, King’s College London, UK
The report presented at the Alzheimer’s Association International Conference 2017 comprised the proficiency of 24 experts across the globe in providing a complete review of dementia, including 10 main messages to help improve dementia care.