Lewy Body Dementia (LBD) is a neurodegenerative condition, the second most common type of dementia after Alzheimer’s disease. It involves the buildup of abnormal protein deposits, called Lewy bodies, in the brain’s nerve cells. This can lead to problems with thinking, movement, behavior, and mood. Understanding factors that may increase an individual’s likelihood of developing LBD is an important area of ongoing research.
Inherent Contributing Factors
Increasing age is a significant factor in LBD development. While LBD can occur at age 50 or older, the risk rises considerably with advancing years, particularly for those over 60. The prevalence of dementia with Lewy bodies (DLB), a form of LBD, consistently increases with age.
While LBD is not purely hereditary, a family history of LBD or Parkinson’s disease can increase an individual’s risk. Certain genetic variants are associated with a higher likelihood. For instance, the APOE gene, particularly the APOE4 variant, is a known risk factor for both LBD and Alzheimer’s disease. This variant is thought to disrupt the transport of the alpha-synuclein protein, which can then accumulate to form Lewy bodies.
Additional genes, such as GBA and SNCA, are also linked to an increased LBD risk. The SNCA gene provides instructions for making alpha-synuclein, the primary protein found in Lewy bodies. Mutations or variations in this gene can heighten the risk of developing LBD. Similarly, mutations in the GBA gene can interfere with the normal breakdown of alpha-synuclein, leading to its accumulation and an increased risk of LBD.
Medical Conditions and LBD Risk
Parkinson’s disease is strongly connected to LBD, as both conditions share underlying pathological features involving Lewy bodies. Individuals with Parkinson’s disease often eventually develop dementia, known as Parkinson’s Disease Dementia (PDD), which is considered a form of LBD. A high percentage of people with Parkinson’s disease develop dementia, potentially reaching at least 75%, often around 10 years after onset.
Cardiovascular diseases, including high blood pressure, high cholesterol, and heart disease, can impact brain health and potentially increase the risk of dementia, including LBD. These conditions indirectly contribute to dementia by affecting blood flow to the brain. Maintaining heart health is beneficial for overall brain health.
Diabetes is also associated with an increased risk of dementia, possibly through inflammation and damage to blood vessels. Keeping blood glucose levels in check for individuals with type 2 diabetes may reduce dementia risk. While not a direct cause, these systemic health conditions can contribute to a less resilient brain environment.
Sleep disorders, particularly REM sleep behavior disorder (RBD), are significant early indicators and risk factors for synucleinopathies, including LBD. In RBD, individuals physically act out their dreams during the rapid eye movement (REM) stage of sleep, a period normally characterized by temporary muscle paralysis. Approximately 90% of people with RBD eventually develop either Parkinson’s disease or LBD. This disorder can serve as an early signal that the brain’s regulatory mechanisms are beginning to falter.
Lifestyle and Environmental Influences
Severe head injuries have been linked to an increased risk of various neurodegenerative diseases, including LBD. While a direct causal link for LBD is still being investigated, head injuries are generally recognized as a factor in neurodegeneration.
Unlike some other forms of dementia, specific lifestyle factors such as diet, exercise, and smoking have less direct evidence as distinct risk factors for LBD itself. While these factors support overall brain health and prevent conditions that indirectly increase LBD risk, their direct influence on LBD development is still being researched. A healthy lifestyle, including regular exercise, mental stimulation, and a balanced diet, may help reduce the chance of developing age-associated dementias.
Research is ongoing regarding potential links between environmental toxins and neurodegenerative diseases. Some studies suggest that exposure to air pollutants, certain metals, and some microorganisms may increase the risk of Lewy body disease. For example, mercury exposure has been reported to cause cognitive impairment and may induce alpha-synuclein aggregation, a hallmark of LBD. However, concrete evidence for a widespread, direct causal link is still emerging or less defined compared to other risk factors.
Distinguishing Risk from Certainty
Understanding risk factors provides insights into potential predispositions, but having one or more does not guarantee LBD development. Conversely, not having known risk factors does not ensure immunity. LBD is likely the result of a complex interplay between genetic predispositions, environmental factors, and other health conditions.
Identifying and studying these risk factors advances research, facilitates earlier recognition, and potentially aids in developing future preventive strategies. This understanding should inform continued scientific inquiry and personal health awareness, rather than causing undue alarm.