A new Canadian study adjusted for age, sex, education, race, cognitive diagnosis, depression, and apolipoprotein E (APOE) ε4 has been released. It was known that lower vitamin D status may be associated with increased risk of developing Alzhimer's and dementia.
Although about 70 genetic regions are associated with Alzheimer's, one quite well known gene is the Apolipoprotein E (APOE) gene. The APOE gene is involved in making a protein that helps carry cholesterol and other types of fat in the bloodstream. Problems in this process are thought to contribute to the development of Alzheimer’s. APOE comes in several forms, called alleles (e.g., ε2, ε3).
APOE ε2 may provide some protection against the disease. If Alzheimer’s occurs in a person with this allele, it usually develops later in life than it would in someone with the APOE ε4 gene. Roughly 5% to 10% of people have this allele.
APOE ε3, the most common allele, is believed to have a neutral effect on the disease — neither decreasing nor increasing risk of Alzheimer’s.
APOE ε4 increases risk for Alzheimer’s and is associated with an earlier age of disease onset in certain populations. About 15% to 25% of people have this allele, and 2% to 5% carry two copies.
Each person inherits two APOE alleles, one from each biological parent, meaning people can have one of six possible combinations: 2/2, 2/3, 2/4, 3/3, 3/4, and 4/4. Having two copies of APOE ε4 is associated with a higher risk of Alzheimer’s than having one copy. While inheriting APOE ε4 increases a person’s risk of Alzheimer’s, some people with an APOE ε4 allele never develop the disease.
Study Highlights.
Although about 70 genetic regions are associated with Alzheimer's, one quite well known gene is the Apolipoprotein E (APOE) gene. The APOE gene is involved in making a protein that helps carry cholesterol and other types of fat in the bloodstream. Problems in this process are thought to contribute to the development of Alzheimer’s. APOE comes in several forms, called alleles (e.g., ε2, ε3).
APOE ε2 may provide some protection against the disease. If Alzheimer’s occurs in a person with this allele, it usually develops later in life than it would in someone with the APOE ε4 gene. Roughly 5% to 10% of people have this allele.
APOE ε3, the most common allele, is believed to have a neutral effect on the disease — neither decreasing nor increasing risk of Alzheimer’s.
APOE ε4 increases risk for Alzheimer’s and is associated with an earlier age of disease onset in certain populations. About 15% to 25% of people have this allele, and 2% to 5% carry two copies.
Each person inherits two APOE alleles, one from each biological parent, meaning people can have one of six possible combinations: 2/2, 2/3, 2/4, 3/3, 3/4, and 4/4. Having two copies of APOE ε4 is associated with a higher risk of Alzheimer’s than having one copy. While inheriting APOE ε4 increases a person’s risk of Alzheimer’s, some people with an APOE ε4 allele never develop the disease.
Study Highlights.
- In a prospective cohort study, we assessed effects of Vitamin D on dementia incidence in 12,388 participants from the National Alzheimer's Coordinating Center dataset.
- Vitamin D exposure was associated with 40% lower dementia incidence versus no exposure.
- Vitamin D effects were significantly greater in females versus males and in normal cognition versus mild cognitive impairment.
- Vitamin D effects were significantly greater in apolipoprotein E ε4 non-carriers versus carriers.
- Vitamin D has potential for dementia prevention, especially in the high-risk strata.
