A new study found that vitamin D3 supplementation helps to prevent Alzheimer’s disease significantly. Researchers at the Hotchkiss Brain Institute of Calgary University and University of Exeter in the UK followed older patients, with or without vitamin D3 supplementation. At enrolment their age was 71 on average and they were free of Alzheimer’s disease. 12,388 participants of the US National Alzheimer’s Coordinating Center signed up to this trial. 39% took supplements of vitamin D3. The researchers diagnosed 40% less Alzheimer’s disease in those who took vitamin D3 supplements in comparison to controls. They also lived dementia free for longer that controls who did not take vitamin D3 supplements. The clinical trial lasted for 10 years.
Details of the study
As already stated, the main finding was that over 10 years the vitamin D3 supplementation groups had a 40% average reduction of Alzheimer’s disease (AD). The authors stratified each subgroup and measured their risk reduction separately. The demographics examined were age, sex, years of education, race, cognitive diagnosis (mild cognitive impairment vs. no cognitive impairment). In addition, the researchers determined the effect of a depressive state and of the APOE ε4 status (genetic AD risk) on premature AD.
The authors also categorized subgroups who previously had exposure to vitamin D3 supplementation (D+) versus those who did not have previous vitamin D3 supplements (D-).
Onset of dementia for various subgroups
Overall, the study population consisted of 12,388 participants, with 4,637 D+ (average age = 71.2; 70.5% female) and 7,751 D− (age = 71.2; 46.9% female). In comparison to the D- group the D+ group was more educated, had more females, and fewer Black participants. There was a significant association between vitamin D exposure and a higher dementia-free survival. The 5-year survival for the D- group was 68.4% while the D+ group survived 83.6%. The mild cognitive impairment group had a 5-year survival of 38.7% while the group without cognitive impairment had a 5-year survival of 61.3%. With respect to pre-existing depression the 5-year survival in depression-positive cases was only 11.5%, in depression-negative cases 88.5%. Carriers of the apolipoprotein E genetic trait had a 5-year survival of 36.7%, while people who were non-carriers had a 5-year survival of 63.3%.
The original publication of this study contains a detail section with a discussion of the results. It also pointed out that there were several other studies that noted that vitamin D3 was instrumental in delaying the onset of dementia and in many cases even prevented it. But the studies are mixed with others that did not find much effect of vitamin D3. The researcher stated: “Variability in serum vitamin D levels, supplementation dosage, and cognitive tests administered may explain the observed inconsistencies”.
The 40% less Alzheimer disease frequency over 10 years with vitamin D3 supplementation was the most striking finding of the study. However, they did not reveal how much vitamin D3 supplementation the participants received, what their serum vitamin D levels were and whether or not they were exposed to sunlight.
The authors of the study found a comparative publication where there was a reduction of 56% of dementia cases with vitamin D3 supplementation compared to a control group that did not use vitamin D3 supplements.
A new study found that vitamin D3 supplementation helps to prevent Alzheimer’s disease significantly. Over 10 years vitamin D3 supplementation groups had a 40% average reduction of Alzheimer’s disease (AD). This reduction held up against demographics like age, sex, years of education, race and cognitive diagnosis. The researchers measured mild cognitive impairment vs. no cognitive impairment. In addition, there was a determination of the depressive state and APOE ε4 status. The latter measures the effect of the genetic AD risk on premature AD development.
Results of risks for subgroups
The mild cognitive impairment group had a 5-year survival of 38.7% while the group without cognitive impairment had a 5-year survival of 61.3%. With respect to pre-existing depression the 5-year survival in depression-positive cases was only 11.5%, in depression-negative cases 88.5%. Carriers of apolipoprotein E had a 5-years survival of 36.7%, while people with non-carries had a 5-year survival of 63.3%. The authors are starting now a more detailed new study. They want to study vitamin D blood levels and investigate more subgroups of the population. But as a result of the present study they are recommending to take vitamin D3 supplements daily. They say that vitamin D3 supplementation is a potential agent for dementia prevention. They think that this is particularly important for at-risk individuals for AD dementia.