Higher educational attainment is associated with a lower risk for Alzheimer’s disease, according to a Mendelian randomization study published in BMJ.
“The causes of Alzheimer’s disease are largely unknown, and treatment trials have been disappointing. This has led to increasing interest in the potential for reducing Alzheimer’s by targeting modifiable risk factors,” Susanna C. Larsson, PhD, associate professor in the unit of nutritional epidemiology at Institute of Environmental Medicine of Karolinska Institutet in Stockholm, and colleagues wrote. “Conventional observational studies have consistently shown that low educational attainment is associated with an increased risk ... Available evidence is in large part inadequate as observational studies generally rely on self-reported information and are susceptible to confounding and reverse causation bias, and data from randomized trials are scarce and inconclusive.”
Researchers conducted a Mendelian randomization study to determine which of 24 modifiable risk factors — including socioeconomic, lifestyle/dietary, cardiometabolic, and inflammatory factors — are linked to Alzheimer’s disease. They used genetic variants obtained from the International Genomics of Alzheimer’s Project data associated with the modifiable risk factors as instrumental variables to measure the odds ratio of Alzheimer’s per genetically predicted increase in each modifiable risk factor.
The results showed that genetically predicted higher educational attainment was associated with significantly lower odds of Alzheimer’s disease per year of education completed (OR = 0.89; 95% CI, 0.84-0.93) and per unit increase in log odds of having completed college (OR = 0.74; 95% CI, 0.63-0.86). There was a suggestive association between genetically predicted higher quantity of smoking and concentrations of 25-hydroxyvitamin D and reduced chance of Alzheimer’s disease. Researchers also observed a suggestive association between genetically predicted higher consumption of coffee and higher odds of Alzheimer’s disease. Genetically predicted alcohol consumption, serum folate, serum vitamin B12, homocysteine, cardiometabolic factors and C-reactive protein were not linked to Alzheimer’s disease.
“Using a genetic approach, we found evidence that higher educational attainment is associated with a reduced risk of Alzheimer’s disease. Our study also provides suggestive evidence that the correlated trait of intelligence is inversely associated with Alzheimer’s,” Larsson and colleagues wrote. “Further research is necessary to understand the pathways underpinning these associations. Furthermore, more work is needed to determine the possible role of smoking, coffee consumption and vitamin D.” – by Savannah Demko
: The authors report no relevant financial disclosures.