Dairy intake and risk of Parkinson’s disease


Dairy intake may increase risk of Parkinson's disease in men, according a group of investigators. Men of European ancestry with a genetic marker predicting dairy consumption had significantly greater risk of Parkinson's disease than individuals without the marker, suggesting a causal relationship between dairy intake and Parkinson's disease, author Cloé Domenighetti reported.

The investigators evaluated this link by comparing 9,823 cases of Parkinson's disease with 8,376 controls, all individuals of European ancestry from the Courage-Parkinson's disease consortium, comprising 23 studies. Data were analyzed by two-sample Mendelian randomization, a technique that uses genotype to predict behavior, thereby replacing conventional methods of capturing behavior, such as questionnaires. In this case, the investigators screened all participants for rs4988235, a single-nucleotide polymorphism (SNP) upstream of the lactase gene that is well documented to predict dairy intake among individuals of European ancestry.

The approach uncovered a significant association between rs4988235 and Parkinson's disease, with a 70% increase in disease risk per one serving of dairy per day (odds ratio, 1.70; 95% confidence interval, 1.12-2.60; P = .013). Further analysis revealed that this finding was driven by men, who had a 2.5-fold increased risk of Parkinson's disease per one serving per day (OR, 2.50; 95% CI, 1.37-4.56; P = .003) versus women, among whom there was no significant association (OR, 1.04; 95% CI, 0.56-1.92; P = .91). No significant associations were observed among individuals grouped by age or Parkinson's disease duration.

Mediterranean diets so far have the best supporting evidence for a lower Parkinson's disease risk, although data is lacking for benefits in established Parkinson's disease. Given the low risk of the Mediterranean diet and the established benefits for a host of other medical conditions, this is generally a safe and delicious recommendation whether one is living with Parkinson's or not