Serum fatty-acid composition and the risk of Alzheimer's disease: a longitudinal population-based study

It is unknown if a specific fatty-acid composition influences the development of Alzheimer's disease (AD). Nutrition is a possible target for prevention of dementia and especially omega-3-based fatty acids (n-3 FAs) have previously been suggested to be beneficial for cognition. The objective was to ascertain whether serum FAs predicts the risk of incident AD and dementia in a longitudinal population-based cohort.

Uppsala Longitudinal Study of Adult Men started in 1970. The proportions of FAs in serum cholesteryl esters were estimated in men (n=2009) who were 50 years old at baseline. During a 35 year follow-up time, 213 men had developed dementia, out of which 91 AD. The associations were analyzed with Cox proportional hazards and logistic regression; adjusted for age, education and vascular risk factors.

Subjects with a higher proportion of saturated FAs had a decreased risk of AD in crude and multi-adjusted models (hazard ratio for 1-s.d. increase in palmitic acid 0.72; 95% confidence intervals: 0.59-0.89). These associations persisted even in the group of approximately 85-year-old survivors. n-3 FAs FAs were not associated with decreased risk of AD or dementia.

In contrast to experimental studies, saturated FAs were inversely associated with risk of AD. No evidence of a protective effect of n-3 FAs against dementia was found. The results remained essentially unchanged if competing risk from mortality was taken into account.