Abstract 18506: A High Adipose Tissue Arachidonic Acid Content is Associated with a Higher Risk of Myocardial Infarction: A Danish Case Cohort Study

Abstract

Background: Some, but not all studies have reported a positive association between the content of arachidonic acid (AA) in adipose tissue and the risk of coronary heart disease. However, unlike most other polyunsaturated fatty acids, the content of AA in adipose tissue does not seem to reflect the dietary intake of neither AA nor the endogenous source and precursor of AA, linoleic acid (LA).

Aim: The primary aim of the study was to evaluate the association between adipose tissue AA content and the risk of myocardial infarction (MI). The secondary aim was to assess the correlation between adipose tissue AA and dietary intake of AA and LA, as assessed from a validated 192 item food frequency questionnaire.

Methods: We conducted a case-cohort study nested within the Danish Prospective Diet, Cancer and Health (DCH) study. After appropriate exclusions, the study included 2,134 incident MI cases and 3,021 control subjects. Gluteal adipose tissue biopsies were collected at recruitment, and the fatty acid composition (in percentage of total fatty acids) was determined by gas chromatography. A weighted Cox proportional hazards model with sex-specific baseline hazards and age as time axis, was used to evaluate the association between adipose tissue AA content and the risk of MI.

Results: In the crude analysis we observed a significant positive association between adipose AA content and the risk of MI. Although attenuated, the association remained significant when relevant potential confounders were included, where the hazard ratios (HR) of MI relative to the lowest quintile increased across quintiles; two (HR 1.16 95%CI: 0.95-1.41), three (HR 1.18 95%CI: 0.97-1.43) four (HR 1.20 95%CI: 0.97-1.49), and five (HR 1.29 95%CI: 1.03-1.61) (P for trend = 0.048). Adipose tissue AA levels were not correlated with dietary intake of AA (r = 0.03, 95%CI: -0.01, 0.06) and negatively correlated with dietary intake of LA (r = -0.12, 95%CI: -0.15, -0.08).

Conclusions: The adipose tissue content of AA was positively associated with the risk of MI. Adipose tissue AA was not associated with dietary intake of neither AA nor LA and this apparently complex regulation of AA levels in adipose tissue is not well understood and needs to be explored further in future studies.