Linoleic acid and risk of sudden cardiac death.

OBJECTIVE To test the hypothesis that the essential fatty acid, linoleic acid, measured in adipose tissue as an indicator of long term dietary intake, is inversely related to the risk of sudden cardiac death. DESIGN A population case-control study. SETTING A regional health district. SUBJECTS 84 men (age 25-64 years) who died instantaneously or within 24 hours of the onset of symptoms with no history of coronary heart disease or medically treated hyperlipidaemia, and in whom coronary artery disease was diagnosed at postmortem examination as the primary cause of death, were compared with 292 age (to within two years) and sex matched healthy controls and their partners drawn from the general practitioners' records with whom the cases were registered. MAIN OUTCOME MEASURES Fatty acid composition of adipose tissue and the risk of sudden cardiac death. RESULTS Linoleic acid in adipose tissue was inversely related to the risk of sudden cardiac death. The estimated relative risk (95% CI) of sudden cardiac death was 5.7 (1.8 to 17.9) for the lowest quintile and 4.0 (1.2 to 12.9) for the next quintile of adipose linoleic acid in the control population when compared with the highest quintile. This inverse relation was independent of age, reported smoking habits, history of hypertension, and diabetes, although there was a close association with cigarette smoking. The estimated adjusted proportionate increase in risk (95% CI) of sudden cardiac death was 1.14 (1.03 to 1.23) for every 1% reduction of linoleic acid in adipose tissue. CONCLUSIONS The percentage content of linoleic acid in adipose tissue was inversely related to the risk of sudden cardiac death. Populations with a high risk of sudden cardiac death may benefit from increasing their dietary intake of polyunsaturated fatty acid oils, principally from cereals and vegetables.