Association of Dietary Fat Quality Indices and the Risk of Metabolic Syndrome: Tehran Lipid and Glucose Study

Various types of fatty acids are simultaneously present in the diet. Therefore, it is important to investigate their combined effects on the occurrence of metabolic diseases. This study aimed to determine the dietary fat quality indices and investigate the relationship between these indices and the risk of metabolic syndrome in an Iranian adult population.

A total of 1713 adults participating in the third phase of the Tehran Lipid and Glucose Study (TLGS), who were free of metabolic syndrome, were selected and followed up to the sixth phase. Dietary intakes were evaluated using a validated food frequency questionnaire. The risk of metabolic syndrome in the sixth phase of TLGS, adjusted for potential confounders, was estimated across the tertiles of all dietary fat quality indices, including atherogenic index, thrombogenic index, health-promoting index, ratio of polyunsaturated fatty acids to saturated fatty acids (PUFA/SFA), ratio of hypo- to hypercholesterolemia, total omega-3 fatty acids, and ratio of linoleic acid to α-linolenic acid (LA/ALA), using Cox proportional hazard regression models.

Over a median of 7.6 years of follow-up (2006-2008 to 2014-2017), 596 cases of metabolic syndrome were identified. After adjustment for confounding variables, there was no significant association between dietary fat quality indices and risk of metabolic syndrome. However, each 1-unit increment in the LA/ALA was associated with a 3% higher risk of metabolic syndrome [hazard ratio (95% confidence interval): 1.03 (1.00-1.01)].

Further prospective studies are needed to clarify the association between dietary fat quality indices and the risk of metabolic syndrome. In the present study, there was no significant association between dietary fat quality indices and metabolic syndrome incidence.