Dietary variety score and risk of metabolic syndrome incidence: Tehran Lipid and Glucose Study.

Purpose: There are contradictions in the association between dietary variety and metabolic syndrome (MetS). The concept of dietary variety should be merged with other dietary recommendations including diet quality and proportion. We aimed to investigate the association of the healthy food diversity index with MetS and its components in Iranian adults.

Design/methodology/approach: In this prospective study, 4654 subjects (62.0%women) were chosen from participants of the Tehran Lipid and Glucose Study. Diet was assessed based on a valid and reliable semi-quantitative Food Frequency Questionnaire. The healthy food diversity index was based on 26 food groups extracted from the 2020 dietary guideline. MetS was defined based on the Iranian-modified National Cholesterol Education Programme and Adult Treatment Panel III.

Findings: The mean±SD ages of men and women were, respectively, 39.3±14.7and 36.1±12.1 years. The incident cases of MetS were 1129 during a median follow-up of 3.31 years. Participants in the top quartiles of diversity score had higher educational levels, also they were likely to be older, female and were less likely to be current smokers in comparison to those in the lower quartiles (p<0.05). After adjustment of potential confounders, participants in the top quartile of the healthy food diversity score had lower risk of hypertriglyceridaemia (HR 0.14; 95% CI 0.05 to 0.25) and high fasting blood glucose (FBG) (HR 0.11; 95%CI 0.02 to 0.21, P trend=0.004) in comparison to those in the lowest quartile. There was no significant association between the healthy food diversity score and risk of MetS and the other components of MetS after adjustment of confounding factors.

Originality: Increasing diversity score may be sufficient to reduce the risk of hypertriglyceridaemia and high FBG, but the healthy food diversity score is not associated with the risk of MetS incidence in the Tehranian population.