The trends of metabolic syndrome in normal-weight Tehranian adults

In recent decades, more attention has been directed to the clustering of cardiometabolic risk factors in normal-weight adults. This study investigates trends of the prevalence of metabolic syndrome (MetS) in a normal-weight Tehranian adult population during 6.6 years of follow-up.

In this population-based cohort study of 5,269 participants aged ≥ 20 years during the 3 phases (1999-2001, 2002-2005 and 2005-2008) of the Tehran Lipid and Glucose Study, we selected 390 males and 358 females with a normal body mass index (18.5-24.9) during all 3 periods of follow-up. MetS was defined according to the International Diabetes Federation criteria, and waist circumference (WC) cut points were ≥ 89 cm for males and ≥ 91 cm for females.

The overall prevalence of MetS increased from 2.3 and 4.0% in phases I and II to 9.6% in phase III. This trend was significant in males (p < 0.001) but not in females (p = 0.6). No significant changes in components of MetS were seen, except in WC among males. In the 3 study phases, prevalence of abdominal obesity was 3.1, 18.5 and 36.2% in males, respectively.

There was a dramatic 4-fold increase in the prevalence of MetS in the Tehranian normal-weight adult population, highlighting the importance of MetS components, especially of WC, in normal-weight adult males.