GPT and metabolic syndrome: In supporting of our speculation, the male population had higher heterogeneity (I2 = 68.1%, P = 0.077, data not shown) than the female population (I2 = 0%, P = 0.780, Figure 5) in two studies [13], [16] defined MetS by IDF criteria suggesting that gender rather than diagnostic criteria, is the source of heterogeneity in ALT-MetS incidence association.