GSTM1 and Obesity: In the oil-rich countries in the Middle East, where socioeconomic status has improved materially in the last few decades, parental education (but not income) in addition to season of birth and consumption of sugary drinks, were the main predictors of cognitive functioning as measured by the Raven’s SPM while obesity and laboratory markers such as Hb, iron, ferritin and calcium were all not significantly associated with cognitive functioning among adolescents.