CLOCK and insomnia: Therefore, this prospective cohort study aimed to investigate whether the consumption of particular food groups significantly modified the insomnia risk associated with the CLOCK gene rs12649507 and rs4580704 polymorphisms, using the data of 1430 participants (775 males 655 females aged 43−73 years) from the Korean Genome Epidemiology Study (KoGES), a longitudinal study performed over 6 years.