INS and schizophrenia: Phenome-wide analyses also uncovered evidence for epigenetic covariance between schizophrenia DNA methylation variance and risk-altering factors including air pollution exposure [76, 77], BMI [78, 79], C-reactive protein [80–83] and insulin resistance [84, 85], raising the possibility that some schizophrenia-associated DNA methylation variance is interrelated with known correlates of this disorder.