General linear regression results showed that worse ACT scores were significantly associated with every SD increase in waist circumference ( = -1.03 ; 95 % confidence interval [ CI ] , -1.96 to -0.16 ; P = 0.02 ) and waist-to-height ratio ( = -1.16 ; 95 % CI , -2.00 to -0.33 ; P = 0.008 ) , controlling for sociodemographics .