Three results are highlighted. First, as seen in Figure 2A, INT − and INT + did not differ in CU. Second, the INT− group (vs INT+) experienced significantly lower levels of cumulative environmental risk (Figure 2B) during early childhood (birth – age 7; p = .008). Third, as seen in Table 1, correlations between environmental risk, CU and OXTR methylation showed that (a) Parental risks were positively correlated with DNA methylation across both INT− (at birth) and INT+ (at age 7) youth; and (b) OXTR methylation at birth was significantly correlated with higher CU, but only for INT−. This result is visually presented in Figure 1B, where it can be seen that, for INT− youth, OXTR methylation levels increased as CU traits became more severe (≤ 6% beta change). Post-hoc analysis confirmed that the association between OXTR methylation at birth and CU differed for the INT− vs INT+ group (i.e. significant interaction effect; p = .034). Interactions were not significant at age 7 and 9.
