Table 7:

Results for linear models for CpG sites associated with the frequency of vehicles passing by homes of study subject during pregnancy

CpG	Associated gene	Heavy vehicle frequency (ref = never)	Estimate	Standard error	P value	Significant covariates in final model	Dunnett's test (LSMEAN = never)	Linear trend test (F value, df = 1) P value	Direction of methylation in F2 generation	Direction of methylation in F1 generation
cg15730464 (n = 140)	LGI2	>10/hour	–0.02	0.01	0.072	Gender; birthweight		3.22	↓	↓
		1–9/hour	–0.02	0.01	0.040		0	0.07
		10/day	–0.02	0.01	0.095
		Seldom	–0.02	0.01	0.118
cg00347824 (n = 140)	NSMAF	>10/hour	0.02	0.01	0.018	Gender; birthweight	*	7.36	↑	↑
		1–9/hour	0.02	0.01	0.017		*	0.008
		10/day	0.01	0.01	0.032		0
		Seldom	0.01	0.01	0.120

Once the Dunnett’ tests provided statistical evidence of differences in marginal means of the heavy vehicular traffic frequency, a second test for trend is performed to assess a ‘dose–response’ relationship.

^***P < 0.001;

^**P < 0.01;

^*P < 0.05; P < 0.1.