Table 2.

Associations of motor skills with prenatal blood lead, cadmium or mercury concentrations as continuous variables: complete cases (n = 1558).

		Prenatal blood lead		Prenatal blood cadmium		Prenatal blood mercury
		OR (95% CI)	p	OR (95% CI)	p	OR (95% CI)	p
Balance	Heel to toe: ref 15 steps (vs 1–14)
	Unadjusted	1.01 (0.94, 1.07)	0.849	0.81 (0.67, 0.97)	0.025	1.04 (0.95, 1.14)	0.345
	Adjusted	0.98 (0.92, 1.05)	0.609	0.70 (0.52, 0.94)	0.019	1.00 (0.91, 1.10)	0.966
Ball skills	Beanbag: ref 7–10 throws (vs 1–3)
	Unadjusted	0.98 (0.89, 1.07)	0.577	0.99 (0.76, 1.29)	0.926	0.93 (0.82, 1.04)	0.209
	Adjusted	0.98 (0.90, 1.08)	0.743	0.88 (0.60, 1.31)	0.536	0.93 (0.82, 1.06)	0.830
Manual dexterity	Threading lace: ref 9–21 s (vs 22–105)
	Unadjusted	1.01 (0.95, 1.08)	0.762	0.97 (0.80, 1.16)	0.714	0.99 (0.91, 1.09)	0.892
	Adjusted	1.01 (0.96, 1.10)	0.496	0.94 (0.70, 1.25)	0.646	1.01 (0.92, 1.11)	0.894
	Peg board
	Preferred hand: ref 15–22 s (vs 23–46)
	Unadjusted	1.03 (0.97, 1.10)	0.377	1.07 (0.89, 1.28)	0.493	1.03 (0.94, 1.12)	0.585
	Adjusted	1.04 (0.97, 1.12)	0.248	1.00 (0.75, 1.33)	0.972	1.05 (0.95, 1.15)	0.349
	Non-preferred hand: ref 15–25 s (vs 25–62)
	Unadjusted	1.02 (0.95, 1.09)	0.589	1.03 (0.86, 1.24)	0.761	0.93 (0.85, 1.02)	0.101
	Adjusted	1.04 (0.97, 1.11)	0.276	0.98 (0.74, 1.31)	0.911	0.94 (0.86, 1.03)	0.195

Participants with poor attention to task excluded.

Adjusted for: sex, maternal education, smoking in pregnancy, alcohol in pregnancy, maternal age and parity.