Table 4.

Associations of motor skills with quartiles of prenatal blood lead, cadmium or mercury.

			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)	Q4a	0.98 (0.73, 1.31)	0.870	0.80 (0.58, 1.11)	0.181	0.97 (0.72, 1.30)	0.823
Ball skills	Beanbag: ref. 7–10 throws (vs 1–3)	Q4a	1.07 (0.71, 1.63)	0.669	1.19 (0.73, 1.93)	0.486	0.86 (0.56, 1.31)	0.481
Manual dexterity	Threading lace: ref. 9–21 s (vs 22–105)	Q4a	1.01 (0.75, 1.35)	0.744	0.89 (0.65, 1.22)	0.478	1.24 (0.92, 1.67)	0.160
	Peg board
	Preferred hand: ref. 15–22 s (vs 23–46)	Q4a	1.23 (0.92, 1.66)	0.169	0.90 (0.65, 1.25)	0.520	1.16 (0.86, 1.57)	0.333
	Non-preferred hand: ref. 15–25 (vs 25–62 s)	Q4a	0.99 (0.73, 1.32)	0.917	1.05 (0.76, 1.44)	0.786	0.84 (0.63, 1.13)	0.256

Reference category lead <5.00 μg/dl, cadmium <0.25 μg/l, mercury <2.00 μg/l.

Participants with poor attention excluded.

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

^aReference category: Q1.