Table 4.

Pb, Cd, Hg, Se, and Mn exposure and congenital limb abnormalities

Variables	Continuous model				Categorical model
					1st quartile		2nd quartile					3rd quartile					4th quartile
	adjusted OR	95%CI		p-value	cases/non-cases (n)		cases/non-cases (n)	adjusted OR	95%CI		p-value	cases/non-cases (n)	adjusted OR	95%CI		p-value	cases/non-cases (n)	adjusted OR	95%CI		p-value
All congenital limb abnormalities (n = 369)
Pb	0.83	0.61	1.11	0.207	105/22652	ref	41/22350	0.82	0.62	1.10	0.184	58/22540	0.90	0.68	1.19	0.475	35/22252	0.76	0.57	1.02	0.066
Cd	0.87	0.68	1.10	0.242	89/22706	ref	43/22393	1.05	0.79	1.40	0.740	53/22424	1.07	0.80	1.42	0.663	42/22271	0.79	0.58	1.09	0.150
Hg	0.88	0.73	1.07	0.198	94/22499	ref	47/22387	1.01	0.76	1.34	0.942	42/22437	0.94	0.70	1.25	0.662	51/22471	0.91	0.68	1.22	0.540
Se	1.07	0.44	2.59	0.877	97/22536	ref	44/22880	0.96	0.72	1.27	0.765	35/23073	0.85	0.63	1.13	0.259	52/21305	0.99	0.74	1.31	0.916
Mn	0.91	0.64	1.30	0.618	102/22673	ref	42/22981	0.91	0.68	1.20	0.495	46/22274	0.90	0.68	1.20	0.469	47/21866	0.88	0.66	1.18	0.384
All polydactilies (n = 185)
Pb	0.74	0.49	1.14	0.172	51/22652	ref	36/22350	0.80	0.53	1.21	0.300	37/22540	1.12	0.77	1.63	0.560	30/22252	0.67	0.43	1.03	0.067
Cd	0.97	0.69	1.37	0.876	47/22706	ref	44/22393	0.89	0.59	1.35	0.594	35/22424	1.07	0.72	1.60	0.739	33/22271	0.80	0.52	1.24	0.319
Hg	1.02	0.78	1.33	0.879	45/22499	ref	38/22387	1.05	0.69	1.57	0.834	42/22437	0.93	0.61	1.41	0.718	26/22471	1.10	0.74	1.65	0.633
Se	1.47	0.43	5.06	0.538	54/22536	ref	36/22880	0.80	0.54	1.19	0.265	28/23073	0.63	0.41	0.96	0.031	35/21305	1.00	0.68	1.47	0.989
Mn	1.09	0.66	1.80	0.728	50/22673	ref	37/22981	0.83	0.55	1.25	0.378	32/22274	0.94	0.63	1.40	0.759	37/21866	0.97	0.65	1.45	0.896
All syndactilies (n = 142)
Pb	0.75	0.46	1.21	0.235	39/22652	ref	86/22350	0.93	0.59	1.46	0.749	96/22540	0.94	0.60	1.48	0.803	82/22252	0.75	0.47	1.22	0.252
Cd	0.82	0.55	1.21	0.312	30/22706	ref	97/22393	1.44	0.90	2.29	0.127	102/22424	1.11	0.68	1.82	0.674	81/22271	0.99	0.59	1.67	0.977
Hg	0.77	0.57	1.05	0.098	36/22499	ref	96/22387	1.04	0.66	1.65	0.853	90/22437	1.15	0.73	1.79	0.553	89/22471	0.70	0.42	1.16	0.166
Se	0.56	0.13	2.34	0.424	43/22536	ref	95/22880	0.82	0.52	1.27	0.365	85/23073	0.62	0.39	1.01	0.053	92/21305	0.84	0.54	1.32	0.455
Mn	1.01	0.57	1.78	0.982	36/22673	ref	93/22981	1.02	0.65	1.62	0.921	89/22274	0.92	0.57	1.48	0.732	85/21866	1.10	0.69	1.74	0.699

The Odds Ratios were calculated using the natural log transformation of the metal or element in the continuous model, while in the categorical model, the metal or element was divided into quartiles, with the 1st quartile serving as the reference.

Adjusted for maternal age (categorical), maternal smoking (categorical), maternal alcohol intake (categorical), paternal smoking (categorical), infant sex.

The quartile model’s p-value is defined as 0.05/3 = 0.0167 (Bonferroni’s adjustment).