. 2016 Feb 12;16:142. doi: 10.1186/s12889-016-2816-4

Table 4.

Risk of low birth weight associated with maternal urinary manganese levels, stratified by infant sex

Manganese levels^a	Male (n = 404)			Female (n = 412)			P for heterogeneity
Manganese levels^a	Ca/Co	OR^b (95 % CI)	OR^c (95 % CI)	Ca/Co	OR^b (95 % CI)	OR^c (95 % CI)	P for heterogeneity
Tertile 1	22/101	0.73 (0.38, 1.40)	0.64 (0.22, 1.83)	32/103	1.55 (0.81, 2.98)	2.12 (0.86, 5.25)	0.24
Tertile 2	29/101	1.00	1.00	20/103	1.00	1.00
Tertile 3	50/101	1.77 (1.02, 3.06)	1.88 (0.85, 4.79)	51/103	2.65 (1.46, 4.80)	1.94 (0.88, 4.45)

Abbreviations: ca/co, numbers of cases and controls; CI confidence interval; OR odds ratio

^a Manganese levels (μg/g creatinine): male, tertile1 (<0.31), tertile 2 (0.31–1.24), tertile 3 (≥1.25); female, tertile 1 (<0.28), tertile 2 (0.28–1.04), tertile 3(≥1.05)

^b Crude odds ratio

^c Adjusted for gestational age, household income, pre-pregnancy body mass index, parity, passive smoking, and gestational hypertension