Early pregnancy vitamin D and the risk of adverse maternal and infant outcomes: a retrospective cohort study

Table 5 Subclass analysis of relationship between serum vitamin D concentrations and related outcomes stratified by gestational age

		25(OH)D ^a			P ^b	25(OH)D₂ ^a			P ^b	25(OH)D₃ ^a			P ^b
		HR	95%CI	P	P ^b	HR	95%CI	P	P ^b	HR	95%CI	P	P ^b
Gestational diabetes mellitus	< 35 y	0.841	(0.744, 0.951)	0.006	0.744	0.748	(0.608, 0.919)	0.006	0.751	0.842	(0.745, 0.952)	0.006	0.749
Gestational diabetes mellitus	≥35 y	0.900	(0.755, 1.072)	0.238		0.834	(0.622, 1.119)	0.227		0.900	(0.755, 1.072)	0.238
Caesarean section	< 35 y	0.970	(0.909, 1.035)	0.354	0.461	0.950	(0.852, 1.059)	0.353	0.484	0.970	(0.909, 1.034)	0.348	0.466
Caesarean section	≥35 y	0.939	(0.839, 1.052)	0.281		0.995	(0.947, 1.046)	0.850		0.940	(0.839, 1.053)	0.282
Fetal distress	< 35 y	0.941	(0.826, 1.072)	0.362	0.983	0.903	(0.724, 1.125)	0.363	0.972	0.941	(0.825, 1.072)	0.360	0.986
Fetal distress	≥35 y	0.924	(0.642, 1.330)	0.672		0.872	(0.477, 1.593)	0.656		0.925	(0.643, 1.331)	0.675
Preterm birth	< 35 y	0.886	(0.745, 1.054)	0.172	0.264	0.816	(0.610, 1.093)	0.173	0.263	0.886	(0.745, 1.054)	0.171	0.264
Preterm birth	≥35 y	0.773	(0.594, 1.007)	0.056		0.648	(0.416, 1.009)	0.055		0.773	(0.594, 1.006)	0.056
Low birth weight	< 35 y	0.911	(0.760, 1.093)	0.317	0.145	0.855	(0.629, 1.162)	0.317	0.145	0.930	(0.779, 1.110)	0.423	0.145
Low birth weight	≥35 y	0.721	(0.528, 0.984)	0.039		0.575	(0.341, 0.972)	0.039		0.721	(0.528, 0.984)	0.039
Macrosomia	< 35 y	1.139	(0.876, 1.480)	0.331	0.784	1.245	(0.801, 1.935)	0.331	0.425	1.138	(0.876, 1.479)	0.333	0.784
Macrosomia	≥35 y	1.332	(0.511, 3.476)	0.558		1.034	(0.724, 1.477)	0.853		1.331	(0.510, 3.474)	0.559

Cox regression analysis were operated for exploration of associations, and adjusted for covariates including: age, BMI, parity, season of blood collected
^a: Per one SD increase. ^b: P for interaction

ISSN: 1471-2393