Table 3.

Association between maternal dietary selenium intake and selenium intake from supplements and gestational length^*

(β-Coefficients and 95 % confidence intervals)

	Unadjusted			Adjusted†
	β ‡	95 % CI	P	β ‡	95 % CI	P
All subjects (n 72 025)
Se intake from food§	0·07	−0·02, 0·17	0·13	0·25	0·07, 0·43	0·006
Se intake from inorganic supplements§	−0·04	−0·14, 0·05	0·35	−0·08	−0·17, 0·02	0·10
Se intake from organic supplements§	0·07	−0·03, 0·16	0·17	0·07	−0·03, 0·17	0·19
Spontaneous deliveries (n 57 098)
Se intake from food§	0·13	0·03, 0·22	0·007	0·34	0·16, 0·52	1·7 × 10−4
Se intake from inorganic supplements§	−0·08	−0·17, 0·01	0·09	−0·09	−0·18, 0·01	0·07
Se intake from organic supplements§	0·07	−0·03, 0·16	0·17	0·07	−0·02, 0·17	0·14
Subjects with intake levels below RDI (n 41 581)‖
Se intake from inorganic supplements§	−0·12	−0·24, 0·00	0·06	−0·12	−0·23, 0·02	0·05
Se intake from organic supplements§	0·08	−0·04, 0·21	0·19	0·10	−0·02, 0·21	0·10
Subjects with intake levels below 30 µg/d (n 1308)
Se intake from inorganic supplements§	0·32	−0·35, 0·98	0·35	0·41	−0·25, 1·1	0·22
Se intake from organic supplements§	−0·42	−1·19, 0·35	0·28	−0·53	−1·3, 0·23	0·17

RDI, recommended daily intake.

^*Multiple linear regression analysis of Se intake from food and from supplements in relation to gestational length in days for 72 025 participants in the Norwegian Mother and Child Cohort Study. Se intake from food and supplements was assessed with an FFQ in gestational week 22.

^†Adjusted for maternal age, parity, smoking habits, alcohol consumption during pregnancy, maternal education, BMI, iodine intake in five categories, fibre intake, protein intake, n-3 intake and total energy intake. Analyses for the different Se sources are also mutually adjusted in the adjusted model.

^‡ β per standard deviation of Se intake. Standard deviation for Se intake from food is 14·6 μg/d, from inorganic supplements 32·6 μg/d and from organic supplements 10·0 μg/d.

^§Measured in μg/d.

^‖RDI of Se for pregnant women is 60 μg/d.