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. 2023 Mar 27;62(5):2139–2154. doi: 10.1007/s00394-023-03131-x

Table 3.

Median (25–75th percentiles) serum thyroglobulin concentration (serum-Tg, ng/ml), proportion (unadjusted) of pregnant women with elevated serum-Tg ( > 40 ng/mla) and odds (adjusted) of elevated serum-Tg according to food-group intakes and iodine-containing supplement-use by cohort

Generation R (n = 2768) INMA (n = 1155)
Serum-Tg (ng/ml) Elevated serum-Tg ( > 40 ng/ml) a Serum-Tg (ng/ml) Elevated serum-Tg ( > 40 ng/ml) a
Unadjusted Adjusted Unadjusted Adjusted
Total
n 		Median
(25–75th)		 P b n (%) P c OR (95% CI) P d Total
n 		Median
(25–75th)		 P b n (%) P c OR (95% CI) P d
Milk intake 0.113 0.045e 0.004 0.097
 None 148 11.9 (7.3–18.0) 9 (6.1%) Ref 111 14.1 (7.6–21.9) 9 (8.1%) Ref
  ≤ 1 glass  (≤ 200 g/day) 1506 11.2 (7.2–17.4) 54 (3.6%) 0.762 (0.330, 1.761) 0.525 615 10.8 (6.2–18.0) 22 (3.6%) 0.360 (0.155, 0.836) 0.017
  > 1 glass ( > 200 g/day) 1114 10.8 (6.8–16.6) 28 (2.5%) 0.511 (0.203, 1.285) 0.153 429 11.6 (7.9–19.0) 20 (4.7%) 0.347 (0.141, 0.855) 0.021
Fish and shellfish intake 0.093 0.014 0.199 1.000
 None (0 g/day) 555 10.4 (6.9–16.3) 28 (5.0%) Ref N/A N/A N/A N/A N/A
 Some ( > 0 g/day) 2213 11.2 (7.1–17.3) 63 (2.8%) 0.604 (0.360, 1.013) 0.056 N/A N/A N/A N/A N/A
 ≤ 1 portion ( ≤ 120 g/day) N/A N/A N/A N/A N/A 1041 11.6 (7.0–18.8) 46 (4.4%) Ref
  > 1 portion ( > 120 g/day) N/A N/A N/A N/A N/A 114 10.8 (6.1–18.4) 5 (4.4%) 0.912 (0.327, 2.539) 0.860
Bread intake 0.101 0.396 N/A N/A
  ≤ median ( ≤ 98 g/day) 1378 11.2 (7.1–17.9) 50 (3.6%) Ref N/A N/A N/A N/A N/A
  > median ( > 98 g/day) 1377 10.9 (7.0–16.3) 41 (3.0%) 0.980 (0.569, 1.689) 0.942 N/A N/A N/A N/A N/A
Salt intake (inc. iodised) N/A N/A 0.186 0.361
 None (0 g/day) N/A N/A N/A N/A N/A 374 12.0 (6.8–21.1) 20 (5.3%) Ref
 Some ( > 0 g/day) N/A N/A N/A N/A N/A 781 11.3 (6.9–18.1) 31 (4.0%) 0.683 (0.375, 1.242) 0.211
Iodine-supplement usef 0.476 N/A 0.005 0.017
 No 72 12.4 (8.1–15.2) N/A N/A N/A 631 12.1 (7.3–20.1) 37 (5.9%) Ref
 Yes 521 11.2 (7.6–16.2) N/A N/A N/A 537 10.8 (6.4–17.3) 15 (2.8%) 0.524 (0.276, 0.997) 0.049

BMI body mass index, 95% CI confidence interval, N/A data not available or not applicable, OR odds ratio, Ref reference category, serum-Tg serum thyroglobulin concentration, TPO-Ab thyroid peroxidase antibody

aCut-off value for elevated serum-Tg based on previous studies in adults and school-aged children (see “Methods”)

bP-values from a Mann–Whitney U test (for two-categorical variables) or a Kruskal–Wallis test (for variables with more than two categories)

cP-values from a Chi-square test (after Continuity Correction for comparisons in 2 × 2 tables)

dP-values from multiple logistic regression models with elevated serum-Tg as the dependent variable (categorised as > 40 ng/ml). In Generation R: (1) models with food-group intakes were adjusted for energy intake, gestational week at blood extraction, age, pre-pregnancy BMI, TPO-Ab status, ethnicity, parity, smoking status, alcohol consumption, education, net household income, marital status, and child’s sex; and (2) models with iodine-supplement use were not performed (see footnote ‘f’). In INMA: 1) models with food-group intakes were adjusted for energy intake, gestational week at blood extraction, age, pre-pregnancy BMI, ethnicity, parity, smoking status, alcohol consumption, education, living with a partner, and child’s sex; and 2) models with iodine-supplement use were adjusted for gestational week at blood extraction, age, pre-pregnancy BMI, ethnicity, parity, smoking status, alcohol consumption, and education

eFisher's Exact Test P-value was reported due to some cells ( > 20%) with expected count < 5

fData on iodine-supplement use were available only for a sub-sample in Generation R (see “Methods”) and statistical analyses with elevated serum-Tg (i.e., categorical outcome) were not performed in this cohort due to very small numbers; e.g., there was only 1 woman who was an iodine-supplement non-user and had elevated serum-Tg for the models with Tg > 40 ng/ml