Table 5.
Associations between infant UIC and BMIC and infant TSH, fT3 and fT4 concentrations
(Coefficient and 95 % confidence intervals)
| Dependent variables | ||||||
|---|---|---|---|---|---|---|
| Unadjusted | Adjusted‡ | |||||
| Coefficient | 95% CI | P | Coefficient | 95% CI | P | |
| Independent variables | Infant TSH | |||||
| Infant UIC* | –0·06 | –0·27, 0·16 | 0·599 | 0·13 | –0·22, 0·48 | 0·459 |
| BMIC† | –0·22 | –0·92, 0·47 | 0·515 | –0·46 | –1·15, 0·22 | 0·178 |
| Infant fT3 | ||||||
| Infant UIC* | 0·01 | –0·04, 0·23 | 0·149 | 0·06 | –0·06, 0·19 | 0·324 |
| BMIC† | –0·13 | –0·55, 0·30 | 0·555 | –0·07 | –0·45, 0·32 | 0·414 |
| Infant fT4 | ||||||
| Infant UIC* | 0·016 | –0·22, 0·53 | 0·408 | 0·13 | –0·24, 0·51 | 0·471 |
| BMIC† | 0·11 | –0·90, 1·12 | 0·822 | 0·13 | –0·87, 1·12 | 0·801 |
UIC, urinary iodine concentration; BMIC, breast milk iodine concentration; TSH, thyroid-stimulating hormone; fT3, free triiodothyronine; fT4, free thyroxine.
The model includes two time points (infants, 3 and 6 months of age) in linear mixed models. The coefficient is given in per 100 µg/l.
The model includes one time point (infant, 3 months of age) in linear models. The coefficient is given in per 100 µg/l.
Covariates in adjusted model: TSH: maternal pre-pregnancy BMI, maternal current nicotine use, infant ferritin concentration; fT3: infant sex, gestational week born, maternal pre-pregnancy BMI; fT4: gestational week born.