Table 1.
Characteristics of the mothers and newborns in our study population with selenium measurements (n = 861) and in the rest of the population without selenium measurement (n = 1038)
| Mean ± SD or frequency (%) | |||
|---|---|---|---|
| Variable | Without data (n = 1038) | With data (n = 861) | p‐value† |
| Mothers | |||
| Study centre, % | |||
| Poitiers | 53.49 | 45.79 | |
| Nancy | 46.51 | 54.21 | 0.0008 |
| Age (years), mean ± SD | 30.22 ± 4.82 | 29.72 ± 4.96 | 0.07 |
| <25, % | 13.44 | 17.06 | |
| 25–34, % | 69.48 | 68.35 | |
| >34, % | 17.08 | 14.59 | 0.10 |
| BMI (kg/m2), mean ± SD | 26.40 ± 4.58 | 26.29 ± 4.47 | 0.72 |
| Normal, % | 45.20 | 45.76 | |
| Overweight, % | 37.54 | 37.18 | |
| Moderately obese, % | 11.83 | 12.00 | 0.96 |
| Severely obese, % | 5.43 | 5.06 | |
| Educational level, % | |||
| Primary or below | 5.93 | 7.96 | |
| Secondary | 60.80 | 62.35 | |
| Tertiary | 33.27 | 29.69 | 0.10 |
| Household income >2300 euros per month, % | 55.83 | 49.94 | 0.06 |
| Tobacco use during pregnancy, % | 27.00 | 31.05 | 0.11 |
| Maternal atopy | 31.93 | 32.71 | 0.72 |
| Duration of pregnancy (WA), mean ± SD | 39.27 ± 1.69 | 39.17 ± 1.80 | 0.24 |
| Newborns | |||
| Gender (female), % | 48.09 | 46.66 | 0.54 |
| Birthweight (kg), mean ± SD | 3.28 ± 0.50 | 3.28 ± 0.52 | 0.71 |
| Premature birth, %‡ | 5.64 | 6.32 | 0.54 |
| Presence of siblings, % | |||
| 0 | 46.65 | 46.16 | |
| 1–2 | 48.28 | 49.65 | |
| ≥3 | 5.07 | 4.19 | 0.61 |
| Season of birth, % | |||
| Summer | 24.79 | 32.75 | |
| Autumn | 21.89 | 20.82 | |
| Winter | 23.23 | 19.06 | |
| Spring | 30.11 | 27.37 | 0.001 |
| Exclusive breastfeeding for at least 4 months, % | 13.39 | 13.39 | 0.82 |
*WA, weeks of amenorrhea.
†The p‐value in a chi‐squared test (for categorical variables) or a Mann–Whitney U test (for continuous variables), statistically significant p‐values are displayed in bold.
‡<37 weeks of amenorrhea.