TABLE 1.
Study participant characteristics1
| Characteristic | Value |
|---|---|
| n | 551 |
| Age, y | 32.6 ± 0.2 |
| Time from parturition to milk sampling, d2 | 33.7 ± 0.6 |
| Annual family income, % | |
| Lower income (≤$60,000) | 16.9 |
| Middle-high income (>$60,000) | 78.5 |
| Missing | 4.5 |
| Maternal education, % | |
| < Postsecondary | 8.7 |
| College/trade school diploma or undergraduate degree | 63.9 |
| Graduate degree | 27.2 |
| Missing | 0.2 |
| Time of collection, % | |
| Morning | 16.0 |
| Afternoon | 8.0 |
| Evening | 8.3 |
| Overnight | 2.2 |
| Combined | 57.5 |
| Missing | 8.0 |
| Foremilk or hindmilk, % | |
| Foremilk | 13.1 |
| Hindmilk | 8.9 |
| Combined | 68.6 |
| Missing | 9.4 |
| FA-supplement use, %3 | |
| Nonuser | 28.3 |
| User | 71.7 |
| Total daily supplemental FA intake among supplement users (µg), median (range)3 | 1000 (63, 10,000) |
| Breast milk folates (nmol/L) | |
| Total folate4 | 116.1 ± 1.9 |
| Reduced folates5 | 68.9 ± 1.3 |
| 5-methyl-THF | 47.5 ± 1.0 |
| UMFA6 | 47.2 ± 1.6 |
| Prevalence of detectable UMFA in breast milk, %6 | 96.2 |
1
Data are presented as mean ± SE, percentage, or median (range). FA, folic acid; THF, tetrahydrofolate; UMFA, unmetabolized folic acid.
2
n = 522.
3
Based on self-reported consumption of an FA-containing supplement. Total daily FA from supplements was based on the sum of FA content from all vitamin supplements.
4
Total folate is the sum of UMFA, THF, 5-methyl-THF, 5,10-methenyl-THF, and 5-formyl-THF.
5
Reduced folates represents the sum of THF, 5-methyl-THF, 5,10-methenyl-THF, and 5-formyl-THF.
6
The limit of detection for UMFA was <0.9 nmol/L.