Table 4. Mean semen levels among sons estimated for increasing levels of prenatal coffee exposure. An adult follow-up Study of the Environment and Reproduction of the Child Health and Development Studies.
| Maternal coffee level during pregnancy | |||||||
|---|---|---|---|---|---|---|---|
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| 0 cups | 2.5 cups | 5 cups | Test for trend | ||||
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| Adult son's semen measures | Meana | 95% CI | Mean | 95% CI | Meana | 95% CI | P-valueb |
| Concentration (106/ml)c | |||||||
| Unadjusted | 65.9 | 52.7, 81.0 | 57.0 | 48.5, 66.4 | 49.0 | 37.5, 62.7 | 0.09 |
| Adjusted | 64.1 | 45.0, 88.1 | 51.4 | 35.7, 71.1 | 40.5 | 23.2, 64.7 | 0.06 |
| Motility (% motile) | |||||||
| Unadjusted | 50.7 | 46.7, 54.6 | 47.4 | 44.6, 50.2 | 44.1 | 39.8, 48.4 | 0.04 |
| Adjusted | 51.3 | 45.3, 57.4 | 47.6 | 41.9, 53.3 | 43.9 | 36.0, 51.7 | 0.06 |
| Morphology (% normal) | |||||||
| Unadjusted | 8.5 | 7.5, 9.5 | 7.4 | 6.7, 8.1 | 6.4 | 5.3, 7.5 | 0.01 |
| Adjusted | 8.8 | 7.2, 10.4 | 7.8 | 6.2, 9.3 | 6.7 | 4.6, 8.8 | 0.05 |
CI = confidence interval.
a
Estimated from linear regression. Unadjusted models include only the term for maternal coffee intake (cups per day). Adjusted models include terms for maternal coffee intake (cups per day), maternal alcohol (drinks per week), maternal smoking (yes/no), son's coffee (cups per day), son's drinking (drinks per week) and son's smoking (yes/no).
b
P-value for maternal coffee term (continuous).
c
Back transformed from cube root.