Table 2.
Odds Ratio (OR) and 95% confidence interval (CI) of spontaneous preterm birth according to maternal sleep duration and vital exhaustion during the first six months of pregnancy, Lima, Peru, 2009-2010
| Term Controls (N = 480) | Cases (N = 479) | Unadjusted | Adjusted* | Adjusted** | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Exposure parameters | n | % | n | % | OR | (95% CI) | OR | (95% CI) | OR | (95% CI) |
| Hours of sleep per night | ||||||||||
| ≤ 6 hours | 79 | 16.5 | 107 | 22.3 | 1.55 | (1.11-2.16) | 1.56 | (1.11-2.19) | 1.53 | (1.08-2.17) |
| 7-8 hours | 325 | 67.7 | 284 | 59.3 | 1.00 | referent | 1.00 | referent | 1.00 | referent |
| ≥ 9 hours | 76 | 15.8 | 88 | 18.4 | 1.33 | (0.94-1.87) | 1.34 | (0.94-1.91) | 1.50 | (1.04-2.16) |
| Complaint of vital exhaustion | ||||||||||
| Never | 185 | 38.5 | 99 | 20.7 | 1.00 | referent | 1.00 | referent | 1.00 | referent |
| Ever | 295 | 61.5 | 380 | 79.3 | 2.41 | (1.81-3.21) | 2.41 | (1.79-3.23) | 2.46 | (1.83-3.32) |
| 1-3 times/Month | 204 | 42.5 | 201 | 41.9 | 1.84 | (1.35-2.52) | 1.89 | (1.38-2.60) | 1.97 | (1.43-2.72) |
| 4 times/Month - Weekly | 73 | 15.2 | 156 | 32.6 | 3.99 | (2.76-5.78) | 3.85 | (2.64-5.62) | 3.91 | (2.67-5.73) |
| Daily | 18 | 3.8 | 23 | 4.8 | 2.39 | (1.23-4.64) | 2.42 | (1.23-4.76) | 2.23 | (1.12-4.45) |
| P-value for trend | <0.001 | <0.001 | <0.001 | |||||||
*Adjusted for maternal age, pre-pregnancy weight, unplanned pregnancy, and no vitamin use during pregnancy.
**Same as above but now also include sleep duration and vital exhaustion in the model.
Bolded estimates are statistically significant at the α = 0.05 level.