Table 3 Associations between tea consumption and risk of preterm birth by duration and starting age of tea consumption (n = 10 179), Urban China, 2010–2012
From: Maternal tea consumption and the risk of preterm delivery in urban China: a birth cohort study
Drink tea | Term (n) | Preterm (n = 1019) | Moderate preterm (n = 833) | Very preterm (n = 186) | Medically indicated (n = 338) | Spontaneous (n = 68) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
No. | OR(95 % CI) | No. | OR(95 % CI) | No. | OR(95 % CI) | No. | OR(95 % CI) | No. | OR(95 % CI) | ||
Never | 8403 | 900 | 1 | 733 | 1 | 167 | 1 | 295 | 1 | 605 | 1 |
Ever | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Duration, month |  |  |  |  |  |  |  |  |  |  |  |
   ≤ 48 | 321 | 48 | 1.24(0.89–1.73) | 36 | 1.16(0.80–1.68) | 12 | 1.52(0.83–2.83) | 22 | 1.61(0.95–2.73) | 26 | 1.08(0.70–1.64) |
   > 48 | 304 | 52 | 1.49(1.08–2.04) | 46 | 1.62(1.16–2.27) | 6 | 0.84(0.36–1.94) | 17 | 1.14(0.63–2.07) | 35 | 1.65(1.14–2.39) |
    P for trend |  | 0.008 | 0.0028 | 0.65 | 0.26 | 0.012 | |||||
 Start drinking tea age, year |  |  |  |  |  |  |  |  |  |  |  |
   < 20 | 272 | 55 | 1.60(1.17–2.20) | 48 | 1.76(1.26–2.46) | 7 | 0.95(0.43–2.08) | 20 | 1.68(0.97–2.91) | 35 | 1.64(1.13–2.39) |
   ≥ 20 | 340 | 46 | 1.31(0.94–1.83) | 39 | 1.35(0.94–1.94) | 7 | 1.03(0.47–2.26) | 14 | 0.95(0.51–1.80) | 32 | 1.48(1.01–2.17) |