Table 2.
Association of dietary nutrient intakes with risk of preterm delivery
| Nutrients and quartile rangesb | No. of subjects | Odds ratios (95% confidence intervals)a | |||||
|---|---|---|---|---|---|---|---|
| <32 wk | 32–34 wk | 35–36 wk | ≥ 37 | <32 wk | 32–34 wk | 35–36 wk | |
| Carbohydrate (g) | |||||||
| <150.7 | 12 | 36 | 68 | 1316 | 0.8 (0.4, 1.8) | 1.2 (0.7, 2.0) | 1.0 (0.7, 1.4) |
| 150.7–278.9 | 26 | 56 | 144 | 2634 | Reference | Reference | Reference |
| ≥279.0 | 20 | 28 | 81 | 1317 | 1.9 (0.8, 4.4) | 1.1 (0.6, 2.2) | 1.1 (0.7, 1.6) |
| Continuous (128.3-unit change) | 58 | 120 | 293 | 5267 | 1.56 (0.69, 3.54) | 1.12 (0.60, 2.10) | 0.96 (0.66, 1. 41) |
| Protein (g) | |||||||
| <50.1 | 17 | 32 | 70 | 1317 | 1.6 (0.8, 3.1) | 1.0 (0.6, 1.6) | 1.0 (0.7, 1.4) |
| 50.1–84.4 | 27 | 63 | 149 | 2634 | Reference | Reference | Reference |
| ≥84.5 | 14 | 25 | 74 | 1316 | 0.7 (0.3, 1.5) | 0.9 (0.5, 1.5) | 0.9 (0.6, 1.2) |
| Continuous (34.4-unit change) | 58 | 120 | 293 | 5267 | 0.84 (0.49, 1.44) | 0.72 (0.47, 1.09) | 0.93 (0.72, 1.20) |
| Alanine (g) | |||||||
| <2.3 (g) | 16 | 32 | 71 | 1316 | 1.4 (0.7, 2.6) | 1.0 (0.6, 1.6) | 1.0 (0.8, 1.4) |
| 2.3–3.8 | 28 | 64 | 148 | 2634 | Reference | Reference | Reference |
| ≥3.9 | 14 | 24 | 74 | 1317 | 0.7 (0.3, 1.6) | 0.8 (0.4, 1.4) | 0.9 (0.6, 1.2) |
| Continuous (1.6-unit change) | 58 | 120 | 293 | 5267 | 0.99 (0.63, 1.56) | 0.82 (0.57, 1.17) | 0.99 (0.80, 1.22) |
| Methionine (g) | |||||||
| <1.1 | 16 | 30 | 63 | 1317 | 1.3 (0.7, 2.6) | 0.9 (0.5, 1.4) | 0.8 (0.6, 1.2) |
| 1.1–1.8 | 29 | 66 | 160 | 2633 | Reference | Reference | Reference |
| ≥1.9 | 13 | 24 | 70 | 1317 | 0.6 (0.3, 1.4) | 0.8 (0.4, 1.4) | 0.8 (0.5, 1.1) |
| Continuous (0.8-unit change) | 58 | 120 | 293 | 5267 | 0.92 (0.57, 1.47) | 0.82 (0.57, 1.18) | 1.01 (0.81, 1.25) |
| Cysteine (g) | |||||||
| <0.7 | 16 | 39 | 80 | 1316 | 1.4 (0.7, 2.7) | 1.4 (0.9, 2.2) | 1.3 (0.9, 1.7) |
| 0.7–1.1 | 26 | 53 | 135 | 2635 | Reference | Reference | Reference |
| ≥1.2 | 16 | 28 | 78 | 1316 | 1.0 (0.5, 2.1) | 1.1 (0.6, 1.9) | 1.0 (0.7, 1.4) |
| Continuous (0.5-unit change) | 58 | 120 | 293 | 5267 | 0.94 (0.61, 1.45) | 0.81 (0.58, 1.14) | 1.02 (0.83, 1.24) |
| Fat (g) | |||||||
| <33.9 | 15 | 30 | 71 | 1317 | 1.3 (0.6, 2.5) | 0.9 (0.5, 1.4) | 1.1 (0.8, 1.4) |
| 33.9–60.6 | 28 | 61 | 151 | 2634 | Reference | Reference | Reference |
| ≥60.7 | 15 | 29 | 71 | 1316 | 0.8 (0.3, 1.8) | 1.2 (0.7, 2.2) | 0.8 (0.5, 1.1) |
| Continuous (26.8-unit change) | 58 | 120 | 293 | 5267 | 0.70 (0.40, 1.23) | 1.10 (0.72, 1.69) | 1.07 (0.83, 1.39) |
| Glycemic index | |||||||
| <49.2 | 8 | 29 | 62 | 1316 | 0.6 (0.3, 1.3) | 1.1 (0.7, 1.8) | 0.9 (0.6, 1.2) |
| 49.2–55.6 | 28 | 52 | 145 | 2634 | Reference | Reference | Reference |
| ≥55.7 | 22 | 39 | 86 | 1317 | 1.6 (0.9, 2.7) | 1.5 (1.0, 2.3) | 1.2 (0.9, 1.6) |
| Continuous (6.5-unit change) | 58 | 120 | 293 | 5267 | 1.74 (1.21, 2.51) | 1.28 (0.99, 1.65) | 1.12 (0.95, 1.32) |
| Folate (μg DFE) | |||||||
| <339.4 | 15 | 38 | 77 | 1317 | 1.2 (0.6, 2.4) | 1.3 (0.9, 2.1) | 1.1 (0.8, 1.5) |
| 339.4–718.0 | 26 | 56 | 146 | 2633 | Reference | Reference | Reference |
| ≥718.1 | 17 | 26 | 70 | 1317 | 1.2 (0.6, 2.3) | 1.0 (0.6, 1.6) | 0.8 (0.6, 1.2) |
| Continuous (378.7-unit change) | 58 | 120 | 293 | 5267 | 1.12 (0.88, 1.42) | 0.94 (0.74, 1.19) | 0.89 (0.76, 1.04) |
| Thiamin (mg) | |||||||
| <0.9 | 18 | 35 | 78 | 1316 | 1.8 (0.9, 3.5) | 1.2 (0.7, 1.8) | 1.2 (0.9, 1.6) |
| 0.9–1.6 | 22 | 59 | 145 | 2635 | Reference | Reference | Reference |
| ≥1.7 | 18 | 26 | 70 | 1316 | 1.4 (0.7, 2.9) | 0.9 (0.5, 1.6) | 0.8 (0.6, 1.1) |
| Continuous (0.8-unit change) | 58 | 120 | 293 | 5267 | 1.25 (0.89, 1.77) | 0.94 (0.68, 1.29) | 0.86 (0.71, 1.06) |
| Riboflavin (mg) | |||||||
| <1.4 | 17 | 35 | 78 | 1316 | 1.5 (0.8, 2.9) | 1.2 (0.7, 1.8) | 1.2 (0.9, 1.6) |
| 1.4–2.5 | 26 | 59 | 137 | 2635 | Reference | Reference | Reference |
| ≥2.6 | 15 | 26 | 78 | 1316 | 0.9 (0.4, 1.9) | 0.9 (0.5, 1.6) | 1.0 (0.7, 1.4) |
| Continuous (1.2-unit change) | 58 | 120 | 293 | 5267 | 0.91 (0.60, 1.40) | 1.13 (0.83, 1.53) | 0.94 (0.78, 1.15) |
| Niacin (mg) | |||||||
| <13.4 | 12 | 32 | 79 | 1317 | 0.9 (0.4, 1.8) | 1.0 (0.6, 1.5) | 1.2 (0.9, 1.7) |
| 13.4–23.5 | 27 | 65 | 138 | 2633 | Reference | Reference | Reference |
| ≥23.6 | 19 | 23 | 76 | 1317 | 1.4 (0.7, 2.8) | 0.7 (0.4, 1.3) | 1.0 (0.7, 1.4) |
| Continuous (10.2-unit change) | 58 | 120 | 293 | 5267 | 1.33 (0.97, 1.82) | 0.88 (0.64, 1.21) | 0.90 (0.74, 1.09) |
| Vitamin B6 (mg) | |||||||
| <1.4 | 16 | 32 | 72 | 1316 | 1.4 (0.7, 2.7) | 1.0 (0.6, 1.6) | 1.0 (0.8, 1.4) |
| 1.4–2.6 | 28 | 63 | 152 | 2634 | Reference | Reference | Reference |
| ≥2.7 | 14 | 25 | 69 | 1317 | 0.7 (0.3, 1.6) | 0.8 (0.5, 1.5) | 0.8 (0.5, 1.1) |
| Continuous (1.3-unit change) | 58 | 120 | 293 | 5267 | 1.10 (0.75, 1.61) | 0.84 (0.59, 1.18) | 0.88 (0.72, 1.09) |
| Vitamin B12 (μg) | |||||||
| <3.5 | 16 | 33 | 69 | 1317 | 1.4 (0.7, 2.7) | 1.1 (0.7, 1.7) | 1.0 (0.7, 1.3) |
| 3.5–7.3 | 25 | 59 | 155 | 2634 | Reference | Reference | Reference |
| ≥7.4 | 17 | 28 | 69 | 1316 | 1.2 (0.6, 2.4) | 1.0 (0.6, 1.7) | 0.8 (0.6, 1.1) |
| Continuous (3.9-unit change) | 58 | 120 | 293 | 5267 | 0.96 (0.75, 1.23) | 1.13 (1.01, 1.25) | 1.04 (0.96, 1.14) |
| Choline (mg) | |||||||
| <191.6 | 18 | 33 | 80 | 1317 | 1.8 (0.9, 3.5) | 1.0 (0.7, 1.7) | 1.3 (0.9, 1.7) |
| 191.6–342.8 | 23 | 55 | 138 | 2633 | Reference | Reference | Reference |
| ≥342.9 | 17 | 32 | 75 | 1317 | 1.1 (0.5, 2.5) | 1.5 (0.9, 2.6) | 0.9 (0.6, 1.3) |
| Continuous (151.3-unit change) | 58 | 120 | 293 | 5267 | 1.15 (0.75, 1.76) | 1.26 (0.92, 1.74) | 0.98 (0.79, 1.21) |
| Betaine (mg) | |||||||
| <46.6 | 8 | 34 | 72 | 1316 | 0.5 (0.2, 1.0) | 1.1 (0.7, 1.7) | 1.0 (0.7, 1.3) |
| 46.6–123.5 | 36 | 61 | 149 | 2634 | Reference | Reference | Reference |
| ≥123.6 | 14 | 25 | 72 | 1317 | 0.7 (0.4, 1.4) | 0.8 (0.5, 1.4) | 0.9 (0.7, 1.3) |
| Continuous (77-unit change) | 58 | 120 | 293 | 5267 | 1.09 (0.93, 1.27) | 0.93 (0.79, 1.10) | 1.01 (0.92, 1.10) |
| Vitamin A (μg RAE) | |||||||
| <391.5 | 19 | 35 | 84 | 1317 | 1.8 (0.9, 3.3) | 1.1 (0.7, 1.7) | 1.4 (1.0, 1.8) |
| 391.5–854.4 | 24 | 61 | 129 | 2634 | Reference | Reference | Reference |
| ≥854.5 | 15 | 24 | 80 | 1316 | 1.0 (0.5, 2.1) | 0.8 (0.5, 1.4) | 1.1 (0.8, 1.6) |
| Continuous (463-unit change) | 58 | 120 | 293 | 5267 | 1.01 (0.81, 1.25) | 1.06 (0.91, 1.23) | 1.05 (0.96, 1.15) |
| Alpha-carotene (μg) | |||||||
| <158.6 | 20 | 41 | 89 | 1317 | 1.6 (0.9, 2.8) | 1.4 (1.0, 2.2) | 1.4 (1.1, 1.9) |
| 158.6–843.4 | 26 | 57 | 125 | 2633 | Reference | Reference | Reference |
| ≥843.5 | 12 | 22 | 79 | 1317 | 0.9 (0.4, 1.7) | 0.8 (0.5, 1.3) | 1.2 (0.9, 1.6) |
| Continuous (684.9-unit change) | 58 | 120 | 293 | 5267 | 1.02 (0.86, 1.22) | 0.75 (0.58, 0.96) | 1.02 (0.93, 1.11) |
| Beta-carotene (μg) | |||||||
| <1072.2 | 22 | 36 | 86 | 1317 | 1.9 (1.1, 3.5) | 1.1 (0.7, 1.7) | 1.3 (1.0, 1.7) |
| 1072.2–3591.2 | 24 | 64 | 135 | 2633 | Reference | Reference | Reference |
| ≥3591.3 | 12 | 20 | 72 | 1317 | 0.9 (0.4, 1.8) | 0.6 (0.4, 1.1) | 1.0 (0.8, 1.4) |
| Continuous (2519.1-unit change) | 58 | 120 | 293 | 5267 | 1.05 (0.86, 1.28) | 0.82 (0.65, 1.04) | 0.99 (0.89, 1.10) |
| Lutein (μg) | |||||||
| <762.3 | 16 | 33 | 74 | 1316 | 1.2 (0.6, 2.2) | 1.1 (0.7, 1.7) | 1.1 (0.8, 1.4) |
| 762.3–2212.2 | 29 | 58 | 145 | 2634 | Reference | Reference | Reference |
| ≥2212.3 | 13 | 29 | 74 | 1317 | 0.8 (0.4, 1.6) | 1.0 (0.7, 1.6) | 1.0 (0.7, 1.3) |
| Continuous (1450-unit change) | 58 | 120 | 293 | 5267 | 1.02 (0.86, 1.22) | 0.98 (0.85, 1.14) | 1.00 (0.91, 1.09) |
| Vitamin C (mg) | |||||||
| <60.0 | 15 | 41 | 81 | 1316 | 1.2 (0.6, 2.3) | 1.6 (1.0, 2.4) | 1.2 (0.9, 1.6) |
| 60.0–154.7 | 26 | 52 | 140 | 2635 | Reference | Reference | Reference |
| ≥154.8 | 17 | 27 | 72 | 1316 | 1.2 (0.6, 2.3) | 1.1 (0.6, 1.8) | 0.9 (0.7, 1.3) |
| Continuous (94.8-unit change) | 58 | 120 | 293 | 5267 | 1.03 (0.77, 1.37) | 0.97 (0.77, 1.22) | 0.93 (0.80, 1.07) |
| Vitamin E (mg) | |||||||
| <2.9 | 19 | 32 | 78 | 1316 | 1.9 (1.0, 3.6) | 1.0 (0.6, 1.5) | 1.2 (0.9, 1.6) |
| 2.9–6.1 | 23 | 64 | 145 | 2634 | Reference | Reference | Reference |
| ≥6.2 | 16 | 24 | 70 | 1317 | 1.1 (0.5, 2.3) | 0.8 (0.5, 1.3) | 0.8 (0.6, 1.2) |
| Continuous (3.3-unit change) | 58 | 120 | 293 | 5267 | 0.79 (0.55, 1.15) | 0.97 (0.78, 1.21) | 0.85 (0.72, 0.99) |
| Iron (mg) | |||||||
| <8.7 | 19 | 39 | 78 | 1316 | 1.9 (1.0, 3.7) | 1.5 (0.9, 2.3) | 1.2 (0.9, 1.6) |
| 8.7–17.6 | 23 | 50 | 150 | 2634 | Reference | Reference | Reference |
| ≥17.7 | 16 | 31 | 65 | 1317 | 1.1 (0.5, 2.3) | 1.3 (0.8, 2.2) | 0.7 (0.5, 1.0) |
| Continuous (9-unit change) | 58 | 120 | 293 | 5267 | 1.11 (0.84, 1.46) | 1.04 (0.83, 1.31) | 0.83 (0.70, 0.99) |
| Calcium (mg) | |||||||
| <495.2 | 14 | 34 | 75 | 1317 | 1.0 (0.5, 2.0) | 1.1 (0.7, 1.7) | 1.1 (0.8, 1.5) |
| 495.2–1036.6 | 31 | 63 | 141 | 2634 | Reference | Reference | Reference |
| ≥1036.7 | 13 | 23 | 77 | 1316 | 0.7 (0.3, 1.4) | 0.7 (0.4, 1.3) | 1.0 (0.7, 1.4) |
| Continuous (541.5-unit change) | 58 | 120 | 293 | 5267 | 0.66 (0.43, 1.02) | 0.91 (0.67, 1.22) | 0.94 (0.78, 1.12) |
| Copper (mg) | |||||||
| <0.7 | 17 | 35 | 75 | 1317 | 1.6 (0.8, 3.3) | 1.2 (0.7, 1.9) | 1.2 (0.8, 1.6) |
| 0.7–1.2 | 23 | 54 | 138 | 2634 | Reference | Reference | Reference |
| ≥1.3 | 18 | 31 | 80 | 1316 | 1.3 (0.6, 2.8) | 1.4 (0.8, 2.3) | 1.0 (0.7, 1.5) |
| Continuous (0.6-unit change) | 58 | 120 | 293 | 5267 | 0.92 (0.70, 1.21) | 1.09 (0.98, 1.21) | 1.03 (0.95, 1.12) |
| Magnesium (mg) | |||||||
| <173.5 | 16 | 38 | 75 | 1317 | 1.4 (0.7, 2.8) | 1.4 (0.9, 2.2) | 1.1 (0.8, 1.6) |
| 173.5–306.1 | 27 | 55 | 146 | 2634 | Reference | Reference | Reference |
| ≥306.2 | 15 | 27 | 72 | 1316 | 0.8 (0.3, 1.8) | 1.0 (0.6, 1.8) | 0.8 (0.5, 1.2) |
| Continuous (132.7-unit change) | 58 | 120 | 293 | 5267 | 0.72 (0.43, 1.22) | 0.65 (0.43, 0.97) | 0.79 (0.62, 1.00) |
| Selenium (μg) | |||||||
| <54.0 | 15 | 35 | 68 | 1317 | 1.3 (0.6, 2.5) | 1.2 (0.7, 1.8) | 1.0 (0.7, 1.3) |
| 54.0–92.6 | 26 | 58 | 146 | 2634 | Reference | Reference | Reference |
| ≥92.7 | 17 | 27 | 79 | 1316 | 1.1 (0.5, 2.4) | 1.0 (0.6, 1.8) | 1.0 (0.7, 1.4) |
| Continuous (38.7-unit change) | 58 | 120 | 293 | 5267 | 1.31 (0.85, 2.01) | 0.77 (0.53, 1.11) | 0.98 (0.79, 1.21) |
| Zinc (mg) | |||||||
| <8.0 | 20 | 37 | 72 | 1316 | 2.3 (1.2, 4.5) | 1.3 (0.8, 2.0) | 1.1 (0.8, 1.5) |
| 8.0–14.2 | 20 | 61 | 141 | 2635 | Reference | Reference | Reference |
| ≥14.3 | 18 | 22 | 80 | 1316 | 1.4 (0.6, 3.1) | 0.7 (0.4, 1.2) | 1.1 (0.7, 1.5) |
| Continuous (6.3-unit change) | 58 | 120 | 293 | 5267 | 0.91 (0.59, 1.41) | 0.84 (0.60, 1.18) | 0.89 (0.73, 1.09) |
| Diet Quality Index | |||||||
| <9 | 16 | 40 | 90 | 1485 | 1.1 (0.6, 2.0) | 1.2 (0.8, 1.8) | 1.2 (0.9, 1.6) |
| 9–16 | 29 | 60 | 140 | 2591 | Reference | Reference | Reference |
| ≥17 | 13 | 20 | 63 | 1191 | 0.8 (0.4, 1.7) | 0.7 (0.4, 1.3) | 0.9 (0.6, 1.2) |
| Continuous (8-unit change) | 58 | 120 | 293 | 5267 | 0.92 (0.56, 1.50) | 0.78 (0.55, 1.10) | 0.83 (0.66, 1.03) |
| Mediterranean Diet Score | |||||||
| <11 | 16 | 37 | 82 | 1228 | 1.5 (0.8, 2.8) | 1.5 (1.0, 2.4) | 1.3 (0.9, 1.7) |
| 11–15 | 23 | 50 | 137 | 2570 | Reference | Reference | Reference |
| ≥16 | 19 | 33 | 74 | 1469 | 1.4 (0.8, 2.6) | 1.2 (0.8, 1.9) | 0.9 (0.7, 1.2) |
| Continuous (5-unit change) | 58 | 120 | 293 | 5267 | 0.96 (0.68, 1.36) | 0.92 (0.72, 1.18) | 0.88 (0.75, 1.03) |
Abbreviations: DFE, dietary folate equivalents; RAE, retinol activity equivalents.
a
Odds ratios were adjusted for total energy intake.
b
Odds ratios reflect a comparison of the lowest quartile and highest quartile of intake with intake in the middle two quartiles as reference, based on the distribution among the controls. Odds ratios based on continuous specification of each nutrient reflect the unit difference between the 25th and 75th percentiles of the distribution of the nutrient among the controls.