Among 280 participants who investigated GWG and HEI/A-HEI, the mean age was 29.73 ± 0.58 years old, 19.4% were insufficient weight gain, 7.8% were adequate weight gain, and 72.8% were excessive weight gain, as shown in Table 1. Among 333 participants who investigated GDM and DII/DASH, the mean age was 28.24 ± 0.40 years old, 15.6% with GDM and 84.4% without GDM.
Table 1
Basic characteristics of the participants
Variables | GWG | GDM |
HEI/A-HEI N = 280 | DII/DASH N = 667 | HEI/A-HEI N = 138 | DII/DASH N = 333 |
Age | 29.73 ± 0.58 | 29.26 ± 0.41 | 28.07 ± 0.50 | 28.24 ± 0.40 |
Race | | | | |
| Non-Hispanic White | 113(49.3) | 297(50.7) | 62(54.0) | 159(54.1) |
| Other races | 167(50.7) | 370(49.3) | 76(46.0) | 174(45.9) |
Education levels | | | | |
| Less than high school | 80(21.0) | 191(20.5) | 40(30.3) | 98(22.4) |
| High school diploma | 62(19.6) | 136(17.7) | 28(15.0) | 60(12.7) |
| College or above | 138(59.5) | 340(61.8) | 70(54.7) | 175(65.0) |
Marital status | | | | |
| Married | 190(72.0) | 467(70.8) | 95(68.5) | 238(70.3) |
| Others | 90(28.0) | 200(29.2) | 43(31.5) | 95(29.7) |
Family PIR | | | | |
| ≤ 1.3 | 106(25.4) | 244(27.6) | 52(26.1) | 121(26.0) |
| 1.3–3.5 | 103(37.2) | 245(40.5) | 54(45.0) | 126(46.9) |
| > 3.5 | 71(37.4) | 178(31.9) | 32(28.9) | 86(27.1) |
Smoking | | | | |
| No-smoker | 199(74.4) | 456(67.4) | 90(58.6) | 218(57.3) |
| Current smoker | 32(9.4) | 72(11.1) | 14(12.2) | 32(9.8) |
| Former smoker | 49(16.2) | 139(21.5) | 34(29.2) | 83(32.9) |
Physical activity | | | | |
| Inactive | 83(29.5) | 177(25.3) | 42(35.2) | 90(27.6) |
| Moderate | 98(28.4) | 185(24.7) | 51(27.7) | 93(20.6) |
| Vigorous | 99(42.1) | 305(49.9) | 45(37.0) | 150(51.8) |
Number of live births | | | | |
| 0 | 16(2.9) | 48(6.1) | 8(3.4) | 26(7.9) |
| 1 | 134(55.4) | 314(52.6) | 66(51.4) | 157(54.1) |
| ≥ 2 | 130(41.7) | 305(41.3) | 64(45.2) | 150(38.1) |
Advanced maternal age | | | | |
| Yes | 33(25.6) | 90(21.9) | 12(11.9) | 40(12.9) |
| No | 247(74.4) | 577(78.1) | 126(88.1) | 293(87.1) |
History of diabetes | | | | |
| Yes | 4(0.8) | 11(0.9) | 1(0.2) | 5(0.8) |
| No | 276(99.2) | 656(99.1) | 137(99.8) | 328(99.2) |
GDM | | | | |
| Yes | - | - | 23(19.9) | 44(15.6) |
| No | - | - | 115(80.1) | 289(84.4) |
GWG | | | | |
| Insufficient | 66(19.4) | 138(20.2) | 31(20.5) | 73(25.1) |
| Adequate | 25(7.8) | 100(12.7) | 12(8.2) | 54(12.2) |
| Excessive | 189(72.8) | 429(67.1) | 95(71.3) | 206(62.8) |
Total energy intake (Kcal) | 2135.83 ± 66.48 | 2197.32 ± 40.25 | 2246.47 ± 114.38 | 2269.76 ± 59.11 |
HEI | 52.98 ± 1.21 | - | 51.08 ± 0.64 | - |
AHEI | 46.46 ± 0.99 | - | 46.13 ± 0.89 | - |
DII | - | 0.19 ± 0.14 | - | 0.27 ± 0.18 |
DASH | - | 2.30 ± 0.08 | - | 2.16 ± 0.10 |
Note: The non-total of the component ratios of 100 percent is due to rounding. |
The results of the logistic regression showed that HEI increasing reduced the risk of insufficient GWG (P = 0.002), OR was 0.888(0.825,0.956), after adjusting for all covariates. A-HEI increasing reduced the risks of insufficient GWG and excessive GWG (P = 0.002, P < 0.001), ORs were 0.840(0.754,0.935) and 0.797(0.729,0.871), respectively. No statistically significant linear associations between DII or DASH and the prevalence of insufficient or excessive GWG were observed, as shown in Table 2. However, increased DII was a risk factor for the development of GDM (P = 0.012), OR was 1.931(1.163,3.205), and DASH increasing reduced the risk of GDM (P = 0.028), OR was 0.677(0.479,0.957), as shown in Table 3. After deleting participants with a history of diabetes, none of the above results have changed, as shown in Supplement 5.
Table 2
Logistic regressions of GWG with diet quality scores
Diet quality scores | GWG | Model1a | | Model2b | | Model3c |
β | P | OR (95%CI) | β | P | OR (95%CI) | β | P | OR (95%CI) |
HEI N = 280 | Insufficient | -0.074 | 0.158 | 0.929(0.838,1.030) | | -0.098 | 0.054 | 0.907(0.820,1.002) | | -0.092 | 0.076 | 0.912(0.824,1.010) |
Excessive | -0.086 | 0.073 | 0.918(0.835,1.009) | | -0.120 | 0.008 | 0.887(0.814,0.967) | | -0.119 | 0.002 | 0.888(0.825,0.956) |
A-HEI N = 280 | Insufficient | -0.093 | 0.142 | 0.912(0.804,1.033) | | -0.139 | 0.021 | 0.870(0.774,0.978) | | -0.175 | 0.002 | 0.840(0.754,0.935) |
Excessive | -0.117 | 0.012 | 0.890(0.813,0.974) | | -0.182 | < 0.001 | 0.834(0.765,0.909) | | -0.227 | < 0.001 | 0.797(0.729,0.871) |
DII N = 667 | Insufficient | 0.076 | 0.578 | 1.079(0.822,1.416) | | 0.027 | 0.829 | 1.027(0.804,1.313) | | 0.176 | 0.279 | 1.193(0.865,1.645) |
Excessive | 0.220 | 0.088 | 1.246(0.967,1.605) | | 0.172 | 0.120 | 1.188(0.955,1.476) | | 0.288 | 0.064 | 1.333(0.983,1.808) |
DASH N = 667 | Insufficient | -0.184 | 0.261 | 0.832(0.602,1.150) | | -0.126 | 0.455 | 0.882(0.631,1.232) | | -0.043 | 0.778 | 0.958(0.705,1.300) |
Excessive | -0.286 | 0.031 | 0.751(0.579,0.974) | | -0.242 | 0.074 | 0.785(0.602,1.024) | | -0.237 | 0.076 | 0.789(0.607,1.026) |
a Model1: Dietary index. b Model2: Model1 + age + race + education levels + marital status + family PIR. c Model3: Model2 + smoking + physical activity + number of live births + total energy intake. |
Table 3
Logistic regressions of GDM with diet quality scores
Diet quality scores | Model1a | | Model2b | | Model3c |
β | P | OR (95%CI) | β | P | OR (95%CI) | β | P | OR (95%CI) |
HEI (N = 138) | -0.019 | 0.241 | 0.981(0.949,1.014) | | 0.008 | 0.695 | 1.008(0.968,1.049) | | -0.074 | 0.123 | 0.929(0.845,1.022) |
A-HEI (N = 138) | -0.002 | 0.968 | 0.998(0.924,1.079) | | 0.078 | 0.086 | 1.082(0.988,1.184) | | 0.059 | 0.314 | 1.060(0.942,1.194) |
DII (N = 333) | 0.087 | 0.578 | 1.091(0.799,1.489) | | 0.055 | 0.750 | 1.056(0.750,1.487) | | 0.658 | 0.012 | 1.931(1.163,3.205) |
DASH (N = 333) | -0.424 | 0.011 | 0.654(0.475,0.902) | | -0.324 | 0.038 | 0.724(0.534,0.981) | | -0.390 | 0.028 | 0.677(0.479,0.957) |
a Model1: Dietary index. b Model2: Model1 + age + race + education levels + marital status + family PIR. c Model3: Model2 + smoking + physical activity + number of live births + total energy intake + GWG. |
Then considering the high risk of adverse pregnancy outcomes in pregnant women of advanced maternal age, we performed a multiplicative interaction analysis, as shown in Table 4. The interaction coefficient (β-interaction) of advanced maternal age on in-sufficient GWG and excessive GWG per 1 count HEI increase were − 0.460(-0.713, -0.207) (P-interaction = 0.001) and − 0.446(-0.673, -0.217) (P-interaction < 0.001), respectively. The β-interaction of advanced maternal age on insufficient GWG and excessive GWG per 1 count A-HEI increase were − 0.307(-0.555, -0.057) (P-interaction = 0.017) and − 0.288(-0.514, -0.062) (P-interaction = 0.014), respectively. These suggested negative interaction on the multiplicative scale. However, for GDM, we did not find an interaction between dietary index and advanced maternal age, as shown in Supplement 6.
Table 4
Interaction results on the multiplicative scale for the effect of advanced maternal age on GWG per 1 count diet quality scores increase
Advanced maternal age*Diet quality scores | Sample size(N) | GWG | β-interaction(95%CI) | P-interaction |
Advanced maternal age*HEI | 280 | Insufficient | -0.460(-0.713, -0.207) | 0.001 |
Excessive | -0.446(-0.673, -0.217) | < 0.001 |
Advanced maternal age*A-HEI | 280 | Insufficient | -0.307(-0.555, -0.057) | 0.017 |
Excessive | -0.288(-0.514, -0.062) | 0.014 |
Advanced maternal age*DII | 667 | Insufficient | 0.008(-0.832, 0.847) | 0.986 |
Excessive | -0.316(-0.911, 0.281) | 0.296 |
Advanced maternal age*DASH | 667 | Insufficient | 0.057(-0.681, 0.794) | 0.878 |
Excessive | 0.369(-0.260, 0.999) | 0.247 |
Note: Adjusted for race, education levels, marital status, family PIR, smoking, physical activity, number of live births, and total energy intake. |
Subsequently, considering the effects of GWG for GDM, we performed a multiplicative interaction analysis, as shown in Table 5. The β-interaction of insufficient GWG and excessive GWG on GDM per 1 count DASH increase were − 2.263(-3.912, -0.625) (P-interaction = 0.008) and − 2.137(-3.772, -0.498) (P-interaction = 0.012), respectively.
Table 5
Interaction results on the multiplicative scale for the effect of GWG on GDM per 1 count diet quality scores increase
GWG*Diet quality scores | Sample size(N) | β-interaction(95%CI) | P-interaction |
Insufficient*HEI | 138 | -0.056(-0.132, 0.021) | 0.146 |
Excessive*HEI | -0.046(-0.248, 0.157) | 0.644 |
Insufficient*A-HEI | 138 | -0.006(-0.202, 0.191) | 0.949 |
Excessive*A-HEI | -0.282(-0.726, 0.160) | 0.199 |
Insufficient*DII | 333 | 0.034(-0.860, 0.928) | 0.939 |
Excessive*DII | -0.270(-1.056, 0.513) | 0.491 |
Insufficient*DASH | 333 | -2.263(-3.912, -0.625) | 0.008 |
Excessive*DASH | -2.137(-3.772, -0.498) | 0.012 |
Note: Adjusted for age, race, education levels, marital status, family PIR, smoking, physical activity, number of live births, and total energy intake. |