Table 3.

Additive interaction of leucine and Isoleucine with SFA16:0 for the risk of GDM.

	Unadjusted OR/estimate (95% CI)	P value	Adjusted OR/estimate (95% CI)a	P value
Leu and SFA16:0
Additive interaction models
Leu < 153.3 & SFA16:0 < 17.1 nmol/mL	Reference		Reference
Leu < 153.3 & SFA16:0 ≥ 17.1 nmol/mL	2.02 (1.27-3.21)	0.0028	2.22 (1.33-3.72)	0.0024
Leu ≥ 153.3 & SFA16:0 < 17.1 nmol/mL	1.30 (0.71-2.37)	0.3899	1.45 (0.74-2.84)	0.2815
Leu ≥ 153.3 & SFA16:0 ≥ 17.1 nmol/mL	3.99 (2.21-7.19)	< 0.0001	4.56 (2.37-8.75)	< 0.0001
Measures of additive interactionb
RERI	1.66(-0.42 to 3.75)	-	1.89 (-0.78 to 4.56)	-
AP	0.42 (0.06 to 0.78)	-	0.41 (0.01 to 0.82)	-
SI	2.26 (0.83 to 6.15)	-	2.13 (0.77 to 5.87)	-
Ile and SFA16:0
Additive interaction models
Ile < 36.2 & SFA16:0 < 17.1 nmol/mL	Reference		Reference
Ile < 36.2 & SFA16:0 ≥ 17.1 nmol/mL	1.99 (1.27-3.11)	0.0025	2.12 (1.29-3.48)	0.0029
Ile ≥ 36.2 & SFA16:0 < 17.1 nmol/mL	1.28 (0.72-2.28)	0.4018	1.27 (0.66-2.44)	0.4768
Ile ≥ 36.2 & SFA16:0 ≥ 17.1 nmol/mL	3.96 (2.22-7.04)	< 0.0001	4.41 (2.30-8.43)	< 0.0001
Measures of additive interactionb
RERI	1.69 (-0.33 to 3.70)	-	2.01 (-0.53 to 4.56)	-
AP	0.43 (0.08 to 0.77)	-	0.46 (0.09 to 0.82)	-
SI	2.33 (0.88 to 6.16)	-	2.45 (0.86 to 6.93)	-

Abbreviations: AP, attributable proportion due to interaction; GDM, gestational diabetes mellitus; Ile, isoleucine; Leu, leucine; RERI, relative excess risk due to interaction; SFA, saturated fatty acid; SI, synergy index.

^aAdjusted for prepregnancy body mass index, systolic blood pressure, Han nationality, family history of diabetes in first-degree relatives, parity, education attainment, current smoker before or during pregnancy, alcohol drinker before or during pregnancy, and weight gain to glucose challenge test.

^bStatistically significant, with RERI > 0, AP > 0, or SI > 1 indicating significant additive interaction.