Joint effect of maternal pre-pregnancy body mass index and folic acid supplements on gestational diabetes mellitus risk: a prospective cohort study

Table 4 Interaction analysis of pre-pregnancy BMI and FA supplement intake dose on the risk of GDM

Interaction	Crude OR	P-value	Adjusted OR	P-value
FA-S*BMI (< 25.0 kg/m²)	Rf		Rf
FA-D*BMI (< 25.0 kg/m²)	0.95(0.59–1.54)	0.831	0.99(0.60–1.66)	0.997
FA-S*BMI (25.0 kg/m²≤ BMI < 30.0 kg/m²)	2.29(1.71–3.07)	< 0.001	2.17(1.60–2.95)	< 0.001
FA-D*BMI (25.0 kg/m² ≤ BMI < 30.0 kg/m²)	3.11(1.52–6.36)	0.002	3.27(1.55–6.92)	0.002
FA-S*BMI (≥ 30.0 kg/m²)	3.32(1.91–5.79)	< 0.001	3.57(2.02–6.34)	< 0.001
FA-D*BMI (≥ 30.0 kg/m²)	8.54(1.42–51.38)	0.019	10.82(1.69–69.45)	0.012

Adjusted OR: adjusted for age, education level, monthly income, passive smoking, drinking, family history of diabetes mellitus, fertilization way, history of GDM, the use of vitamin B₁₂ supplement. Variables with statistical significance were shown in boldface

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