APOB and hydrops fetalis: ApoB and ApoB/ApoA-I ratio categories were not associated with incident AF in either subgroup, except for low level of ApoB (<1.05 g/L) and ApoB/ApoA-I ratio (<0.42) that was associated with a higher risk of AF only among those who developed incident HF/CHD (p for interaction = 0.019 and 0.009, respectively).