Nucleon electric dipole moments originating from strong CP-violation are being calculated by several groups using lattice QCD. We revisit the finite volume corrections to the CP-odd nucleon matrix elements of the electromagnetic current, which can be related to the electric dipole moments in the continuum, in the framework of chiral perturbation theory up to next-to-leading order taking into account the breaking of Lorentz symmetry. Achiral extrapolation of the recent lattice results of both the neutron and proton electric dipole moments is performed, which results in d(n) = (-2.7 +/- 1.2) x 10(-16)e theta(0) cm and d(p) = (2.1 +/- 1.2) x 10(-16)e theta(0) cm. (C) 2014 The Authors. Published by Elsevier B.V.