This paper addresses the problem of interference coordination in relay-aided cellular OFDMA systems, aiming at exploiting the benefits of RNs while minimizing the negative effects of interferences introduced. We first analyze the possible interference scenarios in multi-cell OFDMA systems. Based on the insights in our analysis, we propose an Integrated Interference Coordination Scheme (IICS) for cellular OFDMA systems. IICS consists of two phases, each performing a resource allocation algorithm, to mitigate interferences and thus enhance system throughput. We conduct simulation experiments based on the model with realistic broadband channel propagation conditions. Numerical results show that our proposed IICS can effectively improve system throughput compared with the resource allocation schemes without adequate interference coordination.