Background Medical care systems in Iwate, Miyagi and Fukushima prefectures were greatly damaged by the Great East Japan Earthquake (GEJE), which struck on 11 March 2011. The shortage of nurses in this area was concerning; however, temporal trends have not been investigated. This study aimed to investigate the trends in the geographic distribution of total nursing staff per population in the secondary medical areas (SMAs) of these prefectures before and after the GEJE. We also aimed to qualify the above trends. Methods We conducted a longitudinal study at four time points (July 2007, 2010, 2011 and 2013) over 6 years using reports of basic hospitalization charges from all hospitals within Iwate, Miyagi and Fukushima prefectures that experienced severe damage from the GEJE. We calculated the number of total nursing staff per population in the SMAs and compiled descriptive statistics. Changes from 2010 to 2013 were qualified and mapped. Results In coastal SMAs, the ratios of total nursing staff per population decreased immediately after the GEJE. In most SMAs in 2013, the ratios increased and exceeded the pre-GEJE level. However, the changes in total nursing staff per population from 2010 to 2013 were negative in Ryouban (−4.0%), Ishinomaki–Tome–Kesennuma (−1.9%), Sousou (−47.7%) and Iwaki (−1.9%). In Sousou, which is closest to the Fukushima Daiichi Nuclear Power Plant, the changes in total nursing staff per population qualified by job role were −33.7% for nurses, −57.7% for associate nurses and −63.2% for nursing aides. Conclusions Our study indicated that the temporal trends in the number of total nursing staff per population due to the GEJE differed between the physically damaged areas and those affected by radiation. We also found the difference in the trend by qualifications: the reduction in total nursing staff per population was larger in Sousou, the area most affected by radiation, than in any other SMAs. Moreover, the number of nursing aides was most affected among the three types of staff. To promote the post-GEJE reconstruction of medical care systems, it might be necessary to develop policies to secure both nurses and nursing aides after nuclear disasters.
