Night-Time Urinary Frequency Is Increased after the Great East Japan Earthquake along with Seasonal Variation: A Five-Year Longitudinal Study in Kesennuma City

Disasters influence various health conditions; however, little has been reported about urinary symptoms. The objective of this study is to evaluate whether night-time urinary frequency was influenced by the Great East Japan Earthquake (GEJE) in March 2011. We also evaluated seasonal variation of night-time frequency, which may affect the primary objective. A retrospective chart review was conducted on 300 evaluable patients who resided in the impacted area: 263 men with benign prostatic hyperplasia and/or overactive bladder and 37 women with overactive bladder. Data concerning night-time frequency were collected repeatedly every three months from March 2009 until March 2014, then compared yearly and seasonally among same patients. In addition, night-time frequency was analyzed for potential relations to sex, age, comorbidities, and whether residences had been destroyed. There was a significant increase of night-time frequency during 2011-2013 when compared yearly with 2009 and 2010. In seasonal comparisons of the entire period, night-time frequency was greater during autumn and winter compared with summer. In quarterly comparisons, a sudden increase was not observed after the GEJE, but night-time frequency was increased significantly in spring, summer and autumn in 2011 when compared with the corresponding seasons in 2010. While hypertension was related to exacerbation of night-time frequency during winter, we did not find any factors associated with increase after the disaster out of sex, age, comorbidities or residential situations. In conclusion, night-time urinary frequency is increased shortly after the GEJE and remains elevated for the following three years along with seasonal variation.