Age Related Change of Nocturia in Women

PURPOSE The precise etiology and classification of nocturia in women is not enough. We evaluated age related changes and classified the type of nocturia by age in women. METHODS We included 118 women 20 years or older with nocturia at least one time during night time. Subjects were divided into three groups by the age: group 1, under 40 years; group 2, 40 through 59 years; group 3, 60 years and above. The causes of nocturia and its pattern changed by age in women were evaluated using 3 days frequency volume chart. Nocturia was devided into three types: nocturnal polyuria, decreased nocturnal bladder capacity and mixed type. RESULTS The mean age was 57.2±11.8 and the mean nocturnal frequency was 2.7±1.8. In all age group, noctural polyuria was the major cause for noturia (40.8%), followed by low nocturnal bladder capacity (23.7%). As a major cause of nocturia, there was a significant increase of the incidence of nocturnal polyuria in aged people: group 1, 32.4%; group 2, 41.0%; group 3: 47.6% (P<0.04). CONCLUSIONS Nocturnal polyuria and decreased nocturnal bladder capacity are the major causes of nocturia in women. Nocturnal polyuria was the major cause of nocturia with age over 60 years old. In aged women, nocturnal polyuria should be considered as a main cuase of nocturia and treated based on these result.