Indoor cold exposure and nocturia: a cross-sectional analysis of the HEIJO-KYO study

To investigate the association between indoor cold exposure and the prevalence of nocturia among elderly, we conducted the present study.

Temperature in the living room and bedroom of 1065 home dwelling elderly volunteers (≥60 years) was measured for 48 h.

Nocturia (≥2 voids per night) and nocturnal urine production were determined using an urination diary and nocturnal urine collection, respectively.

The mean age of participants was 71. 9±7. 1 (standard deviation) years, and the prevalence of nocturia was 30. 8%. A 1°C decrease in daytime indoor temperature was associated with higher odds ratio (OR) for nocturia (1. 064, 95% confidence interval (CI) 1. 016-1. 114, p = 0. 008), independent of outdoor temperature and other potential confounders such as basic characteristics (age, gender, body mass index, alcohol intake, smoking), comorbidities (diabetes, renal dysfunction), medications (calcium channel blocker, diuretics, sleeping pills), socioeconomic status (education, household income), nighttime dipping of ambulatory blood pressure, daytime physical activity, objectively measured sleep efficiency, and urinary melatonin excretion. The association stayed significant after adjustment for nocturnal urine production rate (OR 1. 084, 95% CI 1. 032-1. 138, p = 0. 001).

Indoor cold exposure during daytime was independently associated with nocturia among elderly participants. The mechanism is explained by cold-induced detrusor over activity. The prevalence of nocturia could be reduced by modification of the indoor thermal environment. This article is protected by copyright. All rights reserved.

BJU international. 2015 Sep 23 [Epub ahead of print]

Keigo Saeki, Kenji Obayashi, Norio Kurumatani

Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara, Japan. , Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara, Japan. , Department of Community Health and Epidemiology, Nara Medical University School of Medicine, Nara, Japan.

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