Energetic pathway to lower urinary tract symptoms in older adults: associations with cardiorespiratory fitness and walking energetics in the study of muscle, mobility and aging.

Lower urinary tract symptoms (LUTS) are associated with older age and mobility limitations. We evaluated whether energetic determinants of mobility-maximum oxygen consumption (VO2peak), energetic cost of walking (ECw), and cost-capacity ratio (CCR) were associated with LUTS in community-dwelling older adults. We used baseline data from 629 participants aged ≥ 70 years in the Study of Muscle, Mobility and Aging. The 10-item LURN Symptom Index (LURN SI-10; range: 0-38, higher = worse) assessed LUTS in the past week. A treadmill cardiopulmonary exercise test using a symptom-limited modified Balke protocol measured VO2peak (mL/min). ECw (mL/min) was defined as average oxygen consumption from a 5-min slow walking speed (0.67 m/s) treadmill test. CCR = 100%* ECw/VO2peak. Linear and logistic regression tested associations of cardiorespiratory fitness and walking energetics with LUTS adjusted for demographics, anthropometrics, smoking, multimorbidity, and obstetric factors. Cross-product terms tested for interactions by sex. Higher ECw and CCR were both associated with higher LURN SI-10 total score in minimally adjusted models (β per 1SD of CCR = 0.36 [95%CI 0.05, 0.67]), although 95%CI included 0 in fully adjusted models. Higher ECw was associated with greater odds of urinary incontinence in men (OR = 1.67; 95%CI 1.10, 2.54) but not women in fully adjusted models. VO2peak was not associated with LUTS in any adjusted models. No other statistically significant associations were observed. As the energy required to walk slowly approaches one's capacity to generate energy, older adults report more severe LUTS, although associations are modest. Energetic capacity may represent a novel intervention target for co-occurring LUTS and mobility limitations.