Physical Activity, Obesity, and Lower Urinary Tract Symptoms

The relationship between aging, the development of benign prostatic hyperplasia (BPH), and lower urinary tract symptoms (LUTS) has been well described. Briefly, BPH may lead to increased bladder outlet obstruction and compensatory changes in the bladder. Eventually these changes may manifest as LUTS (eg, frequency, urgency, nocturia) and ultimately lead to a diminished quality of life and an increased risk for depression, falls, and mortality as nicely reviewed by Parsons et al in this issue of the journal [1]. Aside from quality-of-life measures, the medical and surgical management of LUTS creates significant costs to the health system. Due to increasing cost constraints, methods of primary prevention for LUTS are attractive. Another chronic medical condition that increases medical costs and has become epidemic in both the United States and Europe is obesity. Growing evidence suggests that elderly men with higher body mass index (BMI) are at increased risk for the development of LUTS, although other studies suggest no association between BMI and LUTS. Whereas the Baltimore Longitudinal Aging Study found that men with higher BMI were at higher risk for the development of BPH [2], another study found no association between anthropometric measures at baseline and the subsequent development of LUTS [3]. Data from the Health Professionals Follow-up Study showed that men with higher BMI and men with higher levels of abdominal obesity were more likely to undergo prostatectomy, and among men who did not have a prostatectomy, higher BMI was associated with urinary frequency [4]. Finally, data from a 2008 meta-analysis of 11 previous studies found that increased physical activity was associated with reduced risk of BPH and LUTS [5]. Although most men who live long enough will have BPH, not all men will experience LUTS (ie, symptoms). Further investigation of the relationships between physical activity level, obesity, and the development of LUTS may help identify men at higher risk for LUTS who may benefit from lifestyle modifications. The current report by Parsons et al describes the risk of developing LUTS over a mean 4.6-yr follow-up in a prospective cohort of 1695 men from the Osteoporotic Fractures in Men Study (MrOS) who were 65–91 yr of age [1]. They found that overweight and obese men had a 29% and 41% higher risk of developing LUTS when compared with men with BMI <25 kg/m 2 . Men with the highest quartile of Physical Activity Scale for the Elderly scores were 29% less likely to develop LUTS during the follow-up than those in the lowest quartile. Additionally, men who reported daily walking were 20% less likely to develop LUTS. These prospective data support previous cross-sectional studies showing an association between increased physical activities and decreased risk of LUTS [5]. They also support previous findings that higher BMI is associated with an increased risk of LUTS [2]. There are a number of potential mechanisms to explain the author’s results suggesting a link between increased physical activity and decreased risk of LUTS. Abdominal obesity, which is associated with decreased physical activity, may be associated with increased sympathetic activity [4]. A subanalysis of the Medical Therapy of Prostatic Symptoms study found that increased sympathetic activity was associated not only with the development and progression of BPH [6] but also with the severity of LUTS. In this small study evaluating 38 men, sympathetic activity was assessed by pulse, blood pressure, response to circulatory stress via tilt table, and serum and urinary catecholamine levels. However, some of the measures used in this study may be altered due to aging, and thus the association between elevated sympathetic activity and the