Benign Prostatic Hyperplasia and Metabolic Syndrome greater LUTS risk [72]. Similarly, Schatzl et al found a di- rect correlation between elevated estradiol levels and pro- static volume determined with transrectal ultrasound [73]. In the Physicians’ Health Study, elevated estradiol level was an independent predictor of BPH surgery in men with low testosterone or DHT levels [74]. Haider et al stud- ied hypogonadal men and observed an improvement in IPSS and postvoiding volume after a period of treatment with testosterone undecanocate [75]. Similarly, Kalin- chenko et al treated 30 hypogonadal men with either tes- tosterone gel or testosterone undecanoate and reported IPSS improvement in both groups [76]. However, the regu- lation and impact of sex hormones on prostatic growth and BPH/LUTS is quite complex, and not all authors found evi- dence of such definitive relationships [77,78]. 　In addition to the aforementioned mechanisms, other unknown mechanisms may contribute to the relationship between MetS and BPH/LUTS. Moreover, the afore- mentioned mechanisms may interact and articulate with each other. The mechanisms that regulate the potential re- lationship between MetS and BPH/LUTS are quite com- plex and require further scientific inquiry. PHYSICAL ACTIVITY, METABOLIC SYNDROME, AND BENIGN PROSTATIC HYPERPLASIA If MetS is indeed associated with an increased risk of BPH/LUTS, then it can be hypothesized that physical ac- tivity, which is known to decrease the cardiovascular mor- bidity risk associated with MetS, may also decrease the risk of BPH/LUTS. Several epidemiologic data support this hypothesis. Platz et al examined the data of 30,634 men who participated in the HPFS and observed that physical activity was associated with lower risk of total BPH (OR: 0.75; 95% CI: 0.64-0.90; p＜0.001), surgery for BPH (OR: 0.76; 95% CI: 0.64-0.90; p＜0.001), and symptomatic BPH (OR: 0.75; 95% CI: 0.64-0.87; p＜0.001) [79]. 　Similarly, Rohrmann et al analyzed the data of 2797 in- dividuals who participated in NHANES III [80] and re- ported that men with the highest rate of physical activity (highest quartile) had almost half the risk of suffering from LUTS (defined as having three of the following four urinary symptoms: nocturia, incomplete bladder emptying, weak stream, and hesitancy) as did their counterparts who re- ported no physical activity (OR: 0.49; 95% CI: 0.29-0.84; p=0.05). In an interesting report, Dal Maso et al observed that “heavy” occupational activity (eg, farmers, con- struction workers) led to a lower risk of developing BPH than did sedentary occupational activity [81]. However, not all investigators observed a significant inverse rela- tionship between physical activity and BPH/LUTS [82]. Nonetheless, a recent meta-analysis that examined the da- ta from eight reports, with a total of 35,675 patients in- cluded, confirmed that physical activity reduces the risk of BPH/LUTS [83]. 　In summary, it appears that sustained physical activity reduces the overall risk of BPH/LUTS in men. However, 513 none of the aforementioned studies exclusively addressed patients with MetS. Consequently, the real benefit of phys- ical activity in patients with MetS and how it may modify the risk of BPH/LUTS in these patients has yet to be clarified. In addition to physical activity, other lifestyle changes, such as dietary strategies to reduce postprandial glucose and triglyceride spikes and to increase the intake of dietary antioxidants, potassium, and omega-3 fatty acids may be helpful in reducing the incidence of metabolic syndrome [84] and its association with BPH/LUTS. CONCLUSIONS Numerous reports have documented a direct and sig- nificant relationship between components of MetS and the BPH/LUTS complex. However, differences in the strength and the statistical significance level of this relationship were observed. These differences may originate from the use of different descriptions to define the examined risk fac- tors and endpoints as well as differences in the character- istics of the examined populations. Although the associa- tion between these two pathologic conditions seems plau- sible, the underlying mechanisms that create such an asso- ciation need to be clarified. 　Further study of the interplay between MetS and BPH/ LUTS may provide new insight into the cause of these dis- eases and novel targets for their treatment and prevention. In the meantime, obesity, dyslipidemia, hypertension, and diabetes should be considered risk factors when advising patients with LUTS. 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