Motoaki Saito

Objectives: To identify latent classes of sexual activity among Japanese adult men using multiple sexual behavior indicators and to investigate their associations with household income. Methods: This cross‐sectional study analyzed data from a 2023 nationwide Internet‐based survey of 5 735 Japanese men aged 20–79 years. Latent class analysis used six indicators: Sexual intercourse frequency, masturbation frequency, morning erection frequency, and International Index of Erectile Function items 6, 11, and 12. Household income data were available for 4 824 men, who were categorized into low (<¥4 million/year), middle (¥4 to <¥8 million/year), or high (≥¥8 million/year) income groups. Results: Four latent classes were identified: Low desire/inactive (Class 1, 37.3%), high desire/non‐coital (Class 2, 25.8%), moderate desire/sexually active (Class 3, 14.7%), and high desire/high‐function active (Class 4, 22.1%). Higher household income was independently associated with Classes 3 and 4, with dose–response relationships, but not with Class 2. The overall income‐by‐marital‐status interaction was significant ( p = 0.0004), whereas the class‐specific interaction was significant only for Class 3 ( p = 0.021) and not for Class 4 ( p = 0.255). These post hoc interaction findings were considered exploratory. Sensitivity analyses yielded consistent results. Conclusions: Approximately one‐quarter of Japanese men belonged to a class characterized by moderate‐to‐high sexual desire and relatively frequent morning erections despite predominantly little or no intercourse. Household income was associated with intercourse‐involving classes but not with Class 2. These findings support a multidimensional assessment of sexual health and warrant further research on socioeconomic factors associated with partnered sexual activity.

Objectives: To describe early physiologic deobstruction after contemporary 980‐nm diode‐laser contact vaporization of the prostate (CVP) in patients with evaluable paired preoperative and 3‐month postoperative pressure‐flow studies (PFS). Methods: This single‐center retrospective cohort included 94 consecutive men who underwent CVP between March 2023 and August 2025. Paired full PFS was evaluable in 48 patients. Baseline characteristics were compared between patients with and without evaluable paired PFS. Perioperative outcomes, symptom scores, and complications were summarized in the full cohort, whereas paired PFS parameters were analyzed in the paired PFS cohort. Results: In the full cohort, IPSS total and voiding scores and QOL improved from 1 month postoperatively, whereas storage symptom improvement was more gradual. OABSS showed transient mild worsening at 1 month, followed by improvement. In the paired PFS cohort, voiding parameters improved markedly, with significant reductions in BOOI, P _det Q _max , and PVR and increases in Q _max and voided volume. In contrast, filling‐phase parameters, including first desire to void, normal desire to void, maximum cystometric capacity, and bladder compliance, showed limited short‐term changes. Postoperative complications occurred in 31/94 patients (33.0%), accounting for 37 events. The most common complications were transient urinary retention and urinary tract infection, each occurring in 12/94 patients (12.8%). Conclusions: CVP was associated with substantial early outlet relief on paired PFS, accompanied by improvements in patient‐reported symptoms. Early filling‐phase changes were limited, suggesting that bladder storage recovery may lag behind outlet relief. Prospective comparative studies with longer follow‐up are needed.

Objectives: To establish a reproducible male rat model exhibiting myogenic underactive bladder (UAB)‐like features by applying bladder cryoinjury following direct saline instillation via fine‐needle puncture, thereby providing a useful platform for studying UAB pathophysiology and treatment. Methods: Male Wistar rats underwent bladder cryoinjury using dry ice‐cooled aluminum rods placed on the bladder wall after filling the bladder with saline through a 30G needle. Sham‐operated rats received room‐temperature rod application. Two weeks post‐injury, continuous and single cystometry were performed to evaluate voiding pressure (VP), post‐void residual volume (PVR), and voiding efficiency (VE). Bladder strips were examined in organ bath studies for carbachol‐induced contractility. Hematoxylin and eosin staining was conducted for histological evaluation. Results: Cryoinjured rats showed a significant increase in PVR and significant decreases in VP and VE compared to sham rats, indicating impaired voiding function consistent with UAB. No significant differences were observed in intercontraction interval or carbachol‐ or KCl‐induced contractile responses in bladder strips between cryoinjured and sham rats. In bladder sections, cryoinjury induced acute inflammation with neutrophil infiltration and notable appearance of foamy macrophages, suggesting phagocytic activity. Conclusions: We established a practical and minimally invasive male rat model exhibiting myogenic UAB‐like features 2 weeks after cryoinjury. While ex vivo cholinergic and KCl‐evoked contractility was largely preserved at this time point, in vivo voiding remained impaired, suggesting contributions beyond muscle contractility. This model may facilitate mechanistic and therapeutic studies for UAB.

Objectives: To evaluate the agreement between initial straining, a proxy for Question 6 of the International Prostate Symptom Score (IPSS Q6), and three voiding symptoms (hesitancy, straining during voiding, and terminal straining). Participants and Methods: Data from a nationwide survey of lower urinary tract symptoms in adults conducted by the Japanese Continence Society were analyzed. The agreement was evaluated by the weighted kappa coefficient. In addition, the correlation between these four voiding symptoms and other voiding symptoms (slow stream, intermittency, and terminal dribbling) was evaluated by Spearman's rank correlation. Results: Overall, 3122 male and 3088 female participants were included in the analysis. In both male and female groups, substantial agreement on initial straining was observed for hesitancy (kappa, 0.625 and 0.639, respectively) as well as straining during voiding (kappa, 0.790 and 0.801, respectively). Initial straining correlated moderately with other voiding symptoms (rs, 0.442 to 0.597), while hesitancy was moderately correlated with other voiding symptoms (rs, 0.461 to 0.638). Straining during voiding was moderately correlated with intermittency (rs, 0.591 to 0.617). Conclusion: The IPSS Q6 should not be used lightly as either a hesitancy or straining score because it substantially represents both hesitancy and straining during voiding.

Objectives: To investigate the prevalence, impact on health‐related quality of life (HRQOL), and predictive factors of co‐existent overactive‐underactive bladder (COUB) in women. Methods: 3088 Japanese women aged ≥ 20 years responding to a nationwide internet survey on lower urinary tract symptoms (LUTS) were included. Participants were divided into COUB, overactive bladder (OAB) alone, underactive bladder (UAB) alone, and non‐OAB/UAB groups based on the OAB symptom score and the International Continence Society‐Working Group definition of UAB. In addition to the prevalence, we assessed each group's HRQOL and physician visit rates. We further explored predictors of COUB as well as OAB and UAB using multinomial logistic regression analysis. Results: The prevalences of COUB, OAB alone, and UAB alone were 1.6%, 8.2%, and 2.4%, respectively, and all increased significantly with age. The proportions of COUB in OAB and UAB overall were 16.4% and 40.7%, respectively. The proportions of participants who responded that their HRQOL was affected and those visiting physicians were both highest in the COUB group. Multinomial logistic regression analysis showed that age, frailty, neurological disorders, anorectal dysfunction, pelvic organ prolapse, and parity (≥ 3) were independent predictors for COUB, of which age, neurological disorders, and parity were exclusively associated with COUB. Conclusions: Although not highly prevalent, COUB may have a significant impact on adult women, especially frail and multimorbid elderly women. More attention should be paid to this unique condition for optimal LUTS management.

Objectives: The aim of the present epidemiological study was to evaluate the sex‐related prevalence of stress urinary incontinence (SUI) and the associated factors using data from the 2023 Japan Community Health Survey.Methods: We investigated 3097 males and 3056 females aged 20–99 years. All participants answered web‐based questionnaires on their health status and lower urinary tract symptoms. Data on the frequency of SUI, comorbidities and health‐related behaviour were extracted. The Cochran‐Armitage trend test was used to evaluate the trend between the prevalence of SUI and age. Multivariate analysis was performed using logistic regression analysis to identify factors associated with SUI.Results: SUI was consistently observed in about 10% of individuals in their 20s and 30s, including in males. There were no age‐related differences in the prevalence of SUI in males (P = 0.55). In females, the prevalence of SUI statistically significantly increased with age (P < 0.0001). The frequency of SUI was, however, low in both sexes. Drinking habits (OR, 1.43; 95% CI, 1.10–1.87) and frequent spicy food intake (OR, 1.55; 95% CI, 1.19–2.01) were associated with SUI only in males. Age (OR, 1.36; 95% CI, 1.13–1.62), BMI (OR, 1.87; 95% CI, 1.50–2.32) and history of vaginal delivery (OR, 2.15; 95% CI, 1.77–2.63) were only associated with SUI in females.Conclusions: Although the frequency of SUI was low in both sexes, the correlation between the prevalence of SUI and age was different between both sexes. Female SUI might involve weakness of the pelvic floor muscle, while male SUI might be affected by health‐related behaviours.

Objectives: Seated voiding may be an attempt to obviate voiding dysfunction, improve physical stability during voiding, and prevent messy bathroom contamination. Therefore, we hypothesized that seated voiders had a higher prevalence of lower urinary tract symptoms (LUTS), deteriorating health conditions, and a higher marriage rate than standing voiders.Methods: Of the participants from the 2023 Japan Community Health Survey conducted by the Japanese Continence Society, 2936 men (mean age: 53.6 years old) were divided into sitting and standing groups based on their posture when voiding at home. Characteristics of the two groups were compared, and factors associated with seated voiding stratified by age were investigated using multivariable logistic regression analysis.Results: One‐thousand six‐hundred and sixty men (57%) voided in the sitting position at home, and the proportion of seated voiding decreased with age. On multivariable analysis, comorbidities other than benign prostatic hyperplasia were associated with the standing group aged 40–59, and storage symptoms were associated with the seated group aged 60 and older. Being married was significantly and consistently associated with seated voiding across all ages.Conclusions: Approximately 60% of Japanese men void in the sitting position at home. There are certain differences in the associations of LUTS and health conditions with voiding position by age, while seated voiding is consistently associated with marital status throughout all ages, which implies that sanitation matters.