The association between serum serotonin levels and overactive bladder: results from a community-based cross-sectional study in Japan

Cognitive function and bladder health among midlife adult women in the Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

The aim of this study was to examine whether different aspects of women's cognitive function are associated with lower urinary tract symptoms (LUTS) and their impact.

METHODS

In 2010-2011, women aged 42 to 57 years in the Coronary Artery Risk Development in Young Adults study completed different tests of cognitive function, including the Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and Stroop test. Two years later, data on LUTS and their impact were collected. LUTS/impact, a four-level composite variable ranging from bladder health to mild, moderate, and severe LUTS/impact, was regressed on each cognitive test separately, as well as a cognitive function composite variable. The analytic sample was composed of 1,021 women with complete data.

RESULTS

When adjusting for sociodemographic variables (age, race, education) and gynecologic/obstetric variables (parity, menopausal status, hysterectomy, hormonal use), better performance on the cognitive function composite and Digit Symbol Substitution Test were both associated with lower odds of membership to a more severe LUTS/impact category (odds ratio, 0.90 [95% confidence interval, 0.83-0.98] and 0.89 [95% confidence interval, 0.82-0.97], respectively). These associations became nonsignificant when additionally adjusting for mechanisms that might explain an association between cognitive function and LUTS/impact, including health behaviors and health conditions that may covary with cerebral and peripheral vascular health and cognitive function.

CONCLUSIONS

In this sample of midlife adult women, a modest association was found between better cognitive function and lower likelihood of LUTS/impact. Longitudinal studies are needed to further investigate the association between cognitive function and LUTS/impact, as well as potential explanatory mechanisms, particularly as women age and cognitive function varies to a greater degree.

Correlations between serotonin impairments and clinical indices in multiple system atrophy

BACKGROUND AND PURPOSE

Multiple system atrophy (MSA) is a neurodegenerative disease with characteristic motor and autonomic symptoms. Impaired brain serotonergic innervation can be associated with various clinical indices of MSA; however, the relationship between clinical symptoms and cerebrospinal fluid (CSF) levels of 5-hydroxyindole acetic acid (5-HIAA), a main serotonin metabolite, has not been fully elucidated.

METHODS

To compare CSF 5-HIAA levels between patients with MSA and healthy controls, we included 33 controls and 69 MSA patients with either predominant parkinsonian or cerebellar ataxia subtypes. CSF 5-HIAA levels were measured using high-performance liquid chromatography. Additionally, we investigated correlations between CSF 5-HIAA and various clinical indices in 34 MSA patients.

RESULTS

CSF 5-HIAA levels were significantly lower in MSA patients than in controls (p < 0.0001). Probable MSA patients had lower CSF 5-HIAA levels than possible MSA patients (p < 0.001). In MSA patients, CSF 5-HIAA levels were inversely correlated with scores in Parts 1, 2, and 4 of the Unified Multiple System Atrophy Rating Scale, and with systolic and diastolic blood pressure in Part 3. Structural equation modeling revealed significant paths between serotonin and clinical symptoms, and significance was highest for activities of daily living, walking, and body sway.

CONCLUSIONS

Serotonin dysfunction, as assessed by CSF 5-HIAA levels, may implicate greater MSA severity.

Financial strain across 25 years and women's bladder health: a life course perspective

BACKGROUND

A small number of cross-sectional studies have found that financial insecurity-a social determinant of health-is associated with lower urinary tract symptoms.

OBJECTIVE

This study aimed to examine (1) whether women in the Coronary Artery Risk Development in Young Adult Study with higher levels of financial strain, assessed at 7 time points across 25 years beginning in 1985-1986, were more likely to report lower urinary tract symptoms and impact after the 2010-2011 financial strain assessment and (2) whether healthcare access and comorbidities mediated potential associations.

STUDY DESIGN

This prospective cohort study recruited Black and White participants aged 18 to 30 years at baseline (1985-1986) from the populations of 4 US cities. The analytical sample was composed of women with complete data for analyses involving financial strain trajectories across 7 assessments (n=841) and mediation tests of data collected at 4 assessments (n=886). The outcome variable was previously developed through a cluster analysis of urinary incontinence severity, urinary incontinence impact, other lower urinary tract symptoms severity, and their impact in 2012-2013, which yielded 4 lower urinary tract symptoms and impact cluster categories: women with no symptom or very mild symptoms and no impact vs women with mild, moderate, or severe symptoms and impact. Financial strain was defined as finding it "very hard," "hard," or "somewhat hard" (vs "not very hard") to pay for the very basics, such as food, heating, and medical care. Using proportional odds logistic regression, cluster categories were regressed on the financial strain trajectory group, adjusting for age, race, education, and parity. For mediation analyses, separate financial strain variables (difficulty paying for the very basics, such as food and heating, and difficulty paying for medical care) were created by combining 1995-1996 and 2000-2001 values. Two healthcare access variables (difficulty receiving care and underutilization of care) and a single comorbidity index (smoking, physical inactivity, body mass index, hypertension, diabetes mellitus, and depressive symptoms) were created by combining 2005-2006 and 2010-2011 values. Regression analyses and structural equation modeling were used to test whether healthcare access and comorbidities mediated associations between financial strain and lower urinary tract symptoms and impact cluster categories.

RESULTS

In comparison to women who were consistently not financially strained, women who were consistently strained (odds ratio, 2.10; 95% confidence interval, 1.13-3.91), shifted into being strained (odds ratio, 2.00; 95% confidence interval, 1.29-3.10), or experienced >1 shift in strain (odds ratio, 1.99; 95% confidence interval, 1.46-2.71) had roughly twice the odds of reporting greater lower urinary tract symptoms and impact. Underutilization of healthcare and comorbidities mediated the association between difficulty paying for medical care and lower urinary tract symptoms and impact. In the structural equation model, difficulty paying for medical care and underutilization of care were associated (β=.31; P<.01), as was underutilization of care and greater lower urinary tract symptoms and impact (β=.09; P<.01). Moreover, difficulty paying for medical care and the comorbidity index were associated (β=.34; P<.01), as was the comorbidity index and greater lower urinary tract symptoms and impact (β=.24; P<.01). Collectively, these mediation pathways eliminated a direct association between difficulty paying for medical care and lower urinary tract symptoms and impact.

CONCLUSION

Underutilization of healthcare and comorbidities explained an association between financial strain (difficulty paying for medical care) and lower urinary tract symptoms and impact. Research is needed to confirm the findings and examine other mechanisms that may further explain the association. Accumulated evidence may inform future policies and practices.

Discrimination and bladder health among women in the CARDIA cohort study: Life course and intersectionality perspectives

OBJECTIVE

This study examines whether discriminatory experiences are associated with lower urinary tract symptoms (LUTS) and their impact among 972 women in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort study, which recruited participants from 4 cities in the United States.

METHOD

Exposure to discrimination was assessed 3 times (1992-93, 2000-01, 2010-11) and averaged across assessments. Participants separately reported whether they experienced discrimination on the basis of their gender, race or color, and socioeconomic position or social class. For each social identity, discrimination was assessed in 6-7 settings (e.g., when getting a job, medical care, or housing). At different time points, women who reported discriminatory experiences for a given social identity were asked how frequently the discrimination occurred and how stressful experience(s) were. Following the 2010-11 assessment, data on LUTS and their impact were collected. Women were classified into bladder health versus mild, moderate, or severe symptoms/impact clusters.

RESULTS

More Black than White women reported discriminatory experiences across all social identities and most settings. Perceived stress of discriminatory experiences did not differ between Black and White women. In analyses stratified by race and social identity, White women reported LUTS/impact with discriminatory experiences in more settings, more frequent discriminatory experiences across settings, and each additional social identity for which discrimination was experienced. Black women reported LUTS/impact with more frequent discriminatory experiences across settings. For Black women, greater perceived stress of both gender and race discrimination were associated with LUTS/impact. For White women, only greater perceived stress of race discrimination was associated with LUTS/impact.

CONCLUSIONS

This is one of the first studies to examine discrimination in relation to LUTS/impact. Additional research is needed to better understand differences in how discriminatory experiences based on potentially intersecting identities may be related to bladder health among women.

Trajectories of depressive symptoms over 20 years and subsequent lower urinary tract symptoms and impact among women

OBJECTIVE

The aim of the study is to examine the association between depressive symptoms and subsequent lower urinary tract symptoms (LUTS) and impact (a composite outcome) among women (N = 1,119) from the Coronary Artery Risk Development in Young Adults study.

METHODS

The Center for Epidemiologic Studies-Depression Scale (CES-D) was administered in 1990-1991 and every 5 years through 2010-2011. In 2012-2013, LUTS and impact data were collected for the first time. Accumulation of risk was examined in the following three ways: (1) mean CES-D score across 20 years (5 observations); (2) depressive symptom trajectory group, determined by group-based trajectory modeling; and (3) intercepts and slopes obtained from women's individual CES-D score trajectories through two-stage mixed effects modeling. For each approach, ordinal logistic regression analyses examined odds of having "greater LUTS/impact" for each unit change in a depressive symptom variable.

RESULTS

(1) With each one-unit increase in mean CES-D score over the 20-year period, women were 9% more likely to report greater LUTS/impact (odds ratio [OR] = 1.09, 95% CI = 1.07-1.11). (2) In comparison with women with consistently low depressive symptoms, women with consistently threshold depression or consistently high depressive symptoms were twice (OR = 2.07, 95% CI = 1.59-2.69) and over five times (OR = 5.55, 95% CI = 3.07-10.06) as likely, respectively, to report greater LUTS/impact. (3) Women's individual symptom intercept and slope interacted. Increases in depressive symptoms across 20 years (greater slopes) were associated with greater LUTS/impact when women's initial CES-D score (intercept) was in the moderate-to-high range relative to the sample.

CONCLUSIONS

Depressive symptoms over 20 years, examined with different degrees of nuance, were consistently associated with subsequently measured LUTS and impact.

Activation of uroepithelial 5-HT4R inhibits mechanosensory activity of murine bladder afferent nerves

Serotonin (5-HT) is known to act via multiple 5-HT receptors at spinal and supraspinal levels to regulate micturition. However, the contribution of peripheral 5-HT and its receptors in bladder physiology and pathology is not very well understood, despite evidence showing expression of multiple 5-HT receptors in the bladder wall and 5-HT may activate bladder afferent nerves. The current study was designed to investigate the possible role of 5-HT4R in modulation of the sensitivity of bladder afferents to bladder filling. Immunofluorescent staining showed abundant 5-HT4R immunoreactivity largely confined to the uroepithelium in wild type (WT) but not 5-HT4R−/− mice. In the ex vivo bladder-pelvic nerve preparation, intravesical application of the 5-HT4R agonist RS67333 (1–30 μm) caused concentration-dependent decreases of the pelvic nerve response to bladder filling. Such effect was not observed in the presence of 5-HT4R antagonist GR125487 or in 5-HT4R−/− preparations. A cohort of 5-HT4R−/− and WT control mice were treated with intraperitoneal injections of cyclophosphamide (CYP) (75 mg/kg, three times at 2 days interval) to induce chronic cystitis. Void spot analysis showed that CYP-treated 5-HT4R−/− mice urinated more frequently than their CYP-treated WT counterparts. Concomitantly, bladder afferents of CYP-treated 5-HT4R−/− mice displayed exaggerated sensitivity to bladder filling in comparison with the CYP-treated WT controls. These data suggest that 5-HT4R expressed on uroepithelial cells plays an inhibitory role in mechanosensory transduction in the bladder. Loss of 5-HT4R-mediated inhibition may enhance bladder afferent sensitivity and exacerbate bladder overactivity in pathological conditions. We propose that 5-HT4R agonists might be exploited for the treatment of overactive and painful bladder symptoms.

Efficacy of salt reduction for managing overactive bladder symptoms: a prospective study in patients with excessive daily salt intake

This study aimed to investigate the efficacy of salt intake restriction on overactive bladder (OAB) symptoms in patients with excessive salt intake. Patients received a brochure on nutritional guidance regarding salt intake reduction and received health education every 4 weeks for 12 weeks. Data from overactive bladder symptom score (OABSS) questionnaires and frequency volume charts (FVCs) were evaluated. The daily salt intake was estimated by determining the urinary sodium and creatinine concentrations using spot urine samples. Of the 98 patients included, 71 (72.4%) successfully restricted their daily salt intake after 12 weeks (salt restricted [R] group), while 27 (27.6%) did not (salt non-restricted [N-R] group). The scores to each OABSS question and the resulting total score improved significantly in the R group; however, the individual scores remained unchanged and the total score increased in the N-R group. The FVC data indicated improved voided volumes in the R group as compared to in the N-R group. Ultimately, 17 (23.9%) patients in the R group no longer fulfilled the OAB diagnostic criteria after salt intake reduction. Thus, salt intake reduction improved urinary symptoms in patients with OAB and may be a therapeutic option for OAB in patients with excessive daily salt intakes.

Overactive bladder and sleep disturbance have a significant effect on indoor falls: Results from the community health survey in Japan

OBJECTIVES

To evaluate the effect of overactive bladder (OAB) and frailty on indoor fall events in community-dwelling adults aged 50 or older.

METHODS

We conducted a cross-sectional study involving 723 adults between 2016 and 2017 in Hirosaki, Japan. OAB symptoms and sleep disturbance were assessed using the Overactive Bladder Symptom Score (OABSS) and the Pittsburgh Sleep Quality Index (PSQI). Indoor fall events (falls or near-falls) within 1 year were evaluated. Frailty was evaluated by the frailty discriminant score. We investigated the association of OAB symptoms with sleep disturbance, frailty, and indoor fall events. Multivariate logistic regression analysis was performed to investigate the effect of OAB symptoms on fall events controlling for confounding factors such as age, gender, comorbidity, frailty, and sleep disturbance.

RESULTS

The median age was 64. We observed OABSS ≥6 in 98 participants (14%), nocturia ≥2 in 445 (62%), urgency score ≥3 in 80 (11%), urge incontinence score ≥3 in 36 (5.0%), PSQI ≥6 in 153 (21%), frailty in 169 (23%), and indoor fall events in 251 (35%). Older age, diabetes, OABSS, nocturia, urgency, urge incontinence, and the PSQI were significantly associated with indoor fall events. Multivariate logistic regression analyses showed that OAB symptoms and sleep disturbance were significantly associated with fall events.

CONCLUSIONS

The effect of OAB symptoms and sleep disturbance on indoor fall events was significant. The causal relationship between OAB and falls needs further study.

The impact of microalbuminuria on overactive bladders: Results from a community-based four-year longitudinal study in Japan

AIMS

To investigate the longitudinal association of microalbuminuria with overactive bladder (OAB).

METHODS

This longitudinal study investigated 561 participants of the Iwaki Health Promotion Project in both 2015 and 2019 in Japan. Microalbuminuria and OAB symptoms were assessed using the urine albuminuria creatinine ratio (ACR) and the overactive bladder symptom score (OABSS), respectively. Urine ACR was defined as high if ≥9.3 mg/gCr. Differences in OABSS between 2015 and 2019 were evaluated as ∆OABSS. Participants were divided into two groups according to ΔOABSS: high (ΔOABSS > 1) and control (≤1). We used baseline data acquired in 2015, such as urine ACR, the Pittsburgh Sleep Quality Index (PSQI), and arterial stiffness expressed by brachial-ankle pulse wave velocity (baPWV). Predictive factors of a ΔOABSS > 1 were assessed by multivariable logistic regression analysis.

RESULTS

This study included 332 women and 229 men. Of those, 86 (34 males and 52 females) were classified into the ΔOABSS > 1 group. There were significant group differences in age, renal function, and hemoglobin A1c. Participants in the ΔOABSS > 1 had a higher prevalence of PSQI > 5, baPWV ≥ 1400 seconds/cm, and urine ACR ≥ 9.3 mg/gCr (49% vs 20%, P = .001) than those in the control group. Multivariable analysis revealed that PSQI > 5 (odds ratio [OR], 2.57; 95% confidence interval [CI], 1.15-4.60; P = .002) and urine ACR ≥ 9.3 mg/gCr (OR, 1.93; 95% CI, 1.15-3.23; P = .013) were independent risk factors for ΔOABSS > 1.

CONCLUSIONS

Microalbuminuria may be an independent risk indicator for OAB symptom exacerbation.