Association between joint hypermobility and primary nocturnal enuresis: a cross-sectional study in children aged 6-13 years.

Background: Nocturnal Enuresis (NE) is a prevalent childhood condition with a multifactorial pathogenesis comprising genetic, neurological, and connective tissue factors. Recent evidence points toward a possible link between joint hypermobility and NE, but the underlying mechanisms remain unclear, and existing data are limited. The objective of this study is to determine the prevalence of joint hypermobility in patients with primary nocturnal enuresis (PNE) relative to healthy controls and investigate potential correlations between these conditions.

Methods: This cross-sectional study was conducted in 2024 at Imam Reza Clinic, the largest pediatric outpatient clinic affiliated with Shiraz University of Medical Sciences in Shiraz, Iran. A total of 180 children aged 6-13 years were recruited, including 90 children with primary nocturnal enuresis (study group) and 90 healthy children without nocturnal enuresis (control group). Participants were assessed for generalized joint hypermobility (GJH) using the Beighton score (≥ 6 indicating hypermobility). Demographic and clinical information was gathered on structured checklists. Statistical tests, such as chi-square tests, t-tests, and logistic regression, were carried out using SPSS (version 25) at a significance level of p < 0.05.

Results: The prevalence of joint hypermobility was significantly higher in children with NE (87.8%) than in controls (28.9%) (p < 0.0001). Conversely, NE was present in 75.2% of hypermobile children compared with 14.7% of non-hypermobile children (p < 0.0001). Logistic regression analysis revealed that children with nocturnal enuresis were 19.87 times more likely to have joint hypermobility compared to non-enuretic children following the adjustment for age, gender, and BMI (p < 0.05). Gender-specific analysis indicated that hypermobile girls with nocturnal enuresis at a greater likelihood of suffering from urinary incontinence and frequent urinary tract infections (UTIs), whereas hypermobile boys with nocturnal enuresis had increased rates of constipation and urinary symptoms during the day.

Conclusion: This study shows a strong association between GJH and PNE. Further research is needed to determine causal direction and underlying mechanisms.