Higher Vitamin D Levels Linked to Lower Risk for Female Pelvic Floor Disorders

Laurie Barclay, MD

April 01, 2010

April 1, 2010 — Higher vitamin D levels are linked to a lower risk for female pelvic floor disorders, according to the results from the National Health and Nutrition Examination Survey (NHANES) reported in the April issue of Obstetrics & Gynecology.

"Because vitamin D receptors are present in human muscle tissue, a direct effect of vitamin D on muscle physiology is biologically plausible," write Samuel S. Badalian, MD, PhD, and Paula F. Rosenbaum, PhD, from SUNY Upstate Medical University and St. Joseph's Hospital Health Center in Syracuse, New York. "Thus, it is not surprising that vitamin D deficiency has long been clinically associated with impaired muscle strength and loss of muscle mass. Given that vitamin D insufficiency or deficiency is epidemic among adults, it is plausible that low vitamin D status contributes to the development of poor muscle strength and can lead to different pelvic floor disorders such as urinary/fecal incontinence and POP [pelvic organ prolapse]."

The goal of the study was to determine the rate of vitamin D deficiency in women with pelvic floor disorders and to examine possible relationships between vitamin D levels and pelvic floor disorders. This cross-sectional analysis of 2005-2006 NHANES data included 1881 nonpregnant women older than 20 years in whom data on pelvic floor disorders as well as vitamin D measurements were available. Insufficient vitamin D levels were defined as those lower than 30 ng/mL. Data were analyzed regarding demographic factors, pelvic floor disorders, and vitamin D levels, accounting for the multistage sampling design. After controlling for known risk factors, the investigators calculated odds ratios (ORs) and 95% confidence intervals (CIs) to determine associations between vitamin D levels and pelvic floor disorders.

Nearly one quarter (23%) of women reported 1 or more pelvic floor disorders. Regardless of age, women reporting at least 1 pelvic floor disorder and those with urinary incontinence had significantly lower mean vitamin D levels.

With increasing vitamin D levels, risks for 1 or more pelvic floor disorders were significantly decreased in all women at least 20 years old (OR, 0.94; 95% CI, 0.88 - 0.99) and in the subset of women 50 years and older (OR, 0.92; 95% CI, 0.85 - 0.99), based on adjusted logistic regression models. In women at least 50 years old with vitamin D levels of 30 ng/mL or higher (OR, 0.55; 95% CI, 0.34 - 0.91), the likelihood of urinary incontinence was significantly reduced.

"Higher vitamin D levels are associated with a decreased risk of pelvic floor disorders in women," the study authors write. "The vitamin D association was strongest among older women reporting urinary incontinence in the NHANES survey. The pattern was similar for fecal incontinence although not significant."

Limitations of this study include drifts in the assay performance of vitamin D levels with time, limited power regarding subtype analyses, and lack of gynecologic examination to assess the severity of pelvic organ prolapse. Contrary to expectation, vaginal bulge was reported more frequently among those with higher vitamin D levels.

"Given the increase in the number of patients with pelvic floor disorders, further evaluation of the role of vitamin D is warranted, particularly future research to assess the relationship between vitamin D levels and pelvic muscle strength in women of all ages and racial/ethnic groups," the study authors conclude. "Our findings suggest that treatment of vitamin D insufficiency and deficiency in both premenopausal and postmenopausal women could improve pelvic muscle strength, with a possible reduction in the prevalence of pelvic floor disorders including urinary incontinence."

The study authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2010;115:795-803. Abstract


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