Multiple Sclerosis and Renal Calculi, What Does Vitamin D Have to Do with It?

Background: Vitamin D deficiency has been found to be a risk factor for the development of multiple sclerosis (MS) as well as disease activity and progression. Thus vitamin D supplementation is highly recommended to all MS patients; however, standardized vitamin D serum levels have not been established. Vitamin D toxicity is uncommon; side effects are not well known, but may include renal calculi. The prevalence of renal calculi in the US has increased from 5.2% in 1994 to 8.8% in 2012. This rise has been thought to be related to the increase of metabolic syndrome. Other risk factors of renal calculi include male gender, increasing age, high-sodium diet, neurogenic bladder and urinary tract infections.

Objectives: A retrospective analysis was done to evaluate people with MS and renal calculi to look for a possible relationship between vitamin D serum levels and renal calculi in the MS population.

Methods: Patients were identified using the Healthcare Enterprise Repository for Ontological Narration (HERON), using MS as a primary diagnosis and a secondary diagnosis of renal calculi. Patients under the age of 18 were excluded. A chart review included analysis of those on vitamin D supplementation, serum vitamin D levels, renal calculi type, and other risk factors for calculi. 

Results: HERON identified 6210 MS patients in the system, of which 306 had a secondary diagnosis of renal calculi. Chart review, however, revealed only 128 (2% of all MS) with a demyelinating disease and renal/bladder calculi. Of the 128 only 91 had MS.  Other diagnoses included transverse myelitis or other spinal cord disease (18), possible MS (13), and neuromyelitis optica (6). Age ranged from 26-81 years old, with average age 56.6 years old. Race was predominately Caucasian 114 (89%) and gender predominately female 92 (71.9%). Body mass index averaged 29.24. 51 (40%) had neurogenic bladder. 89 (69.5%) subjects were listed as taking vitamin D supplementation. Only 62 (48.4%) had a vitamin D level recorded. Vitamin D levels ranged from 10.9-116ng/ml with an average of 36. 

Conclusions: This small sample showed no significant relationship of vitamin D supplementation or vitamin D levels with risk of renal/bladder calculi in those with MS. Surprisingly only 2% of those with MS in our system had a secondary diagnosis of renal/bladder calculi. Not surprisingly 40% of subjects had documented neurogenic bladder. Our cohort is too small to determine if any relationship exists between renal/bladder stones, MS and vitamin D. However, this relationship should be further studied; we suggest close monitoring of vitamin D levels to look for potential toxicity.