Spectrum of 25 (OH) D3 Status in Urinary Tract Stone Formers in North-Eastern Nigeria

Abstract

Many studies, none in northeastern part of Nigeria, investigated the association between serum/plasma vitamin D and nephrolithiasis, with no consistent result, couple with the hot weather (as high as 44oC) in most part of the year in Maiduguri and its surroundings, and assay of vitamin D today is not yet part of evaluation of urinary stone formers in Maiduguri, warrant this study to assess status of vitamin D in urinary tract stone formers in Maiduguri. Patients diagnosed with urinary tract stone disease attending Urology Clinic, University of Maiduguri Teaching Hospital and consented were recruited. The first two who consented were recruited per week for a period of 24 months (1st April 2017 to 31st Match 2019) to cover the seasonal changes in weather for the year. Serum for vitamin D is stored at -20oC for batch analysis. Vitamin D was assayed by ELISA technique (Accu-Bind, 100 North Pointe Drive, Lake Forest, California 92630 USA), other parameters were analyzed weekly using autoanalyzer (Cobas C311, ISN, Roche, Germany). Result indicated 58 (36.2%) of patients had Vitamin D values below the optimal level either having deficiency/insufficiency. Forty-nine (30.6%) showed vitamin D concentration above the optimum level out of which 4 (2.5%) had hypervitaminosis D, while 53 (33.1%) patients had optimal vitamin D values. It showed 17 (10.6%) of patients had hypercalcaemia, however, out of the 114 patients with normocalcaemia, 42 (36.5%) had their values at the upper limit of normal (2.6 mmol/L). It also indicated that though 3 of the hypercalcaemic patients had vitamin D insufficiency, majority (14) are either having optimal level or above optimal vitamin D level. Excessive and prolong exposure to ultraviolet sunlight resulting in raised vitamin D synthesis and action is an important factor associated with urinary tract stone formation in this environment cannot be excluded. The high prevalence of hypercalcaemia in the study cannot be accounted for by raised vitamin D alone, therefore measurement of serum vitamin D (25(OH)D) and PTH in evaluation of urinary tract stone formers in this environment is recommended.