Retinol deficiency and urinary stone disease: clinical evidence is missing

Serum retinol levels were studied in: (a) 95, 56 and 43 normal subjects belonging to lower, middle and upper socio-economic groups respectively, (b) 35 adult males suffering from night blindness, (c) 27 subjects with low retinol levels, (d) 8 retinol deficient subjects (e) 17 male infants suffering from overt retinol deficiency, (f) 43 radiologically confirmed stone patients and (g) age and sex matched controls (infants 20; adults 120). The subjects included in groups b to f were clinically and radiologically examined for stone disease. Some inhibitors and promotors of stone disease were estimated in urine in groups b to g. It was found that 68% of subjects in lower socioeconomic group had serum retinol levels between 10 and 19 ug%, and 4% below 10 ug%, but none of them showed any symptoms of retinol deficiency. The subjects included in groups b to e did not show any significant difference in their urine chemistry although oxalate excretion was slightly but not significantly higher in comparison to controls. None of them showed radiological evidence of urinary stones. Thus, our results do not support an association between retinol deficiency and urolithiasis in the population studied.