Female stone disease: the changing trend.

This paper has attempted to assess the changes noted in the trends in the incidence and biochemical pattern of female urolithiasis patients during the period 1971-2008. A prospective descriptive clinical study was done on 8,590 stone patients belonging to both sexes treated at the urinary stone clinic. The incidence of stone disease among the two sexes was plotted. The various metabolic parameters including 24-h urine volume, urine calcium, phosphorus, uric acid, oxalate, magnesium, creatinine and citrate, serum creatinine, calcium, phosphorus, uric acid and magnesium and calculated parameter calcium:magnesium ratio were studied. The possible causes for the change in incidence of stone disease in the female sex were elucidated. Of the patients studied, 12.7% (1,091) were females. There was a definite increase in the incidence of female urolithiasis over the past 37 years (P < 0.001). There were significant variations in urine biochemical parameters. There was a definite increase in the excretion of urinary calcium over the years (P < 0.001). The excretion rate of oxalate in urine of females also increased steadily over the years (P < 0.001). The magnesium in urine of females reduced over the years (P < 0.001). Urinary citric acid has however shown an increase over the years (P < 0.001). Urinary excretion of phosphorus (P < 0.001) and urinary uric acid (P < 0.001) showed a decreasing trend. There was a considerable increase in the percentage of females with high calcium:magnesium ratio over the years (P < 0.001). There was a definite decrease in female patients with hypercalcemia over the years. Serum phosphorus and magnesium also increased significantly with the passage of time. Serum uric acid did not vary significantly through the years. The decrease in the excretion rate of magnesium which is inhibitory to stone genesis, together with the increased excretion of calcium and oxalate may have contributed to the increasing incidence of stone disease in females. This might be due to changes in living standards and dietary habits.