A study on the etiological factors of bilharzial bladder cancer in Egypt: 5-urinary nitrite in a rural population.

Urinary nitrite was present in 5.6% of 2379 individuals from a rural population infested with "Schistosoma haematobium". A higher frequency was observed in symptomatic patients with active bilharzial cystitis (25%) and patients with bladder cancer associated with schistosomiasis (66.2%); conversely, urinary nitrite was absent in normal urban individuals. The frequency of urinary nitrite was higher in females (6.4%) than males (4.6%), and was more frequent in adults than extremes of age. The presence of urinary nitrite was associated with urinary infection and was commonly accompanied by cellular atypia in urine, in the form of dysplasia. Under these circumstances, carcinogenic nitrosamines are liable to be produced in the bladder from urinary nitrite and amines. These observation support the possible role of urinary bacterial infection, commonly associated with bilharzial cystitis, in bladder carcinogenesis.