Nephritis among young Finnish men.

During an eight-year period (1975-1982) 174 military conscripts (out of a total of 314,000) were submitted to Helsinki University Central Hospital, Fourth Department of Medicine, on suspicion of renal disease. Eighty-four had isolated hematuria, 61 hematuria and concomitant proteinuria and 29 persistent proteinuria. In 100 of them the urinary abnormality was an incidental finding, 62 suffered from symptoms of infection and the rest had other complaints. A renal biopsy was performed, yielding a representative sample in 171 cases, after other causes of the urinary abnormality had been excluded. Morphological analysis showed that 131 patients had glomerulonephritis, IgA nephropathy being the most common type (70 patients). Tubulo-interstitial nephritis was seen in two cases, and nephrocalcinosis in one. Among 37 cases with apparently normal glomeruli under light microscopy, immunofluorescence analysis revealed glomerular deposits other than IgA in 19 cases and no deposits in 15 (three were inadequate for this analysis). On the basis of the figures in this study the average number of annually detected cases of nephritis was 48 per 100,000 Finnish conscripts. During the same period an annual average of 46 per 100,000 young men were exempted from military service because of nephritis, giving an overall figure of 94 cases of nephritis detected annually per 100,000 young Finnish men.