Study (dates) | Number of study subjects | Type A number | Type B number | Type C number | Type D number | Type E number |
German, et al. [9] (1964-1974) | 102 | 6 | 2 | 83 | 9 | 2 |
Sillen, et al. [10] (1967-1984) | 110 | 7 | 1 | 100 | 1 | 1 |
Holder, et al. [11] (1973-1986) | 100 | 2 | 1 | 85 | 6 | 6 |
Poenaru, et al. [12] (1969-1989) | 95 | 8 | 0 | 80 | 1 | 6 |
Engum, et al. [3] (1971-1993) | 227 | 29 | 2 | 178 | 5 | 13 |
Spitz, et al. [1] (1988-1994) | 410 | 27 | 4 | 353 | 9 | 17 |
Total | 1044 | 79 (8%) | 10 (1%) | 879 (84%) | 31 (3%) | 45 (4%) |