Table 2 Use of combination oral contraceptive (OC) preparations among control subjects
From: Hormonal content and potency of oral contraceptives and breast cancer risk among young women
Oestrogen/progestin content | Controls | Year of first OC use | Age at interview (y) | Age at first OC use (y) | Months of use | |
|---|---|---|---|---|---|---|
Any OC | Specified OC | |||||
Any OC use | 1086 (100%) | 1972 | 38.5 (4.46) | 19.9 (3.21) | 68.1 (52.6) | |
Potency | ||||||
High progestin/high oestrogen | 130 (12%) | 1969 | 40.6 (2.88) | 19.1 (2.54) | 72.9 (51.4) | 58.5 (41.0) |
Low progestin/high oestrogen | 270 (25%) | 1970 | 39.7 (3.67) | 19.4 (2.65) | 74.0 (55.1) | 59.3 (45.1) |
High progestin/low oestrogen | 193 (18%) | 1972 | 39.0 (3.46) | 19.8 (3.08) | 80.0 (53.5) | 62.1 (43.3) |
Low progestin/low oestrogen | 546 (50%) | 1973 | 36.7 (4.81) | 20.0 (3.45) | 79.9 (56.8) | 67.9 (49.7) |
Oestrogen content and dose | ||||||
Mestranol | ||||||
>100 μg | 212 (20%) | 1969 | 40.6 (3.04) | 19.0 (2.60) | 72.0 (52.8) | 57.6 (42.8) |
51–99 μg | 141 (13%) | 1971 | 39.1 (3.78) | 19.6 (2.79) | 75.9 (56.2) | 58.3 (40.5) |
⩽50 μg | 242 (22%) | 1973 | 37.7 (4.05) | 19.9 (3.23) | 77.2 (52.6) | 63.7 (45.2) |
Ethinyl oestradiol | ||||||
>35 μg | 247 (23%) | 1972 | 38.4 (4.29) | 20.0 (3.26) | 80.1 (55.0) | 62.6 (43.9) |
⩽35 μg | 354 (33%) | 1974 | 35.9 (5.03) | 19.8 (3.45) | 84.2 (59.2) | 67.0 (48.5) |
Progestin content | ||||||
Dimethisterone | 3 (<1%) | 1966 | 42.3 (1.15) | 18.0 (1.73) | 75.3 (73.1) | 70.2 (78.7) |
Chlormadinone acetate | 17 (2%) | 1966 | 42.5 (1.62) | 19.2 (1.55) | 66.9 (65.4) | 41.5 (41.5) |
Norethynodrel | 29 (3%) | 1969 | 40.6 (3.76) | 19.0 (3.16) | 64.1 (51.6) | 45.3 (42.2) |
Ethinyl diacetate | 180 (17%) | 1971 | 39.6 (3.44) | 19.3 (2.83) | 73.0 (52.1) | 63.9 (48.1) |
Norethindrone | 663 (61%) | 1972 | 38.0 (4.65) | 19.8 (3.23) | 72.5 (54.4) | 66.1 (50.9) |
Norethindrone acetate | 70 (6%) | 1972 | 38.2 (3.81) | 20.0 (3.24) | 81.2 (55.3) | 70.7 (48.6) |
Norgestrel | 247 (23%) | 1972 | 37.6 (4.38) | 19.5 (2.93) | 83.4 (55.1) | 65.4 (46.4) |
Levonorgestrel | 54 (5%) | 1978 | 33.4 (5.26) | 20.8 (4.21) | 75.4 (48.6) | 55.7 (36.8) |
