Table 1.

Characteristics of the study subjects (n = 45,065)

VariablesCases (n = 7,407), n (%)Controls (n = 37,658), n (%)
Age at diagnosis or enrollment (y)
    17-29148 (2.0)868 (2.3)
    30-39741 (10.0)3,974 (10.6)
    40-492,003 (27.0)10,177 (27.0)
    50-592,594 (35.0)13,054 (34.7)
    60+1,921 (26.0)9,585 (25.4)
Parity
    12,071 (28.0)8,653 (23.0)
    23,313 (44.7)16,498 (43.8)
    31,418 (19.1)8,430 (22.4)
    4 or more605 (8.2)4,077 (10.8)
Age at 1st childbirth (y)
    14-191,350 (18.2)6,490 (17.2)
    20-243,158 (42.6)16,179 (43.0)
    25-292,011 (27.2)10,557 (28.0)
    30-34673 (9.1)3,365 (9.0)
    35+215 (2.9)1,067 (2.8)
Education level (y)
    <93,652 (49.3)18,086 (48.0)
    ≥93,503 (47.3)18,536 (49.2)
    Missing information252 (3.4)1,036 (2.8)
Area of residence
    Urban3,985 (53.8)20,775 (55.2)
    Rural3,422 (46.2)16,883 (44.8)
Gender of offspring
    All girls2,007 (27.1)8,836 (23.5)
    All boys2,103 (28.4)10,007 (26.6)
    Mixed boys and girls3,297 (44.5)18,815 (50.0)