The logistic regression model included age divided into tertiles, gender, and body mass index (categorized).
BMI, body mass index, categorized by median value; family history, first-degree or second-degree family history; analyses adjusted for age (unless used as stratifiying variable) and region of residence; n.a., not estimatable, bold indicates p < 0.05.
BMI, body mass index, categorized by median value; family history, first-degree or second-degree family history; analyses adjusted for age, region of residence, oral contraceptive use, hormone therapy use, age at first birth, age at menarche, menopausal status (unless used as stratifiying variable), and pack years of smoking; n.a., not estimatable, bold indicates p < 0.05.
Body mass index was categorized into 4 levels according to the WHO categorization: (1) < 18.5 (underweight), (2) 18.5–25 (normal weight), (3) 25 30 (overweight), (4) > 30 (obese).
Age, height and body mass index were categorized in two groups, split at median level.
BMI (Body mass index) was categorized as 3 groups of <25 kg/m, 25 to <30 kg/m2 (overweight), and ≥ 30 kg/m2 (obese).
Prepregnancy body mass index was categorized into 4 categories (underweight [<20.0 kg/m], normal weight [20.0 24.9 kg/m], overweight [25.0 29.9 kg/m], and obese [≥30.0 kg/m]).
The body mass index was categorized as <23.0, 23.0–27.4 and ≥27.5 kg/m (coded as 0, 1 or 2) following the World Health Organization (WHO) guideline for Asian populations [ 16].
Maternal pre-pregnancy body mass index were categorized based on the 1990 IOM standards of desirable weights (ref 2, table 1).
Continuous covariates, which included height, waist/hip ratio, and body mass index, were categorized on the basis of the median values of each variable in all controls.
Leptin and absolute mammographic density were log-transformed, reported means are back-transformed bAdjusted for body mass index (BMI), categorized as <20, 20 22, 23 24, 25 26, 27 28, 29 31, 32 34, >34.
