Fig. 1: Associations of lactation duration with the risk of ischemic heart disease among parous postmenopausal females (N = 130,147).

Notes: IHD ischemic heart disease, aHR adjusted hazard ratio, CI confidence interval. Colors in yellow, blue, and purple represent the lactation duration of a lifetime per child and first child, respectively. Cases (%) were expressed in numbers with percent. Incidence density was expressed per 100,000 person-years. The model was adjusted for age, marital status, residence, highest education attainment, occupation, annual household income, body mass index, waist circumference, smoking status, passive smoking, alcohol intake status, physical activity in metabolic equivalents of task hours/day, history of anticoagulation therapy, history of hypolipidemic therapy, history of stroke, history of diabetes, history of hypertension, history of oral contraceptive pill use, parity, age of first birth, age of menopause.