Methods

Questionnaire Data and Anthropometry

A common, standardized questionnaire is administered by trained health workers to cases and controls in Spanish. This questionnaire includes information on sociodemographic factors, health history, reproductive history, use of hormones, early risk factors, body silhouette at different ages, physical activity, diet, occupation, environmental risk factors, ethnicity, and family history of cancer.

Anthropometry and silhouette at different ages. Women are asked to identify a body silhouette from 9 options (from very thin to very fat) at 6 different ages: before menarche, 2 years after menarche, at age 18-20 years, before their first pregnancy, at age 25-35 years, and at their current age. Responses to these pictograms have been validated in different settings and proven to be reliable. Anthropometric measurements are performed by previously trained personnel using standardized methods according to Lohman's recommendations.