Association Between Risk of Breast Cancer and Fertility Factors - a Latent Variable Approach

Background: Breast cancer is the most common malignant tumor in females. Many studies have been carriedout in order to assess the reproductive risk factors. Particular attention has focused on information regardingfertility, including breastfeeding, age at first birth and number of live births. These factors are highly correlatedwith each other. The objective of this study was to employ latent variables to reduce the confounding effect ofthis correlation with a logistic regression analysis.
Methods: The investigation drew upon results from a datasetbelonged to a hospital based case-control study covering 303 breast cancer patients and 303 hospital controls.Data were collected through interview and reproductive variables included age at first full-term pregnancy andlive birth, number of pregnancies and live births, and total length of breast feeding. Latent variables weregenerated using factor analysis and principal components analysis.
Results: The study revealed that for bothlatent variable approaches the odds ratios of two latent variables significantly indicated a protective impact ofnumber of pregnancy and live birth and breastfeeding and a prognostic relation with age at first pregnancy orlive birth.
Conclusion: The findings suggest that breastfeeding and decreasing age at first live birth have protectiveinfluences on breast cancer risk. Also using statistical model with latent variables in the presence of collineardata leads to reliable results.