Reproductive and menstrual factors in relation to mammographic parenchymal patterns among perimenopausal women

Academic Article


  • The relationship between mammographic patterns and reproductive and menstrual factors was examined in 3640 Norwegian women, aged 40-56 years, participating in the Third Troms√∂ study conducted in 1986-87. Epidemiological data were obtained from questionnaires. The mammograms were categorised into five groups. This categorisation is based on anatomic-mammographic correlations, following three-dimensional (thick slice technique) histopathologic-mammographic comparisons, rather than simple pattern reading. Patterns 1-3 were combined into a low-risk group and patterns 4 and 5 into a high-risk group for analysis. Women who had more than four children were 90% less likely to have a high-risk pattern than nulliparous women (OR = 0.09, 95% CI 0.04-0.16) controlling for age, weight, height and menopausal status. Furthermore, those who first gave birth over 34 years of age were more than twice as likely to have a high-risk pattern than those giving birth in their teens (OR = 2.37, 95% CI 1.23-4.56) adjusting for parity. Among post-menopausal women, age at menarche was negatively (P for trend = 0.015) and late age at menopause positively (P for trend = 0.072) related to high-risk patterns. Among premenopausal women, age at menarche was positively related to high-risk patterns (P for trend = 0.001). Also, menopausal status rather than age was associated with high-risk patterns. These findings support the opinion that reproductive and menstrual factors are involved in determining the mammographic parenchymal pattern among perimenopausal women. ¬© 1995 Stockton Press. All rights reserved.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Gram IT; Funkhouser E; Tabar L
  • Start Page

  • 647
  • End Page

  • 650
  • Volume

  • 71
  • Issue

  • 3