University of Oulu

Katuwal, S., Tapanainen, J. & Pukkala, E. Multivariate analysis of independent roles of socioeconomic status, occupational physical activity, reproductive factors, and postmenopausal hormonal therapy in risk of breast cancer. Breast Cancer Res Treat 193, 495–505 (2022).

Multivariate analysis of independent roles of socioeconomic status, occupational physical activity, reproductive factors, and postmenopausal hormonal therapy in risk of breast cancer

Saved in:
Author: Katuwal, Sushmita1; Tapanainen, Juha2,3; Pukkala, Eero1,4
Organizations: 1Faculty of Social Sciences, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland
2Department of Obstetrics and Gynecology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
3Department of Obstetrics and Gynecology, PEDEGO Research Unit, Medical Research Center, Oulu University Hospital, University of Oulu, Oulu, Finland
4Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
Persistent link:
Language: English
Published: Springer Nature, 2022
Publish Date: 2022-09-19


Purpose: This case–control study assesses the independent roles of reproductive history, postmenopausal hormonal therapy (HT), socioeconomic status (SES), and occupational physical activity on the risk of breast cancer (BC).

Methods: Odds ratios (OR) were estimated from conditional logistic multivariate regression model in a data set of 19,253 Finnish women diagnosed with BC between 1994 and 2013 and 96,265 age-matched population controls.

Results: Both pre- and postmenopausal white-collar workers had significantly increased risk of ductal and lobular BC as compared to manual workers. Moderate occupational physical activity reduced risk of lobular BC by 14%. There was a transient increase in the risk of BC observed after each birth followed by a protective effect starting some years after the delivery. As the number of children increased, the short-term excess risk was lower and protective effect was observed earlier. Continuous estrogen-progestin therapy (EPT) significantly increased the risk of both ductal and lobular BC and the magnitude of risk was directly proportional to duration of use (OR for 5+ years of use 2.26, 95% confidence interval 2.12–2.42). Monthly EPT for 5+ years increased the risk (OR 1.32, 95% CI 1.20–1.45). Users of estradiol plus levonorgestrel intrauterine system devices showed ORs of 1.56 (95% CI 1.45–1.69) and 2.18 (95% CI 1.81–2.64) for ductal and lobular BC, respectively.

Conclusions: This study concludes that pregnancy has a dual effect on BC risk, with a transient increase in risk followed by a long-term protective effect. The SES and HT have a large effect on BC risk while occupational physical activity has only a small independent effect.

see all

Series: Breast cancer research and treatment
ISSN: 0167-6806
ISSN-E: 1573-7217
ISSN-L: 0167-6806
Volume: 193
Issue: 2
Pages: 495 - 505
DOI: 10.1007/s10549-022-06571-x
Type of Publication: A1 Journal article – refereed
Field of Science: 3122 Cancers
Funding: This study was supported by the funds from Tampere University Foundation sr. The funding bodies had no role in the design of the study, collection, analysis, and interpretation of the data or in writing the manuscript.
Dataset Reference: The online version contains supplementary material available at
Copyright information: © The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit