Cancer Causes & Control

, Volume 27, Issue 10, pp 1239–1252

Sedentary time and breast cancer incidence in African American women

  • Sarah J. O. Nomura
  • Chiranjeev Dash
  • Lynn Rosenberg
  • Julie Palmer
  • Lucile L. Adams-Campbell
Original paper

DOI: 10.1007/s10552-016-0803-9

Cite this article as:
Nomura, S.J.O., Dash, C., Rosenberg, L. et al. Cancer Causes Control (2016) 27: 1239. doi:10.1007/s10552-016-0803-9

Abstract

Purpose

The objective of this study was to evaluate whether time spent sitting at work or watching television was associated with breast cancer risk among African American women.

Methods

The Black Women’s Health Study (analytic cohort = 46,734) is an ongoing prospective cohort study of African American women ages 21–69 at baseline (1995). Questionnaire data were used to estimate sedentary time. Total time spent sitting at work and watching television (individually and combined) at baseline and updated through follow-up (1995–2001) and breast cancer incidence (n = 2,041 incident cases, 1995–2013) was evaluated using proportional hazards regression.

Results

Higher total time spent sitting at baseline (≥10 vs. <5 h/day, HR 1.27, 95 % CI 1.06, 1.53) and updated through follow-up (≥10 vs. <5 h/day, HR 1.38, 95 % CI 1.14, 1.66) was associated with an increased breast cancer risk. Associations were stronger for hormone receptor-negative tumors (≥10 vs. <5 h/day, HR 1.70, 95 % CI 1.12, 2.55) compared to hormone receptor-positive tumors (≥10 vs. <5 h/day, HR 1.16, 95 % CI 0.88, 1.52), but tests for heterogeneity were not statistically significant (p heterogeneity = 0.31). Positive associations between total time spent sitting and breast cancer incidence did not differ by physical activity level or body composition measurements.

Conclusions

Our findings suggest that high sedentary time may increase risk for breast cancer among African American women.

Keywords

Breast cancer Physical activity African American Sedentary time 

Abbreviations

BWHS

Black Women’s Health Study

BMI

Body mass index

cm

Centimeters

CI

Confidence intervals

ER−

Estrogen receptor negative

ER+

Estrogen receptor positive

FFQ

Food frequency questionnaire

HR

Hazard ratio

HR−

Hormone receptor negative

HR+

Hormone receptor positive

HER2−

Human epidermal growth factor 2 negative

kcal

Kilocalories

kg

Kilograms

m

Meters

PR−

Progesterone receptor negative

PR+

Progesterone receptor positive

TV

Television

WHR

Waist-to-hip ratio

Supplementary material

10552_2016_803_MOESM1_ESM.docx (168 kb)
Supplementary material 1 (DOCX 168 kb)

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Sarah J. O. Nomura
    • 1
  • Chiranjeev Dash
    • 1
  • Lynn Rosenberg
    • 2
  • Julie Palmer
    • 2
  • Lucile L. Adams-Campbell
    • 1
  1. 1.Division of Cancer Prevention and Control, Georgetown-Lombardi Comprehensive Cancer CenterGeorgetown UniversityWashingtonUSA
  2. 2.Slone Epidemiology Center at Boston UniversityBostonUSA

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