Study type: Epidemiological study (observational study)

Use of electric bedding devices and risk of breast cancer in African-American women. epidem.

Published in: Am J Epidemiol 2003; 158 (8): 798-806

Aim of study (acc. to author)

A case-control study was conducted in the USA to examine the association between use of electric bedding devices and breast cancer in African-American women.

Further details

Estrogen receptor status was measured in tumor tissue samples using the immunohistochemical methods.
Electric bedding devices included electric blankets, electric mattress pads, and heated water beds. For detailed analysis of electric blankets, women who used an electric bedding device for more than 6 months per year (and therefore were more likely to have used a heated water bed, which generates lower magnetic fields) were excluded.

Endpoint/type of risk estimation

Type of risk estimation: (odds ratio (OR))

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 use of electric bedding devices: no
Group 2 use of electric bedding devices: yes
Reference group 3 number of years of use: 0
Group 4 number of years of use: 1 - 5 years
Group 5 number of years of use: 6 - 10 years
Group 6 number of years of use: > 10 years
Reference group 7 number of months of use per year: 0
Group 8 number of months of use per year: < 3
Group 9 number of months of use per year: > 3
Reference group 10 mode of use: no use
Group 11 mode of use: used to warm bed only
Group 12 mode of use: kept on most of the time

Population

Case group

Control group

Study size

Cases Controls
Eligible 670 -
Participants 304 305
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

An increased risk for breast cancer was observed for women who used an electric bedding device (group 2) as compared to the reference group 1 (OR 1.4, CI 0.9-2.2). The risk increased with increasing number of years of use (use for more than 10 years: OR 4.9, CI 1.5-15.6). The risk appeared to be higher for use in more than 3 months per year as compared with use in 3 months or less (OR 1.7, CI 0.9-3.2). No risk was observed for using the device for warming the bed only (group 11: OR 1.0, CI 0.5-2.2), however an increased risk was found for keeping the device on most of the time (group 12: OR 1.7, CI 1.0-3.0).
Restricting the analyses to women who presumably used an electric blanket, the corresponding dose-response relations were more striking. Similar results were found for both premenopausal and postmenopausal women and for both estrogen receptor-positive and estrogen receptor-negative tumors.
The authors conclude that the use of electric bedding devices may increase breast cancer risk in African-American women.

Study funded by

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