Illness Perceptions of Breast Cancer in Japanese Middle- and Early Old-Aged Women: Psychometric Properties of the Brief Illness Perception Questionnaire for Use in Diagnosing Breast Cancer in Japan

Objectives: The present study was aimed at constructing the Japanese version of the Brief Illness Perception Questionnaire for breast cancer (Brief IPQ-JBC), for use with Japanese middle- and early old-aged women who had not previously undergone mammography. We also examined the psychometric properties of the translated instrument.

Methods: Patients were 824 middle- and early old-aged women living in all parts of Japan, who completed surveys on the Internet in January 2014. Of these, 282 had not previously undergone mammography and were included in this study, completing the Internet survey again, six months later, in July 2014.The participants were evaluated on the basis of a battery of questionnaires comprising demographic details, the tentative version of the Brief IPQ-JBC, the Japanese version of the Illness Perception Questionnaire (J-IPQ), Self-Directedness subscale from the Japanese version of the Temperament and Character Inventory-125 items, perceived breast cancer risk, and anticipated worry about breast cancer.

Results: The Brief IPQ-JBC was found to have good long-term test-retest reliability, as well as concurrent validity with the J-IPQ. The scale also showed good construct validity, based on the results of a path model using structural equation modeling, thus supporting the theoretical perspective of the common-sense model of self-regulation.

Conclusion: We have validated the Brief-JBC in a sample of Japanese middle- and earlyold-aged women and believe our results will be useful for subsequent research.