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Title:A case for multiple item response theory: The Cancer Health Literacy Measure-Breast and Cervical Cancer-Uruguay
Author(s):Linares, Deborah Elizabeth
Director of Research:Schwingel, Andiara
Doctoral Committee Chair(s):Schwingel, Andiara
Doctoral Committee Member(s):Buki, Lydia P.; Andrade, Flavia; Anderson, Carolyn J.
Department / Program:Kinesiology & Community Health
Discipline:Community Health
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):health measurement
breast cancer
cervical cancer
health literacy
item response theory
cultural and conceptual knowledge
health behavior
cancer control and prevention
survey research
women's health
Abstract:Uruguay has the second highest breast cancer incidence rate in Latin America (Ferlay et al., 2013). Cervical cancer is the second leading cause of death in Uruguay (Rodríguez, Fazzino, & Larrosa, 2010). Despite these troubling statistics, an opportunity exists to improve the lives of women through early detection of both cancers. Yet, there is a dearth of information about factors influencing early cancer screening in Uruguay. Furthermore, research in this area is hampered because there is no survey to assess these factors among Uruguayan women. Thus, the field of cancer prevention is substantially hindered and cannot move forward without a valid measure. Information obtained through such a measure can help health professionals understand psychosocial barriers (e.g., lower breast cancer knowledge) preventing women from screening and develop targeted health education interventions that have the potential to save women’s lives. This study addresses this gap by using item response theory (IRT) to examine and refine the first Uruguayan breast and cervical cancer measure, the Cancer Health Literacy Measure-Breast and Cervical Cancer-Uruguay (CLM-BCC). This measure assessed women’s cultural and conceptual knowledge, which is an area of health literacy that is understudied at this point in time. Cultural and conceptual knowledge is comprised of women’s attitudes, beliefs, emotions, and knowledge towards breast and cervical cancer. In 2011, data were collected using the CLM-BCC by partnering with the Universidad Católica del Uruguay and the Comisión Honoraria de Lucha contra el Cáncer. Participants included 411 native Uruguayan women (≥ 40 years in 5 regions across the country). By design, approximately 50% of women were up to date on their mammogram and Pap test screenings (within the past 2 years). CLM-BCC knowledge items examined in this study consisted of 22 items assessing women’s knowledge of breast and cervical cancer and screening. IRT, more specifically explanatory item response modeling and Mokken scaling, are novel and uncommon approaches in health measurement making this one of the first public health studies to use these beneficial procedures. Findings revealed three Mokken scales for breast and cervical cancer knowledge items: (a) breast cancer self-detection, (b) breast cancer other detection, and (c) the cervical cancer knowledge scales. IRT analyses indicated that each scale item significantly contributed to the overall models and identified 7 unscalable items. Item parameter estimates were further refined for 2 out of 3 subscales by adding participant-based characteristics (fixed effects) into the model, which also significantly contributed to each scale or helped explain or account for the differences in cancer knowledge. Women who obtained a mammogram in the last 2 years were 2.07 times likely to have more breast cancer self-detection knowledge compared to those who were not. Those who had obtained a Pap test in the past two years and resided in the city of Artigas (city in the province farthest from Uruguay's capital of Montevideo) had significantly higher cervical cancer knowledge scores. Women who were up to date for their Pap test were 2.26 times likely to have more cervical cancer knowledge when compared to those who had not. Similarly, Artigas residents were 2.21 times more likely to have more cervical cancer knowledge compared to women from other areas. Overall, this study provided evidence that there is a direct link between screening status and knowledge levels for breast cancer self-detection and cervical cancer knowledge. These findings provide practical implications for developing knowledge based cancer promotion interventions. Using IRT helps researchers move the field of health measurement forward by providing an example of how to validate knowledge item scores on the first cultural and conceptual knowledge measurement instrument and articulate psychosocial processes influencing breast and cervical cancer screening. Thus, this study contributes to survey research by providing a tangible example of how IRT can be used in measurement development and how EIRM surpasses traditional IRT (i.e., one and two parameter logistic regression) to provide more information for developing a concise, theoretically-driven, and psychometrically sound measure for clinical and health education settings. Study findings extend the field by bridging theory with advanced statistics.
Issue Date:2015-06-23
Rights Information:Copyright 2015 Deborah Linares
Date Available in IDEALS:2015-09-29
Date Deposited:August 201

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