WITHDRAWN: Development and Psychometric Properties of a Prostate Cancer Knowledge Scale for African-American Men

Background/Purpose: Prostate cancer (PrCA) is the number one non-skin cancer among all men. An estimated 164,690 men will be diagnosed, and 29,430 men will die from the disease in 2018, but African-Americans have PrCA morbidity and mortality at two or more times their White counterparts. There are a myriad of factors that have contributed to this disparity, but it may be partly explained by African-American men’s consistently lower PrCA knowledge when compared to Whites. However, while there have been multiple studies that have reportedly measured PrCA knowledge among African-American men, most researchers either do not report the psychometric properties of their PrCA knowledge scale/index or have low representation of African-American men in their studies. For the small majority of studies that report on the reliability of their PrCA knowledge scales in African-American populations, Cronbach’s alpha values were consistently low (ranged from α.= 45 to α.=.66). Therefore, new measures for assessing PrCA knowledge among African-Americans is warranted.

One PrCA knowledge scale which amalgamates items from prior scales, but has not undergone psychometric testing for use in African-American populations, is Cormier’s 20-item PrCA Knowledge scale. Knowledge domains on this scale include prostate anatomy and function, PrCA risk factors, PrCA screening, and PrCA symptoms. Response options for each item are ‘true,’ ‘false,’ and ‘I don’t know.’ Our study focuses on evaluating the psychometric properties of a slightly modified version of Cormier’s 20-item PrCA Knowledge scale for use among African-American men.

Methods: Participants: The study included a purposive sample of 354 self-identified, African-American men aged 40+ who (a) self-identify as African-American; (b) speak and comprehend English; (c) have no personal history of PrCA; and (d) have no self-reported history of cognitive decline. These men were recruited from several venues in South Carolina between July 2015 and February 2016. Data analysis: Exploratory factor analysis was conducted using squared multiple correlations as prior communality estimates. The maximum likelihood method was used to extract factors followed by varimax and promax rotations. Factor loadings were assessed by Scree plot, eigenvalues, and proportion of variance. Internal consistency reliability was assessed using Cronbach’s alpha for the total scale and each of four subscales. All data analyses were performed using SAS/STAT® statistical software, version 9.4.

Results: Our scree plot, eigenvalues, and the proportion of variance explained by each suggested four meaningful factors for the 20-item scale. Fifteen items loaded positively on four different factors at 0.35 or above with factor loadings ranging from 0.36 to 0. 72. Findings show a positive correlation between the four factors and the total subscale ranging from .40 to .83. The reliability of each subscale ranged from 0.41 to 0.77 with a total scale reliability of 0.78.

Conclusions and Implications: While Cormier’s PrCA Knowledge scale is far more reliable for use among African-American men than previous scales, some subscales (e.g., PrCA anatomy), need further refinement. Having a reliable measure of African-American’s PrCA knowledge is critical for determining if disparity-focused PrCA-interventions are effective.