Predictors of perceived susceptibility of breast cancer and changes over time: a mixed modeling approach.

The construct of perceived risk is included in many health behavior models (e.g., Health Belief Model, (Janz & Becker, 1984) Precaution Adoption Process Model, (Weinstein, 1988) and Protection Motivation Theory (Rogers & Prentice-Dunn, 1997)) and is used to inform the development and evaluation of interventions designed to increase cancer screening. The Health Belief Model delineated separate constructs for perceptions of risk susceptibility and risk severity; however, risk severity has been less useful in explaining cancer prevention behaviors due to overwhelming agreement that cancer is very severe, negative, and undesirable (Janz & Becker, 1984). Therefore, perceived risk in this paper refers to individuals’ perceptions of risk susceptibility, which Weinstein (1989) defined as “the likelihood of experiencing personal harm if no action is taken” (p. 144). Increased awareness and perceived susceptibility are expected to increase preventive health behaviors, such as cancer screening (Weinstein, 1988). Although perceptions of susceptibility are not sufficient to change behavior, people rarely adopt precautions when they do not believe they are at risk (Weinstein, 1989). Despite some concerns that very high perceived susceptibility would decrease mammography use, most of the evidence supports a positive linear association (McCaul, Branstetter, Schroeder, & Glasgow, 1996). Small but significant direct effects of perceived susceptibility to breast cancer on mammography screening behavior ranged from r = .10 to r = .21; stronger associations were observed when measures of lifetime mammogram use or cross-sectional data were used (McCaul et al., 1996). Perceived susceptibility may be more accurately characterized as a distal predictor of behavior whose direct effect is largely mediated by other factors such as perceived benefits, norms, and self-efficacy (Aiken, West, Woodward, Reno, & Reynolds, 1994; Fishbein, 2000; McQueen, Vernon, Myers, & Tilley, 2006). Because perceived susceptibility is expected to begin the process of precaution adoption, it is important to understand what factors predict or determine such risk perceptions. The positive correlates of perceived susceptibility to breast cancer identified in a recent meta-analysis of mostly cross-sectional studies included: younger age, less education, White race/ethnicity, personal or family history of breast problems, mammography adherence, and breast cancer concern or worry (Katapodi, Lee, Facione, & Dodd, 2004). Better understanding of what promotes changes in perceived susceptibility over time would help researchers to develop more effective health behavior interventions. However, longitudinal research examining predictors of perceived susceptibility has been scarce. Only one study used prospective data to examine predictors of perceived susceptibility to breast cancer (Aiken, Fenaughty, West, Johnson, & Luckett, 1995), but the only predictor examined was past mammography use, which was positively associated with perceived susceptibility. Another longitudinal study examined cross-sectional and prospective associations with perceived susceptibility of colorectal cancer (CRC) among male autoworkers (Vernon, Myers, Tilley, & Li, 2001). Several variables including family history, cancer worry, intent to be screened, screening history, and family support for CRC test use were significant correlates as well as predictors, but other variables were only significant in cross-sectional analysis. These findings suggest that relying on cross-sectional associations of perceived susceptibility in the design of interventions to increase cancer screening may not be useful if the associations are not stable over time or predictive of changes in perceived susceptibility. Thus, it is important to examine previously identified correlates of perceived susceptibility to breast cancer in prospective analyses. Because there is no consensus on the best way to measure perceived susceptibility (Vernon, 1999), multiple measures should be examined whenever possible. Although absolute and comparative measures of perceived susceptibility have been shown to be strongly associated and factor together (Gerend, Aiken, West, & Erchull, 2004; Lipkus et al., 2000), other studies have reported different results for the two measures (Blalock, DeVellis, Afifi, & Sandler, 1990; Lipkus & Klein, 2006; Lipkus, Klein, Skinner, & Rimer, 2005; Weinstein et al., 2004). We conducted a secondary data analysis using three waves of survey data collected as part of Project H.O.M.E. (Healthy Outlook on the Mammography Experience), a randomized behavioral intervention trial to increase regular mammography screening in a national population of women veterans age 52 years and older. The specific aims of this study were to 1) examine whether correlates of perceived susceptibility to breast cancer reported in the literature were prospectively associated with perceived susceptibility to breast cancer, as well as with changes in perceived susceptibility over time, 2) examine additional variables that have been previously associated with perceived susceptibility for other cancer types for their prospective association with perceived susceptibility to breast cancer and changes over time, and 3) explore potential differences in the predictors of perceived susceptibility using three different dependent measures.