Reasons and risk: Factors underlying women's perceptions of susceptibility to osteoporosis

Abstract

Objectives

To assess women's perceptions of risk for osteoporosis and to identify factors that shape those perceptions.

Methods

A community sample of 358 women (aged 40–86) rated their perceived risk of osteoporosis and provided detailed information about factors underlying their risk perceptions. Their open-ended responses were content analysed.

Results

On average, participants believed they were less likely to develop osteoporosis than other women their age. In all, 63% perceived their risk as lower than other women their age; only 16% as higher. In explaining their risk, women mentioned more risk-decreasing factors than risk-increasing factors. Women who rated their risk as low attributed their risk primarily to their own preventive behaviors (e.g. taking calcium, exercising), whereas women who rated their risk as high attributed their risk primarily to their family history. Risk-increasing and risk-decreasing personal actions, hereditary factors, and physiological factors accounted for 53% of the variance in perceived risk for osteoporosis. Only one-half and one-third of all women, however, mentioned calcium consumption and exercise, respectively, as protective factors employed to reduce osteoporosis risk. Women also held misconceptions about osteoporosis risk and protective factors.

Conclusions

The current findings yield a detailed portrait of women's risk perceptions for osteoporosis. Increasing awareness of osteoporosis should be a priority for future osteoporosis prevention campaigns. Interventions should address misconceptions women may hold about their risk for the disease and promote specific behavioral strategies for osteoporosis prevention.

Introduction

The purpose of this study was to assess women's perceptions of risk for osteoporosis and to identify factors that shape those perceptions. Investigating women's risk perceptions for osteoporosis is important for two main reasons. First, perceptions of susceptibility are a central component of most models of health behavior, including the health belief model [1], protection motivation theory [2], the precaution adoption process model [3], and the transtheoretical model of change [4]. Evidence supporting these models suggests that feeling personally vulnerable to a health threat motivates people to take action to reduce the threat. Second, understanding women's beliefs about osteoporosis risk is important for the development of osteoporosis prevention interventions. People's cognitive representations of illness (e.g. their theories about the causes and consequences of a chronic illness) predict whether they engage in health protective behavior [5], [6], [7]. Effective interventions, therefore, require insight into how a disease or illness is understood by the intended audience.

Unfortunately, we know little about how perceptions of susceptibility to osteoporosis develop [8]. Some evidence suggests that risk perceptions are informed by people's implicit theories about the risk and protective factors associated with a health threat [6], [9], [10]. Although a few studies have examined women's risk perceptions for osteoporosis [11], [12], [13], little is known about women's beliefs about osteoporosis and the extent to which those beliefs contribute to women's estimates of their own risk for the disease.

The present study was designed to redress this conceptual hole in the literature. We had three primary goals. First we examined the extent to which women believe they are at risk for developing osteoporosis. Second we examined women's explanations of their risk for osteoporosis to identify those factors women believe serve to increase or decrease their risk (e.g. being small-boned; taking calcium supplements). Third, we assessed the extent to which these factors uniquely predict women's judgments of risk.

Osteoporosis is characterized by reduction in the strength and density of bone tissue, which leads to increased bone fragility and susceptibility to fractures [14]. It is referred to as a “silent disease” because bone loss occurs without any overt symptoms. In fact, most people are not aware of their condition until they experience a fracture. Women are greatly over-represented among those with osteoporosis and experience a substantial increase in risk following menopause [15]. Approximately one in two women over age 50 will experience an osteoporosis-related fracture in her lifetime [16]. Although most bone growth occurs during childhood, preventive actions adopted in adulthood (e.g. taking calcium supplements, engaging in weight-bearing exercise) can prevent or at least delay onset of the disease [17], [18].

Multiple factors influence a woman's chances of developing osteoporosis. Genetic and physiological factors associated with increased susceptibility to osteoporosis include family history, advanced age, oophorectomy, early menopause, race (Asians and Caucasians are at higher risk), being small-boned, and having a low body weight (<127 lbs) [17]. Behavioral factors associated with osteoporosis risk include diet and physical activity. Adequate calcium intake, particularly during childhood, is essential for the development and maintenance of healthy bone [19], [20]. Bone density is enhanced or diminished by other nutritional factors as well (e.g. vitamin D, phosphorous, respectively) [21], [22]. Strength training and weight-bearing exercise—particularly high-impact activities involving jumping and sprinting—are recommended for osteoporosis prevention [23]. Lifestyle factors harmful to bone include excessive alcohol intake and smoking [16], [24]. Bone damaging medications include corticosteroids and excessive thyroid hormone therapy [16]. Lower fracture rates are associated with use of post-menopausal hormone therapy [25], [26], [27].

Research suggests that women's knowledge about osteoporosis and its risk factors and protective factors is minimal [13], [28], [29], [30], although some evidence suggests that older women are more knowledgeable than are younger women [13], [31]. Previous studies [30] have shown that women may have poorer knowledge of uncontrollable osteoporosis risk factors (e.g. race, age of menopause) than more controllable factors (e.g. taking calcium supplements, exercising).

The few studies that have investigated women's risk perceptions for osteoporosis suggest that, in addition to having limited knowledge about osteoporosis, women tend to underestimate their chances of developing the disease [12], [13]. For example, one study of post-menopausal women found that although participants agreed that risk of osteoporosis increases after menopause, most did not consider themselves to be personally vulnerable to the disease [11].

That most women underestimate their risk for osteoporosis may imply that they are selective in their attention to or consideration of factors that influence their risk. This would be consistent with research suggesting that, when thinking about risk, people tend to cite factors that decrease rather than increase risk [9], [10], [32]. Evidence also suggests that people give disproportional weight to certain types of risk-decreasing factors over others. Of the many factors that might decrease a person's risk for a health threat, people tend to emphasize their own risk-reducing behaviors (e.g. one's daily intake of calcium) [10], [33]. Attention to risk-reducing behaviors may reflect the fact that these factors are more salient or more personally controllable than other types of factors [34].

The first goal of the present study was to assess women's perceptions of susceptibility to osteoporosis. We evaluated the extent to which women felt at risk for osteoporosis, relative to other women their age. The second goal was to identify specific factors women believe confer protection or risk for osteoporosis. Using a procedure developed by Weinstein [10], we asked participants to list, in open-ended fashion, all of the reasons believed to underlie their risk of osteoporosis. Given people's tendency to focus on risk-decreasing factors, we predicted that women would be more likely to report risk-decreasing factors than risk-increasing factors. Moreover, of the many factors to which women could attribute their risk (e.g. genes, body type), we predicted that they would be most likely to cite behavioral factors they engage in to reduce their risk. Third, we assessed the extent to which specific categories of factors made independent contributions to women's quantitative judgments of their risk for osteoporosis.