Osteoporosis is a progressive systemic bone disease caused by an imbalance between osteogenesis and osteolysis, resulting in a decrease in bone mass and density, which can increase the risk of fractures. One-third of menopausal women are affected worldwide[12]. Two major osteoporosis risk factors are reduced bone mass, which is formed during adolescence and adulthood, and rapid bone loss due to aging and menopause [3]. When middle-aged women develop a fracture caused by osteoporosis, they are suffering not only a physical disability but also a mental disability, such as increased social isolation and depression, due to decreased ability for daily living activities and soaring medical care costs [45]. Considering medical perspectives and social problems, it is critical to detect bone loss at the early stage after middle age, provide appropriate intervention, and prevent or delay complications. However, symptoms of osteoporosis or bone loss rarely appear before it they have advanced to the fracture stage[6]. Therefore, one of the best ways to prevent such complications is to take corrective action through early detection of high-risk groups of women who are vulnerable to fracture[7].

Breast cancer is the second most common form of cancer among women in Korea, and the number of women with breast cancer is increasing steadily[89]. Among women with breast cancer, those who receive medical treatment that adversely affects the skeletal system are highly vulnerable to develop osteoporosis [10111213]. Chemotherapy for breast cancer directly reduces bone mineralization and indirectly deteriorates ovarian function in pre-menopausal women, resulting in decreased concentrations of estrogens and an increased risk of osteoporosis. Furthermore, hormone replacement therapy decreases bone density, and radiation therapy can increase the risk of rib fracture[13]. As a result, women with breast cancer have bones that are more prone to fracture[14151617]. Therefore, women with breast cancer should understand the importance of preventing osteoporosis and actively follow health promoting behavior conducive to prevent osteoporosis.

Little research has been conducted on preventing and managing osteoporosis in women with breast cancer in Korea. Among the few studies, the majority have been survey-based and focused on the importance of osteoporosis education[311]. They did not apply education as an intervention but compared the interventional effect between intervention and control groups. Study was conducted to identify the effect of an osteoporosis educational intervention on osteoporosis knowledge and health promoting behaviors in patients with breast cancer and to allow patients to manage their own health conducive to preventing osteoporosis. The specific objectives of this study was to compare the osteoporosis knowledge and behavior of intervention group to those of control group.

As the overall five year breast cancer survival rate is increasing, the need to understand and manage the long-term effects of chronic diseases is growing[23]. Therefore, this study was conducted to identify the effect of osteoporosis preventive education on the osteoporosis knowledge and health promoting behavior in patients with breast cancer in Korea.

Our findings demonstrate that the knowledge level increased significantly in the intervention group compared to that in the control group. It was not possible to compare our results to those of other studies, as no study has been conducted on osteoporosis preventive education using patients with breast cancer. However, our results were consistent with another study done in male subjects who had received a 90-min osteoporosis education program. Changes in knowledge level were measured three weeks later and showed an increase in osteoporosis knowledge level[24]. Another study with young female subjects, who had received a 45-min group education program with additional education using a booklet for calcium and vitamin D intake, also demonstrated an increase in knowledge eight weeks after the intervention[25]. However, the results of that study did not agree with those of a study done with elderly subjects who received a 60-min osteoporosis education program with slides and booklets, followed by 30-min of reinforcement instruction one year after the initial education. Gaines et al.[26], measured knowledge levels one and two year after an education intervention and did not show any significant gain in knowledge. Existing studies and our study may be different, as no substantial diversity in the frequency or length of time to provide education was used, and the difference might result from different subject age brackets or the time that the posttest was conducted. Therefore, the frequency and method of intervention implemented in our study was effective for female patients in their fifties to gain knowledge. Further studies should focus on repeated measurements to determine when the most appropriate time point is to reinforce education and consolidate the effect of education.

The results demonstrate that the health promoting behavior scores were significantly higher in the intervention group than those in the control group 3 months after intervention[24]. In contrast, two studies did not show any improvement in health behavior. One study [27] was conducted with pre-menopausal women who received a two hour per week educational intervention over four weeks using leaflets containing diet, exercise, cigarette smoking, and calcium intake information. Behavioral changes were measured two year after the intervention and showed no change in health behavior. Another study with elderly subjects also showed no change in behavior[26]. A possible explanation for the discrepancy may be different time points to effectively assess the intervention. In other words, Tung and Lee [24] measured behavioral changes three weeks after the intervention, whereas both Gaines et al.[26], and Winzenberg et al.[27], measured changes two year after the intervention. We measured behavioral changes three months after the intervention. Therefore, other studies focusing on repeat education and/or reinforcement education every three months to maintain educational effectiveness emphasized that the effect of education intervention on behavioral change appears to increase three months after an intervention but declines thereafter[19].

More specifically, we demonstrated that although female patients with breast cancer participated in significantly less physical exercise since the intervention, no behavioral changes in dietary habits were observed among the health promoting behavior subcategories. These findings are not consistent with a study on osteoporosis by Chan et al.[28], on women in Hong Kong. Although they applied a similar intervention to that used in our study, the dietary habit change improved one month later the intervention, but physical exercise, which focuses on a combined intervention of lectures with exercise therapy, did not improve. A change in dietary habits can occur in a relatively short time, whereas education-induced changes in exercise frequency cannot be accomplished with only one education intervention. The improvement in exercise performance in our study resulted from the education intervention and self-care activities. Further studies on the effectiveness of self-care activities to prevent osteoporosis are needed.

We revealed no difference in unhealthy food or drink intake, such as caffeine, carbonated drinks, alcohol, and tobacco, in the intervention group before and after the intervention. No difference was observed between the two groups before and after the intervention. Sedlak et al.[29], investigated osteoporosis prevention in female college students living in a community with nurses. That study showed that only the college group, which received intensive education intervention on caffeine intake, significantly decreased caffeine intake after the intervention. This result indicates that providing an education intervention once is not expected to change behavior, as a repeated and enriched educational approach to change behavior was demanded for addictive substances.

Our results demonstrate that osteoporosis preventive education provided in a group and including self-care activities for patients with breast cancer appeared to improve patient knowledge and behavior conducive to preventing osteoporosis and was significantly effective for improving and changing physical exercise behaviors. Therefore, the significance of the results for nursing science can be explained by the relationship between breast cancer and osteoporosis emphasized in other studies. Health education to prevent osteoporosis should be provided as early as possible during breast cancer treatment. The education should take all measures to prevent osteoporosis and to transfer the patient's knowledge into action. This study appeared to play a critical role inducing voluntary participation of patients in self-care activities. We suggest that nurse specialists, such as advanced practice registered nurses with expertise in oncology, should be involved in the program to support the patients with breast cancer and enhance their self-care activities.