Osteoporosis Prevention Among Young Women: Psychosocial Models of Calcium Consumption and Weight-Bearing Exercise

Objective: To examine the putative determinants of two osteoporosis-preventive behaviors, calcium consumption and weight-bearing exercise, in 2 samples of young women (Sample 1, n = 202; Sample 2, n = 209). A common psychosocial model of both behaviors, comprising the health belief model and augmented with constructs drawn from social cognitive theory and the theory of planned behavior, was developed, tested, and replicated. Design: A prospective 2-panel design was used. Baseline data were obtained in fall 1997 for Sample 1 and in spring 2002 for Sample 2. Behavioral follow-up data were obtained 6 months after initial data collection for both samples. Main Outcome Measures: Baseline measures of behavioral intentions served as proximal outcomes. Behavioral measures obtained 6 months later served as distal outcomes. Results: Perceived barriers and self-efficacy directly predicted intentions to consume calcium and to exercise. Descriptive norms predicted intentions, in part indirectly through barriers and self-efficacy. Constructs specific to osteoporosis (e.g., susceptibility, severity) did not contribute to prediction. With initial behavior controlled, intentions to consume calcium and to exercise predicted the corresponding behaviors measured 6 months later; intentions fully mediated the relationship of model constructs to behavior. Conclusion: Health beliefs associated with a negative health outcome, here osteoporosis, distal to young women's lives did not contribute to prediction. In contrast, constructs related to the current behaviors of calcium consumption and weight-bearing exercise (barriers, self-efficacy, norms) were highly predictive. Implications for behavioral interventions are discussed.