ABSTRACT
PURPOSE: To evaluate the effects of two interventions on calcium intake and exercise and assess whether intervention effects varied as a function of participants' stage of change. DESIGN: The study used a 2 by 2 factorial research design. Baseline, 3-, 6-, and 12-month follow-up data were collected. SETTING: Twelve counties in western North Carolina. SUBJECTS: Of 714 women recruited, 547 (76.6%) completed all data collection procedures. INTERVENTION: One intervention, conducted at the individual level, compared the effects of tailored vs. nontailored educational materials. The tailored educational intervention was delivered via two packets of written materials and one telephone counseling session. The written materials and counseling session were tailored according to participants' current calcium intake and exercise level, perceived adequacy of these behaviors, stage of change, behavioral goals, and perceived barriers to change. A community-based intervention was also evaluated. This intervention, implemented in 6 of the 12 counties, included establishing an Osteoporosis Resource Center, conducting a workshop on osteoporosis prevention, and offering free bone density screening. MEASURES: Outcome measures were calcium intake and exercise level. Stage of change was assessed as a moderating variable. RESULTS: Irrespective of intervention group, among women not consuming adequate calcium at baseline, intake increased an average of about 500 mg/d over the course of the study. Changes involving exercise were more modest. Repeated measures regression analyses were used to evaluate intervention effects. The effect of the tailored educational intervention varied, in appropriate ways, among women in different stages of change at baseline (F2,527 = 6.37, p < .002). Among women in the Engaged stage, the tailored intervention was associated with a greater increase in calcium intake. In contrast, among women who were obtaining adequate calcium at baseline (i.e., Action stage), the tailored intervention appeared to forestall inappropriate increases in calcium intake. The community-based intervention had no consistent effects on calcium intake, either alone, or in combination with the tailored intervention. Finally, neither intervention had an effect on exercise, either alone or in combination. CONCLUSIONS: Limited support for the superiority of tailored vs. nontailored educational interventions was found. The differential effects observed could be due to the telephone counseling received by women in the Tailored Education Group, however.