1 BSc in Public Health, Students Research Committee, Faculty of Health, Mazandaran University of Medical Sciences, Sari, Iran

2 Assistant Professor of Health Education and Promotion, Department of Public Health, School of Health, Mazandaran University of Medical Sciences, Sari, Iran.

3 Assistant Professor of Nutrition, Department of Nutrition, School of Health, Diabetes Research Center Mazandaran University of Medical Sciences, Sari, Iran.

4 Health Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran


Background: Osteoporosis is one of the most common problems in health systems and a hidden epidemic in the modern world. The aim of the present study was to investigate osteoporosis-related nutritional behaviors based on the theory of planned behavior (TPB) in adolescent girls in Sari, Iran.
Methods: This cross-sectional study was performed on 341 12-16-year high school students who were selected by multi-stage random sampling method in Sari, Iran. Data collection was carried out using a TPB-based researcher-made questionnaire consisting of three parts; part A included questions on demographic characteristics and osteoporosis-related diseases, part B discussed osteoporosis nutritional behaviors based on TPB constructs, including behavioral attitudes, subjective norm, perceived behavioral control, and intention, and part C was the Food frequency questionnaire (FFQ).  Part A and B were completed by students and part C was completed through an interview, taking into account the number of food units based on the recommended standards of the Food Pyramid. Data analysis was also performed using regression analysis, Pearson correlation and ANOVA in SPSS ver. 20.
Results: The present study demonstrated a significant relationship between perceived behavioral control and osteoporosis predisposing nutritional behaviors (P<0.05). Also, among TPB constructs, subjective norm (β=0.138) and intention (β=0.136) were the main determinants of osteoporosis-preventive behaviors; and subjective norm (β=0.182) and knowledge (β=0.155) played the most important roles in determining osteoporosis-predisposing nutritional behaviors.
Conclusion: Based on the results, there is a significant relationship between TPB constructs and osteoporosis-related nutritional behaviors. Considering the role of TPB constructs and lower consumption of the osteoporosis-preventing group, there is a need for educational interventions among adolescents, parents and other people influencing adolescents.