Associations between calcium intake, osteoporosis knowledge and osteoporosis health beliefs among young adult women in the Lower North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Human Nutrition at Massey University, Manawatu, New Zealand

Abstract

Background/Aim: Osteoporosis is becoming the most prevalent bone disease in the world nowadays. While osteoporosis is often regarded as a disease of the elderly, however, maximising peak bone mass (PBM) during the adolescent and young adults’ stages is crucial to prevent or delay osteoporosis later in life. Osteoporosis is a preventable disease and making lifestyle changes or following health recommendations such as consuming adequate calcium is essential to prevent or delay osteoporosis. The first three decades of life is a crucial time to act, as it is the period to achieve optimal peak bone mass (PBM). Understanding an individual’s osteoporosis knowledge and health beliefs and factors influencing calcium intake may help to prevent osteoporosis. Therefore, this study aimed to examine the associations between calcium intake, osteoporosis knowledge and health beliefs among young female adults in the lower North Island in New Zealand. It also aimed to state the level of osteoporosis knowledge, osteoporosis health beliefs, calcium intake and validation of the food frequency questionnaire (FFQ). Study design: This was a secondary data analysis of 130 females (university students) between 18-25 years of age who voluntarily participated. Participant’s knowledge and health beliefs on osteoporosis were measured using the osteoporosis knowledge test (OKT) and osteoporosis health belief scale (OHBS). A FFQ was completed to estimate the calcium intake. Descriptive analysis, bivariate correlation and multiple regression were used to analyse the data of osteoporosis knowledge, health beliefs and associations with calcium intake. Validity was evaluated using the Spearman correlation coefficient (SCC), Wilcoxon signed rank test, Cross-classification, Weighted kappa statistics and Bland Altman analysis. Result: Findings show osteoporosis knowledge was significantly associated with calcium intake, susceptibility, calcium barriers, health motivation and one of the predictors of calcium intake as with perceived severity. In general, the university students had moderate mean knowledge on osteoporosis (16.9±3.7) and perceived moderate median susceptibility (15) and severity (19) to osteoporosis. The students perceived many benefits of taking calcium intake with lower calcium barriers and they were highly health motivated. Median daily calcium intake of 692mg (462, 10250) was below the estimated average requirement (EAR) of 1050mg (15-18 years old) and 840mg (19-30 years old) with acceptable findings on the validity analysis of the FFQ. Conclusion: Overall, the findings confirm the HBM theory that some perceptions such as severity and knowledge influence individual’s likelihood of engaging in health promoting behaviour (calcium intake) among this study population. Surprisingly most HBM constructs were not linked to behaviour (calcium intake). This is interesting but may not be causal. The findings show that increasing knowledge or improving awareness of osteoporosis especially related to physical activity, dairy and non-dairy calcium food sources and seriousness of getting osteoporosis may be the recommended preventive intervention for these university students.