¹Faculty of Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran

²Center of Health, Isfahan University of Medical Sciences, Isfahan, Iran

*Department of Health Education and Health Promotion, Faculty of Health, Shahid Beheshti University of Medical Sciences, Tabnak Ave., Daneshjou Blvd., Velenjak, Tehran, Iran P.O. Box 19835-35511

Article Publishing History

Introduction

Osteoporosis is a disease characterized by low bone mass and deterioration of bone tissue which has hit millions of people globally.This leads to increased bone fragility and risk of fracture (broken bones), particularly of the hip, spine, wrist and shoulder. Osteoporosis is often known as “the silent thief” because bone loss occurs without symptoms. Osteoporosis is sometimes confused with osteoarthritis, because the names are similar. WHO (World Health Organization) estimate of 2010 indicated that about 22 million women and 5.5 men in Europe aged 50-84, and 52 million American men and women over 50 suffer from osteoporosis. The global figures estimate that more than 1.7 million Iranians over 50 is subject to broken bones, (Lesan et al., 2010, (IOF, 2013 and MHME, 2016).

Broken bones because of the osteoporosis wields considerable costs on the health system and would have serious implications if gone untreated. Gender (osteoporosis in women is twice that in men), menopause, bright skin (Caucasians), skeleton size, smoking, caffeine, alcohol, reduced level of oestrogen, premature menopause (before 45), lower calcium and vitamin D intake, inactivity, and family history are the most important risk factors. Among factors contributing to prevention of osteoporosis are consumption of dairy products such as such as cheese, milk, eggs, fish and poultry, honey, fruit and calcium supplements (Keramat, 2012, Ghaffari, et al., 2013, Anderson, 2014 and Bonura, 2015).

The recommended daily level of calcium for young and adult people is between 1000 and 1300 mg. and intake of sufficient calcium (500 mg/day, in daylight) in individuals with osteoporosis could help prevent broken bones. WHO has provided six general recommendations to prevent osteoporosis: Increase physical activity, reduce sodium intake, increase consumption of fruits and vegetables, keep weight in a healthy condition, avoiding smoking, and restrict alcohol consumption. Research conducted in Iranian context have often reported calcium intake below the recommended levels among university students (Khadem Haghighian, 2015, NIH, 2016, WHO, 2016).

Thus, examination of the reasons behind such lower calcium intake is necessary. A preventive measure of osteoporosis is improving the bone density through health education and promotion programs (HEP) (WHO, 2016). Health education is a learning process where public receives information to change the behaviour for better in a direction to improve health. It draws upon models to explain how a behaviour takes shape; how health education is guided; and, how health education wield influence on individual’s future behaviour (Mudest & Tamayoz, 2012).

Evidence has shown that with adoption of some change in lifestyle (for example, increased calcium intake and physical activity), it is possible to prevent osteoporosis or procrastinate it (Torshizi et al., 2009). A prevalent cause of adoption of changes in behaviour to prevent osteoporosis is a fallacy that the disease is not serious. According to Health Belief Model (HBM), individuals would change their behaviour only when they understand that the disease is really serious, since otherwise, rarely would they change their behaviour for healthy lifestyle. Health belief model is an attempt to explain why some individuals engage in behaviours to prevent the disease, but some do not.

According to the model, adoption of a healthy lifestyle hinges upon two issues: first, the perception the individual has of the danger threatening him; and second, his assessment of the barriers and benefits in healthy behaviour (Glanz et al., 2008). With this in mind, the present research seeks to identify the determinants of osteoporosis-related calcium intake among university students according to Health Belief Model, to provide insights to the nature of disease to authorities to further policy decisions.

Material & Methods

A cross-sectional descriptive-statistical study was conducted with female students in Department of Health, Shahid Beheshti University of Medical Sciences in the educational year of 2011-12. The number of female students in the department determined the number of questionnaires as the method of data collection. Of 400 questionnaires distributed among the sample population, a total of 239 questionnaires were answered to. The first part of the questionnaire collected demographic data; the second part included 24 questions about the health belief model constructs; and the third part included the standard Food Frequency Questionnaire (FFQ).

The first part collected data on marital status, students’ and their parents’ employment, parents’ education, income level, and university major. Of 24 questions in the second part, each construct (perceived susceptibility, severity, benefits, and perceived barriers of calcium intake) had six questions. Responses to each question was 5-point Likert scale, and had values of ‘completely agree,’ to ‘completely disagree.’ A ‘completely agree’ received 5 points and a ‘completely disagree’ was assigned only 1 point. Total scores ranged between 6 and 30. With perceived susceptibility, benefits, and severity, higher scores indicated higher perception of the constructs. Lower scores in perceived barriers indicate higher perception of the barriers. Validity and reliability of HBM constructs was confirmed in Baheiraei et al., with Cronbach’s alpha coefficient of 0.78, 0.8, 0.77, and 0.7 for susceptibility, severity, benefits, and barriers, respectively (WHO, 2013). The third part included 19 question of food frequency, which measured consumption of variety of foods such as high-tat, low-tat, fatless milk, cacao mixed with milk, milk chocolate, high-fat and normal-fat yogurt, yogurt drink, traditional ice-cream, raw and boiled spinach, and turnips.

The responses was in 9-point Likert scale, ranging from never consumed to more than six times and more per day. Scoring to responses was based on calcium content of consumed items. For calculating calcium content, we drew upon a table giving the daily permitted amount of food in gr/day. The unit was calcium content of each 100 gr of the given food, thus calculating the total calcium intake of the individual per day. We demanded that each student carefully study the questionnaire, and if willing, fill the questionnaires. The data collected was fed into SPSS-18 statistical software, which gave us an analysis of the data drawing upon Pearson’s correlation coefficient, independent t-test, one-way analysis of variance and multivariate regression, and in the significance level of 0.05 per.

Table 1: Student’s demographic information
Variable	Demographic distribution
University major	Number (per cent)	Number (per cent)	Number (per cent)	Number (per cent)	Number (per cent)
	General Health	Occupational Health	Environmental Health	Health Education	Epidemiology
	(24.3)58	(21.3)51	(50.6)121	(2.1)5	(1.7)4
Degree to be awarded	BA		MA	PhD
	(95.4)228		(3.8)9	(0.8)2
Father’s education	No education	Grade school	Middle school	High school diploma	University degree
	(7.5)18	(15.9)38	(18.4)44	(30.5)73	(27.6)66
Mother’s education	No education	Grade school	Middle school	High school diploma	University degree
	(8.8)21	(25.1)60	(20.5)49	(32.6)78	(13)31
Father’s job	Unemployed	Blue-collar job	White-collar job		Other
	(3.3)8	(5.4)13	(56.9)136		(34.4)82
Mother’s job	Housewife	White-collar job			Other
	(87.9)210	(2.5)6			(9.6)23
Family income*	Low	Average	Good		High
	(5)12	(25.5)61	(64)153		(5.4)13
Marital status	Single			Married
	(91.6)219			(8.4)20
Students’ job	Employed			Unemployed
	(7.1)17			(92.9)222
*low= insufficient for living; average= below sufficient level; good= sufficient for living; high= well above the sufficient level.

Results And Discussion

A total of 239 female students filled in the questionnaire, of which 228 females (95.3 per cent) was BA students. They averaged 22.17±2.66 (range of 18-44) in age. 219 students were married (91.6 per cent) and 20 students were singles (8.54 per cent). Male parent of 66 students (27.6 per cent) and female parent of 31 students (13 per cent) had university degrees. The female parent of 210 students (87.9 per cent) were housewives and male parent of 136 students (56.9 per cent) had white-collar jobs. Only 5.4 per cent of students gave their parents income level as quite high.

Students received a mean of 945.63±629.19 mg/day calcium through consumption of variety of the above items. There was a significant relationship between calcium intake and perceived susceptibility, severity, and barriers (P<0.05) (Table 2). Students with female parents who had high school diploma, reported highest level of calcium intake, thus showing a significant relationship (P<0.05). we also did not find a significant relationship between calcium intake and perceived susceptibility, students’ employment, marital status, parents’ employment, their education, and students’ income level (P>0.05). The multivariate regression produced perceived barriers as the most single strong determinant of calcium intake (beta= -0.14, P= 0.04). The results are given in Table 3.

Table 2: Correlation between calcium intake and Health Belief Model constructs.
		Pearson’s correlation of coefficient
Variable	Mean & standard deviation	Calcium intake	Perceived susceptibility	Perceived severity	Perceived benefits	Perceived barriers
Daily calcium intake	945.63±629.19	1	-0. 201**	-0.15*	0.04	-0.206**
Perceived susceptibility	15.19±4.45	-0. 201**	1	0.34**	-0.05	0.31**
Perceived severity	18.19±4.45	-0.15*	0.34**	1	-0.06	0.26**
Perceived benefits	13.79±2.72	0.04	-0.05	-0.06	1	0.03
Perceived barriers	13.49±3.96	-0.206**	0.31**	0.26**	0.03	1
*significance in 0.05 level, ** significance in 0.01 level

Table 3: Logistic regression model between the amount of daily calcium intake of students and the independent variables
	Unstandardized coefficients
	B	Std. Error	Beta	T	Sig
Constant	1600.57	314.23	–	5.09	0.000
Perceived susceptibility	-170.95	10.20	-0.12	-1.75	0.08
Perceived severity	-9.44	10.33	-0.06	-0.91	0.36
Perceived benefits	7.82	15.48	0.03	0.5	0.61
Perceived barriers	1600.57	11.16	-0.14	5.09	0.000

Osteoporosis or reduced bone density has hit people in all populations globally (Heidarnia, 2003). The most important method to induce a behaviour change is developing an understanding of people’s behaviour and determinant factors of their behaviour (Anastasia et al., 2014). The present study aims to find these factors. We discuss the findings in following five sections.

University students’ calcium intake

The daily level is 945 mg/day, below the daily recommended level of 1000-1300 mg/day for young and adolescent people. Khadem Haghighian (2012) and Ghaffari et al. (2010) reported 810 and 620 mg/day, respectively, of calcium intake for female and male university students (Ghaffari et al., 2010), which are also below the recommended standard level. Anastasia et al. (2014) reported in their interventional study that pre-intervention level of calcium intake was 650 mg/day, and post-intervention level was improved to 1400 mg/day of calcium intake (Shojaeezadeh, 2011). They designated a descriptor of ‘very unsatisfactory’ for 650 mg/day of intake; an ‘unsatisfactory’ descriptor for 650-1300 mg/day of calcium intake; and a ‘satisfactory’ descriptor for above 1300 mg/day of calcium intake. They found that 36.9 per cent of students were in ‘very unsatisfactory’ level; 40.1 per cent were in ‘unsatisfactory’ level; and only 23 per cent of students were classified as ‘satisfactory.’

Shojaezadeh et al. (2011) noted in their study that only 16 per cent of the females had satisfactory level of calcium intake, with other 78 per cent in unsatisfactory level (Ebadi et al., 2012). Ebadifard Azar et al. (2012) reported that only 14 per cent of females consumed dairy products in acceptable levels (Khorsandi et al., 2013). The most frequently consumed item is common yogurt (with average of 222 mg/day of calcium), and in the second place is low-fat milk with calcium intake of 126 mg/day. The least frequently consumed items are milk-produced tasty fat. Given the low intake of calcium among university female students and other female groups, an understanding of the causes of such low intakes is necessary to prevent osteoporosis. Thus, we recommend that the health authorities consider this issue in their strategies of health promotion and education to improve the level of calcium intake among the young and adolescent population.

Perceived susceptibility

Perceived susceptibility describes the extent to which individuals assess themselves susceptible to a disease and or they think they would suffer the disease (Glanz et al., 2008). The present study found a moderate level of perceived susceptibility among female students about osteoporosis with 15.91 out of 30. Khorsandi et al. (2013) reported a similar level (53.2 out of 100) for perceived susceptibility (Shojaezadeh et al., 2012). However, Ghaffari et al. (2010), Shojaezadeh et al. (2011), and Ellen et al. (2010) reported a score well below the average for perceived susceptibility (Ghaffari et al., 2010; Ellen et al., 2012; Khorsandi et al., 2010). Some other studies reported a satisfactory score for the construct (Khorsandi et al., 2013); different methods of data collection, environment, and different target groups could contribute to diversity and disparity of the scores. We found a negative significant relationship between calcium intake and perceived susceptibility. Given the role of this construct in improving nutritional behaviour, it is recommended that interventions based on health education models (HBM and other models) be made in a group of young and adolescents.

Perceived severity

Perceived severity denotes the extent to which the individuals understand the severity of a disease and whether they think that the disease may bring death, disability and pain for them (Glanz et al., 2008). We reported an above-average level of the construct for female students with 18.19 out of 30, well in line with results found in Ebadifard Azar et al. and Shojaezadeh et al. (Khorsandi et al., 2013; Ellen et al., 2012). Ellen et al. (2012) reported a similar score (17.34 out of 30) for the construct (Khorsandi et al., 2010). We found also a positive and significant relationship between calcium intake and perceived susceptibility and severity. We recommend interventions to improve the scores of perceived susceptibility and severity about the disease.

Perceived benefits

This construct denotes to what extent the individuals evaluates the benefits of a preventive behaviour and they thus seek beneficial behaviour (Glanz et al., 2008). Students in our study received score of 13.79 out of 30 which was not in acceptable levels. Other studies reported scores well above the average (Ghaffarfi et al., 2010; Khorsandi et al., 2010). Differences in scores could be accounted for by the different target groups and research environment. We found no significant relationship between students’ daily calcium intake levels and perceived benefits. We recommend interventions to improve this construct among students.

Perceived barriers

Perceived barriers denotes the negative and potentially harmful aspect of a health behaviour, which could act as barriers in the way of a healthy behavoir (Glanz et al., 2008). Costs, being received and loved, abandoning other behaviours and students’ attitudes to type of foods are examined in finding score of this construct. The present study reported an above average score of 13.49 out of 30, which denoted that students have an average and thus satisfactory understanding of barriers on calcium intake, well in line with other research (Ghaffari et al., 2010, Ebadi Fard et al., 2012; Khorsandi et al., 2010). This study found a negative and significant relationship between perceived barriers and calcium intake. Multivariate regression analysis showed the perceived barriers as the strongest determinant of calcium intake. The study recommends further research to improve perceived barriers.

Demographic variables and calcium intake

There was a significant relationship between parents’ education; students reporting their mothers’ education as high school diploma, received the highest levels of calcium. No further significance was found between other demographic variables and calcium intake. Other studies found similar trend (Ghaffari et al., 2010; Ellen et al., 2012). Given the role of the family, further research is necessary to investigate parents’ education and its role in healthy behaviour.

Conclusion

The present research enjoyed some advantages, mainly, a homogenous group of subjects (female university students), a single theoretical framework, and data collection method. The study found that the level of 945.63 mg/day of calcium intake was not satisfactory. Students are low in their perceived susceptibility and severity of osteoporosis and very low in their perceived benefits; however, they showed an average understanding of barriers of calcium intake. We also found a significant relationship between calcium intake and perceived susceptibility, severity, barriers and female parents’ education, but no significance between other variables was detected. The study suggests perceived barriers as the strongest determinant of calcium intake. Further studies with holistic approach and with inclusion of other variables are recommended to examine calcium intake and WHO’s six strategies of osteoporosis and measurement of bone density.

Acknowledgements

The authors would like to thank all the Department of Health officials and female students in Shahid Beheshti University of Medical Sciences who helped in conducting this research.

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