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Journal of the American College of Nutrition, Vol. 27, No. 1, 88-95 (2008)
Published by the American College of Nutrition

A Prospective Study to Identify Factors Affecting Adherence to Recommended Daily Calcium Intake in Women with Low Bone Mineral Density

Melissa R. French, MSc, Filomena Vernace-Inserra, RD and Gillian A. Hawker, MD, MSc

Osteoporosis Research Program (M.F., G.A.H.)
Multidisciplinary Osteoporosis Program (F.V.-I.)
Women's College Hospital, Institute for Clinical Evaluative Sciences, Department of Medicine and Department of Health Policy, Management and Evaluation, University of Toronto (G.A.H.), Toronto, ONTARIO

Address reprint requests to: Melissa R French, MSc, Osteoporosis Research Program, Women's College Hospital, 76 Grenville Street, Toronto, Ontario M5S 1B2, CANADA. E-mail: melissa.french{at}wchospital.ca


   ABSTRACT
TOP
 FOOTNOTES
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Objective: Factors that influence calcium intake among women with low bone mass have not been clearly identified. The objective of this study was to evaluate confidence, attitudes and beliefs regarding calcium intake and to identify determinants of adherence to calcium recommendations among women with low bone mineral density (BMD).

Methods: Participants were 104 women with low BMD attending an initial visit to an osteoporosis program. Prior to participation in a one-on-one standardized nutrition counseling session with a dietitian, daily calcium intake was assessed using four-day food records and use of calcium supplements was reported. Calcium related knowledge and beliefs were assessed by questionnaire. Barriers and facilitators to obtaining adequate calcium intake were also reported. Six months following baseline, food records and study questionnaire were repeated. Adherence was defined as meeting ≥85% of recommended calcium intake. Logistic regression was used to examine baseline predictors of adherence to calcium recommendations at follow-up.

Results: Mean dietary calcium intake was 952 ± 384 mg/day at follow-up and 91.3% were using calcium supplements. Combining dietary and supplemental calcium, approximately 77% of women were adherent to calcium recommendations at follow-up. Uncertainty regarding calcium food sources and supplements, concerns related to weight gain and the fat content of some calcium-rich foods were the most frequently reported barriers to obtaining adequate calcium intake. The only significant independent predictor of calcium adherence at follow-up was use of a calcium supplement (adjusted OR = 5.970, p = 0.012).

Conclusions: Due to the nutrient synergy of foods, dietary sources of calcium should continue to be promoted in nutritional counseling efforts as the optimal method of obtaining adequate calcium. Nutrition education should emphasize strategies to decrease side effects associated with calcium-rich foods and alleviate concerns regarding the cholesterol and fat content of some calcium-rich foods. In addition to strategies to increase consumption of dietary sources of calcium, supplementation should be considered as an acceptable method of increasing calcium intake among women with low BMD.

Key words: adherence, calcium, dietary recommendations, low bone mineral density, women


   INTRODUCTION
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Adequate calcium nutrition is essential to the attainment and maintenance of peak bone mass and is critical to both the prevention and treatment of osteoporosis [1–3]. Observational studies of both pre- and post-menopausal women suggest that a higher lifetime intake of dietary calcium is associated with greater bone mineral density [4,5], and reduced risk of osteoporosis-related fractures [6,7]. In randomized, controlled trials, calcium supplementation has been found to reduce rates of bone loss [8–10]. Despite this compelling evidence, surveys show that many women fail to meet daily calcium recommendations [11,12].

Research to date suggests that dietary habits are guided by a complex interaction of psychological, cultural, environmental and behavioural factors. Few studies have investigated factors affecting calcium intake among women with low bone mass. To date, most research has been conducted in healthy populations at low risk for osteoporosis [13–16] and may not reflect the experiences of women with low bone mass or osteoporosis.

Identifying factors that influence dietary calcium intake, and understanding the impact these factors may have on a patient's ability to follow dietary recommendations, is key for dietitians and other health care professionals to succeed in influencing dietary behaviour. The objectives of this study were: to evaluate the knowledge, attitudes and beliefs regarding calcium intake in a cohort of women with reduced bone mineral density (BMD); and, to identify the determinants of adherence to daily calcium recommendations six months following a standardized dietitian counseling session.


   MATERIALS AND METHODS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Study Population
We considered for inclusion women who presented consecutively as new patients to a multidisciplinary osteoporosis program between November 2001 and August 2002. Approximately three weeks prior to their first clinical program appointment, patients were mailed a letter explaining the study. Potential participants were then contacted by phone and women who expressed an interest in participating in the study were screened for eligibility. Eligibility criteria included English-speaking, 40 years of age or older and diagnosis of reduced BMD (t score ≤ –1.0) at the hip or spine. (BMD assessments were performed prior to the initial program visit as part of the process of referral to the multidisciplinary osteoporosis program.) Women who had secondary causes of osteoporosis, history of severe intolerance to calcium supplements, diagnosis of hyperparathyroidism, disturbances in calcium metabolism, osteomalacia or kidney disease were excluded. Ethics approval was obtained from the local research ethics review committee. All women provided written informed consent prior to participation.

Questionnaire Development
A questionnaire was designed to evaluate subjects calcium-related behaviours, attitudes and factors perceived to influence adherence to calcium recommendations. In brief, factors perceived to affect adherence to calcium recommendations among post-menopausal women with low BMD were explored using focus group methodology (data previously reported) [17]. Several major themes associated with one's ability to achieve adequate calcium intake were identified and used to generate the study questionnaire. The 25-item questionnaire asked about demographics and lifestyle characteristics (age, education, income, employment status, alcohol and smoking use, fracture history). Behaviours related to optimizing bone health, such as efforts to consume food sources of calcium and limitation of caffeine and alcohol intake, were also assessed. Subjects were asked to indicate whether or not they were confident in their calcium knowledge and their ability to meet calcium recommendations. The questionnaire also asked subjects to identify factors with the potential to affect one's ability to obtain adequate calcium either through diet or supplement use. Factors considered included barriers such as access to calcium sources, cost, side effects from calcium rich foods or supplements and conflict with other health conditions. After revisions for content and comprehensiveness, we pilot-tested our questionnaire to ensure ease of completion and clarity of questions and response options. Additional revisions were then made as appropriate prior to its use (questionnaire available upon request).

Study Protocol
Prior to the baseline visit, participants were asked to record their dietary intake during four consecutive days, including two weekdays and two weekend days. Instructions and recording forms were mailed to participants in advance; questions regarding how to complete a food record were clarified by telephone by the study coordinator. Prior to their appointment with the multidisciplinary osteoporosis program, participants attended the baseline study visit. At this visit, participants completed the study questionnaire and returned their completed food records. Food records were reviewed to clarify food descriptions or portion sizes. Calcium supplement use was assessed at this visit. Daily supplemental calcium intake was calculated by multiplying the calcium content of the supplement (from calcium supplements and/or multivitamins) in milligrams by the number of supplements per day.

Immediately following the baseline study visit, participants attended the multidisciplinary osteoporosis program. This program provides one-on-one counseling by a team of healthcare professionals including a physician, pharmacist, occupational therapist, physical therapist and dietitian. During a 20 minute nutrition counseling session, a registered dietitian discussed the relationship between calcium and osteoporosis and the importance of adequate calcium intake. All participants were provided the calcium requirements for women. Calcium recommendations were based on the current Dietary Reference Intakes for calcium of 1000–1300 mg/day [18] and the current Canadian clinical practice guidelines recommending 1500 mg of calcium per day for adults with low bone density [19]. The dietitian suggested strategies for increasing dietary calcium intake and provided information on the calcium content of both dairy and non-dairy foods. The nutrition session also included a discussion of other factors that affect calcium balance such a caffeine, alcohol and salt intake, and advice about calcium supplement use where appropriate. Some strategies were individualized as needed. For example, an individualized approach was provided for subjects presenting with cholesterol and body weight concerns. Subjects were provided with educational materials including a list of calcium food sources (dairy, non-dairy foods and calcium-fortified foods) and a guide to calcium supplements.

Six months after their initial study visit, participants completed a second 4-day food record and returned to the study office to complete the follow-up study questionnaire. Dietary records were verified and calcium supplement use was also assessed at this visit.

Data Analysis
Food records were entered into Nutribase IV dietary analysis software (CyberSoft, Incorporated, Phoenix, Arizona, 2002) and analyzed for daily calcium and caloric intake. The Nutribase database uses food composition data from the 1997 Canadian Nutrient File and the USDA Nutrient Database for Standard Reference, Release 14. The calcium content of fortified foods not included in the nutrient database was obtained from food labels and adjusted accordingly for reported serving size. Adherence to calcium recommendations was defined as a total calcium intake (diet + supplements) at 6 months follow-up ≥ 85% of the daily calcium intake recommended by the program dietitian.

Descriptive statistics were performed on all data. Changes in behaviours and calcium intake from baseline to 6-month follow-up were assessed using Chi square and Fisher's exact tests for categorical variables, and paired t-tests for continuous variables. Logistic regression was used to identify baseline predictors of adherence (adherent versus non-adherent) to recommended calcium intake at 6-month follow-up. Baseline predictors of adherence that were considered were: patient characteristics (age, BMD, history of fracture and history of hypercholesterolemia) and reported barriers to adherence (confidence in calcium knowledge, body weight and fat concerns, forgetfulness, food preferences, access to calcium sources, cost of food and supplements and side effects from recommended foods or supplements). Significant variables in univariate analyses were entered into the final multivariate model. Model fit was assessed using the Hosmer-Lemeshow Goodness of Fit statistic [20]. Statistical significance was assumed at the two-tailed level of 0.05. All analyses were performed using SPSS Version 11.0.1 (SPSS Inc, 2001, Chicago, IL).


   RESULTS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Participant Characteristics
Three hundred and sixty-eight women presenting at the multidisciplinary osteoporosis program during the recruitment period were approached for participation in this study. Of these, 70 refused, 136 did not meet eligibility criteria and 44 were non-responsive to recruitment efforts. One hundred and eighteen participants who were eligible and willing attended the baseline study visit. Of these, 14 (12%) did not complete the 6-month follow-up (6M) visit (2 sick, 3 unable to contact, 2 moved out of country, 3 refused, 3 incomplete diet records, 1 ineligible). We limited our analyses to the 104 women who attended both the baseline and 6M study visits. Mean age of these 104 women was 60 years, most had completed post-secondary education, and nearly half had an annual household income greater than $60,000. All had been diagnosed with low BMD at either the hip or spine (55.8% had a T score < –2.5 at one or both sites). One in five had a history of at least one prior low trauma fracture. Baseline subject characteristics are presented in Table 1.


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  		Table 1. Baseline Characteristics of Study Participants (n = 104)

 
Osteoporosis Health Beliefs, Behaviours and Confidence
At baseline, more than half of the participants (57.7%) reported that they had known about their low bone mass for greater than one year. Most (92.3%) indicated that it was "very' or "extremely important' to prevent or treat low bone mass compared with their other health concerns. Eighty-nine participants (85.6%) had been trying to include calcium rich foods in their diet. Of these 89, 80% had been trying to include calcium rich foods in their diet for at least one year. Of the subjects that did not currently consume calcium rich foods (n = 13, 12.5%), two thirds (n = 9, 9%) had thought about trying to include these foods in their diet. Most participants (82.7%) reported that they had a daily target for calcium intake. Women using a calcium supplement were more likely to be confident that they were getting enough calcium most days than women who were obtaining their calcium from dietary sources alone (89.4% versus 10.6%, respectively, p = 0.019).

Factors Influencing Calcium Intake
The factors most frequently identified by participants with the potential to affect their calcium intake were uncertainty regarding calcium food sources and supplements, concerns related to weight gain and the perceived high fat content of calcium-rich foods (such as dairy products) (Table 2). Forgetfulness, dietary limitations due to existing medical problems, such as high cholesterol, and side effects from food and supplements, were also common concerns.


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  		Table 2. Factors That Have the Potential to Affect Calcium Intake Identified by Participants at Baseline (n = 104)

 
Baseline to Follow-up Changes
Compared to baseline, a greater proportion of women at 6M were confident that they were getting enough calcium most days and more reported that they were able to consume calcium rich foods on a consistent basis (Table 3). Participants were also more likely to report that they had made dietary changes such as using a multivitamin or vitamin D supplement and decreased consumption of alcohol, caffeinated beverages and salt in an effort to improve their bone health. When asked about timing of supplement use, participants reported using calcium supplements in a more appropriate manner (i.e. taking calcium carbonate with food, not exceeding an intake of 500 mg of supplemental calcium at one time etc.) at the 6M visit compared to baseline.


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  		Table 3. Confidence, Diet and Behaviour Variables at Baseline and 6 Month Follow-Up (n = 104)

 
Adherence to Calcium Recommendations
Ninety-six percent of participants were recommended a calcium intake of 1500 mg/day by the program dietitian. Calcium intakes are reported in Table 4. Only 12.5% of the women at baseline, and 15.4% at follow-up, met our criteria for "adherence' to calcium recommendations based on dietary calcium intake alone. At both visits, nine out of ten women reported that they were currently using a calcium-containing supplement. Including supplemental calcium, the proportion meeting our definition for adherence was greater at 6M compared to baseline (Table 4) (76.9% versus 66.3%, respectively, p = 0.004). Consistent with this, fewer participants had a calcium intake below the Adequate Intake (AI) level of 1200 mg calcium/day for adults [18] at the 6M visit compared to baseline (17.3% versus 33.7%, respectively, p < 0.001). The proportion of subjects exceeding the Tolerable Upper Intake Level (UL) of 2500 mg/day remained unchanged from baseline to 6M visit (4.8% versus 4.8%, respectively).


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  		Table 4. Dietary and Supplemental Calcium Intake (Mg/Day) at Baseline and 6 Month Follow-Up Visits (n = 104)

 
Baseline Predictors of 6-Month Adherence (Table 5)
In univariate logistic regression analyses, adherence to recommended calcium intake at 6M was positively associated with baseline use of a calcium supplement (OR = 7.82, p = 0.003) and negatively associated with high cholesterol concerns and difficulty carrying some calcium rich foods due to the physical weight of products such as milk (OR = 0.35, p = 0.04 and OR = 0.20, p = 0.04, respectively). In multivariate logistic regression analysis, however, the only significant independent predictor of calcium adherence at 6M was use of a calcium supplement (adjusted OR = 5.97, p = 0.012).


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  		Table 5. Correlates of Adherence to Dietary Calcium Recommendation at 6-Months Based on Logistic Regression Analysis (Baseline Variables) (n = 104)

 

   DISCUSSION
 
The objectives of this study were to evaluate confidence, attitudes and beliefs regarding calcium intake and to determine factors influencing adherence to calcium recommendations among women with low BMD. The majority of our participants indicated that although they had a target goal for calcium intake, they were not confident in their ability to obtain adequate calcium. Uncertainty regarding calcium food sources and supplements, concerns related to weight gain and the fat content of calcium-rich foods were the most frequently reported barriers to obtaining adequate calcium intakes. In this study, the use of a calcium supplement was the best predictor of adherence to calcium recommendations.

To our knowledge, this is the first study to examine factors influencing adherence to calcium recommendations in individuals with low bone mass, taking into consideration both dietary intake of calcium rich foods and calcium supplement use. Past studies have focused on exploring factors that influence intake of dairy products only. A study of American women aged 20 years or older reported that 45–67% of variance in behaviours of milk consumption was influenced by intention, attitudes and sensory evaluation of milk [21]. Among older Americans, nutrition knowledge, frequency of milk consumption as an adolescent, perceived milk tolerance and following a diabetic diet increased the likelihood of drinking milk more often [22]. Chapman and colleagues examined factors influencing dairy calcium intake among women and reported results similar to our study. High cholesterol, concern about calories and gastrointestinal upset were the most common complaints [16]. The results of our study identify a similar range of factors influencing dietary calcium intake and provide support for the use of calcium supplementation as a method of improving calcium intake.

Mean intake of calcium from food sources at baseline was 863 mg calcium/day, higher than [16,23,24] or comparable [25–27] to previous studies, where intake has varied from 600–1000 mg/day. For most of our subjects, the ability to reach recommended intakes of calcium was achieved through the combination of diet and calcium supplements. Few subjects (< 16%) met the recommendations through dietary sources alone. Troppmann et al. also reported that the use of a calcium supplement was the best assurance of adequate calcium intake among Canadian women [23]. Given the barriers identified by patients that impact one's ability to meet calcium goals, such as side effects and special dietary concerns, it may not be reasonable to expect individuals with low BMD to achieve their calcium goals through dietary sources alone.

Although it may be less difficult for individuals to meet calcium recommendations through the use of supplements than through food sources, dietary sources of calcium provide other nutrients critical to bone health and optimal nutritional status (eg. vitamin D, magnesium, protein) that cannot be obtained through supplementation alone. Food sources of calcium should be strongly emphasized in nutritional counseling efforts. Some of the misperceptions and concerns related to consumption of calcium-rich foods reported by subjects in this study need to be addressed through patient education. For example, subjects reported that concerns related to lactose intolerance, weight gain and hypercholesterolemia affected their ability to get enough calcium. Providing patients with information on low-fat or non-dairy food sources of calcium may reduce such concerns.

Our study supports previous observations that participation in an osteoporosis education session can have a positive influence on bone-related health choices, including calcium intake [28–32]. Following attendance in an osteoporosis program, we observed an increase in dietary calcium intake and improved confidence regarding the ability to get enough calcium through diet and/or supplements. An increase in milk consumption [28, 33], dietary calcium intake [34] and calcium supplement use [28,29,35] has been observed following the provision of educational materials and/or results from BMD testing. Marci and colleagues also reported that women with a diagnosis of low BMD were more likely to start calcium supplements, increase dietary calcium, and decrease caffeine intake than women with normal BMD results [31]. Rolnick et al. also reported that participation in an osteoporosis education class increased the likelihood that participants modified their lifestyle and dietary habits [30]. Finally, Blalock et al. reported an increase in dietary calcium intake among American women participating in an osteoporosis prevention program who had inadequate calcium intake at baseline [32]. It should be noted, however, that our study was not designed to evaluate the effectiveness of the educational intervention. As such, the multidisciplinary program intervention was not administered in a randomized controlled manner. Thus, we cannot rule out the possibility that the observed changes were the result of other factors unrelated to the program visit.

Based on our clinical observations, we had not anticipated that the level of calcium adherence among our study participants would be as high as observed; close to 80% of participants met our definition for adherence at follow-up. This significantly reduced our statistical power to examine independent predictors of adherence in our multivariable model. Most women in the current study had known about their diagnosis of low bone mass prior to baseline and thus had already initiated self-management strategies or been under the care of a physician for this condition. Although not assessed in this study, it is possible that a family history of osteoporosis may have increased the likelihood of participants to comply with recommendations. It has been noted that when a health threat is likely to occur in the near future, intentions to improve health behaviour are strengthened [36]. Women in this study may have been more likely to be adherent to calcium recommendations because they believed that an osteoporosis-related consequence, such as fracture, was imminent.

Participants were selected from patients attending an osteoporosis-specific treatment program in a tertiary care teaching hospital and most were of high socioeconomic status, reflective of the patient population of the treatment program. Higher socioeconomic status is known to be associated with healthier lifestyle choices [37]. As a result, our participants may have been more health conscious, more health motivated and have greater personal resources to comply with recommendations. Thus, our results may not be generalizable to women with less education or income, or to other settings.


   CONCLUSION
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 CONCLUSION
ACKNOWLEDGMENTS
 REFERENCES
 
The factors influencing calcium intake reported by participants in this study can be used by health professionals, particularly dietitians, when counseling patients with low BMD about calcium intake. Consideration of individual patient factors has the potential to enhance dietary counseling approaches and in turn, improve calcium intake. Efforts should be made to improve patient confidence in knowledge of calcium-rich food sources and supplementation. Due to the nutrient synergy of food, dietary sources of calcium should continue to be promoted in nutritional counseling efforts as the optimal method of obtaining adequate calcium. Nutrition education should emphasize strategies to decrease side effects associated with calcium-rich foods and alleviate concerns regarding the cholesterol and fat content of some calcium-rich foods. As demonstrated in this study, the consumption of dietary foods combined with the use of a calcium supplement may be the most effective method of ensuring adherence to recommended levels of calcium intake when calcium recommendations are high. In addition to strategies to increase consumption of dietary sources of calcium, supplementation should be considered as an acceptable method of increasing calcium intake for individuals with low BMD who are having difficulties meeting recommendations through dietary sources alone.


   ACKNOWLEDGMENTS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
REFERENCES
 
This study was supported by the Dairy Farmers of Canada. Dr. Hawker received support through a Canadian Institutes of Health Research Scientist Award and currently as the F.M. Hill Chair in Academic Women's Medicine at the University of Toronto. We would like to thank Bridget King and Katherine Vandenbussche for their assistance with the dietary analysis for this project.


   FOOTNOTES
TOP
 FOOTNOTES
ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Financial disclosure: Research grant support provided by the Dairy Farmers of Canada. Dr. Hawker received support through a Canadian Institutes of Health Research Scientist Award and currently as the F.M. Hill Chair in Academic Women's Medicine at the University of Toronto.

F.V.-I. is currently with Inner Health Nutrition Consulting, Woodbridge, Ontario.

Received April 16, 2006. Accepted February 13, 2007.


   REFERENCES
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 

  1. NIH Consensus Statement: "Osteoporosis Prevention, Diagnosis, and Therapy." March 27–29;17 :1 –36,2000 .
  2. Nordin BEC: Calcium and osteoporosis.Nutrition13 :664 –686,1997 .[Medline]
  3. NIH Consensus Development Panel on Optimal Calcium Intake: Optimal calcium intake.JAMA272 :1942 –1948,1994 .[Abstract/Free Full Text]
  4. Cumming RG: Calcium intake and bone mass: a quantitative review of the evidence.Calci Tiss In47 :194 –201,1990 .
  5. Welten DC, Kemper HC, Post GB, van Staveren WA: A meta-analysis of the effect of calcium intake on bone mass in young and middle aged females and males.J Nutr125 :2802 –2013,1995 .[Abstract/Free Full Text]
  6. Cumming RG, Nevitt MC: Calcium for prevention of osteoporotic fractures in postmenopausal women.J Bone Miner Res12 :1321 –1329,1997 .[Medline]
  7. Matkovic V, Kostial K, Simonovic I, Buzina R, Brodarec A, Nordin BE: Bone status and fracture rates in two regions of Yugoslavia.Am J Clin Nutr32 :540 –549,1979 .[Abstract/Free Full Text]
  8. Dawson-Hughes B: Calcium supplementation and bone loss: a review of controlled clinical trials.Am J Clin Nutr54 (Suppl):274S –280S,1991 .[Medline]
  9. Dawson-Hughes B, Dallal GE, Krall EA, Sadowski L, Sahyoun N, Tannenbaum S: A controlled trial of the effect of calcium supplementation on bone density in postmenopausal women.N Engl J Med323 :878 –883,1990 .[Abstract]
  10. Baran D, Sorenson A, Grimes J, Lew R, Karellas A, Johnson B, Roche J: Dietary modification with dairy products for preventing vertebral bone loss in premenopausal women: a three-year prospective study.J Clin Endocrinol Metab70 :264 –270,1990 .[Abstract/Free Full Text]
  11. Starkey LJ, Johnson-Down L, Gray-Donald K: Food habits of Canadians: comparison of intakes in adults and adolescents to Canada's food guide to healthy eating.Can J Diet Prac Res62 :61 –69,2001 .
  12. Gray-Donald K, Jacobs-Starkey L, Johnson-Down L: Food habits of Canadians: Reduction in fat intake over a generation.Can J Public Health91 :381 –385,2000 .[Medline]
  13. Cashel KM, Crawford D, Deakin V: Milk choices by women: what influences them, and does it impact on calcium intake?Public Health Nutr3 :403 –410,2000 .[Medline]
  14. Gulliver P, Horwath C: Women's readiness to follow milk product consumption recommendations: design and evaluation of a ‘stage of change' algorithm.J Hum Nutr Dietet14 :277 –286,2001 .[Medline]
  15. Klesges RC, Harmon-Clayton K, Ward KD, Kaufman EM, Haddock K, Talcott GW, Lando HA: Predictors of milk consumption in a population of 17- to 35-year old military personnel.J Am Diet Assoc99 :821 –826,1999 .[Medline]
  16. Chapman KM, Chan MW, Clark CD: Factors influencing dairy calcium intake in women.J Am Coll Nutr14 :336 –340,1995 .[Abstract]
  17. French MR, Vernace Inserra F, Moore K, Hawker GA: Exploring factors influencing adherence to calcium recommendations in a group of postmenopausal women with reduced bone mineral density.Can J Diet Pract Res66 :25 –29,2005 .[Medline]
  18. National Academy of Sciences: "Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride." Washington DC: Institute of Medicine,1997 .
  19. Scientific Advisory Council of the Osteoporosis Society of Canada: 2002 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada.Can Med Assoc J167 (Suppl):S1 –S34,2002 .[Medline]
  20. Hosmer DW, Lemeshow S (eds): "Applied Logistic Regression." New York: John Wiley and Sons, p 140,1989 .
  21. Brewer JL, Blake AH, Rankin SA, Douglass LW: Theory of Reasoned Action predicts milk consumption in women.J Am Diet Assoc99 :39 –44,1999 .[Medline]
  22. Elbon SM, Johnson MA, Fischer JG: Milk consumption in older Americans.Am J Public Health88 :1221 –1224,1998 .[Abstract/Free Full Text]
  23. Troppmann L, Gray-Donald K, Johns T: Supplement use: is there any nutritional benefit?J Am Diet Assoc102 :818 –825,2002 .[Medline]
  24. Bell RA, Quandt SA, Spangler JG, Case LD: Dietary calcium intake and supplement use among older African American, white and Native American women in a rural southeastern community.J Am Diet Assoc102 :844 –847,2002 .[Medline]
  25. Smith BA, Morgan SL, Vaughn WH, Fox L, Canfield GJ, Bartolucci AA: Comparison of a computer-based food frequency questionnaire for calcium intake with 2 other assessment tools.J Am Diet Assoc99 :1579 –1581,1999 .[Medline]
  26. Terrio K, Auld GW: Osteoporosis knowledge, calcium intake and weight-bearing physical activity in three age groups of women.J Community Health27 :307 –320,2002 .[Medline]
  27. McPherson RS, Feaganes JR, Siegler IC: Measurement of dietary intake in the UNC Alumni Heart Study.Prev Med31 :56 –67,2000 .[Medline]
  28. Jamal SA, Ridout R, Chase C, Fielding L, Rubin LA, Hawker GA: Bone mineral density testing and osteoporosis education improve lifestyle behaviours in premenopausal women.J Bone Miner Res14 :2143 –2149,1999 .[Medline]
  29. Summers KM, Brock TP: Impact of pharmacist-led community bone mineral density screenings.Ann Pharmacother39 :243 –248,2005 .[Abstract/Free Full Text]
  30. Rolnick SJ Kopher R, Jackson J, Fischer LR, Compo R: What is the impact of osteoporosis education and bone mineral density testing for postmenopausal women in a managed care setting?Menopause8 :141 –148,2000 .
  31. Marci CD, Viechnicki MB, Greenspan SL: Bone mineral densitometry substantially influences health-related behaviours of post-menopausal women.Calcif Tissue Int66 :113 –118,2000 .[Medline]
  32. Blalock SJ, DeVellis BM, Patterson CC, Campbell MK, Orenstein DR, Dooley MA: Effects of an osteoporosis prevention program incorporating tailored educational materials.Am J Health Promot16 :146 –156,2002 .[Medline]
  33. Chan MF, Ko CY, Day MC: The effectiveness of an osteoporosis prevention education programme for women in Hong Kong: a randomized controlled trial.J Clin Nurs14 :1112 –1123,2005 .[Medline]
  34. Tussing L, Chapman-Novakofski K: Osteoporosis prevention education; Behaviour theories and calcium intake.J Am Diet Assoc105 :92 –97,2005 .[Medline]
  35. Winzenburg T, Oldenburg B, Frendin S, De Wit L, Tiley M, Jones G: The effect of behaviour and bone mineral density of individualized bone mineral density feedback and educational interventions in premenopaual women: a randomized controlled trial [NCT00273260].BMC Public Health6 :12 –23,2006 .[Medline]
  36. Smith Klohn LS, Rogers RW. Dimensions of the severity of a health threat: the persuasive effects of visibility, time of onset, and rate of onset on young women's intentions to prevent osteoporosis.Health Psychol10 :323 –329,1991 .[Medline]
  37. Symons KS, Popkin BM: Contrasting socioeconomic profiles related to healthier lifestyles in China and the United States.Am J Epidemiol159 :184 –191,2004 .[Abstract/Free Full Text]




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