Calcium and vitamin D intake in a Canadian population : results from the Canadian Multicentre Osteoporosis Study

Objectives. To estimate calcium and vitamin D intakes in Canadian men and women, to compare these intakes to Canadian guidelines, and to determine factors associated with intake of these nutrients.Methods. We estimated intakes of calcium and vitamin D from both diet and supplements using cross-sectional data from 9,423 randomly selected subjects 25 years of age and older who completed an interviewer administered abbreviated food frequency questionnaire. The participants were recruited from July 1995 to September 1997 in nine centres across Canada. We characterized the relationships of calcium and vitamin D with socio-demographic and lifestyle variables, physical characteristics, medical diagnosis and use of osteoporosis related medications.Results. The median daily intake for calcium was estimated to be 930 (interquartile range (IQR) = 589;1360) mg for women, and 774 (IQR = 507;1155) mg for men; for vitamin D, intakes were 3.6 (IQR = 1.1;10.0) pg and 2.7 (IQR = 0.9;7.5) pg for women and men, respectively. Age and study centre were found to be associated with calcium and vitamin D intakes in both genders. Other variables associated with calcium intake included vitamin D intake, weekly energy expenditure and femoral neck bone mineral density. Factors found to be associated with vitamin D intake in both genders included calcium intake, height and caffeine intake.Conclusions. The only group that on average met adequate daily intake levels for calcium was women aged 51-70. For vitamin D, on average, women and men under age 51 met adequate intake levels. Further education programs may be required to encourage increased consumption of these nutrients

Dietary patterns in Canadian men and women ages 25 and older: relationship to demographics, body mass index, and bone mineral density

Background: Previous research has shown that underlying dietary patterns are related to the risk of many different adverse health outcomes, but the relationship of these underlying patterns to skeletal fragility is not well understood. The objective of the study was to determine whether dietary patterns in men (ages 25-49, 50+) and women (pre-menopause, post-menopause) are related to femoral neck bone mineral density (BMD) independently of other lifestyle variables, and whether this relationship is mediated by body mass index. Methods: We performed an analysis of 1928 men and 4611 women participants in the Canadian Multicentre Osteoporosis Study, a randomly selected population-based longitudinal cohort. We determined dietary patterns based on the self-administered food frequency questionnaires in year 2 of the study (1997-99). Our primary outcome was BMD as measured by dual x-ray absorptiometry in year 5 of the study (2000-02). Results: We identified two underlying dietary patterns using factor analysis and then derived factor scores. The first factor (nutrient dense) was most strongly associated with intake of fruits, vegetables, and whole grains. The second factor (energy dense) was most strongly associated with intake of soft drinks, potato chips and French fries, certain meats (hamburger, hot dog, lunch meat, bacon, and sausage), and certain desserts (doughnuts, chocolate, ice cream). The energy dense factor was associated with higher body mass index independent of other demographic and lifestyle factors, and body mass index was a strong independent predictor of BMD. Surprisingly, we did not find a similar positive association between diet and BMD. In fact, when adjusted for body mass index, each standard deviation increase in the energy dense score was associated with a BMD decrease of 0.009 (95% CI: 0.002, 0.016) g/cm2 for men 50+ years old and 0.004 (95% CI: 0.000, 0.008) g/cm2 for postmenopausal women. In contrast, for men 25-49 years old, each standard deviation increase in the nutrient dense score, adjusted for body mass index, was associated with a BMD increase of 0.012 (95% CI: 0.002, 0.022) g/cm2. Conclusions: In summary, we found no consistent relationship between diet and BMD despite finding a positive association between a diet high in energy dense foods and higher body mass index and a strong correlation between body mass index and BMD. Our data suggest that some factor related to the energy dense dietary pattern may partially offset the advantages of higher body mass index with regard to bone health.Land and Food Systems, Faculty ofMedicine, Department ofMedicine, Faculty ofNon UBCReviewedFacult

Changes in body mass index in Canadians over a five-year period: Results of a prospective, population-based study

Background: The initiation of the Canadian Multicentre Osteoporosis Study in 1996, and subsequent follow-up of the cohort 5 years later, provided longitudinal body mass index (BMI) data for a random sample of Canadians. Methods: Height and weight were measured at baseline and 5 years and used to calculate BMI and assign one of six weight categories. Multiple imputation was used to adjust for missing weight at year 5. Data were stratified by age and gender. The proportion of participants moving between categories was generated, and multivariable linear regression was used to identify factors associated with weight change. Results: Baseline data were available for 8548 participants, year 5 data for 6721, and year 5 weight was imputed for 1827 (17.6%). Mean BMI for every age and gender group exceeded healthy weight guidelines. Most remained within their BMI classification over 5 years, but when change occurred, BMI category was more likely to increase than decrease. Several sociodemographic, lifestyle and clinical characteristics were associated with change. Conclusion: Mean baseline BMI tended to be higher than recommended. Moreover, on average, men under age 45 and women under age 55 were gaining approximately 0.45 kilograms (one pound) per year, which leveled off with increased age and reversed in the oldest age groups. These findings underscore the need for public health efforts aimed at combating obesity.Endocrinology, Division ofLand and Food Systems, Faculty ofMedicine, Department ofMedicine, Faculty ofNon UBCReviewedFacult