| Summary: | Introduction: About 80% of those affected by osteoporosis are postmenopausal women. Therefore, identifying beneficial or harmful dietary factors for postmenopausal osteoporosis may have a significant public health impact.
Objectives: The overall objective of this thesis was to examine the relations between various dietary factors and bone health in postmenopausal women aged ≥ 45 years using different analytical approaches.
Methods: First, the associations between fruit and vegetables (F&V) intake and indicators of bone health were assessed using a systematic review approach. Electronic databases were searched and peer-reviewed observational and interventional studies published in English with F&V intake as a main dietary exposure were included. Data selection, extraction and evaluation of risk of bias were performed independently by two reviewers. Second, the associations between an overall diet quality index (HEI-2005) and its components with bone turnover markers (BTMs) were examined. Third, the relationships between alpha-tocopherol intake, serum alpha- and gamma-tocopherol, two concentration biomarkers of vitamin E intake, and their ratio and BTMs were assessed. For the second and third studies, cross-sectional data from the National Health and Nutrition Examination Survey 1999-2002 were used. Weighted multiple regression models with adjustments for relevant confounders were used to examine the relationship between exposures and serum bone-specific alkaline phosphatase (BAP), a biomarker of bone formation, and urinary N-Telopeptides/Creatinine (uNTx/Cr), a biomarker of bone resorption.
Results: There was significant between-study heterogeneity in design, definition and amount of F&V intake, outcomes, analyses and reporting of results in the eight included studies. Overall, cross-sectional and case-control analyses reported protective associations between F&V intake and bone health, whereas interventional and prospective cohort analyses did not.
There were no associations between total HEI-2005 scores and BTMs. However, the Milk Group component of HEI-2005 had a significant inverse relationship with uNTx/Cr.
Higher serum gamma-tocopherol and lower ratio of serum alpha- to gamma-tocopherol were associated with higher BAP concentrations but had no associations with NTx/Cr concentrations.
Conclusions: The results confirm the existing knowledge that a diet with adequate intake of dairy may reduce bone loss. Further research is needed to examine the potential anabolic effects of gamma-tocopherol on bone in postmenopausal women.
|
|---|
