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Study Title and Description

Long-term coffee consumption in relation to fracture risk and bone mineral density in women.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on bone and calcium balance outcomes?
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Primary Publication Information
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TitleData
Title Long-term coffee consumption in relation to fracture risk and bone mineral density in women.
Author H Hallström,L Byberg,A Glynn,EW Lemming,A Wolk,K Michaëlsson,
Country
Year 2013
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Bone & Calcium Outcomes
Design Details
Question... Follow Up Answer Follow-up Answer
Refid 23880351
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What outcome is being evaluated in this paper? Bone and Calcium
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What is the objective of the study (as reported by the authors)? The aim of the present study was to extend our first analysis, which was based on a subset of the SwedishMammography Cohort, to determine whether high coffee consumption is associated with risk of fractures.We have now used the whole cohort, a better case-ascertainment method, repeated assessment of coffee intake for better precision, and a longer follow-up period with more fracture and hip fracture cases. In addition, the association between coffee consumption and osteoporosis was investigated in the Swedish Mammography Cohort Clinical (SMCC).
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Study population: Swedish Mammography Cohort (initiated in 1987–1990). A food frequency questionnaire (FFQ) covering diet and lifestyle was enclosed with the original invitation and was completed completed by 66,651 women (74%). A second, expanded questionnaire was sent in 1997 to all those who were still living in the study area. The response rate to the follow-up questionnaire was 70%. In the present fracture study, data for 61,433 participants at baseline and 38,984 at follow-up in 1997 were available for analysis. Additionally, the Swedish Mammography Cohort Clinical (SMCC) is a randomly selected subsample of the Swedish Mammography Cohort sample. These women were invited to respond to a third questionnaire together with a clinical investigation that included dual-emission x-ray absorptiometry measurements (n=5022, 65% participation rate). Dietary assessment: 3 self-administered FFQs. Coffee consumption was assessed in all 3 FFQs. In the baseline FFQ, the participants were asked how often, on average, during the previous 6 months they had consumed coffee, black tea, and other foods and beverages according to 8 predefined categories. In the second and third FFQs, the participants were asked open questions on how many cups of coffee they had been drinking per day or week during the previous year. According to a validation study, the correlation coefficient between coffee consumption in the first FFQ and the mean of four 1-week weighed food records was 0.6. Coffee consumption was categorized as <1, 1, 2– 3, or ≥ 4 cups daily. One cup of coffee is estimated to contain on average 177 mL. We also calculated an approximate continuous variable for coffee by consecutive integers, each corresponding to a 200-mL increase of coffee intake. Outcomes: Clinical fractures of any time (ICD, 10th revision) and hip fractures were identified from the Swedish National Patient Registry and from local hospital registers from the date of cohort entry in 1987– 1990 through December 31, 2008. Individual matching of fractures to the study participants enabled complete fracture identification. Total body, proximal femur, and lumbar spine BMD measured by dual-emission x-ray absorptiometry and osteoporosis were regarded as secondary outcomes in the SMCC subcohort. Serum 25-hydroxyvitamin D levels were measured in samples from 5,000 of the women in SMCC through the use of high-pressure liquid chromatography interfaced by atmospheric pressure chemical ionization and tandem mass spectrometry. Comorbidity and lifestyle information: The Charlson weighted comorbidity index was calculated on the basis of diagnostic codes from the Swedish National Patient Registry, lifestyle information was obtained from the questionnaires. Statistical analyses: Survival analysis was used for the study of associations between coffee consumption and fracture risk. Cox proportional hazards models were used to estimate age- and multivariable-adjusted hazard ratios with 95% confidence intervals. The multivariable model included continuous variables of age, body mass index, height, total energy intake, consumption of alcohol, and dietary intakes of calcium, vitamin D, retinol, protein, phosphorous, and potassium; as well as calcium supplementation (yes or no), vitamin D supplementation(yes or no), tea consumption (number of cups per day), educational level (<9, 9– 12, >12 years, or other), physical activity (5 categories), smoking status (never, former, or current), previous fractures before the study period (yes or no), Charlson comorbidity index (continuous, 1– 16), living condition (living alone or not), cortisone use (yes or no), and hormone replacement therapy (yes or no). Logistic regression was used to assess the associations between coffee consumption and the risk of falls and the risk of osteoporosis in the SMCC. We used a multivariable model (described above) modified by the addition of 2 variables: year of birth (replaced age) and current use of bisphoshphonates. We further calculated adjusted means of BMD for categories of coffee consumption by using a general linear model. In the SMCC, coffee consumption and other dietary variables in the model were based on cumulative averages from the 3 dietary questionnaires. Modifying effects of calcium intake and low total serum 25-hydroxyvitamin D concentrations were also evaluated.
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How many outcome-specific endpoints are evaluated? 4
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Fracture (any type, hip fracture)
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Clinical, physiological, other Clinical
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What is the study design? Cohort
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Randomized or Non-Randomized?
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Registries and hospital records, dual-emission x-ray absorptiometry
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Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? coffe, tea
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Measured or self reported? Self-report
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Multiple analyses: <1, 1, 2– 3, or ≥ 4 cups daily
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) The multivariable model included continuous variables of age, body mass index, height, total energy intake, consumption of alcohol, and dietary intakes of calcium, vitamin D, retinol, protein, phosphorous, and potassium; as well as calcium supplementation (yes or no), vitamin D supplementation(yes or no), tea consumption (number of cups per day), educational level (<9, 9– 12, >12 years, or other), physical activity (5 categories), smoking status (never, former, or current), previous fractures before the study period (yes or no), Charlson comorbidity index (continuous, 1– 16), living condition (living alone or not), cortisone use (yes or no), and hormone replacement therapy (yes or no).
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What were the sources of funding? The Swedish Research Council financed the study.
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What conflicts of interest were reported? Conflict of interest: none declared.
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Results & Comparisons

No Results found.