Advanced Search

Study Preview



Study Title and Description

Determinants of plasma total homocysteine concentration in the Framingham Offspring cohort.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
  • Comments Comments (
    0
    ) |

Primary Publication Information
  • Comments Comments (
    0
    ) |
TitleData
Title Determinants of plasma total homocysteine concentration in the Framingham Offspring cohort.
Author PF Jacques,AG Bostom,PW Wilson,S Rich,IH Rosenberg,J Selhub,
Country
Year 2001
Numbers

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


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
  • Comments Comments (
    0
    ) |
What is the objective of the study (as reported by the authors)? We used data on nutrition, health, and lifestyle from the fifth examination cycle of the Framingham Offspring cohort to examine known and suspected determinants of fasting plasma tHcy concentrations.
  • Comments Comments (
    0
    ) |
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 Subjects The offspring of the original Framingham Heart Study cohort and their spouses were invited to participate in the first Framingham Offspring Study, and 5135 of the 6838 eligible individuals participated examination. The fifth examination of the offspring cohort began in January 1991 and was completed in December 1994. Measurements Fasting (> 10 h) blood samples were obtained for determination of homocysteine (tHcy), folate, vitamin B-12, and pyridoxal-5_-phosphate (PLP; the active circulating form of vitamin B-6). Plasma tHcy was measured by HPLC with fluorometric detection. Usual dietary intakes of folate, vitamin B-12, vitamin B-6, and riboflavin were assessed with a validated food-frequency questionnaire. The food-frequency questionnaire also identifies nutrient intake from dietary supplements and from fortified, ready-to-eat breakfast cereals. Of the 3799 individuals who attended the fifth examination cycle of the Framingham Offspring Study, 1960 had valid food frequency questionnaires; complete data on tHcy, vitamin, and creatinine concentrations; were free of diagnosed cardiovascular disease; and were not taking medications that might alter tHcy concentrations. These 920 men and 1040 women comprised the sample for our analyses. Statistical Analyses Because plasma tHcy concentration was positively skewed, analyses were done by using natural logarithmic transformations. Inverse transformations were performed to provide geometric means and their 95% CIs. We determined the age- and sex-adjusted and multivariate-adjusted geometric mean tHcy concentrations and 95% CIs within categories of its known and suspected determinants using SAS PROC GLM. To estimate mean tHcy concentration across levels of established and suspected tHcy determinants, continuous variables were divided into categories for analysis. Categories for most variables were based on quintile cutoff points. The exceptions were age, number of cigarette smoked per day, alcohol intake, and beverage consumption. Analyses of the relations between tHcy and blood pressure excluded individuals who reported use of blood pressure–lowering medications. Tests for trend, which were performed for the continuous variables, were based on the significance of the linear regression coefficient relating the variable in its continuous form to the logarithm of plasma tHcy. The continuous variables were transformed as needed so that they were linearly related to the logarithm of tHcy. Final multivariate models, one based on the plasma vitamin information and one based on the dietary information, were determined by using a backward selection procedure for all factors that were significantly associated with tHcy concentrations after the previously described multivariate adjustment procedure. The continuous variables were entered into these models with use of the appropriate transformations as described previously.
  • Comments Comments (
    0
    ) |
How many outcome-specific endpoints are evaluated? 1
  • Comments Comments (
    0
    ) |
What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Fasting plasma total homocysteine (tHcy) concentrations
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately). 2
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).3
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).4
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).5
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).6
  • Comments Comments (
    0
    ) |
Clinical, physiological, other Physiological
  • Comments Comments (
    0
    ) |
What is the study design? Cohort
  • Comments Comments (
    0
    ) |
Randomized or Non-Randomized?
  • Comments Comments (
    0
    ) |
What were the diagnostics or methods used to measure the outcome? Objective
  • Comments Comments (
    0
    ) |
Optional: Name of Method or short description Plasma tHcy was measured by HPLC with fluorometric detection.
  • Comments Comments (
    0
    ) |
Caffeine (general) Caffeine (general)
  • Comments Comments (
    0
    ) |
Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? Coffee, soda, tea
  • Comments Comments (
    0
    ) |
Measured or self reported? Self-report
  • Comments Comments (
    0
    ) |
Children, adolescents, adults, or pregnant included? Adults
  • Comments Comments (
    0
    ) |
What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Estimates of caffeine were divided into quintiles: <88 mg/d, 89-132 mg/d, 183-355 mg/d, 356-419 mg/d, and >/= 420 mg/d
  • Comments Comments (
    0
    ) |
What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) Dietary folate intake, dietary vitamin B12 intake, dietary vitamin B-6 intake, dietary riboflavin intake, regular use of vitamin B-12 supplements, protein intake, methionine intake, alcohol intake
  • Comments Comments (
    0
    ) |
What conflicts of interest were reported? Any opinions, findings, conclusions, or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of the US Department of Agriculture.
  • Comments Comments (
    0
    ) |
Refid 11237940
  • Comments Comments (
    0
    ) |
What were the sources of funding? Supported in part by the US Department of Agriculture (agreement 58-1950-9-001) and the National Institutes of Health/National Heart, Lung, and Blood Institute’s Framingham Heart Study (contract N01-HC-38038).
  • Comments Comments (
    0
    ) |




Results & Comparisons

No Results found.