NSUP: Vitamin B12 (2008)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To examine the relationship between cognitive malfunction and high-dose vitamins on blood vitamin concentrations in healthy non-vitamin deficient elderly.
Inclusion Criteria:
- Good health
- Ability to see, hear, read and write
- Ability to comprehend language and directions
- Diagnosis of therapeutically controlled hypertension, cardiac disease, orthopedic problems and diabetes
- Mini-Mental State Examination (MMSE) score less than 24
- Currently taking a daily multi-vitamin.
Exclusion Criteria:
- Evidence of dementia, schizophrenia, Parkinson's disease, Alzheimer's disease, confusional problems, mental retardation, neurologic, organic or pharmacological mental syndromes
- Initial hypovitaminemia
- Psychotropic drugs
- Occasional intake of barbiturates or tranquilizers or their derivatives was prohibited for at least seven days before undertaking an MMSE to test cognitive function.
Description of Study Protocol:
- Recruitment: New Jersey Center for the Aged
- Design: Randomized controlled trial
- Blinding used: No
- Intervention: Half of the subjects were given a high-dose multi-vitamin supplement with three meals each day for a year. The other half did not receive a high-dose multi-vitamin supplement.
- Statistical analysis: Percentage change.
Data Collection Summary:
Timing of Measurements
Baseline and one year blood vitamin concentrations were obtained including
- Folic acid
- Vitamin B6
- Vitamin B12
- Vitamin C
- Vitamin A
- Vitamin E
- Riboflavin
- Nicotinates
- Pantothenate
- Thiamin
- Biotin.
Dependent Variables
High-dose vitamin supplementation.
Independent Variables
- MMSE
- Folic acid
- Vitamin B6
- Vitamin B12
- Vitamin C
- Vitamin A
- Vitamin E
- Riboflavin
- Nicotinates
- Pantothenate
- Thiamin
- Biotin.
Description of Actual Data Sample:
- Initial N: 20 (10 multi-vitamin, 10 non-multivitamin)
- Attrition (final N): 20 (10 multi-vitamin, 10 non-multivitamin)
- Age: 79 to 90 years old
- Ethnicity: Not described
- Anthropometrics: Not described
- Location: Department of Preventative Medicine and Community Health: New Jersey Medical School, Newark, New Jersey.
Summary of Results:
Non-Vitamin Supplemented Group Over One Year
- Nine experienced a drop in riboflavin
- Eight experienced a drop in vitamin B6
- Seven experienced a drop in folate and vitamin A
- Six experienced a drop in vitamin B12 and pantothenate
- Five experienced a drop in vitamin C
- Three experienced a drop in vitamin E and nicotinates
- No change in MMSE
- No signs of developing organic dementia.
Vitamin Supplemented Group Over One Year
- Hypervitaminosis, as evidenced by percentage change of 0% to 1,549%
- No evidence of vitamin toxicity
- No change in MMSE
- No signs of developing organic dementia.
Author Conclusion:
- Massive hypervitaminosis did not reverse cognitive malfunctions status
- Vitamin B12 blood concentrations increased by 14% to 189% in non-vitamin B12 deficient elderly and increased folate deficiency by 108% to 1,549% in non-folate deficient elderly, yet no cognitive improvement was seen
- Depression of blood vitamins may be unrelated to worsening cognitive malfunction.
Funding Source:
Reviewer Comments:
- Small sample size
- No description of diet
- No description of demographics
- No description of anthropometrics
- No placebo used
- Unclear if control group continued multivitamin supplement as ordered before the start of the study
- No diary used of compliance
- Limited examination of cognitive function.
Quality Criteria Checklist: Primary Research
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Relevance Questions | |||
1. | Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) | Yes | |
2. | Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? | Yes | |
3. | Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? | Yes | |
4. | Is the intervention or procedure feasible? (NA for some epidemiological studies) | Yes | |
Validity Questions | |||
1. | Was the research question clearly stated? | Yes | |
1.1. | Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? | Yes | |
1.2. | Was (were) the outcome(s) [dependent variable(s)] clearly indicated? | Yes | |
1.3. | Were the target population and setting specified? | Yes | |
2. | Was the selection of study subjects/patients free from bias? | ??? | |
2.1. | Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? | Yes | |
2.2. | Were criteria applied equally to all study groups? | Yes | |
2.3. | Were health, demographics, and other characteristics of subjects described? | ??? | |
2.4. | Were the subjects/patients a representative sample of the relevant population? | ??? | |
3. | Were study groups comparable? | No | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | ??? | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | ??? | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | N/A | |
3.4. | If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? | N/A | |
3.5. | If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) | N/A | |
3.6. | If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? | N/A | |
4. | Was method of handling withdrawals described? | Yes | |
4.1. | Were follow-up methods described and the same for all groups? | Yes | |
4.2. | Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) | Yes | |
4.3. | Were all enrolled subjects/patients (in the original sample) accounted for? | Yes | |
4.4. | Were reasons for withdrawals similar across groups? | Yes | |
4.5. | If diagnostic test, was decision to perform reference test not dependent on results of test under study? | N/A | |
5. | Was blinding used to prevent introduction of bias? | ??? | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | ??? | |
5.2. | Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) | ??? | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | N/A | |
5.4. | In case control study, was case definition explicit and case ascertainment not influenced by exposure status? | N/A | |
5.5. | In diagnostic study, were test results blinded to patient history and other test results? | N/A | |
6. | Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? | Yes | |
6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | Yes | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | Yes | |
6.3. | Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? | ??? | |
6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | ??? | |
6.5. | Were co-interventions (e.g., ancillary treatments, other therapies) described? | N/A | |
6.6. | Were extra or unplanned treatments described? | N/A | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | N/A | |
6.8. | In diagnostic study, were details of test administration and replication sufficient? | N/A | |
7. | Were outcomes clearly defined and the measurements valid and reliable? | No | |
7.1. | Were primary and secondary endpoints described and relevant to the question? | Yes | |
7.2. | Were nutrition measures appropriate to question and outcomes of concern? | Yes | |
7.3. | Was the period of follow-up long enough for important outcome(s) to occur? | ??? | |
7.4. | Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? | Yes | |
7.5. | Was the measurement of effect at an appropriate level of precision? | No | |
7.6. | Were other factors accounted for (measured) that could affect outcomes? | Yes | |
7.7. | Were the measurements conducted consistently across groups? | Yes | |
8. | Was the statistical analysis appropriate for the study design and type of outcome indicators? | Yes | |
8.1. | Were statistical analyses adequately described and the results reported appropriately? | Yes | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | Yes | |
8.3. | Were statistics reported with levels of significance and/or confidence intervals? | Yes | |
8.4. | Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? | N/A | |
8.5. | Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? | Yes | |
8.6. | Was clinical significance as well as statistical significance reported? | No | |
8.7. | If negative findings, was a power calculation reported to address type 2 error? | N/A | |
9. | Are conclusions supported by results with biases and limitations taken into consideration? | Yes | |
9.1. | Is there a discussion of findings? | Yes | |
9.2. | Are biases and study limitations identified and discussed? | Yes | |
10. | Is bias due to study's funding or sponsorship unlikely? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |