VN: Vitamin B-12 (2011)
To determine the relationship between bone mineral density and cobalamin status in Dutch adolescents who followed a macrobiotic diet and in their counterparts.
- Adolescent, aged nine-15 years old
- Recruited from an existing study where they followed a macrobiotic diet until age of six years followed by a lacto-ovo vegetarian or omnivorous diet.
- Caucasian
- Healthy
- No medication-interactions affecting bone or calcium metabolism
- Serum blood samples sufficient for detection of cobalamin status.
None reported
Recruitment
The macrobiotic adolescents, aged nine-15 years old, were recruited from an existing group of macrobiotic families affiliated with the Division of Human Nutrition, Wageningen University.
Blinding used
Not applicable
Design
- Subjects divided in two groups: Macrobiotic Diet vs. Control diet (lacto-ovo vegetarian or omnivorous diet)
- Biochemical Measurements: Non-fasting blood specimens were taken (90% taken from mid May to mid-June 1995, followed by other 10% in the subsequent month)
- Food frequency questionnaire to estimate Calcium intake (mg per day) including questions specific to non-dairy sources of calcium that are present in a macrobiotic diet.
Timing of Measurements
May-June 1995
Dependent Variables
- Bone mineral density, bone mineral content
- MMA
- Homocysteine.
Independent Variables
Dietary pattern
Control Variables
Bone area
- Initial N: 195 adolescents (nine to 15 years)
- Attrition (final N): 170
- 76 previously macrobiotic adolescents
- 94 controls
- Age: Nine to 15 years
- Ethnicity: Caucasian
- Location: Netherlands.
Mean B12 and MMA levels by Group and Sex
- Macrobiotic Boys
- B12 (pmol/L): 212 (103–370)*
- MMA (μmol/L): 0.30 (0.11–0.94)*
- Macrobiotic Girls
- B12 (pmol/L): 286 (115–580)*
- MMA (μmol/L): 0.25 (0.09–0.76)*
- Omnivore Boys
- B12 (pmol/L): 484 (259–813)
- MMA (μmol/L): 0.15 (0.05–0.34)
- Omnivore Girls
- B12 (pmol/L): 458 (219–850)
- MMA (μmol/L): 0.17 (0.07–0.28).
*Significantly different than omnivores
Proportions of Comparison Groups Potentially Deficient
- B12<229 pmol/L
- Macrobiotic: 41%
- Omnivores: 5%
- MMA>0.29 μmol/L
- Macrobiotic: 41%
- Omnivores: 5%.
B12 and MMA Levels by Bone Mineral Parameters
Low Bone Mineral Density (BMD) | Normal Bone Mineral Density (BMD) | Low Bone Mineral Concentration) (BMC) | Bone Mineral Concentration (BMC) | |
All subjects | 60 | 101 | 50 | 111 |
Vitamin B12 (pmol, L) | 344 (24) | 13±1 | P<0.001 | P<0.001 |
MMA (umol,L) | 0.31 (0.26, 0.35) | 19±1 | P<0.001 | P<0.001 |
Only macrobiotic fed adolescents, n | 36 | 20±1 | P<0.001 | P=0.001 |
Vitamin B12 (pmol,L) | 269 (23) | 279 (25) | P<0.001 | P=0.003 |
MMA (umol, l) | 0.40 (0.32, 0.49) | 0.22 (0.13, 0.32) | 0.26 (0.14, 0.39) | P=0.006 |
Magnesium intake was higher in the ovo-lacto vegetarians and low-meat eaters than in the control group.
"The present study shows that serum cobalamin concentrations were significantly lower and MMA concentrations significantly higher in previously macrobiotic-fed adolescents as compared to the controls.
Government: | Dutch Prevention Fund/Netherlands Organization for Health Research and Development | ||
Industry: |
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Not-for-profit |
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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) | N/A | |
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) | N/A | |
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? | No | |
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? | No | |
2.2. | Were criteria applied equally to all study groups? | No | |
2.3. | Were health, demographics, and other characteristics of subjects described? | Yes | |
2.4. | Were the subjects/patients a representative sample of the relevant population? | No | |
3. | Were study groups comparable? | Yes | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | No | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | Yes | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | Yes | |
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? | Yes | |
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.) | Yes | |
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? | No | |
4.1. | Were follow-up methods described and the same for all groups? | No | |
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? | No | |
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? | Yes | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | N/A | |
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.) | Yes | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | Yes | |
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? | No | |
6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | N/A | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | No | |
6.3. | Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? | Yes | |
6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | No | |
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? | Yes | |
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? | Yes | |
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? | Yes | |
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? | Yes | |
7.6. | Were other factors accounted for (measured) that could affect outcomes? | No | |
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)? | No | |
8.6. | Was clinical significance as well as statistical significance reported? | Yes | |
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? | No | |
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 | |