FNOA: Aging Programs (2012)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:

To determine the prevalence and clinical associations of vitamin B12 and folate deficiency in elderly referred for nutrition assessment by directors of nutrition services programs funded by the Title IIIc through the Adminstration on Aging through the US Department of Health and Human Services.

Inclusion Criteria:

Participants enrolled in nutrition services programs in rural northeast Georgia.

Exclusion Criteria:
  • One person was receiving parenteral vitamin B12 and was excluded
  • One person did not take the supplements and was excluded.
Description of Study Protocol:

Recruitment

  • Potential participants were recruited by the nutrition centers' directors and by the centers' employees, who delivered meals to the homes of the elderly
  • Potential homebound participants received a letter describing the study during one meal round
  • The rest of the participants were not confined to their homes and were assessed at their senior nutrition centers.

Design

Cross-sectional study and before-after study.

Intervention

A sub-group (N=27) was treated with vitamin B12, 2.5mg, and a multivitamin with 400μg folic acid, 2mg vitamin B6 and 27mg ferrous fumarate for four months.

Statistical Analysis

  • Differences in means for continuous variables across two categories were evaluated with a T-test and Levene's test for equality of variances
  • A P value of less than 0.05 was considered significant
  • Paired T-tests were used to compare pre- and post-treatment variables in the treatment group. Differences in categorical variables were tested by use of the chi-square statistic. 
  • Multiple stepwise logistic regression analyses were used to evaluate the independent effects of factors on total homocysteine (tHcy) and methylmalonic acid (MMA) concentrations, anemia, cognition and vitamin B12 deficiency
  • Spearman's correlation were used to test correlations between continuous variables.

 

Data Collection Summary:

Timing of Measurements

Initially there were 65 subjects from whom blood samples were collected between September 1997 and September 1998. Because of the high prevalence of vitamin B12 deficiency discovered in the first group, a treatment phase for a new cohort of 38 subjects was added and blood samples were collected in these subjects between April 1999 and September 1999. For those in the treatment phase, blood samples were collected at baseline and after four months of supplement use.

Dependent Variables

Nonfasting blood samples analyzed for tHcy, MMA, vitamin B12, folate, red blood cells (RBC), cystathionine, methylcitric acid, pepsinogen I, creatinine, ferritin, hemoglobin and mean corpuscular volume (MCV).

Independent Variables

  • Title IIIc nutrition services
  • 24-hour food recall and dietary intake of vitamins
  • A subgroup (N=27) was treated with vitamin B12, 2.5mg, and a multivitiamin with 400μg folic acid, 2mg vitamin B6 and 27mg ferrous fumarate for 4 months. Compliance was assessed with patient interview and pill count. 

Description of Actual Data Sample:
  • Initial N: 103 subjects
  • Attrition (final N): 94
  • Age: Ages 60 to 95 with the average age 76.4
  • Ethnicity: 68% White and 32% African American
  • Other relevant demographics: 80% female, 20% male
  • Anthropometrics: 24 subjects were Vitamin B12 deficient and 79 were Vitamin B12 non-deficient
  • Location: Rural Northeast Georgia.
Summary of Results:

Key Findings 

  • Prevalence of vitamin B12 deficiency:
    • Of the 103 subjects in the combined group, 24 met the criteria for vitamin B12 deficiency with vitamin B12 less than 258pmol per L and MMA more thn 271nmol per L and MMA more than methylcitric acid
    • Vitamin B12 deficiency was not associated with body mass index, depression, ADL (activities of daily living), illnesses or medications
    • Those with deficiencies had 63% higher mean concentrations of serum homocysteine (P<0.001), 26% lower mean RBC folate (P=0.005) and 28% lower mean serum folate (P=0.03)
    • The mean serum pepsinogen was lower in those with the deficiency (P=0.082) and a serum pepsinogen concentration of 60mg per L or more was found in a significantly smaller proportion of vitamin B12-deficient subjects than of vitamin B12-adequate subjects (P=0.02)
    • Those with vitamin B12 deficiencies were more likely to be male (P=0.07), less likely to consume at least one serving of meat, poultry or fish daily (P=0.05), less likely to consume one serving of milk, yogurt or cheese daily (P=0.11) and less likely to consume at least two servings of meat, poultry, fish or dairy daily (P=0.02)
    • Dietary intakes of vitamin B12 were similar in those who were B12 deficient and those who had adequate status, and only about one-half of these elderly met the recommended daily allowance for vitamin B12 regardless of their vitamin B12 status.
    • Among those using multivitamin supplements, those with a vitamin B12 deficiency had higher serum tHcy concentrations (P=0.002) and lower mean RBC folate (P=0.01), tended to have impaired cognition (P=0.062) and were less likely to consume at least two servings of meat, poultry or fish daily (P=0.02) than were those who were not vitamin B12 deficient
    • Vitamin B12 deficiency was frequent in men with 33% and four of the five highest MMA values were found in men even though only 20% of the group was male. The percentage of the men in the sub-groups was not statistically significant (P=0.07), but men had significantly higher serum MMA (P=0.038), tHcy (P=0.015), and serum creatinine (P=0.003) than women
  • Vitamin B12 deficiency and cognition:
    • The vitamin B12 deficient subjects were almost three times as likely to have cognitive impairments as the subjects without B12 deficiency (P<0.001)
    • Both the serum folate and the RBC folate were lower in those who had poor cognition
    • Impaired cognition was more frequent in men than in women (P<0.001)
  • Vitamin B12 deficiency and anemia:
    • Anemia was defined was hemoglobin less than 130g per L in men and less than 120g per L in women. It was very prevalent with 23% of subjects meeting the definition. Severe anemia was defined as less than 85g per L and three subjects had severe anemia
    • The anemic subjects had higher mean serum MMA (P=0.044), tHcy (P=0.002), cystathionine (P=0.001) and methylcitric acid (P=0.007) than did the non-anemic subjects
    • The MCV was significantly lower (P=0.001), the pepsinogen (P=0.02) higher, creatinine higher (P=0.082) and the serum ferritin lower (P=0.098) in the  in the anemic subjects compared to the non-anemic subjects
    • Overall, the anemic subjects had coexisting multiple abnormalities in vitamin B12, iron and renal status
  • Prevalence of folate deficiency:
    • Because of consumption of folate-fortified foods during the period of blood sample collection, folate deficiency as previously defined had disappeared. The mean serum folate in this cohort was 39.3nmol per L, which was between the 85th and 90th percentile for groups age 70 or more years in NHANES III
    • Of the subjects with low serum folate concentrations, four of eight subjects met the criteria for vitamin B12 deficiency. None of these subjects had macrocytosis. One subject used a multivitamin and was vitamin B12 deficient. Cognition was impaired in five of the 12 subjects.
  • Effects of multivitamins on metabolites:
    • The mean serum folate was significantly higher in those taking a multivitamin than in those not taking a multivitamin (P<0.001), as was the RBC folate (P<0.001)
    • Cystathionine was significantly lower in those taking a multivitamin than in those not taking one (P=0.25)
    • Impaired cognition was found in only 17% of those taking a multivitamin, but in only 35.3% of those who were not taking one (P=0.08)
  • Atropic gastritis and vitamin B12 deficiency:
    • Pepsinogen I concentration was low in two subjects and high in 28 subjects. MMA was elevated in 16 of the 28 with evidence for atrophic gastritis by pepsinogen I
    • Those with the highest MMA had the lowest values for pepsinogen I
  • Predictors of abnormal values:
    • Predictors of high tHcy (more than 13.9μmol per L) were vitamin B12 deficiency (P<0.001), low RBC folate (less than 580nmol per L) (P=0.024) and high serum creatinine (127μmol per L or more) (P<0.001)
    • Predictors of of high MMA (more than 271nmol per L) were male (P<0.01), white (P=0.023) and high tHcy (P<0.001) 
    • Predictors of anemia were high tHcy (P<0.01) and high sedimentation rate (30 minutes per hour or more) (P<0.0001)
    • Predictors of poor cognition (nine or more) were male (P=0.004) and vitamin B12 deficient (P<0.01)
    • The major predictors of vitamin B12 deficiency were not eating at least two servings of meat, poultry, fish or dairy foods daily (P<0.02) and low serum pepsinogen of less than 60μg per L (P<0.03)
  • Effects of vitamin treatment in the treatment group:
    • Although the mean serum vitamin B12, serum folate and RBC folate was high in these subjects before vitamin therapy, those measures increased after four months of vitamin therapy. The mean serum tHcy fell 32% and MMA fell 49%.
    • The mean MCV was normal before treatment and increased slightly with treatment and hemoglobin fell in 11 subjects, three whom had renal insufficiency and two who had combined iron and vitamin B12 deficiency
    • Among subjects in the treatment group with elevated serum creatinine, pre-and post-treatment tHcy values were significantly correlated (P=0.02) as were the MMA values (P=0.01). The pre- and post-treatment tHcy values were correlated with serum creatinine (P=0.0001 and 0.01, respectively). The pre-treatment MMA was correlated with serum creatinine (P=0.14).

 

Author Conclusion:
  • The authors did not find a folate deficiency in this at-risk group of elderly enrolled in nutrition services, possibly because of the food folate fortification that was started in the United States in 1998. Vitamin B12 deficiency as defined by elevated MMA in combination with low vitamin B12 concentration was highly prevalent being in 23% of subjects.
  • In comparison to other studies, these subjects had higher than expected tHcy values. It was determined that serum vitamin B12 and the MMA values were major determinants of the tHcy, but serum folate or the intake of vitamins was not. The finding of this study suggest that patients with elevated tHcy should either be investigated for vitamin B12 deficiency or treated empirically with high-dose oral or parenteral vitamin B12 therapy. High dose (2.5mg) oral vitamin B12 therapy combined with a  standard multivitamin supplement containing 400μg folic acid was extremely effective in lowering the mean MMA and tHcy to the normal range in this cohort of elderly.
  • The B12 deficient subjects  in our investigation were almost three times as likely to have impaired cognition as were those who were not deficient. Both MMA and tHcy were associated with poor cognition and values were higher in those with impaired cognition. The data from this study shows that treatment of dementia or affective disorders in subjects with hyperhomocysteinemia should include correction of vitamin B12 and folate status.
  • It was likely in this study that the elderly who have the highest incidence of vitamin B12 deficiency would also have the highest risk of masking anemia because of vitamin B12 deficiency. The authors feel that iron deficiency in the subjects in this study many be multifactorial and may result from poor absorption, poor diet and possibly blood loss. Vitamin B12 deficiency should be investigated in anemic elderly regardless of the MCV value. 
  • A high dose of oral vitamin B12 (2.5mg) with folate and B6 was effective in lowering MMA and tHcy. Atrophic gastritis was present in about 50% of vitamin B12-deficient subject, which implies some degree of malabsorption. This may explain why multivitamin use at screening was not associated with lower tHcy or MMA concentrations in this cohort.
Funding Source:
Government: National Institute on Aging, Northeast Georgia Regional and Development Center, Georgia Department of Human Resources and Georgia Agricultural Experiment Station
Reviewer Comments:

The authors note the following limitations to this study:

  • The cohort was referral-, not population-based, so the most poorly nourished elderly from this area may have been included in this study since they were considered by center directors to be at risk
  • Because of this, it was remarkable that their mean serum and RBC folate concentrations were in the high-normal range
  • The treatment phase was limited by the poor compliance with the protocol on the part of the subjects with vitamin B12 deficiency
  • Blinding was not used in the study.
Quality Criteria Checklist: Primary Research
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? No
  2.2. Were criteria applied equally to all study groups? ???
  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? ???
3. Were study groups comparable? ???
  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.) 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? ???
  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? ???
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  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? No
  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? 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? N/A
  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? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  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? 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? 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? 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