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SCI: Pressure Ulcers (2007)

Citation:

Moussavi RM, Garza HM, Eisele SG, Rodriguez G, Rintala DH. Serum levels of vitamins A, C, and E in persons with chronic spinal cord injury living in the community. Arch Phys Med Rehabil 2003;84:1061-1067.

PubMed ID: 12881835
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine serum levels of vitamins A, C, and E among individuals with spinal cord injury (SCI) living in the community, to compare these levels with general population norms, and to assess their association with demographic and injury-related data (age at onset, time since onset, level and completeness of injury), function, nutritional behaviors, and health status.
Inclusion Criteria:
  • Participants had to be able to understand and respond to questions in either English or Spanish.
  • ≥ 18 years of age and have sustained a traumatic SCI at least 2 years before the study entry.
Exclusion Criteria:
  • Persons who were too cognitively impaired or who were too ill to participate were excluded.
Description of Study Protocol:

Recruitment

The study was a component of the Rehabilitation Research and Training Center in Community Integration for Individuals with Spinal Cord Injury sponsored by the National Institute on Disability and Rehabilitation Research.  Recruitment was conducted by telephone.

Part of the sample consisted of 80 persons with chronic traumatic SCI (57 men, 23 women) who were originally recrutied for an earlier study (1988-1993) of the life status of persons with SCI.  All 23 women and 46 of the men were randomly selected from a sampling frame of 661 adults with traumatic SCI.  4 additional men had been selected for the life status study becasue they had been injured a long time (23-41 years), and another 7 men had been selected because they had been injured over the age of 35 years (range 36-68 years).  An additional 20 persons (17 men, 3 women) who were more recently injured (2-7 years) and 10 persons (5 men and 5 women) from Hispanic backgrounds were recruited from an updated sampling frame (1994-1998).

Design

In this cross-sectional study, persons interested in participating were sent a self-report packet and a consent form to obtain the information. The level and completeness of injury were later determined by a physician according to the information from the self-reported packet.

Research technicians visited the participants residences to conduct the consent form, and to obtain the self-report packet and a blood sample.

Blinding used:  Not applicable

Intervention (if applicable):  Not applicable

Statistical Analysis

Descriptive statistics were obtained on all study variables.  The percentage of participants whose serum level was below minimun of the reference range for each of the 3 vitamins was calculated. Correlations were calculated between age, age at onset of SCI, and time since onset of SCI and each of the serum vitamin levels. To assess whether gender differences existed in serum vitamin levels, t-tests were performed. Analysis of variance were performed to assess the relationship between ethnicity and serum vitamin levels and between level and completeness of injury and serum vitamin levels. For analysis of variance, Bonferroni post hoc pairwise comparisons were performed when indicated. The relationships of the 3 serum vitamins with the FIM motor score, the HPLP nutrition subscale, and the SF-36 general health subscale were assessed with correlational analyses.  The associations between the serum vitamins and having or not having a pressure ulcer that broke the skin in the past 12 months were assessed using t-tests.  To correct for multiple comparisons, a p value of .005 was selected to indicate significance.

Data Collection Summary:

Timing of Measurements

Demographic data were collected by self-report for each participant.

Dependent Variables

  • Serum Vitamin A levels μg/dL
  • Serum Vitamin C levels mg/dL

  • Serum Vitamin E levels μg/dL

Independent Variables

  • Age
  • Age of onset of SCI
  • Time since onset of SCI
  • Gender
  • Ethnicity
  • Level and completeness of injury - (ASIA) total motor index score
  • Functional status measured by FIM motor items
  • Health promoting Nutrition-Related Behaviors measured by the Health-Promoting Lifestyle Profile  (HPLP) nutrition subscale
  • Health status measured by the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) general health subscale
  • Pressure ulcer incidence, at least Stage II in the past 12 months 

Control Variables

 None noted

Description of Actual Data Sample:

Initial N: 110 subjects, 79 males, 31 females

Attrition (final N):  110

Age: Mean 44.1 ± 13.2, range 22.4 - 81.9 years

Ethnicity:

  • Caucasian 63 (57.3%)
  • African American 27 (24.5%)
  • Hispanic American 19 (17.3%)
  • Other 1 (0.9%)

Other relevant demographics:

Age at onset of SCI, mean 29.7 ± 11.8, range 9.7-58.9 years

Time since onset of SCI, mean 14.3 ± 9.6, range 2.3-46.9 years

Level and completeness of injury mesured by the American Spinal Injury Association (ASIA) total motor index

  •   Tetraplegia 46 (41.8%)
  •   Paraplegia  43 (39.1%)
  •   Tetraplegia or paraplegia 21 (19.1%)

Anthropometrics:

Location:

 A 13 county area surrounding Houston and Galveston, TX

Summary of Results:

 Relationship Between Serum Vitamin and Demographic and Injury-Related Data

Variables

Vitamin A

Vitamin C

Vitamin E

 

     Pearson Correlations

Age

 

 .24*

 -.07

 .26

Age at onset of SCI

 .29

 .01

 .30

Time since onset of SCI -.03 -.11 -.01
                      Mean ± SD
Gender      
  Female 61.9 ± 32.2 1.1 ± 0.7 8.3 ± 4.1
  Male 65.2 ± 29.0 0.8 ± 0.6 8.1 ± 4.0
Ethnicity      
  White (Non-Hispanic) 70.2 ± 32.0 0.9 ± 0.6 8.4 ± 4.2
  African American 54.8 ± 22.9 0.8 ± 0.6 6.8 ± 3.3
  Hispanic American 56.4 ± 26.8 0.8 ± 0.6 8.8 ± 4.0
Level and completeness of injury      
  Tetraplegia (ASIA class A,, B, or C) 52.6 ± 22.4 1.0 ± 0.7 7.3 ± 2.8
  Paraplegia (ASIA class A, B, or C) 66.0 ± 32.7 0.8 ± 0.5 8.3 ± 4.3
Tetraplegia or paraplegia (ASIA class D) 86.2 ± 25.3 0.9 ± 0.6 9.5 ± 5.1

 *p < .01

†p < .005

p<.001

Age was significantly related to both vitamins A and E. Persons who were older or older at onset had higher levels of vitamins A and E. No relationship existed between time since onset of SCI, gender, or ethnicity and any of the 3 vitamins. The more severe the impairment, the lower level of serum vitamin A.

Other Findings

FIM motor items - mean 62.7 ± 23.4, range 13-91.  The score on the 13 motor items of the FIM was moderately (r=.38) related to the level of serum vitamin A.  Persons who were more independent had higher levels of serum vitamin A.

HPLP nutrition subscale - mean 2.4 ± 0.6, range 1.2 - 4.0.  The relationship between the HPLP nutrition subscale and serum vitamin A approached significance (r=.26).  Persons reporting better nutritional behaviors tended to have higher serum vitamin A levels.

SF-36 general health subscale - mean 65.5 ± 19.7, range 15-100. The SF-36 general health subscale was weakly (r=.28) related to serum vitamin A. Persons who had better health had higher vitamin A levels.

Pressure ulcer (at least stage II) in the past 12 months: No 80 (72.7%); yes 30 (27.3%). Persons who had not had a pressure ulcer of at least stage II severity in the past year had higher levels of serum A than did those with at least 1 pressure ulcer in the past year(t = 3.79, p<.001).

Author Conclusion:
The findings suggest that vitamin levels may be related to function, general health, and pressure ulcer incidence. Additional studies are needed to determine effective interventions to improve vitamin levels and determine the effect of such improvements on overall health and rehabilitation outcomes.
Funding Source:
Reviewer Comments:
Although the total number of participants was 110, the small subsets of women, minorities and less impaired persons may have affected some of the findings.
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? Yes
  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? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
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) N/A
  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.) No
  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.) 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? N/A
  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? Yes
  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? Yes
  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? 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? 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