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SCI: Lipid Abnormalities (2007)

Citation:

Bauman WA, Adkins RH, Spungen AM, Kemp BJ, Walters RL. The effect of residual neurological deficit on serum lipoproteins in individuals with chronic spinal cord injury. Spinal Cord. 1998;36(1):13-17.

PubMed ID: 9471131
 
Study Design:
Cohort study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The relationship of the lipid profile to the degree of neurological impairment was addressed in a large cohort of subjects with spinal cord injury (SCI).

Inclusion Criteria:

Spinal cord injury (SCI) subjects seen for a routine physical from May 1994 to May 1996 at Rancho Los Amigos Medical Center, Downey California.

Exclusion Criteria:

Not discussed by author.

Description of Study Protocol:

Recruitment

Subjects were recruited during a routine annual physical examination at the Comarr Spinal Injury Clinic at Rancho Los Amigos Medical Center, Downey, Ca from May 1994 to May 1996.

Design

  • Serum lipid profiles were perfomed during a 24 month period from May 1994 to May 1996 on SCI subjects being seen for routine physical examination. 
  • Subjects were divided into two groups: tetraplegia (Tetra) and paraplegia (Para). 
  • The two groups were further divided into four subgroups of neurological deficit: complete tetraplegia (Com Tetra), incomplete tetraplegia (Incom Tetra), complete paraplegia (Com Para), incomplete paraplegia (Incom Para), as defined by the ASIA standards.

Blinding used (if applicable)

 Not described.

Intervention (if applicable)

 N/A

Statistical Analysis

Results were reported as mean ± standard error of the mean (SEM). Analysis of variance (ANOVA) applying a Scheffe' post hoc F ratio was used for the continuous variables. Chi-squared analyses were performed to determine differences between the groups and among the subgroups for percent distribution.  Multiple regression analysis was used to determine the effect of neurological deficit controlling for ethnicity. Stepwise regression of BMI, HDL, TG, total cholesterol, ethnicity, neurological deficit, DOI, and age were used to predict uric acid.

Data Collection Summary:

Timing of Measurements

Serum lipid profiles were obtained after an overnight fast when SCI subjects wre being seen for their routine physical examination.

Dependent Variables

  • Total cholesterol (TC) mg/dL
  • Triglycerides (TG) mg/dL
  • HDL cholesterol (HDL) mg/dL
  • LDL cholesterol (LDL) mg/dL
  • Serum urinc acid
  • Ratio of total cholesterol/HDL cholesterol  (LDL/HDL)
  • BMI

Independent Variables

  • Tetra
  • Para
  • Com Tetra
  • Incom Tetra
  • Com Para
  • Incom Para

Control Variables

 None noted by author

Description of Actual Data Sample:

 

Initial N: 541 subjects, 468 men and 73 women.

Attrition (final N):

Same

Age:

  • Men: mean of 36.6 years±0.49 (range =18 -73 years). 
  • Women: mean of 41.4 years±1.39 (range =20-72 years).

Ethnicity:

  • For total group 274 (51%) Latino, 135 (25%) non-Latino white, 132 (24%) African American.

Other relevant demographics:

Duration of Injury (DOI):

  • Men: 11.6±0.38 (range=1 to 57 years).
  • Women: mean 15.2±1.31 (range =1 to 44 years)

Anthropometrics

No differences for gender for age or DOI.

Location:

 Comarr Spinal Injury Clinic at Rancho Los Amigos Medical Center, Downey, CA

Summary of Results:

 Lipid Profile by Group and Subgroup

Variables

Tetra

(n=247)

Mean±SEM

Para

(n=294)

Mean±SEM

Com Tetra

(n=156)

Mean±SEM

Incom Tetra

(n=91)

Mean±SEM

Com Para

(n=206)

Mean±SEM

Incom Para

(n=88)

Mean±SEM

TC (mg/dL0)

 184±2.6

 

 198±2.6*  181±3.1  190±4.5  196±2.4  205±5.3

TG (mg/dL)

 122±5.5

 122±5.5

 122±7.3

 121±8.2  119±6.2  129±11.6

HDL (mg/dL)

  39±0.7

  45±0.8*

   38±0.9

  40±1.2    44±0.9    47±1.4
LDL (mg/dL) 121±2.4 129±2.3*  118±2.8  125±4.4  128±2.6  132±4.6

 *P≤0.01 for Tetra vs Para

Other Findings

  • Ethnicity was found to have a significant effect on HDL cholesterol. Subjects in the Latino and non-Latino white groups had significantly lower serum HDL than those in the African American group (40.5±1.09 and 40.8±1.17 vs 47.3±0.70, P<0.0001).
  • The greater the neurological deficit, the lower the mean HDL value. African American group had a lower total to HDL cholesterol ratio than non-Latino whites or Latinos (4.40±0.15 vs 5.17±0.18 and 5.18±0.12, P<0.005).
  •  Uric acid correlated with BMI (r=0.36, P<0.0001), triglycerides (r=0.30, P<0.0001) and HDL (r=-0.22,P<-.0001).
  • BMI correlated to TG (r=0.33, P<0.0001) and HDL (r=-0.32).
Author Conclusion:

The level of mobility has an effect on the serum HDL cholesterol concentration in persons with SCI, even in  the most severely impaired.  African Americans tend to have higher levels of serum HDL cholesterol than non-Latino whites or Latinos.   However, independent of the effects of ethnicity, the level and completeness of the lesion exerts an effect on serum HDL cholesterol values, possibly due to differences in level of activity among the subgroups. Individuals with spinal cord injury have several of the features of the metabolic constellation of Syndrome X and thus are at increased risk for CHD.

Funding Source:
Government: NIDRR
Reviewer Comments:
  • Baseline confounders were not accounted for.
  • Physical activity was not addressed.
  • Diet, alcohol intake and cigarette smoking was not assessed
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? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
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) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  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? ???
  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")? Yes
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  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? Yes
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? 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.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  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? Yes
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? N/A
  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? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  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? ???
  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? 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