SCI: Lipid Abnormalities (2007)
To investigate a group of men with SCI with different injury levels [tetraplegics (TP), high paraplegics (HPP), and low paraplegics (LPP)] in comparison with non-disabled controls (C) regarding catecholamines and lipoprotein profiles.
- Male
- Long-term spinal cord injury.
- Female
- No evidence of long-term spinal cord injury.
Design
Cross-sectional analysis.
Statistical Analysis
- Average values and standard deviations were calculated
- The groups were compared by means of the non-parametric Mann-Whitney U-test corrected for multiple testing
- Spearman's correlation coefficient was assessed between catecholamines and lipoproteins in SCI subjects
- Spearman correlation analysis was used instead of Pearson correlation analysis because of the skewed distribution of the data
- P-values less than 0.05 were considered statistically significant.
Timing of Measurements
- Weight and height were measured after blood was drawn
- Venous blood was obtained between 8:00 A.M. and 10:00 A.M. after 12-hour fasting
- Subjects rested quietly in an upright seated position for 10 minutes before the resting sample was drawn
- Stimuli to activate autonomic dysreflexia were eliminated by catheterization and bowel care.
Dependent Variables
- Lipid parameters such as TC and TG were determined by means of enzymatic tests on fresh serum
- Lipoprotein(a) [Lp(a)] concentrations were determined quantitatively by mephelometry
- Free plasma adrenaline and plasma noradrenaline concentrations were determined radio-enzymatically.
Independent Variables
Presence or absence of long-term SCI.
Control Variables
16 age-matched, non-disabled Caucasian men.
- Initial N: 80 men with long-term SCI and 16 age-matched, non-disabled Caucasian men
- Attrition (final N): 80 men with 16 age matched, non-disabled Caucasian men
- Ethnicity: Not specified in experimental group, control group was Caucasian.
Other Relevant Demographics
Injury | N | Age (Years) | Weight (kg) | Height (cm) | Duration of Disability (years) | VO2max |
TP | 30 | 34.0±6.8 | 72.6±12.3 | 180.6±6.2 | 13.3±7.9 | 1.10±0.28 |
HPP | 20 | 33.5±9.9 | 72.2±10.5 | 178.9±6.8 | 9.5±6.3 | 1.90±0.75 |
LPP | 30 | 35.2±9.2 | 72.2±9.7 | 177.1±7.6 | 12.9±7.8 | 2.10±0.67 |
C | 16 | 30.0±4.2 | 74.5±10.7 | 173.8±7.4 | 2.34±0.30 |
Findings
- The tetraplegics showed a significantly lower maximal VO2 than the other groups
- Paraplegics with a lesion below T3 reached a higher maximal VO2 than paraplegics with a higher level of lesion
- No significant difference was found in the maximal VO2 between low paraplegics and controls
- Tetraplegics revealed a characteristical lipid profile, increased concentrations of VLDL-C and triglycerides and reduced concentrations of HDL-C, compared in paraplegic and control subjects
- Increasing VLDL-C levels and decreasing HDL-C values were observed from non-disabled subjects to low and high injury levels such as tetraplegics
- No difference in lipid levels was found among paraplegics with a lesion below T1, therefore the high and low paraplegics were regrouped into one paraplegic group
- Overall, paraplegics had higher TC levels due to higher LDL-C than tetraplegics and controls
- Regarding Lp(a), no significant differences were observed between the groups
- Tetraplegics had significantly lower adrenaline and noradrenaline levels than all other examined groups
- The adrenaline and noradrenaline concentrations of the paraplegics with a lesion below T5 were significantly higher than those of the high lesion paraplegics, as well as those of the control subjects
- Correlation analysis revealed a weak but significant relationship between noradrenaline concentrations and TC (R=0.28, P<0.05) and HDL-C (R=0.25, P<0.05)
- Adrenaline was significantly associated with TC (R=0.42, P<0.01) and LDL-C levels (R=0.38, P<0.01). It was also associated with Lp(a) concentrations (R=0.33, P<0.05).
Lipids | TP | HPP | LPP | C |
TG | 1.91±1.08 | 1.43±0.72 | 1.64±0.03 | 1.04±0.41 |
TC | 4,73±1.03 | 5.24±1.09 | 5.34±1.21 | 4.89±1.03 |
HDL-C | 1.1±0.22 | 1.22±0.31 | 1.22±0.31 | 1.32±0.4 |
LDL-C | 2.87±0.8 | 3.40±1.00 | 3.32±1.48 | 2.78±0.89 |
VLDL-C | 0.77±0.37 | 0.61±17.5 | 25.0±10.7 | 19.9±7.5 |
TC, HDL-C | 4.5±1.4 | 4.6±1.6 | 4.8±2.8 | 3.7±1.8 |
Lp(a) | 12.9±24.6 | 7.1±13.1 | 18.0±27.1 | 6.6±12.1 |
Adrenaline | 0.05±0.02 | 0.09±0.04 | 0.16±0.06 | 0.11±0.08 |
Noradrenaline | 0.24±0.07 | 0.34±0.08 | 0.59±0.27 | 0.36±0.09 |
SCI subjects showed a higher, although different, lipid risk profile for atherogenesis. Low serum catecholamine levels due to interruption of sympathetic outflow, extreme inactivity and low VO2max in comparison to control subjects in low paraplegics, were associated with higher TC and LDL-C. No significant differences in Lp(a) were found in SCI individuals with different injury levels and control subjects. However, a correlation between Lp(a) concentrations in subjects with SCI and the adrenaline concentrations could be demonstrated.
Very little discussion of subject pool in this cross-sectional analysis.
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? | ??? | |
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? | Yes | |
2.3. | Were health, demographics, and other characteristics of subjects described? | No | |
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) | Yes | |
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.) | ??? | |
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? | N/A | |
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? | N/A | |
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? | ??? | |
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? | Yes | |
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? | N/A | |
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? | No | |
6.6. | Were extra or unplanned treatments described? | No | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | ??? | |
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? | N/A | |
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? | N/A | |
7.6. | Were other factors accounted for (measured) that could affect outcomes? | ??? | |
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)? | ??? | |
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? | ??? | |
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 | |