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SCI: Lipid Abnormalities (2007)

Citation:

Zlotolow SP, Levy E, Bauman WA. The serum lipoportein in veterans with paraplegia: The relationship to nutritional factors and body mass index. J Am Paraplegia Society. 1992; 15(3): 158-162.

 
Study Design:
Case control, with age-matched controls.
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To determine differences in serum lipids, diet and BMI  between males with paraplegic SCI and age-matched ambulatory controls in a VA Medical Center setting.

Inclusion Criteria:
  • Males between 25 to 65 years of age
  • No known history of CHD, diabetes or hyperlipidemia
  • Patients with SCI: Paraplegic, injured more than or equal to 1.5 years.

 

Exclusion Criteria:

None given.

Description of Study Protocol:

Design

Comparison of BMI, diet (energy, saturated fat and cholesterol based on 24-hour recall) and serum lipid levels (total cholesterol, HDL-c, LDL-c and triglycerides) of paraplegic males with age-matched ambulatory male controls measured at a single point in time.

Statistical Analysis

Pearson moment correlation; unpaired two-tailed Student T-test.

 

Data Collection Summary:

Dependent Variables

  • Calories (24-hour recall with trained interviewers and standardized food models; Nutritionist 3 software)
  • Saturated fat (same as above)
  • Cholesterol (same as above)
  • Total cholesterol (TC) (enzymatic method)
  • HDL-c (enzymatic method)
  • LDL-c (calculated using standard equation): LDL-c = TC - (HDL-c - TG divided by 5)
  • Triglycerides (TG) (enzymatic method)
  • BMI (calculated using standard equation): kg/m2

Independent Variables

Spinal cord injuries.

Control Variables

  • Smoking
  • Anti-hypertensive medications.
Description of Actual Data Sample:

 

  • Initial N: 28 male veterans with paraplegia; 52 aged-matched ambulatory male veterans
  • Age: Mean age of paraplegics, 48; controls, 52
  • Anthropometrics: Mean average BMI for both groups, about 27kg/m2
  • Location: VA Medical Center, Bronx, NY.

 

Summary of Results:

 

Variables

Paraplegia Group

Mean ± SEM

Control Group

Mean ± SEM

Statistical Significance of Group Difference

Energy intake(kcal per kg

 33±3

32±3

NS
Saturated fat intake(gm per kg)

0.43±0.1

0.41±0.1

NS

Cholesterol intake (mg per kg) 4.7±0.7 

4.5±0.4

NS
Total cholesterol (mg per dL) 195±8 209±6 NS
HDL-c (mg per dL) 35±2 49±2 P<0.001
LDL-c (mg per dL) 123±8 134±5 NS
Triglycerides (mg per dL) 153±14 141±11 NS
BMI (kg/m2) 26.9±0.7 27.2±0.7 NS

Other Findings

No significant difference in HDL-c (paraplegic group only) between 13 smokers (34±2 mg per dL) and 15 nonsmokers (37±2 mg per dL).

No significant difference in HDL-c between those taking anti-hypertensives and the normotensive paraplegic group.

Total caloric intake decreases significantly with age in the control subjects (P<0.0005), but not in the subjects with paraplegia.

Inverse correlations are found between serum HDL-c and serum triglyceride levels in both the paraplegic group (R=-0.54, P<0.005) and control group (R=-0.42, P<0.001).

A subset of paraplegics were hyperinsulinemic (data not shown).

Author Conclusion:

Serum HDL-cholesterol is significantly lower in males with paraplegia compared to an age-matched control group; there are no significant differences for the other serum lipids measured, or for energy, dietary saturated fat or cholesterol.

In this group of paraplegic males, serum lipid levels appear to be independent of dietary intake and body weight.

BMI is not reduced in subjects with paraplegia compared to control subjects, suggesting evidence for an increased body fat compartment.

Glucose intolerance, increased adiposity, and depressed HDL-c  place persons with paraplegia at an enhanced risk for the development of CHD.

Funding Source:
Reviewer Comments:

There are several limitations to this study:

  • The study consisted of males only, and ethnicity/race of sample was not specified, limiting generalizability
  • The authors note that use of the 24-hour recall limits generalizability of the food intake results; in addition, there is no indication of whether or not the subjects/controls were hospitalized or in an outpatient clinic when assessed (further limiting 24-hour recall generalizability)
  • There is no indication of lab values being fasting/nonfasting (triglycerides, particularly, reflect food eaten)
  • The accuracy of the Friedwald calculation (for LDL-c) decreases when triglyceride concentrations are more than 200mg per dL, and fail completely when triglycerides exceed 400mg per dL. The figure in the article indicates that a number of paraplegic and control subjects exceeded these cut-offs, and thus the LDL-c information is suspect.
  • There is no description of physical activity, which may affect the lipid values.

The authors acknowledge that this report did not include an estimate of alcohol intake, which may have affected the correlation of caloric intake and serum lipoprotein level. 

Authors recommend a nice list of possible future investigations in individuals with SCI:  

  • Prevalence and severity of carbohydrate intolerance
  • Direct measurements of body composition
  • Attempts to favorably modify body composition by diet and exercise
  • Direct measurement of daily energy expenditure in an effort to precisely determine caloric requirements.

 

 

 

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) 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? ???
  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? 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? ???
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? N/A
  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? N/A
  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? 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? N/A
  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? N/A
  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? ???
  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? 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? 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? Yes
  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? ???
  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? ???
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