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SCI: Lipid Abnormalities (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

Thr purpose of this study was to:

1.  investigate changes in the lipid, lipoprotein, and apolipoprotein profiles in persons with SCI during the first 2 years post-injury

2.  Determine whether changes in the risk profiles were associated with sport activity and/or changes in physical capacity parameters.

 

Inclusion Criteria:
  • All patients who were patients of the Rehailitiation Center Amsterdam (The Netherlands)
  • No Cardiovascular disease
  • Participants of a longitudinal study on physical performance during rehabilitation in persons with SCI
Exclusion Criteria:
  • Persons without SCI
  • Persons with cardiovascular disease
Description of Study Protocol:

Recruitment

 26 patients with SCI were investigated during their rehabilitation period (t1) and +/- 1 year after discharge from the rehabilitation center.

Design

 Cross sectional design

Blinding used (if applicable)

 N/A

Intervention (if applicable)

 SCI Rehabilitation

Statistical Analysis

  •  Paired student t tests were applied to detect significant differences between t1 and t2. 
  • Stepwise multiple regression analysis was used to investigate the determinants of the changes to lipid and  (apo)lipoprotein, using as an independent variables:
    • age
    • gender (men =1, women =0)
    • lesion level (paraplegia = 1, tetraplegia=0)
    • completeness of the lesion (complete = 1, incomplete = 0)
    • Changes in BMI and sum of 4 skinfolds
    • family history of CHD (with CHD history = 1, no CHD history =0)
    • smoking behavior at t2
    • alcohol consumption at t2
    • sport activity at t2 (group 1 <1 hr/week, group 2 >/= 1 hr/week and , 3 hr/week, and group 3 >/= 3 hrs/week)
    • percentage change of physical capacity parameters (% change P30, %change PO max, % change VO2 peak), both expressed absolute and relative to body mass
    • lipid and (apo)lipoprotein parameters at t1 were used to investigate whether the initial levels were associated to changes in risk profile parameters.
  • Results were considered significant at P <0.05
Data Collection Summary:

Timing of Measurements

  •  26 patients with SCI were investigated during their rehabilitation period (t1) and +/- 1 year after discharge from the rehabilitation center.
  • Measurements at t1 were performed at different stages during the rehabilitation process.
  • A variable time elapsed between t1 and t2.
  • Mean time since injury (TSI) was 173 +/- 102 days.
  • Mean time between measurements was 587 +/- 139 days
  • Time between discharge from rehabilitation and t2 was +/- 1 year for all subjects.

Dependent Variables

  • Physical capacity
  • lipid and (apo)lipoprotein profiles, including:
    • TC,
    • HDL-C
    • LDL-C,
    • TC/HDL-C
    • LDL-C/HDL-C
    • TG
    • ApoA1
    • ApoB
    • ApoA1/ApoB
    • HDL-C/Apo-A1

Independent Variables

  • gender (men =1, women =0)
  • age
  • lesion level (paraplegia = 1, tetraplegia=0)
  • completeness of the lesion (complete = 1, incomplete = 0)
  • Changes in BMI and sum of 4 skinfolds
  • family history of CHD (with CHD history = 1, no CHD history =0)
  • smoking behavior at t2
  • alcohol consumption at t2
  • sport activity at t2 (group 1 <1 hr/week, group 2 >/= 1 hr/week and , 3 hr/week, and group 3 >/= 3 hrs/week)
  • percentage change of physical capacity parameters (% change P30, %change PO max, % change VO2 peak), both expressed absolute and relative to body mass
  • lipid and (apo)lipoprotein parameters at t1 were used to investigate whether the initial levels were associated to changes in risk profile parameters.

Control Variables

  •  N/A

    • Description of Actual Data Sample:

     

    Initial N:

    • 26 subjects with SCI
    • 9 persons had tetraplegia (2 females)
    • 10 persons had a paraplegia (2 females)

    Attrition (final N):

    • 7 subjects dropped out due to several reasons
      • moved too far away (n=4)
      • illness or pain (n=2)
      • Too busy with work (n=1)

    Age:

    • Mean age at t1 was 40.7 +/- 14.7 years
    • Range 24-68 years

    Other relevant demographics:

    • All subjects were wheelchair dependent
    • All subjects were able to propel a hand rim wheelchair independently
    • Lesion level ranged from C6 - L3/4
    • 4 subjects with tetraplegia and 3 subjects with paraplegia had incomplete lesions
    • Modified ASIA impairment scale: B (n=2), C (n=3) and D (n=2)

    Anthropometrics (e.g., were groups same or different on important measures)

    Location:

    •  Rehabilitation Center Amsterdam (The Netherlands)
    Summary of Results:

    Subject Findings

    •  Smoking behavior and alcohol consumption showed no changes over time.
    • 8 subjects were inactive (physically active less than 1 hr/week), 3 subjects reported activity for at least 1 hr/week but less than 3 hr/week, and 8 subjects reported activity for at least 3 hrs/week.
    • Body mass and BMI increased significantly from 73 +/- 13 kg and 22+/- 4 kg/m2 at t1 to 80+/- 15 kg and 24 +/-4 kg/m2 at t2 respectively.
    • The sum of 4 skinfolds showed no significant change between t1 and t2.

    Physical Activity

    • P30 and POmax increased significantly at t2 both for absolute values and values relative to body mass.
    • For Fiso and VO2 peak no significant changes were found between t1 and t2.

    Changes in lipid and (apo)lipoprotein profiles

    • Significantly lower values were found at t2 for TC, LDL-C, and the ratios TC/HDL-C and LDL-C/HDL-C.
    • HDL-C showed no significant differences between t1 (0.93 +/- 0.20 mmol.l) and t2 (1.02 =/- 0.26 mmol.l) although a tendency for higher values at t2 could be observed (p=0.06)
    • TG values were not significantly different btween t1 and t2.
    • ApoA1 increased significantly from 1.12 +/- 0.14 g.1 at t1 to1.20 +/- 0.21 g.1 at t2
    • ApoB decreased significantly from 1.11 +/- 0.28 g.1 at t1 to 1.05 +/- 0.29 g.1 at t2
    • The ApoA1/ApoB ratio was significantly higher at t2 (1.22 +/- 0.33) than at t1 (1.07 +/- 0.32)
    • The ratio HDL-C/ApoA1 showed no significant differences between the 2 measurements
    • Regression analysis showed that sports activity at t2, changes in physical capacity parameters, and intital values of the risk profile parameters (at t1) were the most important determinants of changes in the lipid and (apo)lipoprotein profiles.
    • These findings imply that subjects who were physically active showed larger improvements of the risk profiles than sedentary or less active subjects.
    • Initial values of LDL-C, TC/HDL-C, and LDL-C/HDL-C were significant determinants of changes in these parameters, showing that subjects with initially less favorable risk profiles showed larger improvements.
    • Age was the only significant determinant of changes in ApoA1 showing on average larger improvements in older subjects.
    • Age was the second important determinant of changes in ApoA1/ApoB
    • HDL-C showed no significant improvement at t2, but the P value of 0.062 was just above the level of significance, indicating that there was at least a tendency for an increase of HDL-C.
    • Sport activity and/or improvements of physical capacity parameters were significantly associated with favorable changes of the lipid and (apo)lipoprotein profiles. 
    • Sports activity and changes in TC showed an inverse relationship where being physically active may result in a decrease of TC.
    • The significant positive relationship between increases in TG and increases in the sum of 4 skinfolds is in agreement with previous cross-sectional observations in persons with long-stnading SCI, and shows the negative effect of an increase of adipose tissue on the CHD risk profiles. 
    • Subjects with initially unhealthy levels are more likely to benefit from physical training than person with better initial lipid and (apo)lipoprotein levels.
    Author Conclusion:
    • Lipid and (apo)lipoprotein profiles improve in persons with SCI during the first 2 years post-injury.
    • Sport activity and improvements of the physical capacity were associated with more favorable lipid and (apo)lipoprotein profiles, showing that improving the physical capacity by being active in sport activities can improve the CHD risk prociles in persons with a recent SCI.
    Funding Source:
    University/Hospital: Rehabilitation Center of Amsterdam
    Reviewer Comments:

    Initial data results are interesting, however, there is a very small sample size, and the longitudnal time frame of one year may not be enough for statistical significance in some variables.  Further, longer term research is recommended.

    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? ???
    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) N/A
      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.) 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? 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.) 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? No
      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? Yes
      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? No
      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.) ???
      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? 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? 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? Yes
      6.8. In diagnostic study, were details of test administration and replication sufficient? ???
    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)? Yes
      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