NSA: Serum Proteins (2009)

Citation:
Chen Y, Henson S, Jackson AB, Richards JS. Obesity intervention in persons with spinal cord injury. Spinal Cord. 2006 Feb; 44 (2): 82-91.
PubMed ID: 16103891
 
Study Design:
Non-Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To assess the initial effectiveness of a modified weight management program on various health outcomes in persons with spinal cord injury (SCI).

 

 

Inclusion Criteria:
  • Age 19 years or older
  • Traumatic or non-traumatic SCI for more than one year
  • BMI ≥ 25kg per m2 not currently enrolled in a weight loss program, receiving weight loss medication or taking medication that would influence weight change. 
Exclusion Criteria:
  • Pregnancy
  • Concurrent medical conditions for which changes in exercise or diet would be contraindicated.
Description of Study Protocol:

Recruitment  

16 study subjects were recruited at the community level.

Design  

  • Four cohort groups were established between 2001-2003 
  • A face-to-face interview was conducted at the initial visit to obtain socio-economic status information and weight data, medical history and medicine use
  • Then, data on health outcomes were collected over a six-month period at baseline, week 12 (which was immediately after the 12-week course intervention) and at 24 weeks. 

Blinding Used

The information obtained previously was blind to data collectors at each assessment visit.

Intervention

  • Participants received a 12-week weight management program (one 90-minute class per week) which focused on nutrition, behavioral modification and psychosocial issues
  • The dietary approach was one of time-calorie displacement and the course introduced exercise as a key component at week six and also allowed 30 minutes per session for exercise for weeks six through 12.   

Statistical Analysis

  • Numerous health outcomes were examined
  • Significance of the change in each of these health outcomes between initial and follow-up assessments was determined by a paired t-test or equivalent nonparametric method (Wilcoxon's signed rank sum test)
  • The association of weight changed with participants' characteristics was examined by Pearson's correlation analysis
  • Correlation coefficients greater than 0.40 or less than -0.40 were consider to be an important association regardless of the statistical significance level. 

 

Data Collection Summary:

Timing of Measurements 

All measurements were taken at baseline, and then at 12 weeks (immediately following the completion of the course intervention) and at 24 weeks.

 Dependent Variables

  • Physiologic measurements: 
    • Body weight was measured to the nearest  0.1kg on a scale adapted for use with wheelchairs
    • Height was measured to the nearest 0.1cm in a supine position with legs outstretched and feet in dorsiflexion
    • Waist
    • Neck
    • Skinfold thickness over chest, biceps, triceps, subscapula and suprailiac on the right side of the body according to standardized procedure.
    • Dual energy X-ray absorptiometry (DXA)
    • Blood pressure
    • Serum lipids
    • Blood hemoglobin
    • Blood albumin concentration.
  • Diet behavior:
    • Average frequency of food consumption using health habits and history Questionnaire (NCI)
    • Participants ranked their eating habits using a five-point scale
    • Participants also ranked their confidence of their ability to control weight using a five-point scale.
  • Psychosocial well-being: The General Well-Being Schedule was given at the same intervals as the other measurements.

Independent Variables

A 12-week intervention: One class per week for 90 minutes each addressing principles of good nutrition, goal setting, shopping, cooking, stress management and physical exercise. 

Description of Actual Data Sample:
  • Initial N: 16 (9 males, 7 females)
  • Attrition (final N):  13  (distribution unknown)
  • Mean age: 43.8 years (Range: 21-66 years)
  • Ethnicity: 13 white, 3 African American
  • Other relevant demographics: 
    • Six married or living as married
    • Six divorced
    • Four never married 
    • All high school educated or higher
  • Location: University of Alabama, Birmingham, Alabama.

 

Summary of Results:

 

Variables

Initial Measures: Mean and s.d.

Week 12 CHANGE Mean and s.d.

Statistical Significance of Group Difference

BMI (kg/m2)

34.3

-1.3 (1.2)

0.0005

Total fat mass 41.4(11.2) -2.9 (4.6) 0.05

Total lean mass (LBM)

51.8 (10.2)

-0.8 (5.1)

0.58 (NS Δ)

Bone mineral content 2.31 (0.55) 0.02 (0.16) 0.68 (NS Δ)

Waist circumference (cm)

117.4 (17.0)

-4.1 (5.0)

0.005

Neck circumference (cm) 42.7 (5.7) -0.9 (1.4) 0.02
Skinfold thickness (mm) 111.4 (34.5) -10.7 (9.7) 0.0005
Hemoglobin (g/dL) 13.4 (1.5) 0.08 (0.7) 0.63 (NS Δ)
Albumin (mg/dL) 3.8 (0.4) -0.02 (0.3) 0.73 (NS Δ)

 

Variables

Initial Measures: Mean and s.d.

Week 24 CHANGE (from initial to 24 weeks)    Mean and s.d.

Statistical Significance of Group Difference

BMI (kg/m2)

34.3

-1.1 (1.4)

0.01

Total fat mass 41.4(11.2) -2.2 (1.8) 0.007

Total lean mass

51.8 (10.2)

-0.08 (4.97)

0.96 (NS Δ)

Bone mineral content 2.31 (0.55) 0.02 (0.12) 0.69 (NS Δ)

Waist circumference (cm)

117.4 (17.0)

-3.3 (5.0)

0.04

Neck circumference (cm) 42.7 (5.7) -1.1 (2.1) 0.08
Skinfold thickness (mm) 111.4 (34.5) -13.2 (10.6) 0.0007
Hemoglobin (g/dL) 13.4 (1.5) 0.04 (0.7) 0.83 (NS Δ)
Albumin (mg/dL) 3.8 (0.4) -0.04(0.2) 0.57 (NS Δ)

Other Findings

Baseline factors with correlation coefficients >0.4 or <0.4 included being white, tetraplegic, married or living as married, having greater confidence in weight control, being older age and longer duration post-SCI. None were statistically significant except marital status (P=0.005). 

Author Conclusion:
  • This study demonstrates that a carefully planned program with time-calorie displacement dietary approach is effective for overweight/obese individuals with SCI to lose weight at an acceptable rate without compromising total lean mass and overall health
  • Despite the limitations to the study, the present findings establish a baseline for further large-scale RCT with respect to the dietary and behavioral approaches for weight loss in persons with SCI or other disabling conditions. 
Funding Source:
Government: NIH and National Institute on Disability and Rehabilitation Research
Reviewer Comments:
  • This pilot study has a number of limitations due to the small N size and study design, yet as a pilot study or feasibility study, it has important findings.
    • The limitations are pointed out in the discussion and these include lack of a control group. Therefore, would the changes that were seen be seen in an equal contact support group or attention from professionals
    • This was a selective sample (which was not made clear when describing the study design). The education level of this group was relatively high   
    • The clinic-based program precluded persons from participation who could not travel to the institution once a week for 12 weeks  
    • Finally, there were three dropouts. To the authors' credit, these dropouts are discussed thoroughly in the discussion and the rationale for drop out justified and not seen to be related to the intervention (pressure sores for two of the three participants). Obviously, this would need to be studied again in any future investigation of weight loss programs in SCI tetraplegic or paraplegic subjects.
  • Despite these limitations, important variables were measured and followed both at baseline, 12 weeks and 24 weeks. The findings that BMI and body fat decrease while LBM, hemoglobin and albumin stay the same are valuable pieces of information. 
  • The one error I found was in the conclusion when it is stated that this carefully planned program was effective with individuals with SCI in losing weight at an acceptable rate. It did not adequately distinguish that there was successful weight loss at the 12-week point, but some weight had already been gained back at the 24-week measurement point. This is common in weight loss programs among non-SCI individuals as well, so should not be considered a failure, but simply should be pointed out in a thorough conclusion of the program.  
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? N/A
  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.) N/A
  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? 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? N/A
  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? 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? 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? N/A
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)? 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? N/A
  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? No
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes