EAL

NSA: Serum Proteins (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To compare clinical and subclinical aspects of nutritional status of obese and patients with anorexia nervosa with immunological function and coronary risk factors.

Inclusion Criteria:

Persons who were obese (O) diagnosed at a Buenos Aires hospital
Persons who suffered from restrictive anorexia nervosa (AN) in an acute stage under intra-hospital treatment at a hospital in Madrid
Persons in a control group (C) that were free of either psychiatric or somatic disease
12 to 17 years old
Middle class economic and cultural status
Informed consent.

Exclusion Criteria:

Not mentioned.

Description of Study Protocol:

Design

Cross-sectional with three groups.

Blinding Used

Objective measurements: Anthropometrics, biological and immunological tests.

Statistical Analysis

Comparisons among the three groups are done by Student's T-test (two-tailed), using either pooled variance (for equal variance estimates) or separated variance (for unequal variance estimates)
Associations between two continuous variables were done with Spearman rank correlation coefficients
Significance set at P<0.05.

Data Collection Summary:

Timing of Measurements

This is a cross-sectional study with one point of analysis. Biochemical and immunological measurements were taken after 12 to 15 hours of fasting and following 30 minutes of resting. Anthropometric measurement timing is not discussed.

Dependent Variables

Anthropometrics
- Age
- Height
- Weight
- Ideal body weight (IBW) determined by Metropolitan Life Standard Tables and BMI (Quetelet Index)
- Percent IBW
Biochemical and Immunological: Taken after 12 to 15 hours of fasting and following 30 minutes of resting
- Serum albumin (determined by single radial immunodiffusion)
- Serum immunoglobulin A (determined by single radial immunodiffusion)
- C3 complement factor rates (determined by single radial immunodiffusion)
- Serum apoprotein B (determined by rocket immunoelectrophoresis)

Independent Variables

Cross-sectional group (O, AN, or C).

Description of Actual Data Sample:

Initial N: Eight obese (O), 12 anorexia nervosa (AN) and 10 control (C)
Attrition (final N): Eight obese (O), 12 anorexia nervosa (AN) and 10 control (C)
Age: O, 14.1±1.1; AN, 14.4±1.4; C, 15.0±0.8 (ranging from 12 to 17 overall)
Ethnicity: Not mentioned; study took place in Buenos Aires and Madrid.

Anthropometrics (Mean + One Standard Deviation)

Height (cm): O, 157.4±5.4; AN, 161.5±0.9; C, 158.3±5.9
Weight (kg): O, 66.5±5.8; AN, 39.1±4.5; C, 54.1±3.1 (each group is significantly different from the other two groups)
IBW (kg): O, 50.7±2.2; AN, 52.4±2.2; C, 53.4±2.9
Percent IBW (%): O, 133.0±9.7; AN, 68.6±3.4; C, 98.7±7.4 (each group is significantly different from the other two groups)
BMI (kg/m²): O, 26.9±3.8; AN, 15.0±0.7; C, 21.6±7.4 (each group is significantly different from the other two groups).

Location

Buenos Aires and Madrid.

Summary of Results:

Key Findings

Persons in the obese group had lower albumin and higher C₃ factors and apo A compared to the other two groups.
Persons with anorexia nervosa had lower immunoglobulin A compared to the other two groups.

Variables	Obese Group Measures and Confidence Intervals (CI)	Anorexia Nervosa Group Measures and CIs	Control Group Measures and CIs	Statistical Significance Difference Between Groups (at P<0.05)
Albumin (g per L)	35±3.8	44±0.6	43±5	O lower than AN and C groups.
Immunoglobulin A (g per L)	2.52±0.27	0.92±0.07	1.96±0.20	AN lower than O and C groups.
C₃ factor (g per L)	1.9±0.10	0.9±0.08	1.1±0.03	O higher than C, which is higher than AN.
Apo B (g per L)	1.6±0.04	0.90±0.20	0.71±0.16	O higher than AN, which is higher than C.

Other Findings

All variables were correlated by Spearman rank correlation coefficients within each group. In the C group, only a positive and significant correlation was observed between serum albumin and apo B (R=0.74, P=0.01); the AN group showed a positive and significant correlation between the BMI and C₃ complement factor (R=0.58, P=0.05); no significant correlations were found in the obese group.

Author Conclusion:

The authors conclude that the obese adolescents and patients with anorexia nervosa are at risk "for their lives."

The O group has the most unfavorable protein status
The immunological parameters indicate that the nutritional status of the AN group may be more affected than that in control and obese groups
Apo B values might confirm that a risk factor associated with coronary heart disease is shown in obese and anorectic patients. The risk is more significant in the obese group.

Funding Source:

University/Hospital:

Instituto de Nutricion y Bomatologia, Ciudad Universitaria, Madrid, Espana; Department of Nutrition, University of Buenos Aires, Argentina; Nutrition and Diabetes Services, Hospital Doctor Pedro de Elizalde, Buenos Aires, Argentina

Reviewer Comments:

Obesity criteria not clearly defined
Small sample size
Cross-sectional study (does not allow for cause-and-effect determination).

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?	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?		No
	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?	No
3.	Were study groups comparable?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	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.)	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?	No
	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.)	Yes
	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?	Yes
	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?		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?	N/A
	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?	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?		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?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		No
	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?		No
	10.1.	Were sources of funding and investigators' affiliations described?	No
	10.2.	Was the study free from apparent conflict of interest?	Yes