UWL: Caloric Needs (2007)

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

To investigate REE and its relationship with quantity and metabolic activity of fat free mass and to evaluate the influence of functional status on REE in underweight elderly subjects.

Inclusion Criteria:
  • Underweight elders (BMI < 20)
  • Normal weight elders (BMI 20 - 30)
  • Included only subjects with stable weight in past 6 months
Exclusion Criteria:
  • Acute illness
  • Severe liver, heart or kidney failure
  • Endocrinopathy
  • Cancer and other inflammation states
  • Patients treated with steroid hormones and other drugs interfering with resting metabolism
  • Body weight variation >3%
  • Individuals with Mini-Mental State Examination scores < 17
  • Subjects who were unable to collaborate for the execution of all instrumental examinations
Description of Study Protocol:


Underweight subjects were recruited in the Geriatric Hospital in Padova, Italy among patients admitted for nonrelevant clinical problems.  Healthy subjects were volunteers.

Design: Case-Control Study 

Blinding used (if applicable):  not applicable 

Intervention (if applicable):  not applicable

Statistical Analysis

Differences of the variables between normal and underweight people were evaluated in both genders by Student's unpaired two-sided t test.  REE was normalized for FFM variations by ANCOVA and the ratio method.  Relationship between REE and body composition and the Katz index was evaluated in underweight and normal weight subjects by linear regression models.  Multiple regression analysis was used to determine whether the Katz index was associated to REE after adjustment for FFM and FM.

Data Collection Summary:

Timing of Measurements

All subjects submitted to several measurements on the same day.

Dependent Variables

  • Body composition determined by DEXA
  • REE measured using indirect calorimetry and standard protocol
  • Activities of daily living assessed by Katz index
  • Mini-Mental State Examination 
  • Body weight, height, BMI
  • Routine biochemical analyses performed to exclude states of inflammation

Independent Variables

  • Underweight (BMI < 20) vs normal weight (BMI 20 - 30)

Control Variables


Description of Actual Data Sample:

Initial N: 102 elderly subjects divided into 2 groups according to nutritional status.  48 underweight elders (26 women, 22 men), 54 normal weight elderly controls.

Attrition (final N):  102 elderly subjects

Age:  underweight women mean age 80 +/- 7 years, underweight men mean age 79 +/- 9 years.  healthy women mean age 79 +/- 9 years, healthy men mean age 77 +/- 7 years.   

Ethnicity:  not mentioned 

Other relevant demographics:

Anthropometrics:  Age was similar between groups for both genders

Location:  Italy


Summary of Results:


  Measured REE (kcal/day) REE/FFM (kcal/day/kg)

Adjusted REE (kcal/day)

Normal Men (n=27) 1693 +/- 284 30.3 +/- 4.5  1715 +/- 139 
Underweight Men (n=22) 1349 +/- 203, p = 0.000016 34.7 +/- 6.4, p = 0.006788 1287 +/- 85, p = 0.00072
Underweight Able Men (n=15) 1429 +/- 147, p = 0.053859 36.2 +/- 6, p = 0.000703  1301 +/- 91, p = 0.000000
Normal Women (n=27) 1389 +/- 196 35.4 +/- 5.3  1366 +/- 91 

Underweight Women (n=26)

1086 +/- 264, p = 0.000000

34.7 +/- 7.8, p = 0.525

1124 +/- 63, p = 0.000000

Underweight Able Women (n=12)

1255 +/- 217, p = 0.064237

39.9 +/- 6.3, p = 0.024944

1129 +/- 83, p = 0.000000

Other Findings

Underweight elders had significantly lower fat free mass, FFM index (FFM/height2) and REE than healthy subjects. 

REE adjusted for FFM with analysis of covariance remained significantly lower in the underweight group (1287 +/- 85 vs 1715 +/- 139 kcal/day in men, and 1124 +/- 63 vs 1366 +/- 91 kcal/day in women).

Katz index in the underweight group was inversely correlated with REE (r = -0.68, p < 0.001) even after removal of FFM, FM and gender, by multiple regression analysis.

In this model, FFM and Katz index together explained ~54% of REE variability.

Author Conclusion:

In conclusion, in underweight elderly subjects, hypometabolism occurs for a reduction of both FFM quantity and metabolic activity.  Functional status in ADL is an important predictor of REE independently from FFM.  The limited physical activity might be the underlying mechanism in underweight elders, but further investigations are necessary to confirm this.

Funding Source:
University/Hospital: University of Padova (Italy)
Reviewer Comments:

Authors note limitations of not measuring physical activity and using ADLs as sole index of physical impairment and disability.

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? 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? Yes
  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? Yes
  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.) 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? 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? 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? 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? 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? 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)? 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