UWL: Association With Outcomes (2009)

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

To describe the independent association between nutritional risk and death in older adults diagnosed with cognitive impairment.

Inclusion Criteria:
  • Canadian Study of Health and Aging participants who completed a clinical exam and were diagnosed with cognitive impairment
  • Seniors living in the community and in institutions
  • Participants with complete data.
Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:


  • The Canadian Study of Health and Aging is a national survey of Canadians 65 years of age and older, involving 18 study centers in 10 provinces
  • The first phase of the study, CSHA-1, was conducted between February 1991 and May 1992
  • The sample was representatively drawn from urban and surrounding rural areas in each of the provinces; 9,008 seniors living in the community and 1,255 living in institutions were included
  • The community sample was selected from computerized records of the provincial health care plans in nine provinces, and from provincial enumeration records in Ontario
  • The sampling frame was stratified by age group, with the oldest seniors were oversampled
  • Institutions were randomly sampled from a comprehensive list; within chosen institutions, residents over the age of 65 were eligible for random selection.

Design:  Cohort study. 

Statistical Analysis

  • Regression models were used
  • Interaction between nutritional risk status and demographic, cognitive and comorbidity covariates was assessed
  • Descriptive and bivariate relationships were explored with the use of frequency and univariate procedures, chi-square and ANOVA
  • Logistic regression using a maximum likelihood procedure was used to model the relationship between nutritional risk and occurrence of death in cognitively impaired community-living seniors
  • Comparison of the full-model odds ratio and parameter estimate for the nutritional risk variable to subsequent models was the method chosen to determine the final fully adjusted model
  • Wald's Chi-Square Test and Hosmer and Lemeshow's Goodness-of-Fit test were also completed.
Data Collection Summary:

Timing of Measurements

Subjects completed a screening questionnaire and clinical exam at baseline. They were followed for a period of five years.

Dependent Variables

  • Mortality
  • Nutritional risk was defined as the presence of at least one abnormal nutrition indicator identified during the clinical exam: Self-reported weight change (more than 3.0kg in six months), physician-reported weight change, abnormal serum albumin, poor appetite and BMI less than 20.

Independent Variables

  • Clinical exam: Height and weight measurements, date of birth, marital status and other demographic information, medication usage and vital signs
  • Clinical history: Behavioral symptoms, assessment of instrumental activities of daily living, memory difficulties, history of trauma that could influence cognition, assessment of depressive symptoms and older physical complaints, all collected through The Older Americans Resource Inventory and CAMDEX
  • Physical examination and biochemical tests  
  • Cognitive impairment: Cognitive status determined through screening questionnaire, including demographic data, assessment of independence in activities of daily living, the Modified Mini-Mental State Exam to screen for dementia and health questions

Control Variables

  • Demographics (age, marital status, gender, living alone and education level)
  • Type and severity of dementia
  • Smoking status
  • Depression
  • Presence of a mobility impairment
  • Difficulties with IADL or ADL
  • Presence of difficult behaviors
  • Hearing and visual impairment
  • Comorbidity
  • Fall history.
Description of Actual Data Sample:
  • Initial N: 10,263 CSHA-1 participants
  • Attrition (final N): 735 participants, 58% women
  • Age: Mean age, 81±6.6 years.

Other Relevant Demographics

  • 55.8% had cognitive loss with no diagnosed dementia
  • 21.5% had mild dementia
  • 20.6% had moderate dementia
  • 2.1% had severe dementia.




Summary of Results:

Final Model for Risk of Mortality in CSHA Participants with Cognitive Impairment



Odds Ratio

95% CI

Gender (male = 1)


2.4  1.7, 3.3




1.06, 1.1

Nutritional risk 0.45 1.6 1.1, 2.2
Mobility impairment 0.42 1.5 1.1, 2.2
IADL impairment 0.27 0.8 0.48, 1.1
ADL impairment 1.05 2.9 1.8, 4.9
Mild dementia 0.07 1.1 0.71, 1.6
Moderate dementia 0.64 1.9 1.2, 3.2
Severe dementia 1.6 4.8 1.2, 19.5
Hearing impairment 0.23 1.3 0.86, 1.8
Poor perceived health 0.26 1.3 0.88, 1.8
Comorbidity (three to five drugs) 0.38 1.5 1.0, 2.2
Comorbidity (six or more drugs) 0.53 1.7 1.1, 2.7

Other Findings

  • There were 373 deaths during the five-year follow-up period in this sample
  • 41% were considered to be at nutritional risk, although only 13.6% were identified as having two or more nutrition indicators
  • Average BMI was 24.3kg/m2, with 17.9% having a BMI less than 20
  • Almost 10% complained of appetite loss and 12.2% described weight loss
  • Nutritional risk was found to independently increase the likelihood of death (OR=1.6, 95% CI=1.1, 2.2) in these older adults suffering from cognitive impairment.
Author Conclusion:

Nutritional risk was significantly and independently associated with mortality in this analysis, with an odds ratio of 1.6; nutritional risk increases the likelihood that death will occur during a five-year follow-up of demented seniors. Further work is required to determine if interventions can improve nutritional status and quality of life of these older adults. 

Funding Source:
Other: Not reported
Reviewer Comments:

Nutritional risk was only assessed at baseline. Authors note the following limitations:

  • Categorization of nutritional risk based on presence or absence of nutritional parameters
  • Change in nutritional status or weight was not assessed during a follow-up period
  • Missing data in original data set
  • Sample may not be representative of the entire cognitively impaired group studied: The sample used had more males and more living in an institution than the entire data set.
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? ???
  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? N/A
  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? 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? N/A
  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%.) N/A
  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? 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? 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? 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? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? No
  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? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  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)? 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? No
  10.2. Was the study free from apparent conflict of interest? Yes