Unintended Weight Loss in Older Adults

UWL: Association With Outcomes (2009)

Citation:

Shatenstein B, Kergoat MJ, Nadon S. Anthropometric changes over five years in elderly Canadians by age, gender and cognitive status. J Gerontol A Biol Sci Med Sci. 2001; 56(8): M483-M488. 

PubMed ID: 11487600
 
Study Design:
Cohort study.
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To document and examine correlates of anthropometric characteristics and their evolution over a five-year period in a subsample of elderly Canadians who had taken part in both phases of the Canadian Study of Health and Aging.

Inclusion Criteria:
  • Institutionalized and free-living elderly participants from the Canadian Study of Health and Aging
  • Aged 65 years and older
  • Spoke English or French
  • Lived in the study area.
Exclusion Criteria:

Unacceptable values, such as increase in height from CSHA1 to CSHA2, substantial and implausible divergence in height and weight from CSHA1 to CSHA2, or unlikely weight for gender or height, were excluded from analyses.

Description of Study Protocol:

Recruitment

The Canadian Study of Health and Aging was conducted in two phases, with a nationwide prevalence study of dementia in 1991 to 1992 (CSHA1) and a follow-up phase in 1996 (CSHA2). People aged older than 65 years were randomly selected using recruitment procedures that differed for those living in the community and in institutions. The original cohort consisted of 10,263 participants.

Design

Cohort study. 

Statistical Analysis

  • Analyses were conducted separately for community-dwelling vs. institutionalized participants to reflect the different recruitment strategies used
  • Data were stratified by sex, age group, 3MS score and cognitive diagnosis
  • Paired T-tests were used to test changes over the interval, and repeated-measures ANOVA was used to examine the extent of differences within and across categories.
Data Collection Summary:

Timing of Measurements

  • At CSHA1, participants' height and weight were measured in clinics
  • Surviving participants were remeasured at CSHA2.

Dependent Variables

Height and weight were measured by by nurses.

Independent Variables

  • Age
  • Gender
  • Cognitive status assessed with Mini Mental State Examination; final cognitive diagnosis was reached by consensus of the clinician, another physician, and a neuropsychologist, aided by the nurse who had administered the clinical questionnaire, using criteria from the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition.

 

Description of Actual Data Sample:
  • Initial N: 10,263 participants in both CSHA1 and CSHA2. 1,464 community-dwelling, 963 institutionalized participants measured at CSHA1
  • Attrition (final N): 487 community-dwelling, 140 institutionalized participants. Body weight available for 603 community-dwelling, 249 institutionalized participants
  • Age: 65 years and older at CSHA1
  • Ethnicity: 99% Caucasian
  • Location: Canada.
Summary of Results:

Weight Change from CSHA1 to CSHA2 for Community-Dwelling Subjects

Variables

Weight Difference, CSHA2 to CSHA1 (kg) P value

All (N=584)

-2.02±5.92 <0.001
Men (N=236) -2.02±6.41 <0.001
Women (N=348) -2.03±5.57 <0.001
Age 70 to 79 years (N=154) -1.53±6.05 <0.01
Age 80 to 89 years (N=323) -2.07±5.59 <0.001
Age 90+ years (N=107) -2.61±6.63 <0.001
3MS Score less than 78 (N=229) -1.79±6.37 <0.001
3MS Score more than 78 (N=317) -1.65±5.33 <0.001
Normal diagnosis (N=259) -1.60±5.09 <0.001
Cognitively impaired, not demented (N=168) -1.72±5.80 <0.001

Dementia (N=157)

-3.05±7.11

<0.001

Other Findings

  • The average weight loss between study phases in community-dwelling and institutionalized participants was approximately 2.0kg (P<0.001)
  • In institutions, this was statistically significant in most stratification categories, as was the case in community-dwelling participants (by gender, age, dementia screening score and cognitive diagnosis)
  • Among those who were cognitively intact, the greatest weight losses occurred in participants under 90 years old and in those aged 70 to 79 years with a diagnosis of dementia (P<0.01)
  • Stature decreased more in institutionalized (2.0cm) than in community-dwelling participants (1.4cm)
  • In institutions, this was significant among the oldest men (P<0.005), while in the community there were no differences in the extent of height lost in all stratification categories
  • The average BMI was largely stable (24kg/m2).
Author Conclusion:

Body weight and stature declined with aging among elderly Canadian CSHA participants, particularly in the very old and those with dementia. Such longitudinal anthropometric data are needed along with information on dietary intakes and medical, cognitive and functional measures to plan interventions geared to maximizing nutritional and overall health in the elderly population, whatever their cognitive status.

Funding Source:
Government: Seniors' Independence Research Program, National Health Research and Development Program of Health Canada
Industry:
Pfizer Canada, Bayer
Pharmaceutical/Dietary Supplement Company:
Not-for-profit
British Columbia Health Research Foundation
Other non-profit:
Reviewer Comments:

Community-dwelling and institutionalized participants recruited with different methods. Body weight measurements were not made in all subjects. Authors note the following limitations:

  • Only those CSHA participants undergoing clinical examination were weighed and measured
  • Substantial proportion lost to follow-up, mainly due to death
  • Since subjects in the oldest age categories were oversampled, the community-dwelling cohort may not be representative of the home-dwelling elderly population.
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%.) 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? 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? 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? ???
  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? No
  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)? ???
  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