Unintended Weight Loss in Older Adults

UWL: Food, Appetite and Environment (2009)


Lorefalt B, Granerus AK, Unosson M.  Avoidance of solid food in weight losing older patients with Parkinson's disease.  J Clin Nurs 2006;15(11):1404-12.


PubMed ID: 17038101
Study Design:
Longitudinal Prospective Case-Control Study
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate to what extent Parkinsonian symptoms, including mild dysphagia and other eating problems, could influence the choice of consistency and the amount of food intake and if this could be related to weight loss as an expression of the underlying neurodegenerative process.

Inclusion Criteria:
  • 60 years or older
  • For women, at least 5 years should have passed following menopause, and they were not allowed to take any hormonal substitution
  • None of the Parkinson patients or controls was treated with anticholinergic or neuroleptic drugs
  • Criteria were the same for both patients and controls with the exception of Parkinson disease symptoms
Exclusion Criteria:
  • Patients with ongoing depression, dementia, gastrointestinal or endocrine disease, or malignant disease within 5 years prior to the start of the study
  • Other diseases influencing body composition and nutritional status
Description of Study Protocol:


Patients were consecutively enrolled from geriatric and neurological outpatient departments.  Healthy controls were randomly selected from the regional population register corresponding to the same geographical area as the Parkinson disease patients.

Design:  Longitudinal Prospective Case-Control Study 

Blinding used (if applicable):  not applicable 

Intervention (if applicable)

  • Parkinson's disease patients and controls were investigated twice, one-year apart, with focus on Parkinson's disease symptoms as well as swallowing function
  • Intake of food items and food consistency were assessed by food records

Statistical Analysis

  • Mean and standard deviations were given for age, body weight, BMI and Parkinson disease symptoms. 
  • Food consumption were presented as medians and quartiles.
  • Differences between Parkinson disease patients and controls were analyzed by Student's paired t test and Wilcoxon's signed rank test for dependent groups
  • Unpaired t test and Mann-Whitney test were used to analyze differences between 2 independent groups (Parkinson disease with and without weight loss)
  • Parametric tests were used when the data were approximately normally distributed, tested by Skewness analysis, otherwise non-parametric tests were used
  • Stepwise multiple linear regression analysis was also performed 
Data Collection Summary:

Timing of Measurements

  • Parkinson's disease patients and controls were investigated twice, one-year apart.
  • Controls were investigated at the same time of the year as the patients in order to avoid seasonal differences influencing the results

Dependent Variables

  • Parkinson's disease symptoms and eating difficulties assessed as defined by the Unified Parkinson's Disease Rating Scale, shown to be a valid and reliable measure
  • Body weight and height
  • Oral and dental status examined by clinical oral inspection by a physician
  • Swallowing function assessed by same physician using 7-grade scale from normal function to severe dysphagia according to Waxman et al (1990)
  • Intake of food items and food consistency were assessed by food records completed over 3 consecutive days at each investigation

Independent Variables

  • Parkinson's disease patients or matched controls

Control Variables


Description of Actual Data Sample:


Initial N: 26 free-living Parkinson disease patients (17 women, 9 men) and 26 controls

Attrition (final N):  as above

Age:  mean age Parkinson disease patients:  74 ± 5.7 years, mean age controls:  74 ± 4.5 years 

Ethnicity: not mentioned

Other relevant demographics:   Patients had Parkinson disease for a mean of 4.6 ± 3.9 years

Anthropometrics:  Controls were age- and sex-matched

Location:  Sweden  


Summary of Results:


UPDRS score PD with weight loss, Year 1

PD with weight loss, Year 2

PD without weight loss, Year 1

PD without weight loss, Year 2

Activities of daily living 8.3 ± 6.4 10.8 ± 9.0, P < 0.05 9.3 ± 10.4 10.0 ± 10.3

Eating difficulties related to ADL:  salivation, swallowing, cutting food

1.8 ± 1.8

2.2 ± 2.4

1.7 ± 2.2

2.0 ± 2.1

Motor symptoms 18.5 ± 10.2 22.5 ± 13.9, P < 0.01 14.0 ± 11.3 16.7 ± 11.5

Eating difficulties related to motor symptoms:  tremor, hand grips and pronation/supination

4.4 ± 2.8

5.3 ± 3.0, P < 0.05

3.4 ± 2.9

3.4 ± 2.9

Other Findings

19 of 26 Parkinson Disease patients lost body weight during the 1 year period, from 66.4 ± 11.2 to 63.3 ± 12.8 kg (P < 0.001) and their BMI decreased from 24.2 ± 2.8 to 23.2 ± 3.5 (P < 0.01).

7 of 26 Parkinson disease patients gained weight during the 1 year period, from 68.3 ± 6.7 to 70.1 ± 6.3 kg (P < 0.05) and increased BMI (25.9 ± 2.7 to 27.0 ± 3.3, P < 0.05).

There were no significant differences in weight or BMI in the control group.

In patients with weight loss, motor symptoms (P < 0.01), problems with activities of daily living (P < 0.05) and problems with eating related to motor symptoms (P < 0.05) increased and they had more dysphagia compared with controls (P < 0.05 at year 1, P < 0.01 at year 2).

They consumed lower amounts of fluid and solid food on both investigated occasions, compared with controls.

Neither the Parkinson disease patients not controls had any major oral or dental problems.

Multiple regression analysis showed that weight loss was associated with female gender, eating difficulties related to activities of daily living and preference toward soft food, but negatively correlated with age.  This model showed r2 = 0.70, P < 0.002.


Author Conclusion:

The Parkinson disease patients avoiding of solid food may be an expression of dysphagia.  More advanced disease also could lead to other eating problems related to ADL and motor symptoms in Parkinson disease.  Dietary recommendations, in order to increase the amount of adequate food, ought to be a wise measure.  Intervention studies focusing on nutrition in patients with Parkinson disease are needed.

Funding Source:
Government: County Council of Ostergotland
University/Hospital: Health Sciences University of Linkoping
Reviewer Comments:

Authors note following strengths of the study:

  • Longitudinal design
  • Parkinson disease patients were without other diseases
  • Healthy matched controls
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? Yes
  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.) 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.) N/A
  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? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  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? 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? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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? 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