MNT: Disorders of Lipid Metabolism (2015)

Kim HJ, Hong JI, Mok HJ, Lee KM. Effect of workplace-visiting nutrition education on anthropometric and clinical measures in male workers. Clin Nutr Res. 2012; 1 (1): 49-57. doi: 10.7762/cnr.2012.1.1.49. PubMed ID: 23430239
Study Design:
Prospective Cohort Study
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To investigate the effect of workplace nutrition education program based on the self-directed coaching method for changing poor dietary habits to proper dietary behaviors in male workers.
Inclusion Criteria:
Included subjects had abnormal laboratory findings (hypertension, diabetes, dyslipidemia, abnormal liver function indices) among employees of L Company who received a health examination and a comprehensive medical checkup implemented by the National Health Insurance Workplace visiting nutrition education program between June and September 2011.
Exclusion Criteria:
None described.
Description of Study Protocol:


Included subjects had abnormal laboratory findings (hypertension, diabetes, dyslipidemia, abnormal liver function indices) among employees of L Company who received a health examination and a comprehensive medical checkup implemented by the National Health Insurance Workplace visiting nutrition education program between June and September 2011.


Cohort study.

  • Male workers received nutrition education by a clinical dietitian for four months:
    • Clinical nutritionists visited the workplace to provide nutrition assessment and education and to observe the progress of subjects every month
    • Each educational session was carried out for 20 minutes and subjects received consulting two times on average
    • Self-developed nutrition education leaflets were used as educational tools.
  • Anthropometric data (height, weight, waist circumference), blood pressure and biochemical blood indices (fasting blood sugar, liver function tests and total cholesterol panel) were measured before and after the four-month nutrition education period
  • Dietary habits and lifestyle (regularity of meals, drinking and smoking habits) were investigated by self-administered questionnaires based on the medical examination chart provided by the National Health Insurance during health checkup
  • Nutrient intake was determined by 24-hour dietary recall.

Statistical Analysis

  • SPSS Statistic 18 for statistical processing was used
  • Descriptive statistics of mean and standard deviation was used to analyze general characteristics
  • Non-parametric Wilcoxon signed ranked test of the paired T-test was used to analyze clinical and biochemical measurements including blood pressure, blood lipids, blood glucose and liver function indicators
  • Body mass index (BMI) was classified according to normal weight (BMI less than 23.0kg/m2), overweight (BMI between 23.0kg/m2 and 25.0kg/m2) and obese (BMI 25.0kg/m2 or higher) and used the non-sequential variable with the non-parametric method for analysis
  • Spearman's correlation was used to verify factors that influence clinical indicators related to metabolic syndrome in the significance level of P<0.05.
Data Collection Summary:

Timing of Measurements

Measurements were taken at baseline and again after four months of nutrition education.

Dependent Variables

  • Anthropometric measurements taken: Height, weight and waist circumference (WC); BMI was calculated
  • Blood pressure: Systolic blood pressure (SBP) and diastolic blood pressure (DBP)
  • Blood indices:
    • Blood glucose: Fasting blood sugar (FBS)
    • Blood lipids: Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C)
    • Liver function indicators: Serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and Gamma-glutamyl transpeptidase (r-GTP).

Independent Variables

Four months of nutrition counseling at work.

Description of Actual Data Sample:
  • Initial N: 75 males
  • Attrition (final N): 75 males
  • Age: 41.1±5.6 years
  • Ethnicity: Korean; not described in detail.

Other Relevant Demographics
Lifestyle and Dietary Habits

Variables Criteria N (%)
Regularity of meals Yes 34 (59.6)
No 23 (40.4)
Alcohol drinking Drinker 63 (86.3)
Non-drinker 10 (13.7)
Smoking status Smoker 28 (51.9)
Non-smoker 26 (48.1)


Variables Before Nutrition Education
Height, cm 172.2±6.3
Weight, kg 76.2±10.2
BMI, kg/m2 25.7±2.9
  Normal weight (BMI<23.0) 17 (22.7)
Overweight (BMI 23.0 to 25.0) 16 (21.3)
Obesity (BMI≥25.0) 42 (56.0)
WC, cm 88.4±7.7

Values are presented as mean±SD or N (%).


Seoul Korea.

Summary of Results:

Key Findings

Correlation Coefficient Between Clinical Indicators and WT, r-GTP, BMI, TG, HDL-C, SGPT After Nutrition Education*
Dependent Variables Independent Variables Coefficient P-value
Blood pressure
     SBP, mm Hg WT, kg 0.285 P<0.05
     DBP, mm Hg r-GTP, IU per L 0.240 P<0.05
Glycemic control      
     FBS, mg per dL WT, kg 0.235 P<0.05
  BMI, kg/m2 0.233 P<0.05
Lipid profile
     TC, mg per dL TG, mg/dL 0.270 P<0.05
     TG, mg per dL BMI, kg/m2 0.341 P<0.01
  r-GTP, IU per L 0.330 P<0.01
  HDL-C, mg per dL -0.258 P<0.05
  SGPT, IU per L 0.272 P<0.05
     HDL-C, mg per dL WT, kg -0.240 P<0.05
Liver function indicators
     SGPT, IU per L WT, kg 0.327 P<0.01
  BMI, kg/m2 0.259 P<0.05
     r-GTP, IU per L WT, kg 0.307 P<0.01
  BMI, kg/m2 0.255 P<0.05

*Analyzed with Spearman's correlation coefficient.

Other Findings

  • Although SBP was reduced from 120.0mm Hg to 117.8mm Hg and DBP was reduced from 79.1mm Hg to 77.0mm Hg after nutrition education there was no significant difference found
  • FBS was significantly reduced from 100.5mg per dL to 97.0mg per dL after nutrition education (P<0.01)
  • TC was significantly reduced from 211.3mg per dL to 204.4mg per dL (P<0.05)
  • TG was reduced from 216.6mg per dL to 204.0mg per dL after nutrition education without showing a significant difference
  • HDL-C was similar before and after nutrition education
  • LDL-C was significantly reduced from 131.1mg per dL to 123.6mg per dL after nutrition education (P<0.05)
  • All liver function tests were reduced after nutrition education but did not present significant difference.

Nutrition intake surveys showed that on subjects consumed:

  • 2,160 calories on average (90% of the nutrient intake standards for men between 30 years and 49 years)
  • 321.3g carbohydrates (60% total calories)
  • 79.7g protein (15% total calories, consisting of 57% animal protein and 43% plant protein)
  • 61.8% fat (26% total calories)
  • 312.9mg cholesterol (recommendation for dyslipidemia patients is 200mg)
  • 15.6g dietary fiber
  • 900.7mcg RE vitamin A (recommended intake for men between 30 years and 49 years is 750mcg RE)
  • 63.2mg Vitamin C (recommended intake for men between 30 years and 49 years is 100mg).
Author Conclusion:
  • The results of this study verified that the visiting nutrition education provided to male workers through individual-based, self-directed education was effective in reducing body mass index and improving clinical quality index
  • It is important to achieve nutrition management through systematic education or counseling by nutritionists in the workplace and thus the development of a program suitable for the workplace and the regular implementation of the program is necessary 
  • It is possible to consider connecting hospitals with professional clinical nutritionists and health check-up programs with workplaces
  • Nutritionists will actively contribute to the improvement of national health.
Funding Source:
Other: not described
Reviewer Comments:
  • There was no detailed description of how the dependent measurements were taken (e.g., was weight self-reported or measured by nutritionist)
  • Data in Table 2 (lifestyle and dietary habits) and Table 7 (average daily nutrients intake) appear to be baseline data. No data were reported after the four months of nutrition counseling.
  • No data seem to be collected or reported on exercise, which would influence several of the outcomes
  • It is important to note that the BMI categories used in this paper are different that U.S. BMI categories
  • The inclusion and exclusion criteria was not described in detail. Since no other recruitment methods were described, it appears as if subjects did not have a choice in participating. They were identified based on their abnormal findings on a health exam and participated in the study.
  • Had to give a negative rating because there were so many things that were just not described in detail so "unclear" was chosen for many of the answers.
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? ???
  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? 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.) ???
  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? Yes
  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? N/A
  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? 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? ???
  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? No
  6.6. Were extra or unplanned treatments described? No
  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? ???
  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? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? N/A
  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? ???
  10.1. Were sources of funding and investigators' affiliations described? ???
  10.2. Was the study free from apparent conflict of interest? ???