EAL

DM: Prevention of Type 2 Diabetes (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the net effects on risk factors for type 2 diabetes and cardiovascular disease of a community-based 3-year intervention to increase physical activity.

Inclusion Criteria:

Living in a low-income district in Oslo, Norway (district named Romas used as the intervention group; district named Furuset used as the control group)
Age 30-67 years
Voluntary response to letter of invitation for study participation

Exclusion Criteria:

Not discussed

Description of Study Protocol:

Recruitment

Written letter of invitation

Design

Pseudo-experimental cohort design

Blinding used (if applicable)

Not applicable

Intervention (if applicable)

Specially designed leaflets with physical activity information
Individualized counseling offered during biannual fitness tests
Walking groups organized
Group sessions for indoor activities offered at no cost

Statistical Analysis

Measures reported as proportions for categorical variables.
Mean ± standard deviation reported for continuous variables.
Difference between baseline and follow-up measures reported per study group.
Net difference between study groups reported after follow-up.
For categorical data, group differences were tested with nonparametric tests (Mann-Whitney).
For dichotomous variables, z tests were used.
For continuous variables, multiple linear regression analysis was done.

Data Collection Summary:

Timing of Measurements

Baseline
Follow-up

Dependent Variables

Nonfasting laboratory measures: serum cholesterol, triglycerides and glucose
Resting blood pressure and heart rate
Body mass index
Physical activity as measured by subjective survey questions

Independent Variables

Group membership (intervention or control)

Control Variables

Nonfasting laboratory measures were adjusted for time since last meal (ANOVA).
Outcomes in physical activity were adjusted for potential confounding variables.

Description of Actual Data Sample:

Initial N: 6140 sent letter of invitation for baseline assessments / 2644 invited to return for follow-up assessment

Attrition (final N): 2950 completed baseline assessments / 1766 returned for follow-up assessment

Age: 30-67 years

Ethnicity: Norwegian population included imigrant groups

Other relevant demographics: Main languages of imigrant groups were: English, Urdu, Turkish, Vietnamese, and Tamil

Anthropometrics: Baseline variables of those participants who attended follow-up showed the intervention district was less educated (11.6 years vs. 12.5), less employed in full-time work (60% vs 72%) and had greater BMI (27.1 vs 26.5 kg/m²).

Location: Oslo, Norway

Summary of Results:

**Net change during 3 years from intervention to follow-up**
	Net change intervention versus control district	P value
BMI (kg/m²)	Men: -0.42 (-0.63 to -0.21) Women: -0.06 (-0.29 to 0.17)	<0.001 0.61
Cholesterol (mmol/l)	Men: -0.10 (-0.23 to 0.02) Women -0.03 (-0.14 to 0.07)	0.11 0.53
Glucose (mmol/l)	Men: -0.35 (-0.67 to 0.03) Women -0.02 (-0.18 to 0.14)	0.03 0.82

Other Findings

There was a net reduction of 8.1% (P =0.005) in the proportion of subjects reporting "no heavy activity" during the intervention period that was in favor of the intervention district.
There was a net increase of 9.5% (P =0.008) in the proportion of subjects reporting "heavy activity" during the intervention period that was in favor of the intervention district.

Author Conclusion:

The results indicate that the commuity-based intervention led to significant health effects on the risk factors for type 2 diabetes and cardiovascular disease.
Further studies are needed to determine if these observed effects translate into reduction of incidence of disease.

Funding Source:

Government:

Norwegian Instittute for Public Health, Directorate for Health and Social Affairs, Norwegian Research Council

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

The intervention phase was not clearly described. It was unclear how many intervention subjects participated in the offered activities. Authors note risk of selection bias.

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?		No
	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?	???
	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?	Yes
3.	Were study groups comparable?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	No
	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?	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?	Yes
	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?	N/A
	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?		???
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	???
	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?	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?	N/A
	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)?	???
	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