Obesity
Conditions
Keywords
obesity, obesity prevention, worksite, environment, intervention
Brief summary
The primary aim of this research is to evaluate the efficacy of a multicomponent worksite-based, environmental intervention in reducing weight increase and obesity over time in working adults.
Detailed description
This study is a randomized trial designed to evaluate the effectiveness of a multi-component worksite intervention with strong environmental components to prevent weight gain. Six worksites will be randomized to either an intervention or a no-treatment control group. The intervention will be comprised of 1) changing the availability, portion sizes, and prices of foods and beverages sold to employees in their worksites in ways that encourage healthier food choices; 2) increasing the availability of physical activity opportunities at the worksite by implementing walking programs and increasing stairwell access and attractiveness; 3) placing scales in the work environment to encourage body weight monitoring and to enable workers to set goals for their weight; and 4) to provide educational materials to all employees to make them aware of the environmental intervention and of behavioral practices likely to be effective in preventing weight gain. The intervention will be implemented for a 2-year period in each intervention site. Effectiveness will be evaluated by assessing body weight, eating behavior and physical activity in a cohort of employees in both control and intervention sites at baseline and again 2 years later. Weight trends in these populations will also be compared to data from national and state-level annual surveys of weight in representative population samples. Data will be collected on the effects of specific intervention components via aggregate measures of food choice and physical activity.
Interventions
BEHAVIORALweight gain prevention
1. Changes in the food environment that increase the availability of healthy foods and beverages, reduce food and beverage portion sizes, reduce prices on healthy food items, and increase prices on less healthy food items. 2. Changes in the activity environment that increase cues and incentives for walking at work and at home, using stairs, and to increase exposure of employees to information about active recreational opportunities at work and at home. 3. Changes to the environment to increase cues and incentives for regular weight monitoring by providing scales at convenient locations. 4. Changes in the informational environment that increase frequency of exposure of the employee population to accurate information about healthy food and activity choices.
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Minnesota
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* age 18 or older * generally in good health * part- or full-time employee in one of the participating worksites
Exclusion criteria
* work on site \<50% of the time * work second or third shift
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Body Mass Index (BMI) | Baseline to 24 months | Assessed in kilograms per meter squared. |
Countries
United States
Participant flow
Recruitment details
Participants were recruited at worksites between January 2006 and April 2007. Human resources departments provided worksite contact information for all eligible employees; these email addresses and phone numbers were used for recruitment contact purposes.
Pre-assignment details
A company-wide email was sent to eligible employees at all sites, describing the study and the partnership with the University. Employees were notified that a study staff member would contact them about the project within the next two weeks and were given the option to call study staff in advance to opt out or to enroll in the study.
Participants by arm
| Arm | Count |
|---|---|
| Worksite Environmental Intervention Changes to healthy food availability, physical activity opportunities and promotion, body weight scale access, and media enhancements to target weight gain prevention | 752 |
| No-contact Control No-treatment control condition. Worksites were offered program materials upon completion of programs at intervention sites. | 995 |
| Total | 1,747 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | left workforce | 115 | 180 |
| Overall Study | Lost to Follow-up | 18 | 11 |
| Overall Study | Withdrawal by Subject | 8 | 9 |
Baseline characteristics
| Characteristic | No-contact Control | Worksite Environmental Intervention | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 32 Participants | 17 Participants | 49 Participants |
| Age, Categorical >=65 years | 9 Participants | 6 Participants | 15 Participants |
| Age, Categorical Between 18 and 65 years | 954 Participants | 729 Participants | 1683 Participants |
| Age, Continuous | 43.1 years STANDARD_DEVIATION 10.6 | 42.7 years STANDARD_DEVIATION 10.8 | 42.9 years STANDARD_DEVIATION 10.7 |
| Region of Enrollment United States | 995 participants | 752 participants | 1747 participants |
| Sex: Female, Male Female | 608 Participants | 478 Participants | 1086 Participants |
| Sex: Female, Male Male | 387 Participants | 274 Participants | 661 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 752 | 0 / 995 |
| serious Total, serious adverse events | 0 / 752 | 0 / 995 |
Outcome results
Primary
Change in Body Mass Index (BMI)
Assessed in kilograms per meter squared.
Time frame: Baseline to 24 months
Population: Participants with complete data at baseline and two years, and those who were not pregnant at either time, were retained for analysis.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Worksite Environmental Intervention | Change in Body Mass Index (BMI) | 0.315 kilograms per meter squared | Standard Error 0.08959 |
| No-contact Control | Change in Body Mass Index (BMI) | 0.190 kilograms per meter squared | Standard Error 0.07987 |
Comparison: The null hypothesis was no effect of the environmental intervention. The following power assumptions were made:~* Intraclass correlation (ICC) of 0.016, estimated from an earlier study~* Variance of 118 kg, estimated from an earlier study~* Cohort N=400~* 15% attrition (by turnover) Using the external control and a worksite correlation of 0.2 gives a detectable difference of about 1.5 kg or 3 lb, or an effect size of 0.14. The effect size using internal control is 0.20.p-value: 0.3695% CI: [-0.21, 0.46]ANCOVA