Background
Methods/Design
Criteria | Original study protocol: SLIM [10] | Considerations | Adapted study protocol: MetSLIM |
---|---|---|---|
Inclusion criteria | Mean 2-h blood glucose ≥ 7.8 and ≤12.5 mmol/l | Primary outcome measure of MetSLIM will be waist circumference (see considerations Table 2). There is an on-going discussion about the use of different waist cut-off points for different ethnicities. In order to take height differences between ethnic groups into account, waist-to-height-ratio (WHtR) was chosen as selection criterion [14]. In order to observe a change in waist circumference, only persons with an elevated WHtR will be included [15]. | WHtR ≥ 0.5 |
Mean fasting blood glucose ≤ 7.8 mmol/l | |||
Caucasian | The adapted intervention is aimed at individuals of Dutch, Moroccan or Turkish ethnic origin. Moroccans and Turks are the two largest non-Western ethnic minority groups in the Netherlands [16]. | Persons of Dutch, Moroccan or Turkish descent | |
Age 40–70 years | In the Netherlands, life expectancy without chronic diseases is 8.9 years lower in women and 10.9 years lower in men among the least educated group compared to the most educated group [17]. Also, the onset of T2DM among the Moroccan and Turkish population living in the Netherlands occurs at an earlier age compared with Dutch people [9]. Apparently, prevention of chronic diseases should start at an earlier age among our target group. | Age 30–70 years | |
No additional inclusion criteria
| As the adapted intervention study is aimed at low SES individuals, the researchers had to investigate where and how they would ideally reach this target group. Commonly used indicators for SES are income, education level and occupation. However, these are individual level indicators and this could create recruitment difficulties. It might be uncommon and illogical for the target group to be selected for lifestyle programmes on the basis of their individual education level, income or occupation. Furthermore, it is more practical to recruit in specific areas and use the postal code as indicator for SES [18]. A disadvantage of using the postal code is that more highly educated persons will also be able to participate in the intervention study. However, the advantage of recruiting in neighbourhoods is that participants will live in the same neighbourhood. This offers us the opportunity to provide all activities close to the participants’ home and to focus on group cohesion and social support in the community. | Living in deprived neighbourhood | |
Exclusion criteria | Known diabetes mellitus | See consideration WHtR as inclusion criterion. | WHtR ≤ 0.5 |
Mean 2-h blood glucose > 12.5 mmol/l | |||
Mean fasting blood glucose > 7.8 mmol/l | |||
Any chronic disease that makes 5-year survival improbable or that interferes with glucose tolerance, or that makes participation in a lifestyle intervention impossible | Participants must be able to follow a lifestyle programme for one year. | Any mental or physical disability that makes participation in a lifestyle intervention impossible | |
Medication know to interfere with glucose tolerance | Since the adapted lifestyle programme aims to decrease waist circumference and improve other factors of metabolic syndrome, persons taking medication for CVD and/or T2DM will be excluded. | Medication for hypertension, hypercholesterolemia, cardiovascular diseases, diabetes mellitus or/and renal failure | |
Participants in a regular vigorous exercise programme | In order to measure the effectiveness of the lifestyle programme, participants should not already be participating in other lifestyle programmes. | Participation in another regular vigorous exercise and/or diet programme targeting weight loss | |
No additional exclusion criteria
| Since the minimum age of participants was decreased to women’s fertile years, pregnant or lactating were added as exclusion criteria, as these have an influence on the main outcomes of the MetSLIM study. | Pregnant or lactating |
Protocol elements | Considerations | Adapted study protocol: MetSLIM | |
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Objective | To study whether a diet/physical activity intervention programme can improve glucose tolerance in subjects at high risk of developing type 2 diabetes mellitus. | Because of the overlapping risk factors, the initial idea of the MetSLIM study was to focus on persons with metabolic syndrome (MetS), which is associated with an increased risk both of T2DM and of CVD [20]. However, screening for MetS might impose too high a burden on low SES individuals to participate in the study because of: | To evaluate the effectiveness of an adapted version of the SLIM lifestyle programme to reduce elevated waist circumference and improve other components of the metabolic syndrome in individuals with low socioeconomic status of different ethnic origins. |
- unfamiliarity with MetS | |||
- time-consuming screening necessary before potential participants know whether they can actually participate (waiting for laboratory results). | |||
Primary outcome: | Waist circumference was considered because it is: | Primary outcome: | |
Change in glucose tolerance (2-h plasma glucose) | - visible for potential participants and therefore easy to communicate | Change in waist circumference | |
- one of the components of the metabolic syndrome and a risk factor for cardiometabolic diseases [21]. | |||
Study design | Setting: | Distance can be a barrier to participation; target group prefers nearby location, possibly a familiar place. The two universities involved in this study are not located in deprived neighbourhoods. Besides, the number of ethnic minorities living in the cities where the two universities are located is relatively small. | Setting: |
At the university | In the community | ||
Design: | RCT design does not seem appropriate because: | Design: | |
Randomized controlled trial (RCT) | - target group is probably unfamiliar with randomization, which could easily provoke dissatisfaction if participants were randomly allocated to intervention and control group within one community | Quasi-experimental study | |
- participants are allowed to bring a friend or family member to different intervention activities (for social support), which could result in spill-over. | |||
Duration: | The duration of MetSLIM should be shorter given the limited time and budget. | Duration: | |
4.1 year (range 3–6years) | 12 months | ||
Study population |
Inclusion/exclusion criteria:
| See Table 1 |
Inclusion/exclusion criteria:
|
See Table 1 | See Table 1 | ||
Recruitment strategies: | Recruitment strategies should be adapted to needs of target group, taking into account that: | Recruitment strategies: | |
- Potentially eligible persons from a large existing cohort monitoring health and disease in the general population were approached to participate | - Invitation letter from own GP | ||
- a personal approach seems to be appreciated | - Personal approach in community centres | ||
- Through advertisements in the local newspaper | - letterbox drops do not seem to work for this group [24]. | ||
Intervention group | Nutrition advice: | Nutrition advice: | |
- One group meeting a year | - Four group meetings a year, of which one is an introduction/kick-off meeting | ||
- Four 1-hour sessions of individual advice in one year | The spreading of the four hours of individual advice should be flexible. The involved professionals indicated that they preferred to vary the number and length of consultations to the individual needs of the client. This is in accordance with daily practice. | - Four hours of nutrition advice spread over the year, with regard to the needs of the individual | |
Physical activity lessons: |
Physical activity lessons:
| ||
- Once or twice a week | - Once or twice a week | ||
- Provided at the gym on the grounds of the university | - Provided in the community | ||
- In special SLIM groups | - In special MetSLIM groups | ||
- Men and women separately | |||
- Possibility to bring friend or family member | |||
No participation fee | Some local health professionals preferred a participation fee for participating in the lifestyle programme. Their experience was that persons get used to getting everything for free and will switch to other free programmes once a programme is not free anymore. This could be a problem for the maintenance of programmes. At the same time, the target group indicated that financial cost can be a barrier to a healthy lifestyle, and researchers were concerned about not recruiting enough participants. | No participation fee | |
Control group | Activities control programme: | Because of possible low literacy level of the target group, an information meeting instead of only written materials should be considered. | Activities control programme: |
- No additional appointments are scheduled, apart from the annual visits for follow-up measurements | - One group meeting with a dietician about nutrition | ||
- Participants received oral and written information about the beneficial effects of a healthy diet, weight loss and increased physical activity at the appointment for baseline measurements | - Participants will receive oral and written information about the beneficial effects of a healthy diet, weight loss and increased physical activity (where possible, in their mother tongue) | ||
Measurements |
Physical measurements:
| The measurements were reconsidered taking into account: |
Physical measurements:
|
- Anthropometric measurements | - practical feasibility of doing the measurements at different locations, in the community | - Anthropometric measurements | |
- Blood sampling | - possibility of relocating measurements equipment | - Blood and urine sampling | |
- Blood pressure | - participants’ unfamiliarity with different measurements. | - Blood pressure | |
- Oral Glucose Tolerance Test (OGGT) | |||
- 12-lead resting ECG | |||
- Incremental exhaustive exercise test on an electronically braked bicycle ergometer | |||
Physical activity:
| Difficulties were expected with filling in diaries because of illiteracy. Additional information should be gathered about determinants of behaviour. |
Physical activity:
| |
- SQUASH | - SQUASH | ||
- 3-day PA record | - Accelerometers | ||
- Questionnaire on determinants of physical activity | |||
Dietary habits:
| Difficulties were expected with filling in diaries because of illiteracy. Additional information should be gathered about determinants of behaviour. |
Dietary habits:
| |
- FFQ | - Ethnicity-matched FFQ | ||
- 3-day food record | - Questionnaire on determinants of healthy diet | ||
Quality of life:
|
Quality of life:
| ||
SF-36 questionnaire | SF-36 questionnaire | ||
Economic evaluation:
| The economic evaluation of a lifestyle programme is important in the context of possible future implementation of the programme. Because it is not known who might be willing to pay for the programme, it is important to consider the costs and effects from different perspectives. |
Economic evaluation:
| |
Cost-effectiveness analysis was conducted from a healthcare perspective only [13]. | Cost-effectiveness analysis and cost-utility analysis will be done from a societal perspective and a healthcare perspective. | ||
Process evaluation:
| Adherence to the nutrition and exercise part of to the lifestyle programme was reported in SLIM [30]. An elaborate process evaluation was lacking however. MetSLIM should include an elaborate process evaluation. |
Process evaluation:
| |
Limited data available | Elaborate process evaluation by means of: | ||
- Researchers’ logbooks | |||
- Registration forms including an attendance list | |||
- Non-response survey | |||
- Drop-out questionnaire | |||
- Participants’ questionnaire | |||
Additional considerations
| Involved staff: | Staffing should be matched with either ethnicity or gender of the participants, depending on the availability of staff and the needs of participants: | Involved staff: |
- Dutch researcher | - fluency of participants’ Dutch language might be low | - Dutch researcher(s) | |
- Dutch dietician | - dietician should be able to tailor dietary advice to individuals’ (possibly traditional) eating habits and should be familiar with traditions bound to Islam | - Ethnicity-matched research assistants | |
- Sports instructor not gender matched | - gender-matched sports instructors are preferred by some Turkish and Moroccan females. | ||
- Ethnicity-matched dieticians | |||
- Gender-matched sports instructors | |||
Language of information material and questionnaires: | The information materials and questionnaires should be translated because of possible problems with fluency in the Dutch language. | Participants can opt for information in one or more of the following languages: | |
Dutch | - Dutch | ||
- Standard Arabic | |||
- Turkish | |||
Receiving results of measurements:
| Participation in health checks seemed to be popular among the target group according to various health professionals; receiving results could help to motivate control group participants to participate in the study’s baseline and final measurements. Apart from the motivational aspect, it is common in healthcare practice that patients are informed about the results of regular blood tests. |
Receiving results of measurements:
| |
Yes | Yes |