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Lifestyle intervention studies have shown that the development of cardiometabolic diseases can be partly prevented or postponed by the combination of a healthy diet and physical activity. Cardiometabolic diseases and their risk factors are particularly prevalent among individuals with low socioeconomic status and some ethnic minorities, and therefore these groups especially may benefit from participating in lifestyle interventions. Although individuals with low socioeconomic status and ethnic minorities could potentially benefit from lifestyle interventions, it seems that these groups are often not successfully reached for such interventions. Moreover, when they do participate in these interventions, they seem more likely to quit. The overall aim of this thesis was therefore to study opportunities for, and the effectiveness of, lifestyle interventions to reduce the risk of cardiometabolic diseases, targeting individuals with low socioeconomic status of different ethnic origins. To this end, this thesis reports two studies that identified opportunities for adapting lifestyle interventions to the target group’s needs, one study describing the process of adapting an effective lifestyle intervention (SLIM) into a new lifestyle intervention targeting individuals with low SES of different ethnic origins (MetSLIM) and two studies that determined the effectiveness of lifestyle interventions among the target group.
The aim of the study described in chapter 2 was to identify opportunities for adapting lifestyle interventions in such a way as to be more appealing for individuals with low socioeconomic status. The study provided insight into perspectives of groups with different socioeconomic positions regarding their current eating and physical activity behaviour; triggers for lifestyle change; and preferred ways to support lifestyle change. Data were gathered in semi-structured focus group interviews with adults with low socioeconomic status (four groups) and with adults with high socioeconomic status (five groups). In general, three key topics were identified, namely: current lifestyle is logical for participants given their personal situation; lifestyle change is prompted by feedback from their body; and support for lifestyle change should include individually tailored advice and could profit from involving others. The perceptions of the participants with low socioeconomic status were generally comparable to the perceptions shared by the participants with high socioeconomic status. Some perceptions were, however, especially mentioned in the low socioeconomic status groups. Participants with low socioeconomic status indicated that their current eating behaviour was sometimes affected by cost concerns. They seemed to be especially motivated to change their lifestyle when they experienced health complaints but were rather hesitant to change their lifestyle for preventive purposes. Regarding support for lifestyle change, participants with low socioeconomic status preferred to receive advice in a group rather than on their own. For physical activities, groups should preferably consist of persons of the same age, gender or physical condition.
The aim of the study described in chapter 3 was to identify how Turkish and Moroccan adults living in the Netherlands, aged 45 years and older, could be reached to participate in health checks for cardiometabolic diseases and follow-up (lifestyle) advice. In this study, questionnaire data were combined with interview data. This was done in order to use the narratives from the interviews to get a better understanding of the numbers that resulted from the questionnaire data. It turned out that both ethnic groups preferred an invitation from their general practitioner (GP) for a health check and preferred to fill out the health check questionnaire at the GP’s office or at home, on paper. They preferred to receive advice at individual level in relation to personal matters via either a physician or a specialised healthcare professional. Sixty-one percent of the Turkish respondents preferred to receive information in their native language, compared to 37% of the Moroccan respondents. Several participants mentioned a low proficiency in the local language as an explanation for their preference to fill out the health check questionnaire at home, to receive advice from an ethnicity-matched professional and to receive information in their native language. The results of this study suggested that the GP would be a promising contact to reach adults of Turkish and Moroccan origin for health checks or (lifestyle) advice. Furthermore, the findings suggested that it would be necessary to provide information in individuals’ native language to overcome language barriers and that (lifestyle) advice should be tailored towards the needs of the targeted individuals.
The insights gained into the needs and preferences of the target group – as described in chapter 2 and chapter 3 – were taken into account in the design of the MetSLIM intervention study. The MetSLIM study targeted individuals with low socioeconomic status of Dutch, Turkish and Moroccan origin. The MetSLIM study protocol was based on the SLIM study protocol. The SLIM study showed the beneficial effects of nutrition advice and physical activity promotion on the prevention type 2 diabetes, but drop-out was relatively high among low SES participants. Chapter 4 provides a detailed description of the development from the SLIM study protocol to the MetSLIM study protocol. Furthermore, this chapter gives insight into the obstacles encountered in developing the MetSLIM study to target individuals with low socioeconomic status of different ethnic origins. The new elements regarding the lifestyle intervention programme were: 1) additional group meetings about price concerns and social occasions with regard to a healthy diet; 2) ethnicity-matched dieticians; 3) gender-matched sports instructors; 4) all activities in the participants’ own neighbourhood; and 5) activities for women and men separately. The new elements regarding the study design, in order to study the effectiveness of the MetSLIM intervention programme, included: 1) from an university stetting to a community setting; 2) from a randomised controlled trial to a quasi-experimental study; 3) waist circumference – as a visible cardiometabolic risk factor – as main study outcome; 4) recruitment via GPs and in community centres; 5) translated study materials and ethnicity-matched research assistants involved in measuring; and 6) fewer measurements and measurements that could take place at different locations. Adaptations to the original SLIM study protocol were considered necessary in order to overcome practical barriers that hinder the target group’s participation; to suit the target group’s (cultural) needs; and to make it feasible to perform the study in a local (community) setting.
MetSLIM was not the only study set up based on the SLIM study. The SLIMMER study translated SLIM from a university setting to a real-world setting. The intervention was implemented in the public health and primary healthcare setting involving local GPs, practice nurses, dieticians, physiotherapists and sports clubs. The SLIMMER study did not target individuals with low socioeconomic status in particular; however, 52% of the study participants did have a low socioeconomic status, as determined by highest completed educational level. Chapter 5 describes how we explored the role of socioeconomic status in willingness to participate, programme attendance, programme acceptability, adherence to lifestyle guidelines, drop-out and effectiveness in the SLIMMER diabetes prevention intervention. The SLIMMER study was a randomised controlled trial, targeting 40- to 70-year-old adults at increased risk of type 2 diabetes, carried out in Apeldoorn and Doetinchem. The intervention group participated in a 10-month lifestyle programme: weekly training sessions were guided by a physiotherapist, and dietary advice was given by a dietician during 5–8 individual consultations and one group session. Measurements were carried out at baseline, after 12 months and six months after the active intervention period ended. The study showed that participation, attendance, acceptability, adherence, drop-out and effect of the SLIMMER study were mostly not affected by socioeconomic status. The SLIMMER study was able to reach the low socioeconomic status group as effectively as the higher socioeconomic status group, resulting in at least similar health benefits. The SLIMMER sample size was too small to study differences within the low socioeconomic status group, e.g. comparing the low vs. the least educated or comparing ethnic groups. Only 10% of the 316 SLIMMER participants had the lowest educational levels (no education or primary education) and only 11% had a foreign background.
The aim of the study described in chapter 6 was to measure the effectiveness of the MetSLIM intervention on waist circumference and other cardiometabolic risk factors, lifestyle and quality of life among 30- to 70-year-old adults with an elevated waist-to-height ratio. In the MetSLIM study, 220 individuals participated, of whom 40% had no education or only primary education and of whom 64% had a foreign background. MetSLIM had a quasi-experimental design with measurements at baseline and after 12 months. Participants were recruited in deprived neighbourhoods of Arnhem and Eindhoven via either their GP or in community centres. The intervention group participated in a 12-month lifestyle programme: an introductory group meeting was guided by the researcher, weekly physical activity lessons were guided by a sports instructor and dietary advice was given by an ethnicity-matched dietician (in total four hours of individual consultations and three group sessions). The study showed that the MetSLIM lifestyle intervention was effective in reducing waist circumference, other measures of obesity, total and LDL cholesterol, and quality of life. MetSLIM had a drop-out of 31%, which was higher than at 12 months in the SLIM study (10%) and SLIMMER study (13%), but comparable to drop-out in similar studies among ethnic minorities or low socioeconomic status populations.
Finally, in chapter 7, the main results of this thesis are described, followed by a discussion of methodological considerations, public health implications, suggestions for future research and the general conclusion. The adaptation process from SLIM to MetSLIM is discussed, including a reflection on the decision to use SLIM as a starting point and the decision to target three different ethnic groups at the same time. Moreover, difficulties in defining and selecting persons with low socioeconomic status and specific ethnic groups within research are addressed. As SLIMMER and MetSLIM proved that low socioeconomic status populations can be reached, and that their health can be improved when they participate in lifestyle interventions, it is suggested that further implementation should be considered. Insight should be gained into the ‘black box’ of lifestyle interventions; i.e. we should get to know what works for whom. Planned future research includes a process and economic evaluation of MetSLIM.
This thesis has shown that intensive combined lifestyle interventions can be effective in low socioeconomic status populations and identified possible adaptations to make lifestyle interventions more suitable for individuals with low socioeconomic status of Dutch, Turkish and Moroccan origin. The question is not whether a lifestyle intervention can be effective, but how diverse groups can be reached and benefit from it. For this purpose, further insight into the success of different adaptations for different target groups should be obtained to reveal the effective elements to reach, inspire and retain different low socioeconomic status populations and ethnic minorities with lifestyle interventions.
|Qualification||Doctor of Philosophy|
|Award date||26 Apr 2016|
|Place of Publication||Wageningen|
|Publication status||Published - 2016|
- socioeconomic status
- ethnic groups
- cardiovascular diseases
- type 2 diabetes
- glucose tolerance
- physical activity