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Featured researches published by Vera Nierkens.


European Journal of Epidemiology | 2007

Behavioural risk factors in two generations of non-Western migrants: do trends converge towards the host population?

Karen Hosper; Vera Nierkens; Mary Nicolaou; Karien Stronks

Migrant mortality does not conform to a single pattern of convergence towards prevalence rates in the host population. To understand better how migrant mortality develops, it is necessary to further investigate how the underlying behavioural determinants change following migration. We studied whether the prevalence of behavioural risk factors over two generations of Turkish and Moroccan migrants converge towards the prevalence rates in the Dutch population. From a random sample from the population register of Amsterdam, 291 Moroccan and 505 Turkish migrants, aged 15–30, participated in a structured interview that included questions on smoking, alcohol consumption, physical inactivity and weight/height. Data from the Dutch population were available from Statistics Netherlands. By calculating age-adjusted Odds Ratio’s, prevalence rates among both generations were compared with prevalence rates in the host population for men and women separately. We found indications of convergence across generations towards the prevalence rates in the host population for smoking in Turkish men, for overweight in Turkish and Moroccan women and for physical inactivity in Turkish women. Alcohol consumption, however, remained low in all subgroups and did not converge towards the higher rates in the host population. In addition, we found a reversed trend among Turkish women regarding smoking: the second generation smoked significantly more, while the first generation did not differ from ethnic Dutch. In general, behavioural risk factors in two generations of non-Western migrants in the Netherlands seem to converge towards the prevalence rates in the Dutch population. However, some subgroups and risk factors showed a different pattern.


PLOS ONE | 2013

Effectiveness of Cultural Adaptations of Interventions Aimed at Smoking Cessation, Diet, and/or Physical Activity in Ethnic Minorities. A Systematic Review

Vera Nierkens; Marieke A. Hartman; Mary Nicolaou; Charlotte Vissenberg; Erik Beune; Karen Hosper; Irene G. M. van Valkengoed; Karien Stronks

Background The importance of cultural adaptations in behavioral interventions targeting ethnic minorities in high-income societies is widely recognized. Little is known, however, about the effectiveness of specific cultural adaptations in such interventions. Aim To systematically review the effectiveness of specific cultural adaptations in interventions that target smoking cessation, diet, and/or physical activity and to explore features of such adaptations that may account for their effectiveness. Methods Systematic review using MEDLINE, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials registers (1997–2009). Inclusion criteria: a) effectiveness study of a lifestyle intervention targeted to ethnic minority populations living in a high income society; b) interventions included cultural adaptations and a control group that was exposed to the intervention without the cultural adaptation under study; c) primary outcome measures included smoking cessation, diet, or physical activity. Results Out of 44904 hits, we identified 17 studies, all conducted in the United States. In five studies, specific cultural adaptations had a statistically significant effect on primary outcomes. The remaining studies showed no significant effects on primary outcomes, but some presented trends favorable for cultural adaptations. We observed that interventions incorporating a package of cultural adaptations, cultural adaptations that implied higher intensity and those incorporating family values were more likely to report statistically significant effects. Adaptations in smoking cessation interventions seem to be more effective than adaptations in interventions aimed at diet and physical activity. Conclusion This review indicates that culturally targeted behavioral interventions may be more effective if cultural adaptations are implemented as a package of adaptations, the adaptation includes family level, and where the adaptation results in a higher intensity of the intervention. More systematic experiments are needed in which the aim is to gain insight in the best mix of cultural adaptations among diverse populations in various settings, particularly outside the US.


BMC Public Health | 2008

Which factors engage women in deprived neighbourhoods to participate in exercise referral schemes

Melanie Schmidt; Saida Absalah; Vera Nierkens; Karien Stronks

BackgroundExercise referral schemes (ERS) have become a popular way of promoting physical activity. The aim of these schemes is to encourage high risk patients to exercise. In evaluating these schemes, little attention has been paid to lower socio-economic groups in a multi-ethnic urban setting. This study aimed to explore the socio-demographic and psychosocial characteristics of female participants in ERS located in deprived neighbourhoods. The second aim was to determine which elements of the intervention make it appealing to participate in the scheme.MethodsA mixed method approach was utilized, combining a cross-sectional descriptive study and a qualitative component. In the quantitative part of the study, all female participants (n = 523) filled out a registration form containing questions about socio-demographic and psychosocial characteristics. Height and weight were also measured. In the qualitative part of the study, 38 of these 523 participants were interviewed.ResultsThe majority of the participants had a migrant background, a low level of education, no paid job and a high body mass index. Although most participants were living sedentary lives, at intake they were quite motivated to start exercising. The ERS appealed to them because of its specific elements: facilitating role of the health professional, supportive environment, financial incentive, supervision and neighbourhood setting.ConclusionThis study supports the idea that ERS interventions appeal to women from lower socio-economic groups, including ethnic minorities. The ERS seems to meet their contextual, economic and cultural needs. Since the elements that enabled the women to start exercising are specific to this ERS, we should become aware of whether this population continues to exercise after the end of the scheme.


PLOS ONE | 2013

Intensive lifestyle intervention in general practice to prevent type 2 diabetes among 18 to 60-year-old South Asians: 1-year effects on the weight status and metabolic profile of participants in a randomized controlled trial.

Wanda M. Admiraal; Everlina M. A. Vlaar; Vera Nierkens; Frits Holleman; Barend J. C. Middelkoop; Karien Stronks; Irene G. M. van Valkengoed

Aim To study 1-year effectiveness of an intensive, culturally targeted lifestyle intervention in general practice for weight status and metabolic profile of South-Asians at risk of type 2 diabetes. Methods 536 South-Asians at risk of type 2 diabetes were randomized to an intervention (n = 283) or control (n = 253) group. The intervention, which was targeted culturally to the South-Asian population, consisted of individual lifestyle counselling, a family session, cooking classes, and supervised physical activity programme. All components of the intervention were carried out by professionals as part of their daily clinical practice. The control group received generic lifestyle advice. Change in weight status and metabolic profile were assessed after 1 year. Results After 1 year, 201 participants were lost to follow-up. Remaining participants in intervention (n = 177) and control (n = 158) group had similar baseline characteristics. Weight loss in the intervention group was 0.2±3.3 kg, weight gain in the control group was 0.4±3.1 kg (p = 0.08). Changes in other weight-related measurements did not differ significantly between groups. Furthermore, there were no differences between groups in changes of metabolic profile. All results remained similar after repeating analyses in a multiple imputed dataset. Discussion An intensive, culturally targeted, lifestyle intervention of 1 year did not improve weight status and metabolic profile of South-Asians at risk of type 2 diabetes. The laborious recruitment, high drop-out, and lack of effectiveness emphasise the difficulty of realising health benefits in practice and suggest that this strategy might not be the optimal approach for this population. Trial Registration Nederlands Trial Register NTR1499


BMC Public Health | 2012

Feasibility and effectiveness of a targeted diabetes prevention program for 18 to 60-year-old South Asian migrants: design and methods of the DH!AAN study

Everlina M. A. Vlaar; Irene G. M. van Valkengoed; Vera Nierkens; Mary Nicolaou; Barend J. C. Middelkoop; Karien Stronks

BackgroundSouth Asian migrants are at particularly high risk of type 2 diabetes. Previous studies have shown that intensive lifestyle interventions may prevent the onset of diabetes. Such interventions have not been culturally adapted and evaluated among South Asians in industrialized countries. Therefore, we have set up a randomized controlled trial to study the effectiveness of a targeted lifestyle intervention for the risk of type 2 diabetes and cardiovascular risk factors among 18 to 60-year-old Hindustani Surinamese (South Asians) in The Hague, the Netherlands. Here we present the study design and describe the characteristics of those recruited.MethodsBetween May 18, 2009 and October 11, 2010, we screened 2307 Hindustani Surinamese (18–60 years old) living in The Hague. We sent invitations to participate to those who had an impaired fasting glucose of 5.6-6.9 mmol/l, an impaired glucose tolerance of 7.8-11.0 mmol/L, a glycated hemoglobin level of 6.0% or more and/or a value of 2.39 or more for the homeostasis model assessment of estimated insulin resistance. In total, 536 people (56.1% of those eligible) participated. People with a higher level of education and a family history of type 2 diabetes were more likely to participate. The control and intervention groups were similar with regard to important background characteristics. The intervention group will receive a culturally targeted intervention consisting of dietary counseling using motivational interviewing and a supervised physical activity program. The control group will receive generic lifestyle advice. To determine the effectiveness, a physical examination (anthropometrics, cardiorespiratory test, lipid profile, and measures of oral glucose tolerance, glycated hemoglobin, and insulin) and interview (physical activity, diet, quality of life, and intermediate outcomes) were carried out at baseline and will be repeated at 1 year and 2 years. The process and the costs will be evaluated.DiscussionThis trial will provide insight into the feasibility and effectiveness of a targeted, intensive, lifestyle intervention for the risk of type 2 diabetes and cardiovascular risk factors among 18 to 60-year-old South Asians.Trial registrationDutch Trial Register: NTR1499


Primary Care Diabetes | 2011

Changing the odds. What do we learn from prevention studies targeted at people with a positive family history of type 2 diabetes

Wieke H. Heideman; Barend J. C. Middelkoop; Vera Nierkens; Karien Stronks; Arnoud P. Verhoeff; Suzanne C.M. van Esch; Frank J. Snoek

People with a positive family history of type 2 diabetes (T2DM) are at high risk of developing diabetes. We set out to review the literature reporting on the development and/or evaluation of lifestyle interventions specifically aimed at prevention of T2DM in this group. Targeting people with a positive family history of T2DM seems so far an underutilized prevention strategy. They can and should be approached with the aim to raise risk awareness and promote healthy eating, weight loss and physical activity, thereby reducing their risk of developing diabetes.


BMC Endocrine Disorders | 2013

Screening South Asians for type 2 diabetes and prediabetes: (1) comparing oral glucose tolerance and haemoglobin A1c test results and (2) comparing the two sets of metabolic profiles of individuals diagnosed with these two tests

Everlina M. A. Vlaar; Wanda M. Admiraal; Wim B. Busschers; Frits Holleman; Vera Nierkens; Barend J. C. Middelkoop; Karien Stronks; Irene G. M. van Valkengoed

BackgroundThe glycated haemoglobin A1c (HbA1c) level may be used for screening for type 2 diabetes and prediabetes instead of a more burdensome oral glucose tolerance test (OGTT). However, among the high-risk South Asian population, little is known about the overlap of the methods or about the metabolic profiles of those disconcordantly diagnosed.MethodsWe included 944 South Asians (18–60 years old), whom we screened with the HbA1c level and the OGTT in The Hague, the Netherlands. We calculated the area under the receiver-operator characteristic curve (AUROC) with a 95% confidence interval of HbA1c using the American Diabetes Association classifications, and determined the sensitivity and specificity with 95% confidence intervals at different thresholds. Moreover, we studied differences in metabolic characteristics between those identified by HbA1c and by the OGTT alone.ResultsThe overlap between HbA1c and OGTT classifications was partial, both for diabetes and prediabetes. The AUROC of HbA1c for OGTT defined diabetes was 0.86 (0.79–0.93). The sensitivity was 0.46 (0.29–0.63); the specificity 0.98 (0.98–0.99). For prediabetes, the AUROC was 0.73 (0.69–0.77). Each of the 31 individuals with diabetes and 353 with prediabetes identified with the HbA1c level had a high body mass index, large waist circumference, high blood pressure, and low insulin sensitivity, all of which were similar to the values shown by those among the 19 with diabetes or 62 with prediabetes who only met the OGTT criteria, but not the HbA1c criteria.ConclusionsThe HbA1c level identified a partially different group than the OGTT did. However, both those identified with the HbA1c level and those identified with the OGTT alone were at increased metabolic risk.Trial registrationDutch Trial Register:NTR1499


Health Promotion International | 2014

Development of a diabetes prevention program for Surinamese South Asians in the Netherlands

Mary Nicolaou; Evalina Vlaar; Irene G. M. van Valkengoed; Barend J. C. Middelkoop; Karien Stronks; Vera Nierkens

Type 2 diabetes is highly prevalent among South Asian origin groups around the world. Not only is prevalence higher than in other ethnic groups, age at presentation is lower and these groups are more likely to experience complications. Evidence suggests that lifestyle interventions may prevent or delay the onset of diabetes. However, little is known about diabetes prevention in South Asians (SA). DH!AAN is a diabetes prevention program designed for Surinamese SA in The Netherlands. In this paper, we describe the theoretical frameworks and formative research that guided the development and cultural adaptation of DH!AAN. Cultural adaptation was based on analysis of the determinants of diet and physical activity, including socio-cultural factors, within our study population. This led to the incorporation of surface and deep structure elements in the intervention. One-to-one counseling by dieticians using motivational interviewing (MI) was the basis for the intervention. Additionally, we aimed to generate social support by including family members in parts of the intervention and group sessions to address issues relating to traditional food habits. We discuss our reflections on the development process and the choices made in developing this intervention. The results of DH!AAN will provide insight into the use of MI for this population group. Moreover, DH!AAN will provide evidence regarding the feasibility of diabetes prevention among South Asian populations.


BMC Public Health | 2014

Wanting to attend isn't just wanting to quit: why some disadvantaged smokers regularly attend smoking cessation behavioural therapy while others do not: a qualitative study.

Fiona E. Benson; Karien Stronks; Marc C. Willemsen; Nina M. M. Bogaerts; Vera Nierkens

BackgroundAttendance of a behavioural support programme facilitates smoking cessation. Disadvantaged smokers have been shown to attend less than their more affluent peers. We need to gain in-depth insight into underlying reasons for differing attendance behaviour in disadvantaged smokers, to better address this issue. This study aims to explore the underlying motivations, barriers and social support of smokers exhibiting different patterns of attendance at a free smoking cessation behavioural support programme in a disadvantaged neighbourhood of The Netherlands.MethodsIn 29 smokers undertaking smoking cessation group therapy or telephone counselling in a disadvantaged neighbourhood, qualitative interviews were completed, coded and analysed. Major themes were motivations, barriers to attend and social support. Motivations and social support were analysed with reference to the self-determination theory.ResultsTwo distinct patterns of attendance emerged: those who missed up to two sessions (“frequent attenders”), and those who missed more than two sessions (“infrequent attenders”). The groups differed in their motivations to attend, barriers to attendance, and in the level of social support they received. In comparison with the infrequent attenders, frequent attenders more often had intrinsic motivation to attend (e.g. enjoyed attending), and named more self-determined extrinsic motivations to attend, such as commitment to attendance and wanting to quit. Most of those mentioning intrinsic motivation did not mention a desire to quit as a motivation for attendance. No organizational barriers to attendance were mentioned by frequent attenders, such as misunderstandings around details of appointments. Frequent attenders experienced more social support within and outside the course.ConclusionMotivation to attend behavioural support, as distinct from motivation to quit smoking, is an important factor in attendance of smoking cessation courses in disadvantaged areas. Some focus on increasing motivation to attend may help to prevent participants missing sessions.


BMC Public Health | 2011

Social and cultural factors underlying generational differences in overweight: a cross-sectional study among ethnic minorities in the Netherlands

Karen Hosper; Mary Nicolaou; Irene G. M. van Valkengoed; Vera Nierkens; Karien Stronks

BackgroundThe prevalence of overweight appears to vary in people of first and second generation ethnic minority groups. Insight into the factors that underlie these weight differences might help in understanding the health transition that is taking place across generations following migration. We studied the role of social and cultural factors associated with generational differences in overweight among young Turkish and Moroccan men and women in the Netherlands.MethodsCross-sectional data were derived from the LASER-study in which information on health-related behaviour and socio-demographic factors, level of education, occupational status, acculturation (cultural orientation and social contacts), religious and migration-related factors was gathered among Turkish and Moroccan men (n = 334) and women (n = 339) aged 15-30 years. Participants were interviewed during a home visit. Overweight was defined as a Body Mass Index ≥ 25 kg/m2. Using logistic regression analyses, we tested whether the measured social and cultural factors could explain differences in overweight between first and second generation ethnic groups.ResultsSecond generation women were less often overweight than first generation women (21.8% and 45.0% respectively), but this association was no longer significant when adjusting for the socioeconomic position (i.e. higher level of education) of second generation women (Odds Ratio (OR) = 0.77, 95%, Confidence Interval (CI) 0.40-1.46). In men, we observed a reversed pattern: second generation men were more often overweight than first generation men (32.7% and 27.8%). This association (OR = 1.89, 95% CI 1.09-3.24) could not be explained by the social and cultural factors because none of these factors were associated with overweight among men.ConclusionsThe higher socio-economic position of second generation Turkish and Moroccan women may partly account for the lower prevalence of overweight in this group compared to first generation women. Further research is necessary to elucidate whether any postulated socio-biological or other processes are relevant to the opposite pattern of overweight among men.

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Barend J. C. Middelkoop

Leiden University Medical Center

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Karen Hosper

University of Amsterdam

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