Körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern

The purpose of this study is twofold: (1) screening the physical fitness of a professional fire-brigade and (2) testing the influence of a training program on the physical fitness of professional firemen. The sample consisted of 95 professional firemen (42.0 ± 9.1 years) of a professional fire-brigade in Belgium. Stature and body mass were measured. Body composition was estimated by bioelectrical impedance analysis (BIA). Physical condition was determined using the EUROFIT test battery. During 4 months the subjects performed an exercise program twice a week. High values for body mass index (BMI) (27.1±3.3kg/m2) and percentage of body fat (26.0±4.9%), and a low score for endurance capacity were observed. Correlation analyses demonstrate that motor capacity decreases with ageing. Analysing the differences (Test session 2 - Test session 1) indicates that there were no significant changes in physical fitness over the 4-month training period. Comparing the two groups with the different number of training sessions attended did not reveal any significant differences between the two groups. It can be concluded that (1) the firemen of the fire-brigade under study were rather old, had a high BMI and a high percentage of body fat; (2) the performance at the endurance shuttle run did not reach the anticipated standard; (3) the training program did not gain the desired results.Uvod Posao vatrogasca jedan je od tjelesno najzahtjevnijih. Ekstremno visoki profesionalni fizički zahtjevi rezultiraju velikim brojem ozljeda na radu, pa čak i visokom incidencijom prijevremene smrti. Očigledno je, promatra li se sigurnost vatrogasca u odnosu na ostatak populacije, da vatrogasci trebaju biti u odličnoj tjelesnoj kondiciji da bi bili sposobni obavljati tako zahtjevan posao. Potrebno je uravnotežiti profesionalna opterećenja s mogućnostima pojedinog vatrogasca, što je određeno različitim faktorima, kao što su dob, antropometrijske karakteristike (postotak masnog tkiva, bezmasna tjelesna masa, indeks tjelesne mase) i motoričke sposobnosti (snaga i izdržljivost). Pokazalo se da su vatrogasni zadaci, kao što su penjanje do požarnih izlaza, poslovi na dizalici, razvaljivanje ulaza i spašavanje žrtava, značajno povezani s nekim čimbenicima kao što su visina, tjelesna masa, bezmasna tjelesna masa, postotak masnog tkiva, snaga stiska šake, broj izvedenih sklekova, broj izvedenih “trbušnjaka” i izdržljivost. Istraživači u raznim zemljama (npr. Francuskoj, Kanadi, SAD-u) dosta su proučavali fizičku pripremu vatrogasaca. Svaki vatrogasac trenira barem dva puta tjedno kako bi unaprijedio svoju mišićnu snagu, izdržljivost i kardiovaskularni status te kako bi smanjio postotak masnog tkiva i povecao mišićnu masu Te su aktivnosti nužne za održanje fizičke pripremljenosti vatorgasaca. U Belgiji gotovo da i nema istraživanja koja su se bavila vatrogascima. Svrha ovog istraživanja je dvostruka: (1) ispitati fizičku pripremljenost profesionalne vatrogasne jedinice i (2) provjeriti utjecaj trenažnog programa na razinu fizičke pripremljenosti te grupe. Metoda Uzorak ispitanika činilo je 95 profesionalnih vatrogasaca (42.0 ± 9.1 god.). Izmjerena im je tjelesna visina i tjelesna masa. Sastav tijela procijenjen je pomocu BIA. Tjelesna sposobnost određena im je uz pomoć baterije testova EUROFIT. Kroz period od četiri mjeseca ispitanici (N=81) su sudjelovali u programu vježbanja u okviru kojega su radili na unapređenju različitih komponenata fizičke pripreme. Vatrogasci su vježbali dva puta tjedno po 45 minuta pod vodstvom dva trenera. Svaki je trening bio isplaniran tako da je naglasak bio na razvoju različite komponente fizičke pripremljenosti, ali nije bilo ciljanog treninga glede različitih testova baterije EUROFIT. Pojedini treninzi bili su organizirani u okviru dva radna sata u vatrogasnoj stanici. Kako pohađanje treninga nije bilo obvezno, broj ispitanika po pojedinom treningu varirao je od 0 do 23, u prosjeku 13 po treningu. Prisustvovanje treninzima se bilježilo tako da se taj faktor mogao uzeti u obzir u okviru analize rezultata. Rezultati Izmjerene su visoke vrijednosti BMI (27.1±3.3 kg/m2) i postotka masnog tkiva (26.0±4.9%), kao i niska razina tjelesne izdržljivosti. Korelacijska analiza pokazala je da se motorički kapacitet smanjuje sa životnom dobi. Analiza razlika pokazuje da nema statistički značajnih razlika u tjelesnoj sposobnosti nakon provedenog četveromjesečnog trenažnog programa u odnosu na inicijalno stanje. Usporedba dviju grupa s obzirom na razlicit broj ispitanika koji su prisustvovali pojedinim treninzima nije pokazala statistički značajne razlike u tjelesnoj pripremljenosti. Zaključak Može se zaključiti da su (1) vatrogasci ispitivane vatrogasne jedinice prilično stari, visokih vrijednosti indeksa tjelesne mase te imaju visok postotak masnog tkiva; (2) ispitanici nisu postigli zadane norme u primjenjivanom zadatku izdržljivosti, (3) trenažni program nije polučio željene rezultate.Das Ziel dieser Studie war zweifach: die körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern zu überprüfen, und 2) den Einfluss eines Trainingsprogramms auf die körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern zu testen. 95 professionelle Feuwerwehrmänner (die 42,0±9,1 Jahre alt waren) aus einer professionellen Feuerwehr aus Belgien nahmen an dieser Forschung teil. Es wurden sowohl die Statur und als auch die Hörpermasse gemessen. Die Hörperzusammensetzung wurde mittels der bioelektrischen Impedanzanalyse (BIA) geschätzt. Die körperliche Leistungsfähigkeit wurde mittels der EUROFIT-Testbatterie festgestellt. Während des viermonatigen Zeitraumes nahmen die Probanden zweimal pro Woche an einem Übungsprogram teil. Es wurden hohe Werte des Hörpermassenindexes (27,1±3,3kg/m2) und des Anteils vom Hörperfett (26,0±4,9%) erhalten, aber die Werte der Ausdauerkapazität waren niedrig. Die Horrelationsanalysen zeigten, dass sich die motorische Fähigkeit mit dem Alter verringert. Die Analyse von Unterschieden (Testmessung 2 – Testmessung 1) zeigte, dass bei den Feuerwehrmännern keine bedeutende Unterschiede in der körperliche Leistungsfähigkeit nach dem viermonatigen Trainingszeitraum entstanden. Der Vergleich von zwei Gruppen, die unterschiedlich oft an den Trainingsstunden teilgenommen haben, zeigte keine bedeutenden Unterschiede zwischen den Gruppen. Aufgrund der durchgeführten Studie sind die folgenden Schlussfolgerungen möglich: 1) Die Feuerwehrmänner, die an der Forschung teilgenommen haben, waren ziemlich alt, sie hatten sowohl einen hohen Hörpermassenindex als auch den hohen Anteil vom Hörperfett. 2) Die Ergebnisse des Ausdauer- Pendellaufes haben die antizipierte Norm nicht erreicht. 3) Das Trainingsprogram hat die gewünschten Ergebnisse nicht erreicht

Participatie en kwaliteit van leven bij personen met een handicap of beperking : pilootstudie : stad Gent

B

Körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern

The purpose of this study is twofold: (1) screening the physical fitness of a professional fire-brigade and (2) testing the influence of a training program on the physical fitness of professional firemen. The sample consisted of 95 professional firemen (42.0 ± 9.1 years) of a professional fire-brigade in Belgium. Stature and body mass were measured. Body composition was estimated by bioelectrical impedance analysis (BIA). Physical condition was determined using the EUROFIT test battery. During 4 months the subjects performed an exercise program twice a week. High values for body mass index (BMI) (27.1±3.3kg/m2) and percentage of body fat (26.0±4.9%), and a low score for endurance capacity were observed. Correlation analyses demonstrate that motor capacity decreases with ageing. Analysing the differences (Test session 2 - Test session 1) indicates that there were no significant changes in physical fitness over the 4-month training period. Comparing the two groups with the different number of training sessions attended did not reveal any significant differences between the two groups. It can be concluded that (1) the firemen of the fire-brigade under study were rather old, had a high BMI and a high percentage of body fat; (2) the performance at the endurance shuttle run did not reach the anticipated standard; (3) the training program did not gain the desired results.Uvod Posao vatrogasca jedan je od tjelesno najzahtjevnijih. Ekstremno visoki profesionalni fizički zahtjevi rezultiraju velikim brojem ozljeda na radu, pa čak i visokom incidencijom prijevremene smrti. Očigledno je, promatra li se sigurnost vatrogasca u odnosu na ostatak populacije, da vatrogasci trebaju biti u odličnoj tjelesnoj kondiciji da bi bili sposobni obavljati tako zahtjevan posao. Potrebno je uravnotežiti profesionalna opterećenja s mogućnostima pojedinog vatrogasca, što je određeno različitim faktorima, kao što su dob, antropometrijske karakteristike (postotak masnog tkiva, bezmasna tjelesna masa, indeks tjelesne mase) i motoričke sposobnosti (snaga i izdržljivost). Pokazalo se da su vatrogasni zadaci, kao što su penjanje do požarnih izlaza, poslovi na dizalici, razvaljivanje ulaza i spašavanje žrtava, značajno povezani s nekim čimbenicima kao što su visina, tjelesna masa, bezmasna tjelesna masa, postotak masnog tkiva, snaga stiska šake, broj izvedenih sklekova, broj izvedenih “trbušnjaka” i izdržljivost. Istraživači u raznim zemljama (npr. Francuskoj, Kanadi, SAD-u) dosta su proučavali fizičku pripremu vatrogasaca. Svaki vatrogasac trenira barem dva puta tjedno kako bi unaprijedio svoju mišićnu snagu, izdržljivost i kardiovaskularni status te kako bi smanjio postotak masnog tkiva i povecao mišićnu masu Te su aktivnosti nužne za održanje fizičke pripremljenosti vatorgasaca. U Belgiji gotovo da i nema istraživanja koja su se bavila vatrogascima. Svrha ovog istraživanja je dvostruka: (1) ispitati fizičku pripremljenost profesionalne vatrogasne jedinice i (2) provjeriti utjecaj trenažnog programa na razinu fizičke pripremljenosti te grupe. Metoda Uzorak ispitanika činilo je 95 profesionalnih vatrogasaca (42.0 ± 9.1 god.). Izmjerena im je tjelesna visina i tjelesna masa. Sastav tijela procijenjen je pomocu BIA. Tjelesna sposobnost određena im je uz pomoć baterije testova EUROFIT. Kroz period od četiri mjeseca ispitanici (N=81) su sudjelovali u programu vježbanja u okviru kojega su radili na unapređenju različitih komponenata fizičke pripreme. Vatrogasci su vježbali dva puta tjedno po 45 minuta pod vodstvom dva trenera. Svaki je trening bio isplaniran tako da je naglasak bio na razvoju različite komponente fizičke pripremljenosti, ali nije bilo ciljanog treninga glede različitih testova baterije EUROFIT. Pojedini treninzi bili su organizirani u okviru dva radna sata u vatrogasnoj stanici. Kako pohađanje treninga nije bilo obvezno, broj ispitanika po pojedinom treningu varirao je od 0 do 23, u prosjeku 13 po treningu. Prisustvovanje treninzima se bilježilo tako da se taj faktor mogao uzeti u obzir u okviru analize rezultata. Rezultati Izmjerene su visoke vrijednosti BMI (27.1±3.3 kg/m2) i postotka masnog tkiva (26.0±4.9%), kao i niska razina tjelesne izdržljivosti. Korelacijska analiza pokazala je da se motorički kapacitet smanjuje sa životnom dobi. Analiza razlika pokazuje da nema statistički značajnih razlika u tjelesnoj sposobnosti nakon provedenog četveromjesečnog trenažnog programa u odnosu na inicijalno stanje. Usporedba dviju grupa s obzirom na razlicit broj ispitanika koji su prisustvovali pojedinim treninzima nije pokazala statistički značajne razlike u tjelesnoj pripremljenosti. Zaključak Može se zaključiti da su (1) vatrogasci ispitivane vatrogasne jedinice prilično stari, visokih vrijednosti indeksa tjelesne mase te imaju visok postotak masnog tkiva; (2) ispitanici nisu postigli zadane norme u primjenjivanom zadatku izdržljivosti, (3) trenažni program nije polučio željene rezultate.Das Ziel dieser Studie war zweifach: die körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern zu überprüfen, und 2) den Einfluss eines Trainingsprogramms auf die körperliche Leistungsfähigkeit von professionellen Feuerwehrmännern zu testen. 95 professionelle Feuwerwehrmänner (die 42,0±9,1 Jahre alt waren) aus einer professionellen Feuerwehr aus Belgien nahmen an dieser Forschung teil. Es wurden sowohl die Statur und als auch die Hörpermasse gemessen. Die Hörperzusammensetzung wurde mittels der bioelektrischen Impedanzanalyse (BIA) geschätzt. Die körperliche Leistungsfähigkeit wurde mittels der EUROFIT-Testbatterie festgestellt. Während des viermonatigen Zeitraumes nahmen die Probanden zweimal pro Woche an einem Übungsprogram teil. Es wurden hohe Werte des Hörpermassenindexes (27,1±3,3kg/m2) und des Anteils vom Hörperfett (26,0±4,9%) erhalten, aber die Werte der Ausdauerkapazität waren niedrig. Die Horrelationsanalysen zeigten, dass sich die motorische Fähigkeit mit dem Alter verringert. Die Analyse von Unterschieden (Testmessung 2 – Testmessung 1) zeigte, dass bei den Feuerwehrmännern keine bedeutende Unterschiede in der körperliche Leistungsfähigkeit nach dem viermonatigen Trainingszeitraum entstanden. Der Vergleich von zwei Gruppen, die unterschiedlich oft an den Trainingsstunden teilgenommen haben, zeigte keine bedeutenden Unterschiede zwischen den Gruppen. Aufgrund der durchgeführten Studie sind die folgenden Schlussfolgerungen möglich: 1) Die Feuerwehrmänner, die an der Forschung teilgenommen haben, waren ziemlich alt, sie hatten sowohl einen hohen Hörpermassenindex als auch den hohen Anteil vom Hörperfett. 2) Die Ergebnisse des Ausdauer- Pendellaufes haben die antizipierte Norm nicht erreicht. 3) Das Trainingsprogram hat die gewünschten Ergebnisse nicht erreicht

Integrated management of atrial fibrillation in primary care:results of the ALL-IN cluster randomized trial

Aims To evaluate whether integrated care for atrial. fibrillation (AF) can be safely orchestrated in primary care. Methods and results The ALL-IN trial was a cluster randomized, open-label, pragmatic non-inferiority trial performed in primary care practices in the Netherlands. We randomized 26 practices: 15 to the integrated care intervention and 11 to usual care. The integrated care intervention consisted of (i) quarterly AF check-ups by trained nurses in primary care, also focusing on possibly interfering comorbidities, (ii) monitoring of anticoagulation therapy in primary care, and finally (iii) easy-access availability of consultations from cardiologists and anticoagulation clinics. The primary endpoint was all-cause mortality during 2 years of follow-up. In the intervention arm, 527 out of 941 eligible AF patients aged >65 years provided informed consent to undergo the intervention. These 527 patients were compared with 713 AF patients in the control arm receiving usual care. Median age was 77 (interquartile range 72-83) years. The all-cause mortality rate was 3.5 per 100 patient-years in the intervention arm vs. 6.7 per 100 patient-years in the control arm [adjusted hazard ratio (HR) 0.55; 95% confidence interval (CI) 0.37-0.82]. For non cardiovascular mortality, the adjusted HR was 0.47 (95% CI 0.27-0.82). For other adverse events, no statistically significant differences were observed. Conclusion In this cluster randomized trial, integrated care for elderly AF patients in primary care showed a 45% reduction in all-cause mortality when compared with usual care

Managing the Increasing Burden of Atrial Fibrillation through Integrated Care in Primary Care: A Cost-Effectiveness Analysis

INTRODUCTION: Integrated care for patients with atrial fibrillation (AF) in primary care reduced mortality compared to usual care. We assessed the cost-effectiveness of this approach. METHODS: Dutch primary care practices were randomised to provide integrated care for AF patients or usual care. A cost-effectiveness analysis was performed from a societal perspective with a 2-year time horizon to estimate incremental costs and Quality Adjusted Life Years (QALYs). A sensitivity analysis was performed, imputing missing questionnaires for a large group of usual care patients. RESULTS: 522 patients from 15 intervention practices were compared to 425 patients from 11 usual care practices. No effect on QALYs was seen, while mean costs indicated a cost reduction between €865 (95% percentile interval (PI) -€5730 to €3641) and €1343 (95% PI -€6534 to €3109) per patient per 2 years. The cost-effectiveness probability ranged between 36% and 54%. In the sensitivity analysis, this increased to 95%-99%. DISCUSSION: Results should be interpreted with caution due to missing information for a large proportion of usual care patients. CONCLUSION: The higher costs from extra primary care consultations were likely outweighed by cost reductions for other resources, yet this study doesn't give sufficient clarity on the cost-effectiveness of integrated AF care

Safety of off-label dose reduction of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

Aim: To investigate the effects of off-label non-vitamin K oral anticoagulant (NOAC) dose reduction compared with on-label standard dosing in atrial fibrillation (AF) patients in routine care. Methods: Population-based cohort study using data from the United Kingdom Clinical Practice Research Datalink, comparing adults with non-valvular AF receiving an off-label reduced NOAC dose to patients receiving an on-label standard dose. Outcomes were ischaemic stroke, major/non-major bleeding and mortality. Inverse probability of treatment weighting and inverse probability of censoring weighting on the propensity score were applied to adjust for confounding and informative censoring. Results: Off-label dose reduction occurred in 2466 patients (8.0%), compared with 18 108 (58.5%) on-label standard-dose users. Median age was 80 years (interquartile range [IQR] 73.0-86.0) versus 72 years (IQR 66-78), respectively. Incidence rates were higher in the off-label dose reduction group compared to the on-label standard dose group, for ischaemic stroke (0.94 vs 0.70 per 100 person years), major bleeding (1.48 vs 0.83), non-major bleeding (6.78 vs 6.16) and mortality (10.12 vs 3.72). Adjusted analyses resulted in a hazard ratio of 0.95 (95% confidence interval [CI] 0.57-1.60) for ischaemic stroke, 0.88 (95% CI 0.57-1.35) for major bleeding, 0.81 (95% CI 0.67-0.98) for non-major bleeding and 1.34 (95% CI 1.12-1.61) for mortality. Conclusion: In this large population-based study, the hazards for ischaemic stroke and major bleeding were low, and similar in AF patients receiving an off-label reduced NOAC dose compared with on-label standard dose users, while non-major bleeding risk appeared to be lower and mortality risk higher. Caution towards prescribing an off-label reduced NOAC dose is therefore required

External validation of six COVID-19 prognostic models for predicting mortality risk in older populations in a hospital, primary care, and nursing home setting

Objectives: To systematically evaluate the performance of COVID-19 prognostic models and scores for mortality risk in older populations across three health-care settings: hospitals, primary care, and nursing homes.Study Design and Setting: This retrospective external validation study included 14,092 older individuals of >=70 years of age with a clinical or polymerase chain reaction-confirmed COVID-19 diagnosis from March 2020 to December 2020. The six validation cohorts include three hospital-based (CliniCo, COVID-OLD, COVID-PREDICT), two primary care-based (Julius General Practitioners Network/Academisch network huisartsgeneeskunde/Network of Academic general Practitioners, PHARMO), and one nursing home cohort (YSIS) in the Netherlands. Based on a living systematic review of COVID-19 prediction models using Prediction model Risk Of Bias ASsessment Tool for quality and risk of bias assessment and considering predictor availability in validation cohorts, we selected six prognostic models predicting mortality risk in adults with COVID-19 infection (GAL-COVID-19 mortality, 4C Mortality Score, National Early Warning Score 2-extended model, Xie model, Wang clinical model, and CURB65 score). All six prognostic models were validated in the hospital cohorts and the GAL-COVID-19 mortality model was validated in all three healthcare settings. The primary outcome was in-hospital mortality for hospitals and 28-day mortality for primary care and nursing home settings. Model performance was evaluated in each validation cohort separately in terms of discrimination, calibration, and decision curves. An intercept update was performed in models indicating miscalibration followed by predictive performance re-evaluation. Main Outcome Measure: In-hospital mortality for hospitals and 28-day mortality for primary care and nursing home setting. Results: All six prognostic models performed poorly and showed miscalibration in the older population cohorts. In the hospital settings, model performance ranged from calibration-in-the-large 1.45 to 7.46, calibration slopes 0.24e0.81, and C-statistic 0.55e0.71 with 4C Mortality Score performing as the most discriminative and well-calibrated model. Performance across health-care settings was similar for the GAL-COVID-19 model, with a calibration-in-the-large in the range of 2.35 to 0.15 indicating overestimation, calibration slopes of 0.24e0.81 indicating signs of overfitting, and C-statistic of 0.55e0.71. Conclusion: Our results show that most prognostic models for predicting mortality risk performed poorly in the older population with COVID-19, in each health-care setting: hospital, primary care, and nursing home settings. Insights into factors influencing predictive model performance in the older population are needed for pandemic preparedness and reliable prognostication of health-related outcomes in this demographicGeriatrics in primary carePublic Health and primary carePrevention, Population and Disease management (PrePoD

External validation of six COVID-19 prognostic models for predicting mortality risk in older populations in a hospital, primary care, and nursing home setting

Objectives To systematically evaluate the performance of COVID-19 prognostic models and scores for mortality risk in older populations across three health-care settings: hospitals, primary care, and nursing homes. Study Design and Setting This retrospective external validation study included 14,092 older individuals of ≥70 years of age with a clinical or polymerase chain reaction-confirmed COVID-19 diagnosis from March 2020 to December 2020. The six validation cohorts include three hospital-based (CliniCo, COVID-OLD, COVID-PREDICT), two primary care-based (Julius General Practitioners Network/Academisch network huisartsgeneeskunde/Network of Academic general Practitioners, PHARMO), and one nursing home cohort (YSIS) in the Netherlands. Based on a living systematic review of COVID-19 prediction models using Prediction model Risk Of Bias ASsessment Tool for quality and risk of bias assessment and considering predictor availability in validation cohorts, we selected six prognostic models predicting mortality risk in adults with COVID-19 infection (GAL-COVID-19 mortality, 4C Mortality Score, National Early Warning Score 2-extended model, Xie model, Wang clinical model, and CURB65 score). All six prognostic models were validated in the hospital cohorts and the GAL-COVID-19 mortality model was validated in all three healthcare settings. The primary outcome was in-hospital mortality for hospitals and 28-day mortality for primary care and nursing home settings. Model performance was evaluated in each validation cohort separately in terms of discrimination, calibration, and decision curves. An intercept update was performed in models indicating miscalibration followed by predictive performance re-evaluation. Main Outcome Measure In-hospital mortality for hospitals and 28-day mortality for primary care and nursing home setting. Results All six prognostic models performed poorly and showed miscalibration in the older population cohorts. In the hospital settings, model performance ranged from calibration-in-the-large −1.45 to 7.46, calibration slopes 0.24–0.81, and C-statistic 0.55–0.71 with 4C Mortality Score performing as the most discriminative and well-calibrated model. Performance across health-care settings was similar for the GAL-COVID-19 model, with a calibration-in-the-large in the range of −2.35 to −0.15 indicating overestimation, calibration slopes of 0.24–0.81 indicating signs of overfitting, and C-statistic of 0.55–0.71. Conclusion Our results show that most prognostic models for predicting mortality risk performed poorly in the older population with COVID-19, in each health-care setting: hospital, primary care, and nursing home settings. Insights into factors influencing predictive model performance in the older population are needed for pandemic preparedness and reliable prognostication of health-related outcomes in this demographic

Stadsmonitor 2014 : veiligheidsgevoel en omgeving, welke factoren spelen een rol?

De vijfde editie van de Stadsmonitor verscheen in 2015. De Stadsmonitor schetst aan de hand van 167 indicatoren of de Vlaamse centrumsteden al dan niet naar meer duurzaamheid en leefbaarheid evolueren. De helft van de indicatoren wordt samengesteld op basis van administratieve databanken van de hogere overheden en de gemeenten zelf, de andere helft baseert zich op de grootschalige survey bij de stedelingen