Study Design and Characteristics of the Luxembourg European Health
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Bocquet et al. BMC Public Health (2018) 18:1169 https://doi.org/10.1186/s12889-018-6087-0 RESEARCH ARTICLE Open Access Study design and characteristics of the Luxembourg European Health Examination Survey (EHES-LUX) Valéry Bocquet1* , Jessica Barré1, Sophie Couffignal2, Marylène d’Incau3, Charles Delagardelle4, Georges Michel5, Marc Schlesser6, Saverio Stranges2,7,8, Andrea Kuemmerle2 and Maria Ruiz-Castell2 Abstract Background: The European Health Examination Survey in Luxembourg (EHES-LUX) is a population based survey performed from 2013 to 2015 with the aim to establish baseline information on the general health status of the Luxembourg population aged 25 to 64 years. The paper introduces the study design, recruitment method and representativeness of the sample, and summarizes the sociodemographic characteristics of participants and the prevalence of major health outcomes. Methods: EHES-LUX is based on a random sample representative of the population of Luxembourg based on gender, age and district of residence. The sample size of the study was determined to provide accurate prevalence estimates for major chronic conditions. During two visits, data were collected from participants through a questionnaire (personal data, health status and health care), medical examinations (anthropometric measures, electrocardiogram and spirometry) and biological analysis (blood, urine and hair). Means and frequencies were used to describe the general characteristics of the population and a one-way ANOVA to test the representativeness of the sample and the comparability of participants and non-participants. Results: A total of 1529 individuals participated in this study (participation rate of 24.1%). Differences between participants and non-participants based on gender, age and district of residence were corrected by sampling weights. The mean age (±SD) of participants was 44.9 (±10.1) years, of which 52.8% were women. Based on clinical measurements, nearly 20% of participants were obese and more than one in three participants were overweight. From measurements (respectively from self-report), 22.0% (respectively 12.2%) were hypertensive, 49.3% (respectively 22.5%) had hypercholesterolemia, 3.5% (respectively 3.7%) had diabetes and 7.6% (respectively 6.0%) had depressive symptoms. Conclusions: This nationwide epidemiological study on the general health status of Luxembourg residents provides updated prevalence estimates on a range of major health conditions. This information can be used by health authorities to evaluate policies and public health initiatives. At European level, prevalence data obtained by this studyfollowingtheEHES-ReferenceCommittee(EHES-RC) recommendations, will be comparable between European countries participating in this program. Keywords: European Health Examination Survey, Health outcomes, Luxembourg, Recruitment, Representativeness, Study design * Correspondence: [email protected] 1Competence Centre for Methodology and Statistics, Department of Population Health, Luxembourg Institute of Health, 1ab rue Thomas Edison, L-1445 Strassen, Luxembourg Full list of author information is available at the end of the article © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Bocquet et al. BMC Public Health (2018) 18:1169 Page 2 of 9 Background on the general health status of the Luxembourg popula- Registries and population-based surveys are valuable sources tion aged 25 to 64 years (as the minimum selected age of data on the health of populations, informing on a number range defined in EHES recommendations [9]). Individuals of challenges in health systems, such as the prevalence of who met the inclusion criteria filled in a question- health outcomes and risk factors. Health Interview Surveys naire. Physical measurements and biological samples (HISs) and Health Examination Surveys (HESs) are currently were also performed. the two main types of surveys. Information from HISs is obtained through interviews or self-administered question- Inclusion criteria naires, whereas HESs also include objective measures such Four inclusion criteria were applied in this study: 1) be as clinical examination and/or biological samples [1, 2]. After included in the national health insurance registry, 2) be the first HESs carried out in the 1950s and 1960s, many resident in Luxembourg, 3) be 25–64 years old, and 4) countries launched their own national health surveys [1, 3]. sign an informed consent form. People living in institu- However, the lack of a consistent methodology greatly tions (e.g. hospital, nursing home, prison) were not in- limited the comparison of results between countries. A sus- cluded in this study. tainable health monitoring system was suggested by the Community Public Health Programme 2003–2008 of the Sampling design and calculation European Union [4]. This resulted in the development of the Given the small size of the country, a one-stage sampling European Health Survey System, which includes the Euro- procedure was performed. In order to obtain a representa- pean Health Interview Survey (EHIS) and the European tive sample of the population, a random sample of resi- Health Examination Survey (EHES) [5]. Hence, EHES, as a dents of Luxembourg was defined stratified by age (25–34, standardised representative HES of the adult population of 35–44, 45–54, 55–64 years old), gender (male and female) European countries, has focused mainly on major chronic and district of residence (Luxembourg, Diekirch and Gre- diseases and their risk factors as its core measures. venmacher). The representative random sample was drawn In Luxembourg, no HES of the general health status from the national health insurance registry by the General had been done, with the exception of ORISCAV-LUX, a Inspectorate of Social Security (IGSS). Despite its relevance national survey which focused on determining the preva- in the stratification, nationality or country of birth was not lence of major cardiovascular diseases and their risk fac- provided by IGSS. With a 95% social coverage, this registry tors [6]. In 2013–2015 period, the Grand Duchy of is considered the most complete list of inhabitants available Luxembourg performed an EHES (EHES-LUX) with the in Luxembourg. The 5% remaining people are identified as aim of obtaining validated health information along with being mainly the employees of the European Commission the identification of the population’s health care needs. (around 12,000) who have their own health insurance EHES-LUX is designed to produce national health indi- system and also asylum seekers (around 1000 new individ- cators of significant clinical and public health relevance, uals each year) who just arrived and among which almost including cardiometabolic conditions, mental health, re- half are on the way to be registered. spiratory parameters, women’s health, thyroid disorders, To reach the adequate power and precision to perform and exposure to pollutants. age-gender subgroup comparisons, and to observe a 5% The Grand Duchy of Luxembourg (afterwards named prevalence of a specific condition in that subpopulation Luxembourg) is a small multicultural country located in [1], a minimum of 130 participants were fixed for each the heart of Europe (bordered by Belgium, France and age-gender subgroup. Based on this information and on Germany). Foreigners make up for nearly half of the the last Luxembourg census data in 2011 [10], the total population, counting some 150 nationalities including required sample size was 1490 participants. Since the those from the neighbouring countries. The country is minimal participation rate in previous EHES studies was divided into three geographic districts (Diekirch, 25% [2] and given the general declining trend in partici- Grevenmacher and Luxembourg) [7, 8]. pation rates over time in comparable surveys [11], the This paper introduces the study design, recruitment participation rate in this present study was assumed to process and representativeness of the EHES-LUX sam- be 23% corresponding to an estimation of the total num- ple, and summarizes the sociodemographic profile of ber of participants to be invited of 6475. Additional file 1: participants and the prevalence of major health out- Table S1 illustrates the projection of sample size calcula- comes in Luxembourg. tion of each age-sex domain based on the 2011 census. Methods Recruitment Study design A letter signed by the Ministry of Health and the EHES-LUX is a population-based survey performed from Luxembourg Institute of Health (LIH), which realised 2013 to 2015 that aims to establish baseline information the study, was sent to the randomly selected individuals Bocquet et al. BMC Public Health (2018) 18:1169 Page 3 of 9 in order to inform and invite them to participate in the Examinations included blood pressure and anthropo- survey. Along with the letter, an information booklet on metric measurements, spirometry, visual acuity, thyroid the survey, a response card and a pre-paid envelope function