A study from LIH published in the scientific open-access journal “PLOS One” reports for the first time reliable estimates on the prevalence of dementia and cognitive complaints among seniors in Luxembourg. Data of a cross-sectional study on a sample of 438 Luxembourg’s seniors aged over 64 from the MemoVie cohort was used (286 full and 152 partial participants).

Dr Magali Perquin, researcher at the Epidemiology and Public Health Research Unit of LIH’s Department of Population Health (headed by Prof Saverio Stranges) was the project leader of this study which was conducted jointly with the Centre Hospitalier de Luxembourg (Prof Nico Diederich) and a number of national and international partners (MemoVie group), and supported by the Luxembourg National Research Fund (FNR).

The researchers determined prevalence estimates of 3.8% (2.8 % to 4.8%) for dementia and 26.1% (17.8 % to 34.3%) for cognitive complaints. ‘The prevalence of dementia is surprisingly low compared to other countries. In comparison, the estimated mean prevalence is 6.4% for Europe, 7.1% for Latin-America and 8% for Canada’, stresses Dr Perquin. She explains further: ‘On the prevalence of cognitive complaints, there are not many field studies yet. A representative Australian study reported memory complaints for 33.5% of its participants. So, here the percentage determined in Luxembourg is also lower. Of course, when analysing and comparing our data, one has to consider that a bias or underestimation cannot be entirely excluded.’

Dr Perquin and co-workers think that the low occurrence of dementia and cognitive complaints among Luxembourg’s seniors is related to the high cognitive reserve observed in the Luxembourg population.  ‘Cognitive reserve is a brain resource developed by lifelong challenging cognitive activities’, explains Dr Perquin. ‘People with a high education level or those who practice several languages have a higher cognitive reserve. In Luxembourg the native population is multilingual, as the country has three official languages that are taught at school from the youngest age and intensively used in daily life.’

In a previous study, Dr Perquin and co-workers have shown that multilingualism is strongly associated with protection against cognitive impairment. ‘Given the findings, we believe that high cognitive reserve and consequently low levels of dementia could result from multilingualism,’ she states. A further hypothesis that rises from the study is that low occurrence of dementia may corroborate the longer life expectancy without disability observed in the country. Indeed, the “healthy life years at age 65” is 2.5 years greater, on average, in Luxembourg than in several other European countries.

Dr Perquin initiated a new research project this year, named MemoLingua, to better understand how multilingualism can delay the onset of cognitive impairment. With a new neuroimaging approach developed in collaboration with the “Centre Hospitalier de Luxembourg” (Prof Diederich) and “Forschungszentrum Jülich” in Germany (Prof Fink), she aims to determine the functional areas of the brain that are linked to cognitive reserve mediated by multilingualism.

Link to publication: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0138818