Luxembourg: The conjunction of a longer disability-free life expectancy at 65 years, a high cognitive reserve, and a low estimates of dementia?

<p>Luxembourg: The conjunction of a longer disability-free life expectancy at 65 years, a high cognitive reserve, and a low estimates of dementia?</p

Prevalence of Dementia and Cognitive Complaints in the Context of High Cognitive Reserve: A Population-Based Study

<div><p>Objectives</p><p>This study aimed to assess the prevalence of dementia and cognitive complaints in a cross-sectional sample of Luxembourg seniors, and to discuss the results in the societal context of high cognitive reserve resulting from multilingualism.</p><p>Methods</p><p>A population sample of 1,377 people representative of Luxembourg residents aged over 64 years was initially identified via the national social insurance register. There were three different levels of contribution: full participation in the study, partial participation, and non-participation. We examined the profiles of these three different samples so that we could infer the prevalence estimates in the Luxembourgish senior population as a whole using the prevalence estimates obtained in this study.</p><p>Results</p><p>After careful attention to the potential bias and of the possibility of underestimation, we considered the obtained prevalence estimates of 3.8% for dementia (with corresponding 95% confidence limits (CL) of 2.8% and 4.8%) and 26.1% for cognitive complaints (CL = [17.8–34.3]) as trustworthy.</p><p>Conclusion</p><p>Based on these findings, we postulate that high cognitive reserve may result in surprisingly low prevalence estimates of cognitive complaints and dementia in adults over the age of 64 years, which thereby corroborates the longer disability-free life expectancy observed in the Luxembourg population. To the best of our knowledge, this study is the first to report such Luxembourgish public health data.</p></div

Outcome measure reported in published article or conference abstract.

<p>The histogram bars express the total of studies reporting on the primary outcome using the corresponding computation (CR or ERR expressed as arithmetic, geometric mean or both). The curve expresses the cumulative percentage of studies reporting an ERR. All studies reporting an ERR also reported a CR, except for one.</p

Cohort size distribution.

<p>103 cohorts contribute to the histogram, as the number of recruited participants remains unknown for one cohort. The box covers values ranging between the first (60.5 participants) and third (273 participants) quartiles. The red arrow points to the median cohort size (138 participants). Whiskers extend to values up to 1.5 times the interquartile range; dots show outliers (up to a maximum of 1,090 participants).</p

Population pyramid of the overall participants (A) and of seniors from Luxembourg (B): Comparison by gender and age (C).

<p>(A) Overall participants: per age group and gender, numbers compared to the total amount of subjects over 64 years old. (B) Luxembourgish seniors: per age group and gender, numbers compared to the total amount of subjects over 64 years old. (C) Representativeness depending on age groups and gender: the overall participants compared with the Luxembourgish seniors. Overall participants include full-participants and partial participants to the MemoVie study (<i>n</i> = 438). National statistics 2006, from: <a href="http://www.statistiques.public.lu/stat/TableViewer/tableView.aspx?ReportId=385&IF_Language=eng&MainTheme=2&FldrName=1" target="_blank">http://www.statistiques.public.lu/stat/TableViewer/tableView.aspx?ReportId=385&IF_Language=eng&MainTheme=2&FldrName=1</a> (<i>n</i> = 66,000)</p

Answers supplied for “lifestyle.”

<p>(A) Lifestyle distribution depending on population. (B) Representativeness depending on lifestyle: the overall participants compared to the Luxembourgish seniors. From the full-participants (<i>n</i> = 286), the overall participants (<i>n</i> = 421) and from the general population ≥ 65 years of Luxembourg (source: Statec 2001, <i>n</i> = 57,230). For this criteria, the overall participants (<i>p</i> < 0.0001) as well as the group of full-participants (<i>p</i> < 0.0001), were significantly different from the Luxembourgish seniors (Chi-squared test).</p

Characteristics for both full and partial participants.

<p>* to people of a similar age</p><p>^a<i>p</i>-values derived from Chi-squared tests;</p><p>^b<i>p</i>-values derived from Fisher's exact tests.</p><p>^# used with a cut-off based on the algorithm: Total score ≥ 3 or score for question 5 = 1 or score of the sum of questions A, 4, 5, 7, 8 ≥ 2.</p><p>Characteristics for both full and partial participants.</p

Variety of settings in which cohorts were recruited.

<p>Counts correspond to the number of cohorts (total per pie chart, n = 104) recruited at a site with the corresponding characteristic. Country income groups are based on World Bank classification [<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004784#pntd.0004784.ref035" target="_blank">35</a>].</p

Number of cohorts and corresponding participants recruited by country.

<p>Country names and world macro-regions are based on the United Nations Statistics Division (UN data) classification [<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004784#pntd.0004784.ref034" target="_blank">34</a>]. Countries that account for more than 8% of the total IPD are highlighted in yellow. N: Number of participants recruited. * D.R.C.: Democratic Republic of the Congo.</p

Type of <i>Schistosoma</i> infection required for recruitment in the study, depending on the endemic setting and parasite of interest.

<p>Numbers in bold are totals of participants (out of 20,517) recruited in the specified setting (single or mixed endemicity), applying the corresponding criteria (multiple <i>Schistosoma</i> infections tolerated or strictly excluded) and for the study of the corresponding parasite(s) (one or two <i>Schistosoma</i> species, and possibly other parasites as well). Numbers in brackets are corresponding totals of cohorts (out of 104).</p