Prevalence of Depressive Symptoms and Syndromes in Later Life in Ten European Countries the SHARE Study AUTHOR's PROOF
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BRITISH JOURNAL OF PSYCHIATRY (2007), 191, 393^401. doi: 10.1192/bjp.bp.107.036772 AUTHOR’ S P ROOF Prevalence of depressive symptoms and syndromes observed differences in depression prevalence and EURO–D scale scores? in later life in ten European countries METHOD The SHARE study Survey design E. CASTRO-COSTA, M. DEWEY, R. STEWART, S. BANERJEE, F. HUPPERT, The SHARE study (Borsch-Supan et al, C. MENDONCA-LIMA, C. BULA, F. REISCHES, J. WANCATA, K. RITCHIE, 2005) is a consortium survey of health in M. TSOLAKI, R. MATEOSand M. PRINCE older people across Europe. In this study, national survey organisations were res- ponsible for selecting household samples Background The EURO ^ D, a12-item Depression is common in later life. How- and conducting interviews in nationally representativerepresentative samples of people aged 50 self-report questionnaire for depression, ever, there is considerable variation in reported prevalence between studies world- years and over from ten countries: Denmark, was developed withthewith the aim of facilitating wide. There have been relatively few direct Sweden, The Netherlands, Germany, Austria, cross-culturalresearchinto late-life cross-national comparisons of the preva- Switzerland, France, Spain, Italy and Greece. depression in Europe. lence of depression using comparable The SHARE interview was specifically methodology, particularly with respect to designed to cross-link with the US Health Aims To describe the national variation sampling, definition and assessment of out- and Retirement Study (http://hrsonline. in depression symptoms and syndrome come. Methodological differences between isr.umich.edu) and the English Longitudinal prevalence across ten European countries. studies preclude firm conclusions about Study of Ageing(http://www.natcen.ac.uk/ cross-cultural and geographical variation elsa), with the advantage that it encom- Method The EURO ^ D was (Beekman et al, 1999). Improving the passes international variation in culture, health and social welfare systems and administered to cross-sectionalnationally comparability of epidemiological research constitutes an important step forward. public policy. Questions covered health representative samples of non- The EURO–D scale (Prince et al, 1999b) variables (self-reported health, physical institutionalised persons aged 550 years was developed to harmonise data on late- functioning, cognitive functioning, health (n¼2222777).The 777).The effectseffectsofage, of age, gender, life depression from 11 European popu- behaviour, use of healthcare facilities), psy- education and cognitive functioning on lation-based studies (EURODEP). The chological variables (depression, well- being, life satisfaction), economic variables individual symptoms and EURO^DEURO ^ D factor EURO–D scale has more recently been ad- ministered in a large, collaborative house- (current work activity, job characteristics, scores were estimated.Country-specific hold survey of nationally representative opportunities to work past retirement age, depression prevalence rates and mean samples of people aged 50 years and over sources and composition of current income, factor scores were re-estimated, adjusted from ten European countries: the Survey wealth and consumption, housing and edu- for these compositional effects. of Health, Ageing and Retirement in Eur- cation) and social support variables (assis- ope (SHARE). Observed differences in pre- tance within families, transfers of income Results The prevalence of all symptoms valence of depression in later life may be and assets, social networks, volunteer activ- ities). All of the above topics were rated in was higherinthe Latin ethno-lingualgroup accounted for by methodological, composi- tional or contextual factors. In this analysis an interview conducted in the respondent’s of countries, especially symptoms related we sought to answer three questions: home, with an average interview duration to motivation.Women scored higher on of around 90 min. Response rates were ac- affective suffering; older people and those (a)Are there differences in the prevalence ceptable throughout. The data are freely of depression between European coun- withimpairedverbalfluencyscoredhigher available to the research community tries, and are these consistent across (http://www.share-project.org). on motivation. the two factors that underlie the EURO–D measure and its 12 consti- Conclusions The prevalence of tuent symptom-based items? Measurements individual EURO^D symptoms and of (b)Are there compositional differences The EURO–D was originally developed to probable depression (cut-off score 54) between the older European popula- compare symptoms of depression in 11 varied consistently between countries. tions in terms of age and gender European centres (Prince et al, 1999b). Its Standardising for effects of age, gender, (found previously to be associated items are derived from the Geriatric Mental with the ‘motivation’ and ‘affective education and cognitive function State examination (GMS; Copeland et al, suffering’ factors respectively) (Prince 1986) and cover 12 symptom domains: de- suggested thatthese compositional et al, 1999a), education, and cognitive pressed mood, pessimism, suicidality, guilt, function (previously hypothesised to factors did not accountfor the observed sleep, interest, irritability, appetite, fatigue, be associated with motivation factor) variation. concentration, enjoyment and tearfulness. (Prince et al, 1999a)? Each item is scored 0 (symptom not pre- Declaration of interest None. (c)Do these compositional differences sent) or 1 (symptom present), and item Funding detailed in Acknowledgements. account, wholly or partly, for any scores are summed to produce a scale with 393 CASTRO-COSTA ET AL AUTHOR’SAUTHOR’ S PROOFP ROOF a minimum score of zero and a maximum in each country as mutually adjusted preva- list. In mostcountries more than half of of 12. lence ratios from Poisson regression models the sample were retired, the exceptions The psychometric properties of the with 95% confidence intervals. For each being TheNetherlands (32%), Spain EURO–D have been extensively investi- covariate, an effect by country interaction (35%), Switzerland (45%) and Greece gated and criterion validity demonstrated term was added to the final model to test (45%). Mean EURO–D scores were statisti- in the cross-cultural context. Principal com- for heterogeneity. Associations with factor cally different between countries (F¼68.79; ponents analysis generated two factors scores for the two sub-scales were esti- P50.00001) and were highest in France, (affective suffering and motivation) that mated as eta-squared statistics derived from Spain and Italy. The prevalence rates of were common to nearly every participating generalised linear modelling (GLM), again individual depressive symptoms are European country in the EURODEP studies with effect by country interaction terms displayed in Figs 1 and 2 for symptoms (Prince et al, 1999b) and for Indian, Latin- fitted in the final stage. Finally, ‘affective loading principally on affective suffering American and Caribbean centres in the 10/ suffering’ and ‘motivation’ scores were esti- and motivation respectively. These varied 66 Dementia Research Group pilot studies mated, adjusting for age, gender, education, consistently andsignificantly between coun- (Prince et al, 2004). Subsequent analysis verbal fluency and memory using GLM, tries (P50.001) for all 12 symptoms, with a of the EURO–Din the SHARE data-set and the country-specific prevalence of higher prevalencein France, Spain and Italy. using confirmatory factor analysis con- EURO–D depression (a score of 4 or over) Among affective suffering symptoms, de- firmed the two-factor solution of the was standardised separately for age, gen- pressed mood, tearfulness, fatigue and sleep EURO–D and suggested measurement in- der, education, verbal fluency and memory disturbance were most common. Among variance across the ten countries (common and for all effects simultaneously, using the motivation symptoms, poor concentration factor loadings and item calibrations), at direct method to the age, gender, education was reported most frequently. least for the ‘affective suffering’ factor and verbal fluency distribution of the Associations with affective suffering (Castro-Costa et al, 2007). Criterion valid- pooled data-set. All analyses were con- symptoms are summarised in Table 2: ity for this measure was demonstrated in ducted with Stata version 9.1 for Windows. depression, tearfulness, suicidality and fati- each of the EURODEP study sites, with gue were selected because they have the an optimal cut-off point of a score of 4 or highest factor loading for affective suffering above against a variety of criteria for clini- RESULTS (Castro-Costa et al, 2007). The four individ- cally significant depression (Prince et al, ual symptoms and the overall factor score 1999b). The EURO–D was also found to Based on probability samples in all parti- were each consistently associated with gen- be reliable and was validated against the cipating countries, the SHARE sampling der, with higher prevalence of symptoms criterion of DSM–III–R depression in older strategy aimed to represent the non- and higher factor scores among women, people in Spain (Larraga et al, 2006). institutionalised population aged 50 years with negligible influence of age, education The following aspects of cognitive func- and older. The SHARE investigators have or cognitive function. None of these effects tion