Cross-cultural comparison

Measures of quality of life (QoL) have been found to be predictors of mortality and morbidity; however, there is still limited understanding of the multifaceted nature of these measures and of potential correlates. Using two large populations from the UK and US, we aimed to evaluate and compare measured levels of QoL and the key factors correlated with these levels. Participants were 6,472 white subjects (1,829 women) from the Whitehall II Study (mean age 55.8 years) and 3,684 white subjects (1,903 women) from the Western New York Health Study (mean age 58.7 years). QoL was assessed in both using the physical and mental health component summaries of the short form-36 questionnaire (SF-36). Analysis of covariance was used to compare gender-specific mean scores for the two populations across several potential correlates (including socio-demographic, lifestyle and co-morbidity factors). Levels of reported physical QoL tended to be higher in the UK population (51.2 vs. 48.6) while mental QoL was higher in the US group (53.1 vs. 51.1). Age, sleep duration and depressive symptoms were the main factors correlated with both physical and mental QoL in both samples. Increasing age was associated with poorer physical health but higher mental health scores in both populations (P \ 0.001). Sleep duration below 6 or above 8 h was associated with lower levels of QoL. Depressive symptoms were strongly associated with poorer mental health scores (P \ 0.001) while higher BMI, lower physical activity levels and presence of cardiovascular disease were associated with poorer physical health in both samples and gender (P \ 0.05). There were consistent findings for correlates of QoL in this cross-cultural comparison of two populations from the UK and US. Strongest associations were between lifestyle and co-morbidity factors and the physical health component of the SF-36 rather than the O. H. Franco Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK O. H. Franco (&) Department of Epidemiology, Erasmus Medical Center, Office Ee21-79, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands e-mail: o.franco@erasmusmc.nl Y. L. Wong N.-B. Kandala A. Clarke S. Stranges Health Sciences Research Institute, University of Warwick Medical School, Coventry, UK J. E. Ferrie M. Kivimäki A. S. Manoux S. Stranges Department of Epidemiology and Public Health, University College London, London, UK J. M. Dorn Department of Exercise and Nutrition Sciences, State University of New York at Buffalo, Buffalo, NY, USA R. P. Donahue J. L. Freudenheim M. Trevisan S. Stranges Department of Social and Preventive Medicine, State University of New York at Buffalo, Buffalo, NY, USA A. S. Manoux Centre for Research in Epidemiology and Population Health, INSERM, Paris, France M. Trevisan Health Sciences System of the Nevada System of Higher Education, Las Vegas, NV, USA 123 Eur J Epidemiol (2012) 27:255–265 DOI 10.1007/s10654-012-9664-z