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Background: Depression and depressive symptoms have been repeatedly linked to elevated levels of C-reactive protein (CRP) but questions remain as to the statistical robustness of the association and particularly whether the association between depression and CRP reflects the presence of a chronic disease., Methods: A random sample of 6,126 men and women aged 45-69 years was examined in a cross-sectional study in seven towns in the Czech Republic. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression (CESD) scale., Results: Center for Epidemiologic Studies Depression score was significantly related to increased levels of CRP in a linear fashion. After controlling for a range of potential confounders, subjects with depressive symptoms (CESD score >or= 16) had CRP concentrations 0.43 mg/l (95% CI 0.16-0.72) higher than those without symptoms. The association remained significant when study sample was restricted to healthy subjects; among individuals who did not report any chronic disease, the difference between those with and without depressive symptoms was 0.44 mg/l (95% CI 0.14-0.74), and among persons who did not visit a doctor in the last 12 months the difference was 1.20 mg/l (95% CI 0.52-1.87)., Conclusions: These results confirm that there is a statistically robust association between depressive symptoms and increased levels of CRP. We did not find evidence that the association is due presence of a chronic condition.

Objective: The aim of this study was to investigate the association of the common apolipoprotein E gene (APOE) variants with cognitive function and cognitive decline in adult mid-life and explore the possibility that APOE genotype mediates the link between socioeconomic status (SES) and cognitive function., Methods: Data on cognitive function, as measured by five cognitive tests, together with APOE genotype were obtained in an occupational cohort (the Whitehall II study) of 6,004 participants aged 44-69 years (1997-1999). Cognitive change was examined in 2,717 participants who had cognitive function measured at baseline (1991-1993)., Results: SES based on civil service employment grade was strongly related to cognitive function. There was no association between APOE genotype and employment grade. In women, participants with APOE-epsilon4 had a lower memory score (p<0.05), but the result was sensitive to data from a small number of individuals. A marginal cross-sectional difference in the semantic fluency score was found (p=0.07), and there was a relative decline at follow-up (p<0.001, net change=-1.19; 95% CI, -1.90 to -0.49) in those with APOE-epsilon4 genotypes., Conclusions: APOE-epsilon4 has little influence on cognitive decline in mid-life, whereas SES is a strong determinant, although APOE genotype may emerge as an important factor in cognitive function in later life.

Recent evidence suggests that high rates of schizophrenia in first- and second-generation immigrants could be due to exposure to environmental factors such as viral infections in the host country. These findings are discussed alongside parallel data relating to other diseases such as multiple sclerosis and diabetes mellitus. It is argued that in each case the interaction between the environmental agent and constitutional factors related to the immune system need to be considered.