Background Severe mental illnesses (SMI) may be independently associated with cardiovascular risk factors and the metabolic syndrome. 2.37) for diabetes and 1.11 (0.91 to 1 1.35) of hypertension. Restricting SMI to schizophreniform illnesses yielded a pooled risk ratio for diabetes of 1 1.87 (1.68 to 2.09). Total cholesterol was not higher in people with SMI (Standardized Mean Difference -0.10 (-0.55 to 0.36)) and there were inconsistent data on HDL, LDL and triglycerides buy 507-70-0 with some, but not all, reporting lower levels of HDL cholesterol and raised triglyceride levels. Metabolic syndrome appeared more common in SMI. Conclusion Diabetes (but not hypertension) is usually more common in SMI. Data on other risk factors were limited by poor quality or inconsistent research findings, but a small number of studies show greater prevalence of the metabolic syndrome in SMI. Background People with severe mental illness (SMI) such as schizophrenia and bipolar affective disorder are at greater risk of coronary heart disease (CHD) than people without such diagnoses [1-3]. The mutable risk factors for CHD are smoking, hypertension, diabetes mellitus and high ratio of total cholesterol to High Density Lipoprotein (HDL) cholesterol. Although, many people with SMI are likely to be heavy smokers, and less likely to succeed in smoking cessation , the relationship between SMI and CHD mortality is not wholly explained by smoking and there has been increasing interest in the prevalence of diabetes and dyslipidaemia in people with SMI. Second generation antipsychotics may exacerbate features of the metabolic syndrome including abnormal glucose and lipid profiles [2,5,6]. But recent reviews have suggested that people with SMI are at risk of the metabolic syndrome including diabetes irrespective of antipsychotic therapy [7,8]. People with SMI share other risk factors including unhealthy lifestyles CCNE2  obesity and positive family histories . We hypothesised that there were differences in the risk of abnormal glucose, blood pressure or lipid abnormalities between people with and without SMI. We searched for studies comparing the risk of diabetes or hyperglycaemia, hypertension, dyslipidaemia or buy 507-70-0 a combination of these factors (as components of the metabolic syndrome or as an overall CHD risk score). We did not aim to assess smoking since a systematic review has recently been published  and the conclusions are uncontroversial. Methods We searched for studies of diabetes or hyperglycaemia, hypertension, dyslipidaemia or combinations of these factors in people with and without SMI and systematically reviewed the literature to appraise the epidemiological evidence. We estimated the strength of any association between SMI and these CHD risk factors. Data sources and search strategy We electronically searched MEDLINE, EMBASE, CINAHL, the Cochrane Library database & PsycINFO for articles in English, French, German, Italian or Spanish and sought papers published between 1897 and 2005 inclusively. We hand searched reference lists of review papers and made contact with authors and researchers to ensure comprehensive coverage. We piloted and modified our search strategy to retrieve all key papers in this field. The most sensitive search included three broad search themes namely 1) Terms related to SMI, 2) cardiovascular diseases and 3) the risk factors of diabetes, lipid disorders, hypertension, the metabolic syndrome and cardiovascular risk scores. Synonym lists were constructed for each theme and the databases were buy 507-70-0 searched using these synonyms as both thesaurus and free-text terms (Additional file 1). For SMI, we included all terms relating to psychotic disorders, schizophreniform disorders, bipolar affective disorders and psychotic depressive disorder. Similarly all synonyms for search themes 2 and 3 were employed. We included an additional wider term for all those mental disorders in a final search combined with both search themes 2 and 3. A combination of these two approaches provided the most reliable results. Study selection We included cross sectional, case-control, cohort and intervention studies in which the risk factors of interest were available in a group with.