Objective: The metabolic syndrome is more prevalent in South Asians in Britain than in the general population. Furthering our understanding of the underlying mechanisms is important because of the increased risk of cardiovascular disease associated with the metabolic syndrome. As it has been proposed that increased activity of the hypothalamic pituitary adrenal axis might underlie the metabolic syndrome, we hypothesized that plasma cortisol levels would be higher in South Asians and that increased cortisol levels would be associated with cardiovascular risk factors comprising the metabolic syndrome. The aim of the study was to examine ethnic differences in cortisol levels and to compare the relationships between cortisol levels and cardiovascular risk factors in men from different ethnic groups.
Design: Cross-sectional population-based study, Newcastle upon Tyne, UK. (Newcastle Heart project). Participants One hundred men, 40-67 years old, of European and South Asian (Indian, Pakistani, Bangladeshi) ancestry, with and without cardiovascular risk factors of the metabolic syndrome.
Measurements: Measurement of plasma cortisol and corticosteroid binding globulin in stored sera.
Results: After adjustment for age and the presence of cardiovascular risk factors, mean cortisol was 27% (95% CI, 10%, 40%) lower in South Asians compared to Europeans. Cortisol levels were higher in all men with cardiovascular risk factors than those without.
Conclusions: Cortisol levels are lower in South Asian than in European men resident in the UK. Despite lower cortisol levels in South Asians, the relations between cortisol and cardiovascular risk factors remain strong.