Elevated copper in urine of Bangladeshi ethnic group living in the United Kingdom

Abstract

Inductively Coupled Plasma – Mass Spectroscopy (ICP-MS) was used to monitor urinary selenium, copper and zinc in a group of Bangladeshi (n=54), Indian (n=25), Pakistani (n=21), and White Caucasian (n=23) volunteers living in the UK. The most striking findings were far higher urinary copper levels (P<0.001) in the Bangladeshi group (median: 30.2 μg Cu/l) compared to other ethnicities (15.6 μg Cu/l, Pakistani; 14.8 μg Cu/l, Indian; 10.5 μg Cu/l, Caucasians) and to reference values reported for the UK population. Although no significant difference was found for Zn (P=0.22; medians: 430 μg Zn/l for Bangladeshis, 377 μg Zn/l for Pakistani, 350 μg Zn/l for Caucasians, 355 μg Zn/l for Indians), a significantly (P<0.001) higher Cu:Zn ratio was found for the Bangladeshis. Urinary Se of Bangladeshis (17.6 μg Se/l) was significantly (P<0.001) higher compared to Indians (13.8 μg Se/l) and Pakistani (4.1 μg Se/l), although urinary selenium was generally within the reported reference values reported for the UK population. Exposure to copper via ethnic food consumption or altered copper metabolism may contribute to higher levels of Cu and Cu:Zn ratio in the Bangladeshi group. Previous studies have correlated high serum copper levels to cardiovascular diseases (CVD), liver cirrhosis, chronic hepatitis and hepatocellular carcinoma (HCC). Bangladeshis have higher than UK average mortality from HCC and a disproportionately higher incidence of CVD. The high urinary Cu levels and Cu:Zn ratio detected in UK Bangladeshis may therefore reflect early onset of disease process, and may ultimately result in these conditions for members of the Bangladeshi community.