Medical intervention, contrasted with

It is less likely in other forms of liver disease, such as acute hepatitis and cirrhosis. Cirrhosis may actually protect against atherosclerosis [5, 8, 9]. The reasons for this are not clear. Secondary hypercholesterolaemia frequently occurs in cholestatic conditions, but usually does not require treatment [10]. Other risk factors for hyperlipidaemia and cardiovascular disease should be assessed, as their presence may independently indicate a need for medical intervention [9]. In PBC, patients with severe, chronic disease do not appear to have an increased cardiovascular risk as a result of their hypercholesterolaemia this may be due to the presence of cirrhosis. In contrast, in less severe PBC... 

Such epidemiological studies entail cohorts with moderately elevated PbB with no history of chelation treatment or undefined earlier exposures. Children sustaining excessive exposures above medical guidelines during such serial studies would be removed. By contrast, high-risk children presenting with PbB levels requiring that same level of intervention appear to show that maximum or peak Pb is the exposure metric with the closest association with toxic effects (Chisolm, 1982 Chisolm and Harrison, 1956). 

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