The waist circumference cut point for diagnosing the metabolic syndrome in 
sub-Saharan African subjects is based on that obtained from studies in European 
populations. The aim of this study was to measure the prevalence of obesity and 
related metabolic disorders in an urban population of African females, a group 
at high risk for such diseases, and to determine the appropriate waist cut point 
for diagnosing the metabolic syndrome. Anthropometry and fasting lipid, glucose 
and insulin levels were measured in a cohort of 1251 African females 
participating in the Birth to Twenty cohort study in Soweto, Johannesburg. The 
waist circumference cut points for diagnosing metabolic syndrome (as defined 
using the new harmonised guidelines), insulin resistance, dysglycaemia, 
hypertension and dyslipidaemia were obtained using receiver operator 
characteristic curve analysis. The prevalence of obesity, type 2 diabetes and 
metabolic syndrome were 50.1%, 14.3% and 42.1%, respectively. The appropriate 
waist cut point for diagnosing metabolic syndrome was found to be 91.5 cm and 
was similar to the cuts points obtained for detecting increased risk of insulin 
resistance (89.0 cm), dysglycaemia (88.4 cm), hypertension (90.1 cm), hypo-high 
density lipoproteinaemia (87.6 cm) and hyper-low density lipoproteinaemia (90.5 
cm). The present data demonstrates that urban, African females have a high 
prevalence of obesity and related disorders and the waist cut point currently 
recommended for the diagnosis of the metabolic syndrome (80.0 cm) in this 
population should be increased to 91.5 cm. This latter finding demonstrates a 
clear ethnic difference in the relationship between abdominal adiposity and 
metabolic disease risk. The similar waist cut points identified for the 
detection of the individual components of the metabolic syndrome and related 
cardiovascular risk factors demonstrates that the risk for different metabolic 
diseases increases at the same level of abdominal adiposity suggesting a common 
aetiological pathway.