Central Obesity in Africans: Anthropometric Assessment of Abdominal Adiposity and its Predictors in Urban Nigerians.

OBJECTIVE: To assess the occurrence of central obesity and identify its predictors in urban Africans using anthropometric tools. Another objective was to evaluate the anthropometric indices and their interaction with various cardiovascular risk factors. METHODS: In an obesity survey in a major Nigerian city, we measured the prevalence of central obesity in 998 randomly selected men and women using the IDF (International Diabetes Federation) criteria. Normalized values of three anthropometric indices, waist circumference (WC), WHR (waist-to-hip ratio) and WHtR (waist-to-height ratio) were also employed in assessing central adiposity and its predictors in the population. RESULTS: Most (61%) female participants had central obesity compared with 9% of the males based on the IDF waist criteria. Higher income level and physical inactivity were associated with central obesity (p < 0.001). In multivariate analyses, older participants and women were more likely to have central obesity (p < 0.001), but men had higher WHR than women at the same body mass index. WC was a stronger predictor of glucose intolerance than WHR, whereas WHR was more predictive of hypertension than WC. WHR showed a strong relationship with hypertension but not with glucose intolerance. WHtR was predictive of plasma glucose and diastolic blood pressure. WC showed strongest correlation with other indices. CONCLUSIONS: Central obesity was highly prevalent among women in this sample. It was associated with age, gender, socioeconomic status, physical inactivity, and it predicted glucose intolerance and hypertension. WC was a major determinant of both cardiovascular risk factors. It showed best correlation with other anthropometric indices.

Prevalence of diabetes and impaired glucose tolerance in Nigerians, Jamaicans and US blacks

The prevalence of type 2 diabetes, impaired glucose tolerance and associated risk factors were compared in sample surveys in Africa and the Caribbean with the Third National Health and Nutrition Survey (NHANES-III) from the United States. A total of 856 Nigerians, 1286 Jamaicans, and 1827 US blacks were included in the study. Body mass index (BMI) increased in a stepwise fashion across the three population groups, ie, 23 kg/m2 in Nigerians, 26 kg/m2 in Jamaicans, and 28 kg/m2 in US blacks. The persons aged 25-74, were 1 percent, 12 percent, 13 percent. Jamaican women were found to have the same prevalence of type 2 diabetes as US women (14 vs 13 percent, respectively); mean BMI was likewise very similar (28 kg/m2 in Jamaican and 29 kg/m2 in US women). BMI and waist-to-hip ratio were both associated with type 2 diabetes prevalence. Findings of this study confirm the marked gradient in type 2 diabetes risk among these genetically related populations and suggest that the blacks in the island nations of the Caribbean and the United States are at particularly high risk. Nigerians exhibited remarkably well-preserved glucose tolerance. Understanding the factors that limit the risk of type 2 diabetes in West Africa, beyond relative absence of obesity, would have considerable public health significance.(Au)