Obesity, hyperglycaemia and hyperinsulinaemia in Jamaica [abstract]

ABSTRACT

Insulin resistance (IR), with its associated with higher circulating levels of insulin and glucose occurs in non-insulin-dependent diabetes (NIDDM) and obesity and is often present in hypertension (HTN). The prevalence of these diseases is high in Jamaica and this study sought to determine the relationship between several measures of obesity, hyperinsulinaemia and hyperglycaemia. Anthropometric and glycaemic status variables were assessed in 469 men and 704 women. Fasting C-peptide and insulin levels were measured in subjects from the top and bottom 15 percent of a Body Mass Index (BMI) frequency distribution curve. The glucose/insulin ratio (Glu/Ins) was used as a measure of IR and the C-peptide/insulin as a measure of hepatic extraction. The obese (BMI> 32kg/m2) group had higher levels of fasting (Fglu) and postchallenge (2hGlu) glucose, insulin, C-peptide and lower Glu/Ins than the thin group (BMI<20kg/m2), suggesting greater IR. Forty-six percent of the obese were hyperinsulinaemic compared to 25 percent of the thin. Obese normogloglycaemics had higher levels of Fglu and 2hGlu than the thin normoglycaemics. Levels of glucose and insulin correlated with waist-hip ratio (WHR), waist and conicity measurements but not with BMI in the obese. In the thin group, there was correlation between glucose levels and WHR, Hyperglycaemia was more common in women. The higher levels of Fglu and 2hGlu in obese normoglycaemics suggest that the mechanisms responsible for the association between obesity and hyperglycaemia may already be operating. The association between hyperglycaemia, WHR and conicity but no BMI, suggests that `central tendency' may be a more useful indicator of dysglycaemia. The higher levels of hepatic extraction in the obese group indicate that the observed hyperinsulinaemia is not due to low hepatic extraction. (AU)