Search

Epidemiological surveys show a large variation of type 2 diabetes (DT2) prevalence from one country to another, suggesting ethnic discrepancies in insulin sensitivity. Many data seem to confirm this hypothesis. We will show them while concentrating on data provided by surveys performed in French-speaking countries. The mechanisms of the ethnic differences in insulin sensitivity are unclear and further insights are needed. More than genetic factors, environmental factors appear to be involved in the occurence of insulin resistance and DT2. The epidemic nature of obesity and subsequent DT2 in the world urges health authorities in each country to raise campaigns to promote changes in life style and nutritional habits before the announced pandemy of DT2 becomes reality.

This study was designed to estimate the prevalence of hypertension in Guadeloupe, the French West Indies, and to evaluate the risk factors associated with hypertension in the largest ethnic group, that of African origin. Households were randomly selected using a two-stage systematic sample of districts and then of houses; all adults aged 18 years in the household were included. In total, 1043 men and women were studied. Blood pressure, plasma glucose concentrations and gamma-glutamyl transferase activity were measured, hypertensive treatment and lifestyle factors recorded. The prevalence of hypertension, age-standardized to the Guadeloupe population was 21% and 26% in men and women of African origin, 28% and 22% in those of Indian-origin and 18% and 16% for other origins. The vast majority of subjects were unaware of their hypertension (90% of men, 74% of women). After adjustment for age, factors associated with high blood pressure in the 826 adults of African origin were: obesity, hyperglycemia, low educational level and family history of hypertension and of stroke. Additional factors in women were alcohol consumption, gamma-glutamyl transferase activity, physical inactivity, occupational category and a retired status, even after adjustment for age. Measures must be taken to diagnose hypertension early, particularly in individuals of African and Indian origin. An effective education program is needed, with an emphasis on life-style factors associated with obesity: diet and physical activity.

The prevalence of diabetes is known to be high in the West Indies, whereas CVD seems relatively rare. This apparently contradicts the existence of the insulin-resistance syndrome, a cluster of metabolic abnormalities supposedly favoring both diabetes and cardiovascular complications. To address the question of whether this contradiction could be accounted for by specific features of this syndrome, we compared 1505 Caucasian and 181 Afro-Caribbean men, all participants in the French Telecom Study. The Afro-Caribbeans were of the same age and had the same BMI as the Caucasians; they also had significantly higher subscapular skin-fold thickness and fasting insulin level, but similar BP and blood glucose level, and significantly lower plasma triglyceride level. Thus, although some features of the insulin-resistance syndrome were present (central adiposity and high insulin levels), none of the associated metabolic abnormalities were present. However, within the Afro-Caribbean group, subjects with plasma insulin concentrations above the median (> 52 pM) had higher mean BP and glucose and triglyceride levels compared with subjects with insulin concentrations < or = 52 pM (P < 0.001). After adjustment for age and BMI, these differences, though smaller, still were statistically significant. These findings confirm that higher insulin concentrations are associated with higher levels of potentially atherogenic and diabetogenic metabolic parameters. However, depending on ethnic origin, the mean levels of these parameters seem to be different, with the consequence that, even if they are elevated with increasing insulin levels, they may not reach values high enough to determine a substantial risk of disease.