Ethnic differences in glucose tolerance: the diet (fatty acid) rather than genetic variation

This study examined the possible role of plasma fatty acids (FA) and serum lipid composition in ethnic differences in glucose tolerance (GT). In carefully taken population samples (77 percent response) aged 45-74 years, 75 g GT test results were compared between 100 African-Caribbeans (AfC) [53 women (w)], 188 white Europeans (60w) and 113 Gujratis (55w), excluding known diabetics. 2 hr normoglycaemic (ng) AfC (n=70) had considerably lower age and sex adjusted fasting non-esterified (NE) FA at 0.42 (mean, 95 percent CI 0.36-0.48) mmol/l vs 0.58 (0.52-0.64) mmol/l in Europeans and 0.58 (0.51-0.65) mmol/l in Gujratis (F=8.2, p=0.0004). NEfA were significantly (26-52 percent) greater in, with no ethnic difference between, glucose intolerants (GIT). Gujratis had higher proportion of serum linoleate (18.2n-6) at 35.3 (34-36.6 percent) than AfC (27.4, 26-29 percent) or whites (24, 23-26 percent) but half or less of docosahexanoate (22:6n-3) - 1.2(0.8-15)percent vs 2.7(2.3-3) percent and 2.4(2-2.8) percent in both ng and GIT groups. With BMI and insulin, NEFA were independently associated with 2 hr glucose accounting for much of the ethnic difference.(AU)

Dietary and other characteristics relevant for coronary heart disease in men of Indian, West Indian and European descent in London

The origins of the high standardized mortality ratio (SMR) for coronary heart disease (CHD) among Indians in Britain, and the low SMR for West Indian immigrants, have been explored by a community survey in London. Serum lipoproteins, plasma glucose, haemostatic factors and other putative risk characteristics were measured in 75 Indian, 64 European and 24 West Indian men aged 45-54 years. These represented 81 percent of men registered with a general practice and resident within a defined area. In 51 men, diet was assessed by 5-day weighed inventory. Plasma phospholipid fatty acids (PFA) were measured in 18 Indians and 19 Europeans with dietary records. The relatively high HDL and HDL2-cholesterol concentration, reduced fat intake, increased ratio of dietary polyunsaturated/saturated fat, relatively frequent use of alcohol, and lack of obesity in West Indians accorded with thier low SMR from CHD. By contrast, only the relatively low HDL and HDL2-cholesterol concentrations, infrequency of alcohol consumption, and lower proportion of PFA as n-3 fatty acids of marine origin afforded explanations for the high SMR of Indians. Hyperglycaemia appeared similarly prevalent in Indians and West Indians, but less common in Europeans. Of the haemostatic factors, West Indians had a relatively low VIIc (not statistically significant), while Indians had an increased platelet count and reduced platelet volume. Improved understanding of these ethnic differences in CHD mortality may depend upon elucidation of the contrasts in HDL-cholesterol concentration. (AU)