Lipoprotein-genotype associations in Trinidadian neonates

OBJECTIVES: We hypothesized that common variation in the angiotensinogen (AGT), beta-3-adrenergic receptor. intestinal fatty acid-binding protein, serum paraoxonase, paraoxonase-2, hepatic lipase, apolipoprotein E (APOE), and Werner helicase (WRN) genes would be associated with variation in biochemical phenotypes in a previously unstudied neonatal sample. DESIGN AND METHODS: We examined associations of both nongenetic and genetic variables with plasma lipoprotein traits in neonates from Trinidad. RESULTS: Among nongenetic variables, we found significant associations between plasma concentrations of 1.) lipoprotein (a) [Lp(a)] and both ethnicity (p=0.037) and birth weight (p=0.001); 2)total cholesterol and gender (p=0.010); 3)triglyceride and birth weight (p=0.035); and 4)apolipoprotein A1 and gender (p=0.016). Among genetic variables, we found that: 1)common variation on chromosome 1q in AGT codon 235 was significantly associated with variation in plasma apolipoproteins Al (p<0.0001); and 3)common variation in APOE at codons 112 and 158 was significantly associated with variation in plasma triglycerides (p=0.013). CONCLUSIONS: The associations with AGT and WRN are novel and may have resulted either from direct influence of the genetic variants or through linkage disequilibrium with other functional loci, such as the familial combined hyperlipidemia locus on chromosome 1q in the case of AGT. Despite the fact that there are some limitations in making determinations from cord blood, the results suggest that there may be genetic determinants of plasma lipoproteins in neonates. (AU)

Ethnic differences in lipid and lipoprotein metabolism in pregnant women of African and Caucasian origin

AIMS: To investigate differences in serum lipid, lipoprotein and apolipoprotein concentrations in pregnant women of different ethnic origin. METHODS: Serum lipid, lipoprotein and apolipoprotein concentrations were measured in 232 women (114 Caucasians, 118 Africans/Afro-Caribbeans), who presented consecutively for screening for gestational diabetes in the third trimester of pregnancy. RESULTS: African/Afro-Caribbean pregnant women had lower serum concentrations of total cholesterol, low density lipoprotein cholesterol, triglycerides, and apolipoprotein B and higher high density lipoprotein cholesterol and Lp(a) lipoprotein concentrations compared with Caucasian women. Apolipoprotein A1 concentrations were similar in the two groups. The differences were not attributable to differences in weight, age, parity, or postload plasma glucose levels. CONCLUSION: Ethnic origin is an important determinant of serum lipid, lipoprotein and apolioprotein concentrations during pregnancy (AU)

Relationship of glucose intolerance to coronary risk in Afro-Caribbeans compared with Europeans

Afro-Caribbeans have low mortality rates from coronary heart disease, despite a high prevalence of diabetes mellitus. We examined 1166 Afro-Caribbean and European men and women aged 40-64 years in a community survey in London, UK. Prevalence of glucose intolerance (combining impaired glucose tolerance, new and known diabetes) was 31 percent in Afro-Caribbeans and 14 percent in Europeans (p<0.001). In men, the prevalence of probable coronary heart disease was 6 percent in Afro-Caribbeans and 13 percent in Europeans (p<0.01). Triglyceride was lower in Afro-Caribbeans than Europeans; in men, HDL cholesterol was higher. Afro-Caribbeab men were less centrally obese, while Afro-Caribbean women were more centrally obese than their European counterparts. Fasting and 2-h insulin levels were higher in Afro-Caribbeans than Europeans. Glucose intolerance was associated with high triglyceride, low HDL cholesterol and central obesity in European but not in Afro-Caribbean men. In Europeans, fasting triglyceride was 1.49 mmol/l in normoglycaemic and 1.89 mmol/l in glucose intolerant men (p<0.05), in Afro-Caribbean men triglyceride was 1.08 and 1.22 mmol/l, respectively. Waist hip ratio was 0.94 in normoglycaemic, and 0.98 in glucose intolerant European men (p<0.001). In Afro-Caribbean men, waist hip ratio was 0.93 in both groups. At each level of insulin, glucose or central obesity, triglyceride was lower in Afro-Caribbean men and women than in Europeans. We speculate that despite high insulin levels, Afro-Caribbeans have a favourable lipoprotein pattern which persists in the presence of glucose intolerance, and may be related to body fat distribution. This could begin to explain their low rates of coronary heart disease (AU)

The effect of demographic factors on serum lipids in diabetics of Trinidad and Tobago: possible association with ischaemic heart disease

This study was undertaken in order to investigate the effect of race, sex, weight, activity level and residential area on serum lipoprotein patterns, and to determine how this could possibly relate to the incidence ofischaemic heart disease (IHD). Seven hundred (700) diabetics attending outpatient clinics at Sangre-Grande and Port-of-Spain hospitals were screened. There were 132 males and 249 females of African descent; 99 males and 163 females of East Indian extract, and 19 males and 38 females of other ethnic origins. The average age of the population studied was 50 years (+/-15). The results obtained from this study indicate that diabetes mellitus is apparently more common in women than in men, particularly in those women who have borne children, and the incidence rises markedly after menopause. East Indians have higher triglyceride (TG), very low density lipoprotein cholesterol (VLDL-C) and low density lipoprotein cholesterol (LDL-C), but lower high density lipoprotein cholesterol (HDL-C) concentrations than their counterparts of African origin. TG, LDL-C and total serum cholesterol (TC) concentrations are highest in overweight-obese patients while HDL-C concentrations are highest in the lower weight division. The domestic working class, as well as those who were in retirement, have higher TG, LDL-C and TC than members of other occupational status. The fractions mainly affected by a residential area are TG, HDL-C and LDL-C. Moreover, diabetes mellitus and its consequent impact on lipoprotein homeostasis imposes a greater predilection to IHD, especially among members of the East Indian community.

The effect of blood sugar, therapy and blood pressure on lipoprotein profiles of diabetics in Trinidad and Tobago: possible association with ischaemic heart disease

The aim of this investigation was to examine the effects of fasting blood sugar, the type of therapy and blood pressure levels on lipoprotein profiles of diabetics in Trinidad and Tobago, and to determine how these biochemical and physiological risk factors may influence the development of ischaemic heart disease. Seven hundred (700) diabetic patients attending outpatient clinics at Sangre Grande and Port-of-Spain General Hospitals were surveyed. The data obtained in this study on the relationship of serum lipids to diabetic control support the hypothesis that poor control of blood sugar is conducive to accelerated atherosclerosis. Hypertensive patients and those maintained on insulin showed a greater disposition to ischaemic heart disease (IHD) than did non-hypertensives and patients maintained on oral hypoglycaemic agents, respectively. (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)

Lipoprotein profiles of diabetic patients in Trinidad and Tobago - the relationship to the development of ischaemic heart disease

The purpose of this study was to investigate the association between the lipoprotein profiles of diabetic patients in Trinidad and Tobago and the development of ischaemic heart disease. Approx. 700 diabetic patients were seen at specially arranged research clinics, convened in close conjunction with the diabetic outpatient clinics, held at the Sangre Grande and Port of Spain General Hospitals. Fasting blood samples were taken, on which measurements of serum triglycerides and lipoprotein cholesterols were done. Determinations of fasting blood sugar were also performed. In addition, the age, race, sex, blood pressure, electrocardiograph, diet and medication of the patients were examined. From this survey, it is evident that diabetes is more common in women than in men, particularly those who have bourne children, and the incidence rises markedly after menopause. The impact of the diabetic state on lipoprotein homeostasis imposes a greater predilection to ischaemic heart disease, especially amongst members of the East Indian comminity. The elevation of low density lipoprotein cholesterol levels seems to be the most potent risk factor of the profile, predisposing patients to a coronary event. The data obtained in this study on the relationship of serum lipids to diabetic control lend credence to the hypothesis that poor control of blood glucose is conducive to accelerated atherosclerosis. (AU)

Serum lipoproteins and susceptibility of men of Indian descent to coronary heart disease. The St James survey, Trinidad

Prevalence of coronory heart disease (CHD) and fasting serum lipoprotein concentration in ethnic groups of Port of Spain, Trinidad, were compared. In a total community survey of 1416 men aged 35-69 years, angina pectoris, a history of possible myocardial infarction, and major Q waves on the electrocardiogram were significantly more common in men of Indian descent than in other ethnic groups (relative risk about 3/1). Indians had significantly lower high-density-lipoprotein-cholesterol (HDLch) concentrations and significantly higher low-density-lipoprotein-cholesterol (LDLch) concentrations than other groups. After allowance for age and ethnic group, men with major Q waves or a history of possible myocardial infarction had a significantly greater ratio of LDLch/HDLch than men without either. Comparison of surveys in the Caribbean suggests that in this region CDH is prevalent only in communities in which a sizeable portion of men have an LDLch/HDLch ratio greater than 6 and an LDLch concentration above 5mmol/l (Summary)

Serum and liver triglycerides in malnourished Jamaican children with fatty liver

Measurements were made of triglyceride concentrations in the liver, serum, and serum lipoproteins in malnourished Jamaican children with fatty liver. The fasting serum triglyceride concentrations of the patients, before treatment, were highly variable, ranging from 55.6 to 353 mg/100ml. The patterns of change for serum triglyceride concentration during treatment were also variable. Patients were grouped according to whether the concentrations of serum triglycerides after recovery were higher than, lower than, or unchanged from, the concentrations before treatment. The three groupings then exhibited concentrations before treatment that fell in discrete ranges, being respectively low, high, or normal. There was no clinical difference among the three groups of patients. There was also no difference in the serum lipoprotein pattern nor in the composition of the serum very low density lipoprotein. The latter did not change during treatment. In most patients the fasting serum triglyceride concentrations before treatment appeared to be correlated with age. The difference between these findings and those reported from other countries are discussed. (AU)

Serum lipids and lipoprotein patterns in adults in a rural area of Jamaica - abstract

In a cardivascular-diabetes survey we examined 77 percent of a defined population of 695 rural Jamaican aged 25-64. Fastings and 1-hour post glucose load blood samples were drawn. Serum cholesterol, triglycerides and blood glucose were measured in the fasting and glucose in the 1-hour samples using Auto Analyzer techniques. Lipoprotein pater electrophoresis was run on the fasting serum within 48 hours of collection. A 12-lead electrocardiogram, blood pressure and a chest X-ray were taken and an effort pain questionnaire completed. Cholesterol values ranged from 98-545 Mg percent with a mean and standard deviation for males of 204.6, and 41.3 mg percent respectively and for females 226.3 and 37.5 mg percent respectively. Triglycerides ranged from 24-400 mg percent with a mean and standard deviation for males of 80.1 and 43.5mg percent respectively and for females 79.7 and 44.3mg percent respectively. The triglyceride distributions were markedly skewed. Cutting points to distinguish high from normal levels of lipids were determined statistically at the 95 percent points of the distributions for each sex and each of four age groups. Respondents were typed according to the method of Fredrickson et al. by refeference both to the electrophoretic strip and the lipid levels. Overall, 7.3 percent of males and 7.9 percent of females had both abnormal trips and lipids, with predominace of pattern types II and IV. The typeIV abnormality (high triglycerides) was associated with obesity and glucose intolerance type II (high cholesterol) only with glucose intolerance in women. Neither blood pressure nor cardiothoracic ratio was higher nor ECG ischaemia and angina more common among the abnormals than normals. Although high lipids levels are frequently found in Lawrence Tavern they are not apparently associated with manifestations of ischaemic heart disease or high blood pressure (AU)

Fat metabolism in protein malnutrition

The aim of this work was to make an assessment of the role of impaired lipoprotein secretion from the liver in the pathogenesis of the fatty liver caused by protein malnutrition in infants. The only evidence for this role prior to the study was that serum lipid levels were lower than normal in patients with fatty liver. The proposed method for measuring the incorporation of amino acids into the lipoproteins of children with fatty liver was used first with the rat as a model. It was found, in the development of such a model, that there are great variations in the level of liver fat induced by protein depletion in the rat. The variations depend on the age and nutritional state of the animal at the time of introducing the low-protein diet, and depend on the calorie intake while thay are on the diet. It was found that there were always measurable increases in the liver fat content when 70-gram rats were fed a 6 percent casein diet for 7 to 10 days. The use of this model with either single-injection or constant-infusion techniques showed that the incorporation of labelled amino acids into the serum lipoproteins was reduced. The greatest reduction was in the VLDL fraction of the low-density lipoproteins. There was no evidence for any significant contribution to the fatty liver from increased lipogenesis at the time when the defect in lipoprotein synthesis was apparent. The incorporation of methionine-S35 into the low-density lipoproteins of malnourished children was measured; although the changes were not consistent throughout the group studied, there was some evidence that the incorporation of the amino acid into lipoproteins was less when the children were malnourished than when they had recovered. Some modification in the design of future experiments of this type are discussed. Routine measurements of serum triglycerides in the patients during treatment showed that there are some differences between the pattern seen here and that reported elsewhere. The patients had very low triglyceride levels after recovery. These low levels were found to be due to the high fat content of the diet which the patients received during treatment. The changes in serum triglycerides induced by changing the fat content of the diet were found to be more rapid and to be relatively greater than any changes previously reported for adults. No explanation for this is given at present. The unusual patterns for serum triglycerides found during treatment of the malnourished patients with a low-fat diet appeared at first to be inconsistent with reduced synthesis of lipoprotein being associated with the fatty liver; other changes in fat metabolism concurrent with such a defect, however, could account for the unusual patterns.(AU)

A survey of blood glucose and serum lipoprotein in adults in a rural area of Jamaica - abstract

A community survey in Lawrence Tavern was started in October, 1969 in which all 544 perons aged 25-54 living in a particular area were requested to participate. Measurements taken included fasting and 1 hour blood glucose and insulin, serum cholesterol and triglycerides, lipoprotein electrophoresis, heamoglobin concentration, packed cell volume and haemoglobin type as well as blood pressure and anthropometric data. A chest X-ray and ECG were also taken. The aim of the study is to investigate the single joint distributions of the measurements and the relationships existing between glucose tolerance and cardiovascular parameters. Mean fasting blood glucose levels of the first 379 respondents show no trend with age in males and little evidence of any trend in females. However mean 1-hour post-Glucola levels show a striking trend with age. Of the 30 persons qualifying for the diagnosis of diabetes based on a 1-hour blood level of 180 mgm percent or greater, 6 were known diabetics, 13 were confirmed as newly discovered diabetics and 5 confirmed as non-diabetics by a full glucose tolerance test 6 refused the full test. Confirmed diabetic were more common among females than males aged 35-44 (6/92 as against 1/50) but no difference was found in the decade 45-54 (5/65 as against 7/65). Only one case (unconfirmed) eas found below age 35. Results for the other measurements made on blood constituents are not yet available (AU)

Diet, serum cholesterol, protein, blood haemoglobin, and glycosuria in a West Indian community: St. Kitts, W.I

Analyses of diets of St. Kitts negro labourers indicate that they are low in calories, protein, and especially fat, and resemble estimates from other West Indian groups. Serum cholesterol concentrations are lower in men than in women of like age, and those of women do not show a "menopausal" rise. Serum lipoprotein analyses in women yield similar information. Serum totals protein is higher than in North Americans because of high concentrations of gamma-globulin. Blood haemoglobin concentrations are lower than in North Americans, possibly as a result of a marginally adquate protein intake. Prevalence of glycosuria in about 14 per 1,000 at ages 20-49. Ischaemic heart disease attributable to coronary atherosclerosis, or thrombosis, was found in about 1 percent of men aged 40-49 and women aged 45-49. The data again exemplify the concurrence of low subsistence diets, largely of vegetable origin, and of hard work with a low prevalence of ischaemic heart disease.(AU)