From the old world to the new world: an ecologic study of population susceptibility to HIV infection

It remains unclear why the global distribution of human immunodeficiency virus (HIV), between and within continents, is so heterogeneous. This ecologic study of 34 populations of the Americas explored the hypothesis that populations differ in their intrinsic, biological susceptibility to HIV which, together with exposure, might determine the ultimate 'mature' prevalence. If true, national HIV prevalence in populations of the Americas should be predictable from each country's ethnic mosaic, inter-racial admixture and HIV prevalence in regions of Africa, Europe and Asia from where their ancestors migrated. For each country, the adult population (15-49years) was multiplied by the proportion corresponding to each ethnic group by HIV prevalencein the country/region of origin of each group, yielding the predicted prevalences, which were then compared with observed prevalences documented by UNAIDS for 2001. Predicted and observed HIV prevalences were highly correlated (r=0.70, P<0.001). In North America, predicted prevalences were within 0.5 percent of the observed values, except for African-Americans and African-Canadians. In Central and South America, differences between predicted and observed prevalences were <1.0 percent except in Honduras and Guyana. Some Caribbean countries had a predicted prevalence identical to the observed one, but there were outliers. Overall,predicted prevalence was 0.93 percent and observed prevalence 0.64 percent; two-thirds of this difference was attributed to Brazil. Although it was not possible to adjust to the confounding effects of sexual behavior and cofactors of transmission (such as sexually transmitted infections) because of the lack of nationally representative data for each and every country, a number of arguments reviewed in the paper suggest that confounders cannot explain all this association and that differential susceptibility might be an important determinant of steady-state HIV prevalence (AU)

Hepatitis A among health workers in Paris hospitals. Occupational Health Physicians of Paris Hospital (AP-HP)

To design a vaccination strategy against hepatitis A among hospital employees, we carried out a serological survey against hepatitis A virus (HAV) infection in 10 university hospitals in the Paris area. Subjects under 60 years of age were consecutively enrolled by occupational health services and tested for IgG to HAV by ELISA. Of the 1,516 subjects recruited, 926 were health workers (HW), 322 clerks, and 268 cooks or kitchen employees. Among HW and clerks the HAV seroprevalence was 53.8 percent (95 percent CI: 44.0-65.6), increasing with age and being higher among Europe (83.6 percent vs 45.6 percent, P < .001). Age correlated closely with the duration of hospital work, so only age was taken into account for further analysis. The HAV seroprevalences among HW and clerks originating from Europe were close (48.8 percent vs 42.6 percent) and remained so after adjustment for age. HAV seroprevalences in HW caring for adults and those caring for children were also similar (45.2 percent vs 40.1 percent). Seroprevalence was higher in assistant nurses than in nurses (51.3 percent vs 39.8 percent, P < .02). Among cooks and kitchen employees, 53.4 percent were HAV-seropositive. This study shows that hospital employees need not routinely be vaccinated against HAV; the decision should be taken by the occupational physician according to the type of work, but should be routine for cooks and kitchen employees. The need for prevaccinal screening for anti-HAV should be assessed in the light of employees' geographical origin and age.(Au)

Ancestral origin of variation in the triosephosphate isomerase gene promoter

A high frequency of nucleotide substitutions -5A/G, -8G/A, -24T/G in the triosephosphate isomerase (TPI) gene promoter has been demonstrated in African-Americans. The biological significance of these promoter variants, two of which, -8G/A and -24T/G, occur within regulatory elements essential for transcription, is controversial. The geographical distribution and frequency of allelic variation in the TPI promoter was determined in 378 unrelated normal subjects from Sub-Saharan African (n = 103), Caribbean (n = 26), Northern European (n = 57), Mediterranean (n = 55), Middle Eastern (n = 42), Asian Indian (n = 48) and Oriental (n = 47) populations. Five haplotypes were identified: the common haplotype, -5A-8G-24T, -5G, -8A, -5G-8A, and -5G-8A-24G. All, with the exception of the -8A haplotype, were present in geographically dispersed populations. The -5G allele, which was found at varying frequency in the African, Caribbean and Oriental populations. Phylogenetic comparison suggests this may represent the ancestral promoter haplotype. Homozygosity for the -5G-8A haplotype identified in four subjects confirms that these variants are not responsible for a null allele as formerly postulated. Linkage disequilibrium between related TPI promoter haplotypes, -5G, -5G-8A and -5G-8A-24G, and a single nucleotide polymorphism at nt2262 of the TPI gene supports a single ancestral origin for these mutations which preceeds the separation of African populations.(Au)

Estimating African American admixture proportions by use of population-specific alleles

We analyzed the European genetic contribution to 10 populations of Africans descent in the United States (Maywood, Illinois; Detroit; New York; Philadelphia; Pittsburgh; Baltimore; Charleston, South Carolina; New Orleans; and Houston) and in Jamaica, using nine autosomal DNA markers. These markers either are population-specific or show frequency differences >45 percent between the parental populations and are thus especially informative for admixture. European genetic ancestry ranged from 6.8 percent (Jamaica) to 22.5 percent (New Orleans). The unique utility of these markers is reflected in the low variance associated with these admixture estimates (SEM 1.3 percent -2.7 percent). We also estimated the male and female European contribution to African Americans. on the basis of informative mtDNA (haplogroups H and L) and Y Alu polymorphic markers. Results indicate a sex-biased gene flow from Europeans, the male contribution being substantially greater that the female contribution. mtDNA haplogroups analysis shows no evidence of a significant maternal Amerindian contribution to any of the 10 populations. We detected significant nonrandom association between two markers located 22 cM apart (FY-null and AT3), most likely due to admixture linkage disequilibrium created in the interbreeding of the two parental populations. The strength of this association and the substantial genetic distance between FY and AT3 emphasize the importance of admixed populations as a useful resources for mapping traits with different prevalence in two parental populations (AU)

Coverage of maternity care: a listing of available information

All women should have access to basic maternity care during pregnancy and delivery. This includes quality antenatal care, clean and safe delivery whether the delivery takes place at home or in a health facility, as well as postpartum care for mother and infant. A continuum of care is essential for both mother and baby, aimed at improving their health and preventing morbidity and mortality. This document brings together, in a standard format, data on coverage of maternity care worldwide. The data presented have been collected from a variety of sources, including health service reporting and surveys. Country, regional and global estimates derived from the information available are presented. The estimated show that in the developing world only two in three women receive any antenatal care, less than 55 percent of deliveries are attended by skilled personnel and just 40 percent take place in health institutions. Thus, currently more than 45 million pregnant women annually do not receive any antenatal care, some 75 million births still take place at home and almost 60 million without a skilled attendant present. Between 90 and 100 million women do not receive postpartum care. South-central Asia and Western and Eastern Africa contribute heavily to these numbers, accounting for 45 percent of the world's births and also showing the lowest coverage of care during pregnancy and delivery. Whereas women who deliver with the assistance of skilled personnel have usually had at least one antenatal care visit, the reverse does not apply; many women who receive antenatal care do not have a skilled attendant present at delivery. Care is needed throughout delivery and the postpartum period which are prime opportunities to prevent ill health and avert deaths. Nearly all maternal deaths occur in developing countries and among the most disadvantaged population groups. Greater coverage of care during pregnancy, delivery and the postpartum period will help to reduce deaths and disabilities of mothers and infants

Differences in mortality and morbidity in African Caribbean and European people with non-insulin dependent diabetes mellitus : results of 20 year follow up of a London cohort of a multinational study

OBJECTIVE: To examine differences in morbidity and mortality due to non-insulin dependent diabetes in African Caribbeans and Europeans. DESIGN: Cohort study of patients with non-insulin dependent diabetes drawn from diabetes clinics in London. Baseline investigations were performed in 1975-7; follow up continued until 1995. PATIENTS: 150 Europeans and 77 Africans with non-insulin dependent diabetes. MAIN OUTCOME MEASURES: All cause and cardiovascular mortality; prevalence of microvascular and macrovascular complications. RESULTS: Duration of diabetes was shorter in African Caribbeans, particularly women. African Caribbeans were more likely than the Europeans to have been given a diagnosis after the onset of symptoms and less likely to be taking insulin. Mean cholesterol concentration was lower in African Caribbeans than in Europeans. 59 Europeans and 16 African Caribbeans had died by the time of follow up. The risk ratio for all cause mortality was 0.41 (95 percent confidence interval 0.23 to 0.73) (P = 0.02) for African Caribbeans v Europeans. This was accentuated to 0.59 (0.32 to 1.10) (P = 0.1) after adjustment for sex, smoking, proteinuria, and body mass index. Further adjustment for systolic blood pressure, cholesterol concentration, age, duration of diabetes, and treatment made little difference to the risk ratio. CONCLUSIONS: African Caribbeans with non-insulin dependent diabetes maintain a low risk of heart disease. Management priorities for diabetes developed in one ethnic group may not necessarily be applicable to other groups (AU).

Hypertensive retinopathy in Afro-Caribbeans and Europeans: prevalence and risk factor relationships

The prevalence of hypertension is particularly high in people of black African descent throughout the world, and the consequences of hypertension, such as hypertensive heart and renal disease and stroke, are also more common. But there is little consensus on whether hypertensive retinopathy follows a similar pattern. We determined the prevalence of hypertensive retinopathy and its relationships with resting and ambulatory blood pressure in a population study of Afro-Caribbeans and Europeans aged 40 to 64 years in London, UK. Retinal photographs of 651 participants were graded for hypertensive retinopathy. Age- and sex-standardized prevalence of retinopathy was 11 percent (95 percent confidence interval, 8 percent to 14 percent) in Europeans and 21 percent (95 percent confidence interval, 16 percent to 26 percent) in Afro-Caribbeans (P<.0010, respectively. This ethnic difference in prevalence was greatest in normotensive women (8 percent in Europeans versus 20 percent in Afro-Caribbeans, P<.001). Resting systolic pressure was 8 mm Hg higher in normotensive Afro-Caribbean compared with European women, but this could not fully account for the ethnic difference in the prevalence of retinopathy. Examination of the different relationships of age and resting and ambulatory blood pressures with hypertensive retinopathy showed that these relationships were strongest in European women and weakest in Afro-Caribbean women. We concluded that hypertensive retinopathy is more common in Afro-Caribbeans, particularly women, and that ethnic differences in resting blood pressure cannot fully account for this. The relatively weak relationship between resting and ambulatory blood pressures and retinopathy in Afro-Caribbeans suggests of hypertensive retinopathy in this group (AU)

Identification of a unique group of human papillomavirus type 16 sequence variants among clinical isolates from Barbados

The naturally occurring sequence variation of human papillomavirus type 16 (HPV-16) was analysed by direct sequence analysis of the PCR products of the long control region (LCR), the E5 and E7 open reading frames (OFRs), a segment of the L2 ORF overlapping the early viral poly(A) signal and a small segment of the L1 ORF or clinical isolates from Barbados and The Netherlands. Despite the widely different geographical and ethnic origin of the two groups of specimens, sequence analysis revealed relatively few mutational differences. Analysis of the LCR and the E5 ORF appeared to be the minimum requirement for the correct positioning of these variants in the HPV-16 phylogenetic tree. Most of the Barbadian variants appeared to be located at a unique position in the HPV-16 phylogenetic tree, at the internal branch close to the point where the European and Asian branches diverge. In contrast, most of the Dutch samples were located on the European branch. (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)

Resting and ambulatory blood pressure differences in Afro-Caribbeans and Europeans

To investigate why mortality from stroke in people of Afro-Carribean origin is twice the average for England and Wales, we examined 11166 Europeans and Afro-Caribbean people in London. Age-standardized median systolic blood pressure was 6mm Hg higher (128 versus 122mm Hg) in Afro-Caribbean than European men and 17mm Hg higher (135 versus 118 mm Hg) in Afro-Carribean than European women. Migrants from West Africa and the Caribbean had similar bloood pressure. Body mass index was higher in Afro-Caribbean than European women, accounting for 4mm Hg of the systolic difference. Diabetes prevalence was 16 percent in Afro-Caribbeans and 5 percent in Europeans (P < .001), accounting for 1mm Hg of the diffference in systolic pressure in men and 2mm Hg in women. In participants not taking antihypertensive medication, mean fall in ambulatory systolic pressure between daytime and nighttime, adjusted for resting blood pressures, was 24 mm H g in Eropeans and 18 mm Hg in Afro-Caribbeans (P = 015), and percent day-night fall in systolic blood pressure adjusted for resting systolic pressure was 17 percent in Europeans and 12 percent Afro-Caribbeans (P < .05). This difference persisted when men and women and normotensive and hypertensive individuals were examined separately. We estimate that the differences in blood pressure between Afro-Caribbean and Europeans may be enough to account for ethnic differences in stroke mortality in women but not men. The reasons for the high prevalence of hypertension and related morbidity in this and other populations of African descent remain to be established (AU)

Psychiatric morbidity and compulsory admission among UK-born Europeans, Afro - Caribbeans and Asians in central Manchester

Psychaitry admissions in Central Manchester of Europeans, Afro-Caribbeans, and Asians (within three age-bands) were studied over four years. Among the Afro-Caribbean group there were more single or unemployed persons than in either the Asian or European groups, which suggested greater socio-economic disadvantages. Rates for first admissions and readmissions among Afro-Caribbeans were greater; among Asians they were similar except for the 16-29-year age-group, who tended to have lower rates than Europeans. A higher proportion of Afro-Caribbean and Asians were psychotic. In the Afro-Caribbean group, the raised rates of admission were largely attributable to increase rates of schizophrenia. The highest rate occurred in second-generation (UK-born) Afro-Caribbeans and was nine times that among Europeans. The police were more frequently involved in the admissions of Afro-Caribbean compared with Europeans or Asians. Higher proportions of Afro-Caribbeans and Asians who were readmitted were detained under the Mental Health Act 1983, when compared with Europeans (AU)

The age of infection with varicella-zoster virus in St. Lucia, West Indies

Sera from an age-stratified sample of 1810 people from the Caribbean island of St. Lucia were tested for antibodies against varicella-zoster virus. The results indicate that very few infections occur in childhood which agrees with clinical survey data from other tropical countries, but contrasts with the observed high case rate in children in temperate countries. The alternative hypothesis which may explain these results are discussed, and it is suggested that high ambient tempertaures interfere with the transmission of the virus. Irrespective of the cause the pattern of varicella incidence observed has important implications for any vaccination policy adopted in tropical countries (AU)

Diabetes mellitus after GDM

The impact of factors that influence diabetes mellitus (DM) and impaired glucose tolerance (IGT) incidence rates among former gestation diabetes mellitus (GDM) patients undermine attempts at interstudy comparisons. The recommended diagnostic standards for GDM by oral glucose tolerance tests (OGTT) are the O'Sullivan and Mahan criteria and the World Health Organization (WHO) criteria for IGT, which result in prevalence rates of 2.5 and 7.2 percent, respectively, when applied to 752 unselected pregnant women. In applying the O'Sullivan and Mahan criteria, the current open-ended definition of GDM without rules either to exclude overt diabetes uncovered by pregnancy or to require a return to a normal OGTT after pregnancy is shown to be a major source of differences in subsequent incidence rates of diabetes. For subsequent nonpregnant diagnosis, the differences between WHO and National Diabetes Data Group criteria and the allowable modifications within each of the diagnostic standards all result in different incidence rates of diabetes. Review of 12 worldwide studies of diabetes among former GDM patients and control subjects, the excess risk of diabetes among GDM patients was 18 percent in Copenhagen and 30.9 percent in Boston, MA. The potential impact of varying observation periods within studies was seen when the application of an actuarial method added a further 50 percent to the Boston incidence rates of both GDM patients and control subjects. Although the variability in diabetes incidence rates is wide, there is broad general agreement on the predictive nature of gestational blood glucose levels. (AU)

Ethnic differences in fasting plasma C-peptide and insulin in relation to glucose tolerance and blood pressure

The frequency of non-insulin-dependent diabetes mellitus (NIDDM) and of high blood pressure (or hypertension) is higher in some ethnic groups than in others for reasons that remain unclear. To investigate the mechanisms leading to these ethnic differences, plasma C-peptide and insulin concentrations were measured after overnight fast and during an oral glucose tolerance test in subjects aged 45-74 years sampled from the practice lists of two north west London health centres. Ethnic group was defined by grandparental origin as Afro-Caribbean in 106, Gujerati Indian in 107, and white European in 101. The total age-adjusted prevalence of NIDDM was 29 percent in the Afro-Caribbean, 30 percent in the Gujerati, and 3 percent in the white groups, respectively. Fasting C-peptide and insulin concentrations increased from the subgroup with normal glucose tolerance, through impaired glucose tolerance, to new NIDDM, and were lower again in subjects with known NIDDM. The odds ratio for new NIDDM was 1.87 (95 percent confidence interval 1.26-2.77) per 1 SD increase in fasting C-peptide, which was the most powerful independent indicator of new NIDDM (p=0.0005) and accounted for the effect of ethnic group. Fasting insulin had a similarly strong effect. There was no relation between any index of insulin secretion and blood pressure or hypertension. There were differences among the ethnic groups in the C-peptide response relative to the insulin response. These results suggest that factors determining insulin secretion and its hepatic clearance, possibly including dietary fat, are the main causes of ethnic variation in rates of new NIDDM. (AU)