Prevalence of diabetes in various habitats of West Bengal, India.

The epidemiological profile data were collected for diabetes mellitus from the people living in three habitats (rural, industrial and urban) having considerable difference in their lifestyle and socio-economic status. Every 5th (occasionally 4th or 6th) member from each habitat was sampled; no restriction regarding age was kept during screening; OGTT (oral glucose tolerence test) was performed 2 hours after 75 g glucose, in those whose FBS (fasting blood sugar) was >90 mg/dl. Diagnosis of diabetes mellitus was ascertained, if the FBS was >120 mg/dl and/ or postglucose value was >200mg/dl. The per cent prevalence (among all aged people) of diabetes mellitus in rural, industrial and urban habitats were found to be: 1.66 +/- 0.58 (male 1.99 +/- 0.88, female 1.3 +/- 0.75); 3.00 +/- 0.74 (male 3.17 +/- 1.04, female 2.80 +/- 1.04) and 4.8 +/- 0.98 (male 5.31 +/- 1.43, female 4.27 +/- 1.32) respectively.

High-resolution analysis of Y-chromosomal polymorphisms reveals signatures of population movements from Central Asia and West Asia into India.

Linguistic evidence suggests that West Asia and Central Asia have been the two major geographical sources of genes in the contemporary Indian gene pool. To test the nature and extent of similarities in the gene pools of these regions we have collected DNA samples from four ethnic populations of northern India, and have screened these samples for a set of 18 Y-chromosome polymorphic markers (12 unique event polymorphisms and six short tandem repeats). These data from Indian populations have been analysed in conjunction with published data from several West Asian and Central Asian populations. Our analyses have revealed traces of population movement from Central Asia and West Asia into India. Two haplogrops, HG-3 and HG-9, which are known to have arisen in the Central Asian region, are found in reasonably high frequencies (41.7% and 14.3% respectively) in the study populations. The ages estimated for these two haplogroups are less in the Indian populations than those estimated from data on Middle Eastern populations. A neighbour-joining tree based on Y-haplogroup frequencies shows that the North Indians are genetically placed between the West Asian and Central Asian populations. This is consistent with gene flow from West Asia and Central Asia into India.

Ethnic populations of India as seen from an evolutionary perspective.

It is now widely accepted that (i) modern humans, Homo sapiens sapiens, evolved in Africa, (ii) migrated out of Africa and replaced archaic humans in other parts of the world, and (iii) one of the first waves of out-of-Africa migration came into India. India, therefore, served as a major corridor for dispersal of modern humans. By studying variation at DNA level in contemporary human populations of India, we have provided evidence that mitochondrial DNA haplotypes based on RFLPs are strikingly similar across ethnic groups of India, consistent with the hypothesis that a small number of females entered India during the initial process of the peopling of India. We have also provided evidence that there may have been dispersal of humans from India to southeast Asia. In conjunction with haplotype data, nucleotide sequence data of a hypervariable segment (HVS-1) of the mitochondrial genome indicate that the ancestors of the present austro-asiatic tribal populations may have been the most ancient inhabitants of India. Based on Y-chromosomal RFLP and STRP data, we have also been able to trace footprints of human movements from west and central Asia into India.

Projection of HIV infection in Calcutta.

Starting with the base year of 1991, the HIV infection projection for 1992-99 for the total, as well as various high-risk sub-populations of Calcutta, the first of its kind is provided. These projections are based on statistical methodology developed in this paper. Our methodology for spread of HIV infection takes into account various social interactions and practices and also uses available data. Rates of these interactions and practices and estimates of demographic parameters used in making projections were obtained primarily from surveys and census data. Since one of these estimated rates, that of HIV transmission rate through heterosexual encounters between an infected and an uninfected had a large range, we have provided two sets of projections based on the largest of these rates (worst-case scenario) and another that is consistent with the available data. The total projection of the number of HIV infected cases in Calcutta for 1999 is between 49,000 and 1,26,000. Separate projections are also provided for high-risk sub-groups. Among these, the sex workers expectedly will continue to manifest the highest numbers of newly infected cases. The temporal rate of increase in prevalence is projected to be alarmingly higher in the general population than even among sex workers, although the actual prevalence will continue to be the lowest in the general population compared to all other sub-groups of the population.

Genetic & cultural determinants of high-density lipoprotein cholesterol & serum triglycerides among Marwaris of Calcutta.

A genetic epidemiological study of serum lipid and lipoprotein levels was conducted among families of Marwaris residents in Calcutta. A total of 210 families, comprising over 100 individuals, were studied. Analyses were performed to estimate the genetic and environmental effects on the determination of high density lipoprotein cholesterol (HDL-C) and serum triglycerides (TG). Familial correlations for HDL-C and TG were estimated: parent-child and sib-sib correlations were found to be significant. Spouse correlations were not significant. Correlations between environments of siblings were significant. Genetic analysis of data on HDL-C and TG performed under a path model, taking genetic transmission and possible environmental associations among family members into account, indicated that lipid and lipoprotein levels adjusted and standardized for age, gender, education, occupation and disease status are primarily determined by genetic factors. The effects of environmental factors were also significant, although in comparison with genetic factors these effects were much smaller. The estimated genetic heritability for HDL-C was approximately 80 per cent, while that for TG was approximately 55 per cent. The genetic effects and environmental effects were not significantly different between adults and children.

Absence of HTLV-I infection in some Indian populations.

A total of 946 adults belonging to ten population groups of Uttar Pradesh and West Bengal were screened for HTLV-I using a gelatin particle agglutination test. The percentage of seroreactive cases varied from 0 to 5.8 per cent. The overall prevalence of seroreactivity was 2 per cent. Of the 19 seroreactive cases, 15 were subjected to Western blot analysis, none could be confirmed. HTLV-I infection is, therefore, absent in these populations.