High-sensitivity C-reactive protein, adiposity, and blood pressure in the Yakut of Siberia

C-reactive protein (CRP), an acute-phase reactant and marker of inflammatory response, is known to be an important predictor of future cardiovascular mortality, independent of other risk factors. The purpose of this research was to investigate the association between CRP, adiposity, and blood pressure in the Yakut, an indigenous Siberian population undergoing rapid cultural change. We conducted a cross-sectional study of 265 healthy Yakut adults in six villages in rural northeastern Siberia. Plasma CRP was measured by high-sensitivity immunoturbidimetric assay. The median CRP value was 0.85 mg/l, with values for the 25th, 50th, and 75th percentiles of 0.30, 0.85, and 2.28 mg/l, respectively. CRP was positively associated with age (r = 0.19; P = 0.002), but not plasma lipids or smoking status. CRP was associated with measures of central adiposity and characteristics of the metabolic syndrome, particularly in women. We found significantly higher CRP across quintiles (Q) of waist circumference for women (difference = 0.7 mg/l; P = 0.035), but not men (difference = 0.36 mg/l; P = 0.515). CRP was significantly associated with systolic blood pressure in men (difference, Q1 vs. Q5 = 1.1 mg/l; P = 0.044) but not women (difference, Q1 vs. Q5 = 0.03 mg/l; P = 0.713) after adjusting for age, waist circumference, and smoking status. CRP in the Yakut was considerably lower than was reported for other populations. The low CRP levels may be explained in part by a low prevalence of abdominal obesity. Among the Yakut, the high physical-activity demands of a traditional herding lifeway likely play a role through high energy expenditure and maintenance of negative energy balance. Our findings underscore the need for further research on the metabolic activity of adipose tissue, blood pressure, and inflammatory activation in non-Western populations.

Apolipoprotein B 3'-VNTR polymorphism in Eastern European populations

Apolipoprotein B 3' (3' ApoB) minisatellite polymorphism was studied in healthy unrelated individuals from the Russian Federation and the Republic of Belarus, in 10 populations from five ethnic groups: Russians, Byelorussians, Adygeis, Kalmyks and Yakuts. The analysis was carried out using PCR and electrophoresis followed by silver staining. Overall, 25 alleles of the 3' ApoB minisatellite, ranging from 25 to 55 repeats, were detected. Heterozygosity indices were high and varied from 0.73 to 0.84. The distributions of alleles of this minisatellite in the Caucasoid populations (Russians, Byelorussians and Adygeis) had a bimodal character, whereas that for Mongoloid populations (Kalmyks and Yakuts) had a unimodal distribution. Nei's genetic distances between the populations studied and some reference populations of Europe and Asia were estimated. Despite their allele distribution homogeneity, different East Slavonic ethnic groups were clearly resolved by multidimensional analyses. The East Slavonic and Adygei populations revealed a high similarity with European Caucasoids. The Mongoloid populations (Kalmyks and Yakuts) were considerably different from those of the European Caucasoid populations, but were similar to other Asian Mongoloid populations. The results demonstrate the variability of 3' ApoB minisatellite polymorphism not only in distant populations but also, to a certain extent, in genetically relative ones.

Polymorphism of trinucleotide repeats in loci DM, DRPLA and SCA1 in East European populations

A normal polymorphism at three triplet repeat loci (myotonic dystrophy (DM), dentatorubral-pallidoluysian atrophy (DRPLA) and spinocerebellar ataxia type 1 (SCA1)) were examined in healthy unrelated individuals from the Siberian Yakut (Mongoloid) population, the Adygei (Caucasian) population and nine East European populations: populations from Russia (Holmogory, Oshevensk, Kursk, Novgorod, Udmurts, Bashkir), two Ukrainian populations (Lviv and Alchevsk) and one Belarussian. The distribution of alleles for DRPLA and SCA1 were similar for all East-European populations. For the DM locus, East European populations had typical allele distribution profiles with two modes, (CTG)5 and (CTG)11-14, but some differences were found for the Bashkir population where alleles containing 11-14 CTG repeats had relatively higher frequency. The Yakut population had different allele spectra for all types of repeats studied. Higher heterozygosity levels and insignificant differences between expected and observed heterozygosity were found for all tested loci. The latter led us to suggest that the trinucleotide repeat loci analysed are not influenced by selection factors and could be useful for genetic relationship investigations in different populations.