Cross-country skiing is associated with lower all-cause mortality: A population-based follow-up study.

The prospective relationship between leisure-time cross-country skiing and any fatal events is uncertain. We aimed to assess the associations of leisure-time cross-country skiing habits with the risk of all-cause mortality in a general population. A 12-month physical activity questionnaire was used at baseline to assess the frequency, average duration, and intensity of cross-country skiing in a prospective population-based cohort of 2087 middle-aged men from eastern Finland. Hazard ratios (HRs; 95% confidence intervals) were calculated for all-cause mortality. During a median (interquartile range) follow-up of 26.1 (18.7-28.0) years, 1028 all-cause mortality outcomes were recorded. In analyses adjusted for several established risk factors and other potential confounders, when compared to men who did not do any cross-country skiing, the HRs (95% CIs) of all-cause mortality were 0.84 (0.73-0.97) and 0.80 (0.67-0.96) for men who did 1-200 and >200 metabolic equivalent-hours per year of cross-country skiing, respectively. Similarly, compared to men who did not do any cross-country skiing, the corresponding adjusted HRs (95% CIs) for all-cause mortality were 0.84 (0.72-0.97) and 0.82 (0.69-0.97) for men who did 1-60 min/wk and >60 min/wk of cross-country skiing, respectively. The associations were similar across several subgroups, except for evidence of effect modification by body mass index and history of diabetes. Total volume as well as duration of leisure-time cross-country skiing is each inversely and independently associated with all-cause mortality in a middle-aged Caucasian male population.

Analysis of HIV-1 genetic subtypes in Finland reveals good correlation between molecular and epidemiological data.

The molecular epidemiology of HIV-1 genetic subtypes was studied in a cross-sectional sample collected from HIV-infected individuals living in Finland between 1988 and 1994 and compared with independently collected epidemiological data. Subtypes were determined by sequencing and phylogenetic analysis of the gag NCp7 and the env coding regions of PBMC provirus. Finnish viruses belonging to 7 subtypes were found. Two thirds (n = 70) of the sequences could be classified as subtype B, while others belonged to subtypes A, C, D, F and G and the circulating recombinant form AE(CM240) (n = 25). There were significant differences in gender distribution and mode-of-transmission between B-type infections and infections with the other subtypes. Most subtype B strains in Finland were associated with homosexual transmission and about half of these were acquired in Finland, while most individuals harbouring non-B infections indicated heterosexual transmission and direct or indirect contact with Africa or Southeast Asia. The heterogeneity of genetic subtypes in the country was in good agreement with the epidemiological data suggesting that a significant proportion of infections were imported. HIV-1 subtype determination may prove to be a valuable tool for providing objective epidemiological data.

HIV-1 subtype H near-full length genome reference strains and analysis of subtype-H-containing inter-subtype recombinants.

OBJECTIVE: To characterize near-full-length genomes of two HIV-1 subtype H strains. To extend sequence data to include full env and gag, and analyse and redefine, previously documented subtype H strains. DESIGN: Near-full-length genomes of HIV-1 env subtype H strains VI991 and VI997 were amplified, cloned, sequenced, phylogenetically analysed and compared with a panel of 23 HIV-1 group M reference isolates. The mosaic nature of previously published subtype H strains VI557 and CA13 was reanalysed. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMC) from individuals harbouring strains VI991 and VI997 were co-cultivated with PHA stimulated donor PBMC. Near-full-length genomes of VI991 and VI997, and gag and env genes of CA13 and VI557, were amplified by polymerase chain reaction, cloned and sequenced. Intersubtype recombination analyses were performed by similarity plot, bootscanning and phylogenetic analysis. RESULTS: Near-full-length clones of HIV-1 VI991 and VI997 are representative of subtype H. They form a phylogenetic cluster with the only previously described subtype H representative HIV-1 90CF056.1, regardless of the genome region analysed. VI557 is redefined as a gag and env subtype H mosaic virus containing unclassified fragments. CA13 is a complex intersubtype recombinant between subtypes A, H and unclassified strains CONCLUSION: Near-full-length genome analysis identified HIV-1 VI991 and VI997 as two new subtype H representatives. These reagents will allow defining and classifying non-recombinant as well as recombinant HIV-1, eventually helping to solve the puzzle of HIV-1 subtypes.

Near full-length genome analysis of HIV type 1 CRF02.AG subtype C and CRF02.AG subtype G recombinants.

HIV-1 CRF02.AG strains are prevalent in west and west-central Africa, suggesting a longstanding presence of these subtype A/G recombinants in the global epidemic. Cocirculation of CRF02.AG strains with other group M subtypes may give rise to HIV-1 recombinants constituting a mosaic genome comprising fragments of three different subtypes. We report on the genetic analysis of the near-full-length genomes of such recombinants (VI1035 and VI1197) as well as CRF02.AG strains in Belgian individuals. VI1035 and VI1197 may be the result of successful "second-generation" recombinations of HIV-1 strains CRF02.AG with, respectively, subtype C (VI1035) and G (VI1197) strains in a dually infected individual.

Virtually full-length subtype F and F/D recombinant HIV-1 from Africa and South America.

For reliable classification of HIV-1 strains appropriate reference sequences are needed. The HIV-1 genetic subtype F has a wide geographic spread, causing significant epidemics in South America, Africa, and some regions of Europe. Previously only two full-length sequences of each of the HIV-1 subtype F subclusters F1 and F2 have been described. To extend the knowledge of subtype F variation on a complete genome level, three new virtually full-length F1 sequences were cloned and sequenced, two from Africa and one from South America. Comparison of the new and previously described sequences showed that monophyletic clustering of the subcluster F1 of subtype F is consistent and highly supported in all genome regions. Two additional full-length strains were shown to be mosaics of subtypes F and D. These epidemiologically unrelated F/D sequences showed similar chimeric structure, suggesting that they may represent a previously undescribed circulating recombinant form (CRF). This was supported by partial sequences from three additional unlinked F/D recombinants. Genetic distances in the phylogenetic trees suggest that the recombination event leading to the putative CRF occurred relatively long ago, close to the divergence of the F1 and F2 subclusters. Furthermore, all five F/D recombinants are linked to the Democratic Republic of Congo, suggesting that the original recombination event took place in central Africa.

Characterization of subtype A HIV-1 from Africa by full genome sequencing.

OBJECTIVE: To improve our understanding of the genetic complexity of HIV-1 subtype A by increasing the number of subtype A isolates that have been sequenced in their entirety. METHODS: Nine HIV-1-seropositive patients from Africa living in Sweden contributed peripheral blood mononuclear cells (PBMC) for this study. Sequencing of the C2-V3 region of env had shown them to be subtype A. DNA from virus cultures was used for the amplification of virtually full-length proviral sequences, and the resulting fragment was sequenced. RESULTS: Six of the nine viral isolates were subtype A throughout the genome, or non-recombinant, and all of these were from east Africa. One virus from the Ivory Coast had the AG(IbNG) genetic form, a recombinant form common in west Africa. Two of the isolates were novel recombinants: one was an A/C recombinant and the other was A/D. Analysis of gag reveals three subclusters within the A subtype: one containing the AG(IbNG) subtype viruses, one containing the AE(CM240) viruses and one containing the non-recombinant A viruses. These genetic clusters have different geographical distributions in Africa. CONCLUSION: The prevailing view of HIV-1 subtype A forming a uniform band across the center of sub-Saharan Africa needs revision. In all probability, the most common subtype in west Africa and west central Africa is the AG recombinant, AG(IbNG), whereas in east central Africa it is the non-recombinant subtype A.

HIV-1 genetic subtype A/B recombinant strain causing an explosive epidemic in injecting drug users in Kaliningrad.

OBJECTIVES: To investigate the molecular epidemiology and genetic structure of the virus strain(s) causing an outbreak of HIV-1 infection in the Kaliningrad province of the Russian Federation and to investigate the relationship of this outbreak to some other emerging HIV-1 epidemics in the countries of the former Soviet Union. DESIGN: A molecular epidemiological investigation was conducted in the city of Kaliningrad amongst individuals recently diagnosed as HIV-1-positive. Samples were also collected from neighbouring Lithuania and from the Ukraine. METHODS: Incident and population data was collected from official health statistics in Kaliningrad. A standardized questionnaire was administered to newly diagnosed individuals to assess risk factors for HIV-1 infection. For genotyping, two regions of the virus (env C2-V3 and gag NCp7) were directly sequenced. RESULTS: The number of newly diagnosed individuals testing seropositive for HIV-1 infection in Kaliningrad rose from less than one per month to more than 100 per month during the period of July-October 1996. A total of 1335 new infections were identified between 1 July 1996 and 30 June 1997. The main reported risk factor for HIV-1 infection (80%) was injecting drug use, in particular with a locally produced opiate. Sequence analysis of patient viruses in Kaliningrad (n = 50) showed that the epidemic was caused by a highly homogenous HIV-1 strain, recombinant between the genetic subtypes A and B. Comparison with subtype A strains prevalent amongst injecting drug users (IDU) in the Ukraine showed that one of these strains was the direct subtype A parent of the epidemic A/B recombinant strain in Kaliningrad. CONCLUSIONS: The HIV-1 epidemic in Kaliningrad probably started from a single source, with rapid spread of the virus through the IDU population. The origin of the epidemic strain is a recombination event occurring between the subtype A strain virus prevalent among IDU in some southern CIS countries, and a subtype B strain of unknown origin.

[The identification of the genetic subtypes of HIV-1 circulating on the territory of Russia]. / Identifikatsiia geneticheskikh subtipov VICh-1, tsirkuliruiushchikh na territorii Rossii.

In this work the results of the genotyping of HIV strains obtained from 12 patients residing in Russia are presented. Proviral DNA from lysates of mononuclear cells was amplified with the use of primers, complementary to the conservative site of gene gag p7/p9 with the subsequent sequencing of the amplified material and phylogenetic analysis. 9 strains were classified with subtype B (most frequently occurring in Western countries), 2 of them being found closely related (probably, of African origin). In 2 patients infected from the same source the virus of unusual subtype F/1 was identified. This is the second case of the detection of this subtype in the world. One strain belonged to subtype G. in spite of the fact that in accordance with the epidemiological history only 3 patients got infection outside Russia, molecular epidemiological studies showed the genetic heterogeneity of the circulating strains and suggested the diversity of sources of the penetration of HIV infection to Russia.

HIV-1 D subtype viruses in Finland.

BACKGROUND: Human immunodeficiency virus (HIV)-1 strains are divided into seven genetic subtypes based on their gag sequences (A, B, C, D, F, G and H). Strains that have appeared in Finland show unusual heterogeneity compared to most industrialized countries, up to 25% of the strains belong to non-B subtypes (Liitsola et al., 1996). Three D subtype viruses have so far been identified in Finland. All patients were men, one Kenyan immigrant and two Finnish men, who had been infected in Africa. Here we describe some of the characteristics of the genomic diversity of these strains. METHOD: The genotype was determined by direct solid-phase sequencing of the p7 gag region. Phylogenetic analysis was done using standard methods. RESULTS: The analysis showed that the D subtype sequences clustered clearly distinctly from the other non-B strains, but did not suggest any transmission links between the three cases. From one case both cerebrospinal fluid (CSF) and blood leukocyte virus isolates were studied. The analysis revealed significant differences between the blood and CSF viruses. A four amino acid duplication and other differences were observed between the strains. CONCLUSION: The results confirm that D subtype viruses do indeed occur in Finland and they represent quite heterogenic strains within the D cluster.

Genetic characterization of HIV-1 strains in the Baltic countries and Russia.

Proviral nucleotide sequences from the p7 region of the gag gene were compared among 40 Baltic and Russian HIV-1 strains. 33 of the infected persons carried a virus belonging to subtype B. Thus subtype B, which is most prevalent in Western Europe, was the most common subtype in all 3 Baltic countries (Estonia, Latvia and Lithuania) and Russia, and was associated with homosexual transmission. It also seemed that viruses of the same origin have been circulating in these countries; most of the subtype B viruses studied (n = 22) belonged to a closely related virus pool with average inter-nucleotide sequence distances of 2.7%. In 7 cases, viruses of non-B subtypes were found (1 subtype D from Estonia, 1 subtype C from Latvia, 1 subtype A from Lithuania and 1 subtype G from Russia). Three closely related viruses (1 from Lithuania and 2 from Russia) remained unclassified.