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S O Stuver

Publications and source records attributed to S O Stuver.

29 records · Page 2Linked to original sources
PubMed1997

Heterosexual transmission of hepatitis C virus among married couples in southwestern Japan.

The heterosexual transmission of hepatitis C virus (HCV) remains controversial, and data from general populations are scanty. In this cross-sectional study, we assessed the seroprevalence of antibodies to hepatitis C virus (anti-HCV) and the presence and genotype of HCV-RNA among 109 married couples within an endemic, community-based Japanese population. Overall, 25% of the husbands and 32% of the wives had anti-HCV. Spouses with anti-HCV-positive partners were around 2 times more likely to have anti-HCV than spouses with anti-HCV-negative partners (p = 0.01). Of 6 couples in which both spouses had HCV-RNA, however, 3 presented discordant HCV genotypes (type 1b vs. 2b). The couples' anti-HCV concordance status was not significantly influenced by the presence or absence of HCV-RNA among anti-HCV-positive partners (odds ratio [OR]: 0.8 for wives, 0.6 for husbands), nor by the length of marriage, the number of pregnancies or the use of contraceptives. No significant associations with anti-HCV were observed for serum markers of sexually transmitted agents, including human T-lymphotropic virus (OR = 1.1, 95% confidence interval [CI] 0.5-2.3), Treponema pallidum (OR = 0.7; CI 0.1-6.1) and hepatitis B virus (OR = 1.6; CI 0.9-3.0). Our results suggest that the clustering of HCV infection among specific couples within this endemic population may not be attributable to heterosexual transmission. Follow-up studies are necessary to determine the risk of heterosexual transmission of HCV in endemic areas.

Adult↗
PubMed1997

The association between lactation and breast cancer in an international case-control study: a re-analysis by menopausal status.

In the large, hospital-based, international case-control study of breast cancer conducted by MacMahon and colleagues in the 1960s, no protective effect of lactation was observed. However, more recent reports have suggested that such an association may be limited to pre-menopausal women. Therefore, a re-analysis of the data from that original study was performed by menopausal status and with control for additional breast-cancer risk factors since identified. Overall, data from 4,671 parous pre-menopausal and 7,200 parous post-menopausal women were analyzed, from 7 different sites representing areas of high risk (Glamorgan, Wales; Boston, USA), moderate risk (Athens, Greece; Slovenia, ex-Yugoslavia; São Paolo, Brazil), and low risk (Tokyo, Japan; Taipei, Taiwan) of breast cancer. No significant effect of lactation was found for pre-menopausal or post-menopausal women from the high-, moderate-, or low-risk areas; the center-adjusted, combined odds ratio (OR) for having breast-fed was 1.05 (95% confidence interval, 0.86-1.29) among pre-menopausal and 1.04 (0.88-1.24) among post-menopausal women. Moreover, examination of cumulative duration of lactation did not support an inverse association between breast cancer and increased length of total breast-feeding. In conclusion, re-analysis of these data, by menopausal status and adjusting for age at first parity, age at menarche, age at menopause, body-mass index and years of schooling, did not reveal a protective effect of lactation or duration of lactation against breast-cancer occurrence among the pre-menopausal, parous women.

Adult↗
PubMed1997

Infection with hepatitis B and C viruses, social class and cancer.

The hepatitis B and C viruses (HBV and HCV) are major etiological factors in the occurrence of hepatocellular carcinoma (HCC) worldwide, but most especially in developing countries where the majority of liver cancer cases can be found. In parallel with the geographic distribution of HCC, high levels of HBV endemicity are concentrated in the developing world. The association between chronic infection with HBV and low social class is quite strong; socioeconomic factors such as low educational attainment, lower social stratum, and crowded urban residence have been reported to predict higher HBV chronic carrier prevalence in both developed and developing countries. More importantly, the effect of poverty on HBV endemicity is clearly evident among younger age groups, and earlier chronic HBV infection seems to increase the risk of development of HCC. As assays for detecting HCV antibodies have only recently become available, the data on the relationship between HCV infection and socioeconomic status are much fewer. However, the limited number of studies that have investigated the seroepidemiology of HCV report an association between higher prevalence of antibodies to HCV and indicators of low social class. It would appear that the striking correlation between HCC and low socioeconomic status is largely related to the impact of poverty on the spread of HBV and probably HCV.

Age Factors↗
PubMed1996

HCV infection and liver cancer mortality in a Japanese population with HTLV-I.

In a cohort study of human T-lymphotropic virus type I (HTLV-I) infection in Japan, 10 cases of liver cancer death occurred from 1984 through 1993. To analyze the role of hepatitis C virus (HCV), which has been associated with an increasing incidence of hepatocellular carcinoma (HCC) in Japan, a nested case-control study was performed. Five of the 10 liver cancer cases were positive for antibody to HTLV-I (anti-HTLV-I). The possible interaction between HCV and HTLV-I infections in the etiology of HCC was investigated, with each liver cancer case matched to 5 cohort controls by gender, age, serum sample date and anti-HTLV-I status. Using a matched analysis odds ratio (OR) were generated for the relationship between HCV serologic status and death liver cancer. Based on second-generation enzyme immunoassay with confirmation by recombinant immunoblot assay, 8 of 9 cases with adequate serum available (89%) and 9 of 50 (18%) controls were found to be positive for antibody to HCV (anti-HCV). Liver cancer death was highly associated with anti-HCV (matched OR = infinity; p < 0.001). Anti-HTLV-I seroprevalence was some what correlated with HCV infection. However, the high risk of liver cancer death observed for anti-HCV-positive Individuals in this population did not vary with respect to whether or not the subjects were also infected with HTLV-I.

Aged↗
PubMed1996

Evaluation of morbidity among human T lymphotropic virus type 1 carriers in Miyazaki, Japan.

Morbidity associated with human T lymphotropic virus type I (HTLV-I) infection was investigated in a Japanese population within an area in which HTLV-I infection is endemic. Of 1824 subjects enrolled in the Miyazaki Cohort Study between November 1984 and May 1991, 500 (27.4%) were seropositive for HTLV-I antibodies. As expected from previous studies, HTLV-I positively appeared to be associated with baseline history of anemia (adjusted odds ratio [OR]= 1.3; 95% confidence interval [CI]= 0.99-1.7) and kidney disease (OR=1.6; 95% CI= 0.91-2.9); a positive association also was noted for asthma in men (OR=3.4; 95% CI=1.2-9.8). Unanticipated findings included a relationship between HTLV-I infection and cardiac disease history (OR=1.4; 95% CI=0.94-2.2; HTLV-I carriers also were more likely to have an abnormal electrocardiogram at baseline (OR=1.5; 95% CI=1.2-1.9). Furthermore, an apparent protective effect for ulcers (OR=0.62; 95% CI=0.40-0.95) and diabetes (OR=0.49;95% CI=0.22-1.1) was observed. HTLV-I infection may modify the risk of specific disease outcomes by altering host immune function.

Adolescent↗
PubMed1994

Liver cancer.

The trends in liver cancer incidence and mortality were investigated by gender in Japan, Norway, Singapore, Spain, Sweden, the UK and the USA. Cancer Incidence in Five Continents, Vols I-VI, were the principal source of the analysis of age specific incidence rates by sex; additional incidence information was obtained from the published data of the Connecticut Tumor Registry and the Surveillance, Epidemiology and End Results Program in the USA. Mortality rates were calculated using the World Health Organization database. The trends observed were generally weak. Increasing occurrence of primary liver cancer was noted in Japan and the Nordic countries, although the rates seemed to be stabilizing or even decreasing in the most recent data from Sweden. By contrast, decreasing trends were apparent in Spain and Singapore. Changes in the rates appeared to be more evident or somewhat stronger for males than for females. Some biological explanations were offered to account for these trends. However, the dominant determinants of the apparent changes in the incidence and mortality of primary liver cancer were felt to be related to classification and coding revisions as well as to variations over time in diagnostic and certification practices.

Age Factors↗
PubMed1993

Analysis of anti-Tax antibody of HTLV-I carriers in an endemic area in Japan.

Sera from 1197 adult residents in Miyazaki district, an area in Japan endemic for human T-cell leukemia virus type I (HTLV-I), were tested for anti-Tax antibody by the recombinant Tax (r-Tax) Western blot assay. Among HTLV-I-seropositive individuals, including 21.5% of 484 males and 28.6% of 713 females, the prevalence of anti-Tax antibody were 59.6% and 58.3% respectively, with no apparent difference in age. There was a significant 6-fold difference in the prevalence of anti-Tax among seropositive subjects with titer > or = 1:8192 (84.6%) compared with those with the lowest titer of 1:16 (14.3%), suggesting the increased production of antibodies to viral structural proteins in anti-Tax-positive individuals. Furthermore, among those anti-Tax-positive subjects, the intensity of serum reactivity to r-Tax protein in the high antibody titer (1:1024 or higher) group was significantly stronger than that in the lower antibody titer (1:512 or lower) group. We also found that 1.6% (14/889) of individuals without detectable levels of HTLV-I antibody had anti-Tax antibody. HTLV-I pro-viral DNA signals could not be detected in DNA sample from the lymphocytes of these individuals by the nested polymerase chain reaction method. Further evaluation is needed to clarify the significance of an anti-Tax-only status population in which HTLV-I is endemic.

Adult↗
PubMed1993

Heterosexual transmission of human T cell leukemia/lymphoma virus type I among married couples in southwestern Japan: an initial report from the Miyazaki Cohort Study.

To identify factors that may modify the heterosexual transmission of human T cell leukemia/lymphoma virus type I (HTLV-I), 534 married couples enrolled in the Miyazaki Cohort Study between November 1984 and April 1989 were studied: 95 husband HTLV-I-seropositive (H+)/wife seropositive (W+), 33 H+/W-, 64 H-/W+, and 342 H-/W-. After 5 years of follow-up, seven seroconversions occurred and clustered significantly among serodiscordant pairs (relative risk [RR] = 41.2); the rate of transmission was 3.9 times higher if the carrier spouse was male (P = .19). Among H+/W- couples, husband's age > or = 60 years strongly predicted seroconversion in the wives (RR = 11.5). All 4 carrier husbands whose wives seroconverted had HTLV-I titers > or = 1:1024 (P = .04) and were anti-tax antibody positive (P = .06). In cross-sectional analysis, total parity also was independently associated with wife's serostatus but only length of marriage with husband's. Overall, sexual transmission of HTLV-I was primarily from older infected husbands to their wives, with husbands' viral status being an important factor.

Adolescent↗
PubMed1992

Case-control study of factors associated with human T-cell leukemia virus type I infection in southern Miyazaki, Japan.

BACKGROUND: An unusual age- and sex-specific distribution and a remarkably restricted geographic seroprevalence characterize human T-cell leukemia virus type I (HTLV-I) infection. Although the transmission routes of HTLV-I are known, these seroepidemiologic features cannot be fully explained. PURPOSE: This study was designed to identify potential characteristics associated with HTLV-I infection in a highly endemic Japanese community. METHODS: We evaluated occupational, residential, dietary, and medical histories in a case-control study conducted in two neighboring villages in southeastern Miyazaki Prefecture. One hundred forty-four case subjects and 276 control subjects, frequency matched by age, sex, and village, were interviewed. Village-specific profiles of demographic determinants of HTLV-I seroprevalence were generated using multiple logistic regression. RESULTS: Although a different pattern of factors was found for each village, occupations of the subjects and their fathers were associated with HTLV-I infection in both communities--farming in village A and fishing and farming in village B. For village A, there was more than a twofold association both with residence in the township for 55 years or more and with living in a particular area within the village. In addition, case subjects were more likely to have a mother who was deceased (odds ratio = 1.7; 95% confidence interval = 0.96-2.9). CONCLUSIONS: HTLV-I infection is characterized by a high degree of microepidemicity in this population, with seroprevalence related to both sociologic and geographic determinants. Moreover, as carriers' mothers themselves have a higher probability of being HTLV-I positive, an increased mortality among those infected with the virus is suggested.

Adult↗
PubMed1992

Determinants of HTLV-1 seroprevalence in Miyazaki Prefecture, Japan: a cross-sectional study.

To evaluate determinants of the prevalence of human T-cell leukemia virus type I (HTLV-I) antibody positivity in an endemic region, Miyazaki Prefecture, Japan, demographic and serologic data were collected on 7,055 individuals consecutively seen at Miyazaki City Health Promotion Center between September 1983 and December 1984. The overall HTLV-I seroprevalence was 8.5%; age and gender distributions of HTLV-1 antibody positivity were consistent with previous findings for endemic populations. The prefecture could be divided into two geographic areas based on seroprevalence: high prevalence (12.1%) in the southwest and medium prevalence (6.6%) for the rest of the prefecture. Current occupation in fishing, forestry, or livestock raising significantly correlated with HTLV-1 seropositivity [relative risk (RR) = 3.0, 2.5, 2.0, respectively]; farming also was associated but only in the medium prevalence region (RR = 1.3; p = 0.06). For a subset of 157 HTLV-I-positives and 175 negative controls screened for antibodies to the toxoplasmosis organisms, toxoplasma exposure was not significantly associated with HTLV-I infection. In this endemic Japanese population, both geographic and sociologic factors characterized the distribution of HTLV-I seroprevalence, reflecting transmission patterns and historical duration of the infection.

Adolescent↗