Large Cohort Study (large + cohort_study)

Distribution by Scientific Domains


Selected Abstracts


Impact of determination of hepatitis B virus subgenotype and pre-core/core-promoter mutation for the prediction of acute exacerbation of asymptomatic carriers

HEPATOLOGY RESEARCH, Issue 4 2009
Tadashi Ikegami
Aim:, A large cohort study in Japan revealed that the specific viral profile may influence the fulminant outcome in acute hepatitis B virus (HBV) infections, while the genetic influence on outcome has not been clarified in patients with acute exacerbation of chronic liver disease caused by HBV. We experienced a case of fatal liver failure that developed as the result of chronic HBV infection. To determine possible genetic factor involving acute exacerbation, genetic analysis of serum from the patient and his siblings was performed. Methods:, HBV subgenotype as well as pre-core/core-promoter mutations of samples mentioned above were determined. Results:, Patient had HBV-Bj with pre-core (1896/1899) and core-promoter (1762/1764) mutations, the genomic profile frequently seen in fulminant hepatitis caused by acute HBV infection. Conclusion:, This result suggests that determination of the HBV subgenotype and pre-core/core promoter mutations could provide a rationale for development of a treatment strategy in asymptomatic HBV carriers. [source]


Oral contraceptive use, hormone replacement therapy, reproductive history and risk of colorectal cancer in women

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2008
Geoffrey C. Kabat
Abstract Evidence from epidemiologic studies suggests a possible role of exogenous and endogenous hormones in colorectal carcinogenesis in women. However, with respect to exogenous hormones, in contrast to hormone replacement therapy, few cohort studies have examined oral contraceptive use in relation to colorectal cancer risk. We used data from a large cohort study of Canadian women enrolled in a randomized controlled trial of breast cancer screening to assess the association of oral contraceptive use, hormone replacement therapy and reproductive factors with risk of colorectal cancer, overall and by subsite within the colorectum. Cancer incidence and mortality were ascertained by linkage to national databases. Among 89,835 women aged 40,59 at enrollment and followed for an average of 16.4 years, we identified 1,142 incident colorectal cancer cases. Proportional hazards models were used to estimate the associations between the exposures of interest and risk of colorectal cancer. Ever use of oral contraceptives at baseline was associated with a modest reduction in the risk of colorectal cancer (hazard ratio 0.83, 95% confidence interval 0.73,0.94), with similar effects for different subsites within the colorectum. No trend was seen in the hazard ratios with increasing duration of oral contraceptive use. No associations were seen with use of hormone replacement therapy (ever use or duration of use) or reproductive factors. Our results are suggestive of an inverse association between oral contraceptive use and colorectal carcinogenesis. However, given the lack of a dose,response relationship and the potential for confounding, studies with more complete assessment of exogenous hormone use throughout the life course are needed to clarify this association. © 2007 Wiley-Liss, Inc. [source]


Genetic Variation of the Ghrelin Signaling System in Females With Severe Alcohol Dependence

ALCOHOLISM, Issue 9 2010
Sara Landgren
Introduction:, Central ghrelin signaling is required for the rewarding effects of alcohol in mice. Because ghrelin is implied in other addictive behaviors such as eating disorders and smoking, and because there is co-morbidity between these disorders and alcohol dependence, the ghrelin signaling system could be involved in mediating reward in general. Furthermore, in humans, single nucleotide polymorphisms (SNPs) and haplotypes of the pro-ghrelin gene (GHRL) and the ghrelin receptor gene (GHSR) have previously been associated with increased alcohol consumption and increased body weight. Known gender differences in plasma ghrelin levels prompted us to investigate genetic variation of the ghrelin signaling system in females with severe alcohol dependence (n = 113) and in a selected control sample of female low-consumers of alcohol from a large cohort study in southwest Sweden (n = 212). Methods:, Six tag SNPs in the GHRL (rs696217, rs3491141, rs4684677, rs35680, rs42451, and rs26802) and four tag SNPs in the GHSR (rs495225, rs2232165, rs572169, and rs2948694) were genotyped in all individuals. Results:, We found that one GHRL haplotype was associated with reports of paternal alcohol dependence as well as with reports of withdrawal symptoms in the female alcohol-dependent group. Associations with 2 GHSR haplotypes and smoking were also shown. One of these haplotypes was also negatively associated with BMI in controls, while another haplotype was associated with having the early-onset, more heredity-driven, type 2 form of alcohol dependence in the patient group. Conclusion:, Taken together, the genes encoding the ghrelin signaling system cannot be regarded as major susceptibility genes for female alcohol dependence, but is, however, involved in paternal heritability and may affect other reward- and energy-related factors such as smoking and BMI. [source]


Hepatitis C virus infection: prevalence, predictor variables and prevention opportunities among drug users in Italy

JOURNAL OF VIRAL HEPATITIS, Issue 5 2003
G. L. Quaglio
Summary. The study assessed rates and predictor variables of hepatitis C virus (HCV) infection among drug users receiving pharmacological treatment for opiates addiction. There was a large cohort study in 16 public centres for drug users in north-eastern Italy, with data collected by standardized face-to-face interviews between February 2001 and August 2001. Of 1095 participants, 74.2% were HCV seropositive. Anti-HCV status was independently associated with duration of drug use of over 10 years, injecting as a route of drug administration, and hepatitis B virus (HBV) and human immunodeficiency virus (HIV) seropositivity. Further statistical analysis was conducted by dividing the subjects on the basis of the duration of heroin use: more or <10 years. In the multivariate analyses, route of drug administration and HBV status were associated with HCV seropositivity among both groups. Less education was associated with HCV among the shorter term drug users. HIV status and having a sexual partner with a history of drug use were associated with HCV seropositivity among the longer term drug users. Half of the short-term heroin users were still HCV seronegative when starting treatment, suggesting opportunities for reducing new HCV infections. Remarkable was the relationship between vaccination for hepatitis B and HCV serostatus. Being HBV seropositive was strongly associated with being HCV seropositive. But heroin users who had been vaccinated for HBV were not significantly more likely to be HCV seropositive than heroin users who were HBV seronegative. HBV vaccination does not provide biological protection against HCV; however, vaccinating heroin users against HBV may help to create a stronger pro-health attitude among heroin users, leading to a reduction in HCV risk behaviour. [source]


Sociocultural influences on infant feeding decisions among HIV-infected women in rural Kwa-Zulu Natal, South Africa

MATERNAL & CHILD NUTRITION, Issue 1 2005
Lucy N. Thairu msc
Abstract The promotion of exclusive breastfeeding for 6 months, followed by rapid transition to alternative food sources may be an important public health approach to the reduction of mother-to-child transmission of HIV through breastmilk. The basic ethical principle of ,informed choice' requires that HIV positive women are provided with adequate information about their options. However, information is only one factor that affects their decisions. The objective of this ethnographic study was to identify sociocultural influences on infant feeding decisions in the context of a large cohort study designed to assess the impact of a breastfeeding counselling and support strategy to promote exclusive breastfeeding on postnatal transmission of HIV in African women. Following an initial period of exploratory interviewing, ethnographic techniques were used to interview 22 HIV positive women about their views on infant feeding and health. Interviews were tape-recorded, transcribed and analysed with a text analysis program. Five themes of influences on feeding decisions emerged: (1) social stigma of HIV infection; (2) maternal age and family influences on feeding practices; (3) economic circumstances; (4) beliefs about HIV transmission through breastmilk; and (5) beliefs about the quality of breastmilk compared to formula. The study highlights the role of cultural, social, economic and psychological factors that affect HIV positive women's infant feeding decisions and behaviour. [source]