High non-responsiveness of males and the elderly to standard hepatitis B vaccination among a large cohort of healthy employees.

BACKGROUND: Hepatitis B virus infection is a major health problem. Although non-response is known to increase with age, hepatitis B vaccinations are considered to have only minor non-response rates (anti-HBs<10IU/L) in healthy subjects. OBJECTIVES: The aim of this study was to quantify immunosenescence in a large retrospective cohort of 11,439 healthy adults who received HBV immunisation according to the standard vaccination regime. STUDY DESIGN: We evaluated the response to the standard three-dose vaccination regimen, consisting of 20-µg doses of the HbsAg recombinant DNA hepatitis B vaccine, among 11,439 healthy employees using a retrospective cohort design. Logistic regression was applied to predict the non-response rate, and multivariate regression analysis was applied to predict antibody response. Predictors of responsiveness included sex, age and time between the last vaccination and antibody titre measurement. RESULTS: From the age of 29 on in men and 43 on in women, more than 5% of subjects did not respond. Compared with women, men had a higher risk of non-response and exhibited a steeper decline in antibody titres produced with increasing age. CONCLUSIONS: This retrospective cohort study demonstrates that immunosenescence starts at young age, especially among men, underlining the importance of vaccination at a young age to achieve long-lasting immunity. Moreover, HBV vaccination should always include testing for antibodies to facilitate the performance of necessary interventions to prevent long-term fatal complications.

The association between APOE ε4 and Alzheimer-type dementia among memory clinic patients is confined to those with a higher education. The DESCRIPA Study.

We assessed the interaction between the APOE ε4 allele and education level in the etiology of Alzheimer's disease (AD) among memory clinic patients from the multicenter DESCRIPA study. Subjects (n = 544) were followed for 1 to 5 years. We used Cox's stratified survival modeling, adjusted for age, gender, and center. APOE ε4 predicted the onset of AD-type dementia in middle (HR 3.45 95% CI 1.79-6.65, n = 222) and high (HR 3.67 95% CI 1.36-9.89, n = 139) but not in low educated subjects (HR 0.81, 95% CI 0.38-1.72, n = 183). This suggests that mechanisms in developing Alzheimer-type dementia may differ between educational groups that raises questions related to Alzheimer-type dementia prevention.

Do genetic factors contribute to the relation between education and metabolic risk factors in young adults? A twin study.

BACKGROUND: Lower educated people have a higher prevalence of metabolic risk factors (MRF), that is, high waist circumference (WC), high systolic blood pressure, low high-density lipoprotein cholesterol level, high triglycerides and high fasting glucose levels. Behavioural and psychosocial factors cannot fully explain this educational gradient. We aim to examine the possible role of genetic factors by estimating the extent to which education and MRF share a genetic basis and the extent to which the heritability of MRF varies across educational levels. METHODS: We examined 388 twin pairs, aged 18-34 years, from the Belgian East Flanders Prospective Twin Survey. Using structural equation modelling, a Cholesky bivariate model was applied to assess the shared genetic basis between education and MRF. The heritability of MRF across education levels was estimated using a non-linear multivariate Gaussian regression. RESULTS: Fifteen percent (P < 0.01) of the negative relation between education and WC was because of genes shared between these two traits. Furthermore, the heritability of WC was lower in the lowest educated group (65%) compared with the highest educated group (78%, P = 0.04). The lower heritabilities among the lower educated twins for the other MRF were not significant. The heritability of glucose was higher in the lowest education (80%) group compared with the high education group (67%, P = 0.01). CONCLUSION: Our findings suggest that genetic factors partly explain educational differences in WC. Furthermore, the lower heritability estimates in WC in the lower educated young adults suggest opportunities for environmental interventions to prevent the development of full-blown metabolic syndrome in middle and older age.

Identification of hidden key hepatitis C populations: an evaluation of screening practices using mixed epidemiological methods.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of liver diseases worldwide. Due to its asymptomatic nature, screening is necessary for identification. Because screening of the total population is not cost effective, it is important to identify which risk factors for positivity characterize the key populations in which targeting of screening yields the highest numbers of HCV positives, and assess which of these key populations have remained hidden to current care. METHODS: Laboratory registry data (2002-2008) were retrieved for all HCV tests (23,800) in the south of the Netherlands (adult population 500,000). Screening trends were tested using Poisson regression and chi-square tests. Risk factors for HCV positivity were assessed using a logistic regression. The hidden HCV-positive population was estimated by a capture-recapture approach. RESULTS: The number of tests increased over time (2,388 to 4,149, p<.01). Nevertheless, the positivity rate among those screened decreased between 2002 and 2008 (6.3% to 2.1%, p<.01). The population prevalence was estimated to be 0.49% (95%CI 0.41-0.59). Of all HCV-positive patients, 66% were hidden to current screening practices. Risk factors associated with positivity were low socio-economic status, male sex, and age between 36-55. In future screening 48% (95%CI 37-63) of total patients and 47% (95%CI 32-70) of hidden patients can be identified by targeting 9% (men with low socio-economic status, between 36-55 years old) of the total population. CONCLUSIONS: Although the current HCV screening policy increasingly addresses high-risk populations, it only reaches one third of positive patients. This study shows that combining easily identifiable demographic risk factors can be used to identify key populations as a likely target for effective HCV screening. We recommend strengthening screening among middle-aged man, living in low socio-economic neighborhoods.

Revaccination with Fendrix® or HBVaxPro® results in better response rates than does revaccination with three doses of Engerix-B® in previous non-responders.

Because non-response (<10 IU/l anti-HBs) after revaccination for hepatitis B occurs frequently (50%), this study aimed to provide evidence for a more effective revaccination regimen by comparing four different revaccinations: (1) three revaccinations with Engerix-B(®) (n=201); (2) one revaccination with Engerix-B(®) (n=37); (3) one revaccination with HBVaxPro-40(®) (n=108); (4) one revaccination with Fendrix(®) (n=39). The level of anti-HBs antibodies was determined with the AXSYM-MEIA system (Abbott, Chicago, USA). Using linear and logistic regression, the efficacy (antibody response) after the four revaccinations was compared. Analyses were corrected for age, sex, primary titre and time lag between last revaccination and the titre measurement. The height of the primary titre independently predicted antibody response. Compared to the revaccination scheme using three Engerix-B(®) doses, revaccination with a single dose of HBVaxPro-40(®) or Fendrix(®) performed significantly better. The use of these highly potent vaccines should be considered when revaccinating hepatitis B vaccine non-responders.