Factors associated with hepatitis B vaccination among men who have sex with men: a systematic review of published research.

This systematic review identified and synthesised evidence from published research regarding personal and environmental factors associated with hepatitis B virus (HBV) vaccination uptake among gay men and other men who have sex with men (MSM) in low prevalence, high-income countries. A systematic literature search identified 18 eligible papers that addressed factors potentially associated with HBV vaccination uptake among MSM, of which 16 reported research conducted in the US. Studies assessed possible associations between HBV vaccination among MSM and socio-demographic characteristics, behavioural and social-cognitive factors and indicators of health service access. Converging evidence was found for associations between HBV vaccination and younger age, gay self-identification, and not using alcohol and drugs; evidence suggests a lack of association between HBV vaccination and ethnicity. There was converging evidence for associations between HBV vaccination and social-cognitive factors, in particular knowledge, perceived vulnerability and perceived severity regarding HBV infection, and perceived barriers to HBV vaccination. Evidence further supported associations between HBV vaccination and indicators of health service access. While research regarding factors associated with HBV vaccination among MSM remains limited, the identified correlates of HBV vaccination among MSM provide important guidance for the development of health promotion interventions to effectively increase coverage of HBV vaccination among MSM.

Conventional and novel peripheral blood iron markers compared against bone marrow in Malawian children.

AIM: Iron deficiency is an important child health problem. Its diagnosis in areas of high infection exposure remains complicated as inflammation may interfere with the accuracy of peripheral iron markers. With this study, we aimed to validate the conventional iron markers and two novel iron markers, hepcidin and Red blood cell Size Factor (RSf), against the reference standard of iron status, bone marrow iron, in children living in an infectious setting. METHODS: We compared ferritin, soluble transferrin receptor, Soluble Transferrin Log-Ferritin Index (sTfR-F), mean cellular volume, mean cellular haemoglobin concentration, hepcidin and RSf, against bone marrow iron in 87 healthy Malawian children (6-66 months) scheduled for elective surgery. RESULTS: Of all children, 44.8% had depleted bone marrow iron stores. Using optimised cut-offs, ferritin (<18 µg/L) and sTfR-F (>1.85) best predicted depleted iron stores with a sensitivity/specificity of 73.7%/77.1% and 72.5%/75.0%, respectively. Hepcidin (<1.4 nmol/L) was a moderate sensitive marker (73.0%) although specificity was 54.2%; RSf poorly predicted depleted iron stores. CONCLUSIONS: We provide the first bone marrow-validated data on peripheral iron markers in African children, and showed ferritin and sTfR-F best predicted iron status. Using appropriately defined cut-offs, these indicators can be applied in surveillance and research. As their accuracy is limited for clinical purposes, more reliable iron biomarkers are still required in African children.

The role of implementation intention formation in promoting hepatitis B vaccination uptake among men who have sex with men.

This study assessed the separate and joint effects of having a goal intention and the completeness of implementation intention formation on the likelihood of attending an appointment to obtain vaccination against the hepatitis B virus among men who have sex with men (MSM) in the Netherlands. Extending previous research, it was hypothesized that to be effective in promoting vaccination, implementation intention formation not only requires a strong goal intention, but also complete details specifying when, where and how to make an appointment to obtain hepatitis B virus vaccination among MSM. MSM at risk for hepatitis B virus (N = 616), with strong or weak intentions to obtain hepatitis B virus vaccination, were randomly assigned to form an implementation intention or not. Completeness of implementation intentions was rated and hepatitis B virus uptake was assessed through data linkage with the joint vaccination registry of the collaborating Public Health Services. Having a strong goal intention to obtain hepatitis B virus vaccination and forming an implementation intention, each significantly and independently increased the likelihood of MSM obtaining hepatitis B virus vaccination. In addition, MSM who formed complete implementation intentions were more successful in obtaining vaccination (p < 0.01). The formation of complete implementation intentions was promoted by strong goal intentions (p < 0.01).

Alcohol-specific parenting and adolescents' alcohol-related problems: the interacting role of alcohol availability at home and parental rules.

OBJECTIVE: The first aim of this study was to gain more insight into the bi-directionality between alcohol-specific parental factors (i.e., parents' alcohol use, alcohol availability at home, parental rule setting, and frequency and quality of communication about alcohol) and adolescents' alcohol intake and alcohol-related problems. The second aim was to examine the relative impact of alcohol-specific parental factors on adolescents' alcohol intake and related problems by studying them in a comprehensive model. METHOD: A two-wave longitudinal study, with a 2-year interval, was conducted among a sample of 537 adolescents (56% girls) ages 12-15 years in The Netherlands. Under supervision of well-instructed teachers, students filled out questionnaires in a classroom setting. RESULTS: The findings show that perceived alcohol availability at home was the only parenting factor predicting an increase in alcohol intake and alcohol-related problems among adolescents 2 years later. Cross-sectional findings, furthermore, suggest that the effect of alcohol availability on adolescents' alcohol-related problems disappears when adolescents perceive strict alcohol rules. In addition, results indicate that parents respond to their youngsters' experienced alcohol-related problems by engaging in more rigorous alcohol-specific parenting (e.g., by increasing alcohol-specific rules and decreasing alcohol availability at home). CONCLUSIONS: The findings emphasize that parent interventions aiming at the prevention of adolescents' alcohol use should include the advice to restrict the perceived presence of alcohol beverages at home. Moreover, to prevent alcohol problems, parents should be advised to enforce strict rules about drinking, particularly when a total absence of alcohol at home is not feasible.

Erythropoiesis in HIV-infected and uninfected Malawian children with severe anemia.

Anemia is common in HIV infection, but the pathophysiology is poorly understood. Bone marrow analysis in 329 severely anemic (hemoglobin <5 g/dl) Malawian children with (n = 40) and without (n = 289) HIV infection showed that HIV-infected children had fewer CD34(+) hematopoietic progenitors (median 10 vs. 15‰, P = 0.04) and erythroid progenitors (2.2 vs. 3.4‰, P = 0.05), but there were no differences in erythrocyte viability and maturation in later stages of erythropoiesis. Despite an HIV-associated reduction in early red cell precursors, subsequent erythropoiesis appears to proceed similarly in HIV-infected and HIV-uninfected children with severe anemia.

Pathophysiological mechanisms of severe anaemia in Malawian children.

BACKGROUND: Severe anaemia is a major cause of morbidity and mortality in African children. The aetiology is multi-factorial, but interventions have often targeted only one or a few causal factors, with limited success. METHODS AND FINDINGS: We assessed the contribution of different pathophysiological mechanisms (red cell production failure [RCPF], haemolysis and blood loss) to severe anaemia in Malawian children in whom etiological factors have been described previously. More complex associations between etiological factors and the mechanisms were explored using structural equation modelling. In 235 children with severe anaemia (haemoglobin<3.2 mMol/L [5.0 g/dl]) studied, RCPF, haemolysis and blood loss were found in 48.1%, 21.7% and 6.9%, respectively. The RCPF figure increased to 86% when a less stringent definition of RCPF was applied. RCPF was the most common mechanism in each of the major etiological subgroups (39.7-59.7%). Multiple aetiologies were common in children with severe anaemia. In the final model, nutritional and infectious factors, including malaria, were directly or indirectly associated with RCPF, but not with haemolysis. CONCLUSION: RCPF was the most common pathway leading to severe anaemia, from a variety of etiological factors, often found in combination. Unlike haemolysis or blood loss, RCPF is a defect that is likely to persist to a significant degree unless all of its contributing aetiologies are corrected. This provides a further explanation for the limited success of the single factor interventions that have commonly been applied to the prevention or treatment of severe anaemia. Our findings underline the need for a package of measures directed against all of the local aetiologies of this often fatal paediatric syndrome.

'Feeling' risk and seeing solutions: predicting vaccination intention against hepatitis B infection among men who have sex with men.

This study assessed cognitive and affective predictors of intention to obtain vaccination against the hepatitis B virus (HBV) among men who have sex with men (MSM), based on leading social cognitive models of health behavior. The key predictors of vaccination intention were perceived risk of contracting HBV, expectancies regarding the outcome of vaccination, and the interaction between risk perception and outcome expectancies. Negative affect increased risk perceptions, which, in turn, positively affected vaccination intention. It is concluded that MSM should feel they are at risk for HBV, and see solutions to this risk.

What works best: objective statistics or a personal testimonial? An assessment of the persuasive effects of different types of message evidence on risk perception.

OBJECTIVE: In an experimental online study we compared the effects of different types of persuasive evidence in promoting the acceptance of a personal health risk. DESIGN: 118 men who have sex with men (MSM) at-risk for infection with the hepatitis B virus (HBV) were recruited via a range of websites and randomly assigned to one of 4 conditions (2 experimental and 2 control): narrative evidence (i.e., a personal account), statistical evidence (i.e., abstract prevalence data), mere assertion of increased risk, and no risk information. MAIN OUTCOME MEASURES: Narrative evidence was expected to be more effective than statistical evidence in increasing MSM's perceived risk of infection with HBV and intention to obtain vaccination. RESULTS AND CONCLUSION: As predicted, perceptions of personal risk and intention to obtain vaccination against HBV were highest after presentation of narrative evidence, and risk perception mediated the effect of type of message evidence on intention. We propose that narrative evidence effectively promotes a sense of personal risk because it is less affected by defensive message processing resulting from the threat to important self-beliefs that seems inherent in health risk communication.

Social-cognitive determinants of vaccination behavior against hepatitis B: an assessment among men who have sex with men.

BACKGROUND: Many individuals who are at risk for infection with the hepatitis B virus (HBV), including men who have sex with men (MSM), are not vaccinated. This study assessed social-cognitive determinants of obtaining vaccination against HBV. METHODS: A targeted survey was conducted among 432 MSM by means of a written questionnaire that contained assessments of social-cognitive determinants of vaccination behavior derived from the Health Belief Model (HBM) and the Theory of Planned Behavior. Vaccination behavior was anonymously linked to questionnaire data for which informed consent was obtained. RESULTS: Of the 290 men eligible for vaccination, 248 (86%) had obtained vaccination. Multivariate logistic regression analysis showed that these men were younger, more often were in a steady relationship, and had fewer sex partners. In addition, significant effects were also found for central factors proposed by the Health Belief Model. Notably, men who obtained vaccination against HBV perceived more personal threat from HBV. None of the Theory of Planned Behavior variables were related to obtaining vaccination. CONCLUSIONS: Findings suggest that health education interventions that address perceived susceptibility and severity are likely to contribute to increased uptake of HBV vaccination among MSM. Influencing perceived susceptibility in particular is important, more so than increasing perceived severity by scare tactics.