Risk of cancer after blood transfusion from donors with subclinical cancer: a retrospective cohort study.

BACKGROUND: Although mechanisms for detection of short-term complications after blood transfusions are well developed, complications with delayed onset, notably transmission of chronic diseases such as cancer, have been difficult to assess. Our aim was to investigate the possible risk of cancer transmission from blood donors to recipients through blood transfusion. METHODS: We did a register-based retrospective cohort study of cancer incidence among patients who received blood from donors deemed to have a subclinical cancer at the time of donation. These precancerous donors were diagnosed with a cancer within 5 years of the donation. Data from all computerised blood bank registers in Sweden and Denmark gathered between 1968 and 2002 were merged into a common database. Demographic and medical data, including mortality and cancer incidence, were ascertained through linkages with nationwide, and essentially complete, population and health-care registers. The risk of cancer in exposed recipients relative to that in recipients who received blood from non-cancerous donors was estimated with multivariate Poisson regression, adjusting for potential confounding factors. FINDINGS: Of the 354 094 transfusion recipients eligible for this analysis, 12,012 (3%) were exposed to blood products from precancerous donors. There was no excess risk of cancer overall (adjusted relative risk 1.00, 95% CI 0.94-1.07) or in crude anatomical subsites among recipients of blood from precancerous donors compared with recipients of blood from non-cancerous donors. INTERPRETATION: Our data provide no evidence that blood transfusions from precancerous blood donors are associated with increased risk of cancer among recipients compared with transfusions from non-cancerous donors.

Immunogenicity of a locally produced hepatitis B vaccine with the birth dose stored outside the cold chain in rural Vietnam.

The heat stability of hepatitis B vaccine (HepB vaccine) should enable its storage outside the cold chain (OCC), increasing access to the birth dose in areas lacking refrigeration. We compared the immunogenicity of a locally produced vaccine among infants who received three doses stored within the cold chain (n = 358) or for whom the first dose was stored OCC for up to one month (n = 748). Serum was collected from these infants at age 9-18 months. The vaccine was protective in 80.3% of all infants. There were no differences in the prevalence of a protective level of antibody or antibody titer among groups of infants according to storage strategy. Differences in antibody titer between certain groups of infants could be explained by different vaccination schedules. Where birth dose coverage will be improved, HepB vaccine can be taken OCC for up to one month without affecting its immunogenicity.

Life time suicidal thoughts in an urban community in Hanoi, Vietnam.

BACKGROUND: Suicidal thought is a risk factor and a stage in the suicidal process from planning to attempting and dying by suicide. To date, studies on suicidal thought in the general population, especially in Asian communities, have been limited. METHOD: The WHO SUPRE-MISS (the multisite intervention study on suicidal behaviours) community survey questionnaire was filled in for 2,280 randomly selected residents of the DongDa district of Hanoi, Vietnam by means of face-to-face interviews. This multi-factor questionnaire includes such variables as sociodemographic information, suicidal thought and history of suicide attempts, physical health, alcohol consumption and medication. RESULTS: Prevalence rates for life time suicidal thoughts, suicide plans and suicide attempts were 8.9%, 1.1% and 0.4% respectively. Suicidal thoughts are associated with multiple characteristics, such as female gender, single/widowed/separated/divorced marital status, low income, lifestyle (use of alcohol, sedatives and pain relief medication), but not with low education or employment status. Having no religion and being a Buddhist appear to be protective factors for suicidal thought. The ratio of suicidal thoughts, suicide plans and suicide attempts on a lifetime basis is 22.3:2.8:1. CONCLUSION: In Vietnam, as in Western and other Asian countries, suicidal thoughts are associated with similar negative psychosocial risk factors, lifestyle and emotional problems, which implies that suicide preventive measure developed elsewhere can be adjusted to Vietnamese condition. Understanding the unique and common risks in a culture may assist in prediction and control.

Drug use among female sex workers in Hanoi, Vietnam.

AIMS: To describe the drug use practices among female sex workers (FSWs) in Hanoi and to identify factors associated with their drug injecting. DESIGN, SETTING AND PARTICIPANTS: A two-stage cluster survey of 400 FSWs was conducted from June to September, 2002. Participating FSWs were both establishment- (160) and street-based (240), who were practising in seven urban and one suburban districts of Hanoi. MEASUREMENTS: Subjects were interviewed face to face using a structured questionnaire. FINDINGS: Among the middle-class FSWs, 27% used drugs, of whom 79% injected. Among low-class FSWs, 46% used drugs and 85% injected. Among drug-using FSWs, 86% had started using drugs within the past 6 years. Among drug-injecting FSWs, 81% had started injecting within the past 4 years. Cleaning of injecting equipment was not common among those who shared. Having drug-injecting 'love mates', drug-using clients, longer residence in Hanoi, more clients and not currently cohabiting were found to be independently associated with drug injecting among FSWs. CONCLUSIONS: The high prevalence of injecting drug use among FSWs makes them susceptible to HIV infection, and is a threat to their clients. There is a strong relationship between drug-using FSWs and male drug-using clients and non-client partners. Intervention to prevent drug use initiation among non-drug-using FSWs and harm reduction among drug-using FSWs are urgently needed.

Awareness and knowledge of human papillomavirus in the Swedish adult population.

PURPOSE: To assess awareness and knowledge of human papillomavirus (HPV) in the adult Swedish population. METHODS: A cross-sectional study among young adults aged 18-30 years and the parents of children aged 12-15 years was conducted in 2007 to collect information on awareness and knowledge of HPV. Correlates of HPV knowledge were investigated. RESULTS: Awareness of cervical cancer and condyloma were high but awareness of HPV was low. Many participants were uncertain or did not know about the causal relation between HPV and condyloma, and cancers other than cervical cancer. Among parents, gender, age, country of origin, and education were the most important correlates of HPV knowledge. Among young adults, these factors were gender, income, and education. CONCLUSIONS: HPV education campaigns should particularly target young men and those with low education. Educational messages should clarify the risk of HPV, and the causal relationship between HPV and condyloma, and other cancers.

Safety of Zostavax™--a cohort study in a managed care organization.

BACKGROUND: Zostavax™ is a live, attenuated varicella-zoster virus vaccine indicated for the prevention of herpes zoster (shingles). An observational post-licensure (Phase IV) study was conducted at Kaiser Permanente Northern California (KPNC), a US managed care organization, to assess the safety of zoster vaccine in people 60 years of age or older, vaccinated in routine medical care. METHODS: We performed a cohort study, comparing rates of clinical events resulting in hospitalizations or emergency department visits in a 42-day risk time period immediately following vaccination with rates in the same cohort in a subsequent comparison time period. The study data were reviewed and interpreted by an external safety review committee of 3 independent experts. RESULTS: Approximately 29,000 people ≥ 60 years of age were vaccinated with zoster vaccine from July 2006 to November 2007. Of the 386 comparisons performed for the main analysis, 4 had an increased relative risk with a nominal p-value ≤ 0.05. After medical records review, the timing of these conditions and procedures was found to be often prior to vaccination, and no clear increase in health events was observed in the risk period following vaccination compared to later. Persons receiving zoster vaccine appeared to be in their optimal health at the time of vaccination, which led to an apparent protective effect of the vaccine for some health outcomes, due to the study design. CONCLUSIONS: There was no evidence of a safety concern for zoster vaccine.

Acceptability of HPV vaccination among young adults aged 18-30 years--a population based survey in Sweden.

Acceptability of human papillomavirus (HPV) vaccination seems to be high in the Western world but fewer data are available for men than for women. There are also concerns that HPV vaccination might lead young people to change their healthcare-related behaviours. We investigated these issues in a population-based survey performed in Sweden during January-May, 2007, just after HPV vaccination had been licensed. A total of 10567 men and women aged 18 to 30 years participated. The intention to accept HPV vaccination among these young adults was relatively high but could likely be improved with higher awareness of HPV-related diseases as well as of the safety and efficacy of vaccines in general. Also, the cost of the vaccine needs to be affordable. Even though few young adults stated their healthcare-related behaviours would change after HPV vaccination, a significant number were uncertain, suggesting a need for continued educational efforts when HPV-vaccinating this group.

Donation frequency, iron loss, and risk of cancer among blood donors.

BACKGROUND: Long-term deleterious effects of repeated blood donations may be masked by the donors' healthy lifestyle. To investigate possible effects of blood donation and iron loss through blood donation on cancer incidence while minimizing "healthy donor effects," we made dose-response comparisons within a cohort of Swedish and Danish blood donors. METHODS: We used a nested case-control study design, in which case patients were defined as all donors who were diagnosed with a malignancy between their first recorded blood donation and study termination (n = 10866). Control subjects (n = 107140) were individually matched on sex, age, and county of residence. Using conditional logistic regression, we estimated relative risks of cancer according to number of blood donations made or estimated iron loss 3-12 years before a case patient was diagnosed with cancer. All statistical tests were two-sided. RESULTS: No clear association was observed between number of donations and risk of cancer overall. However, between the lowest (< or = median, < 0.75 g) and highest (> 90th percentile, > 2.7 g) categories of estimated iron loss, there was a trend (P(trend) < .001) of decreasing risk for cancers of the liver, lung, colon, stomach, and esophagus, which are thought to be promoted by iron overload (combined odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.58 to 0.84), but only among men and only with a latency of 3-7 years. The risk of non-Hodgkin lymphoma was higher among frequent plasma donors (> 25 vs 0 donations, OR = 2.14, 95% CI = 1.22 to 3.74). CONCLUSIONS: Repeated blood donation was not associated with increased or decreased risk of cancer overall. The lack of consistency across latency periods casts doubt on an apparent association between reduced cancer risk and iron loss in men. The positive association between frequent plasma donation and risk of non-Hodgkin lymphoma deserves further exploration.

The burden of genital warts: a study of nearly 70,000 women from the general female population in the 4 Nordic countries.

OBJECTIVE: To assess the burden and correlates of genital warts in women. METHODS: We conducted a population-based cross-sectional study in 69,147 women (18-45 years of age) randomly chosen from the general population in Denmark, Iceland, Norway, and Sweden. Information on clinically diagnosed genital warts and lifestyle habits was collected using a questionnaire. RESULTS: Overall, 10.6% reported ever having had clinically diagnosed genital warts. In addition, 1.3% reported having experienced genital warts within the past 12 months. The cumulative incidence for different birth cohorts, estimated on the basis of age at first diagnosis of genital warts, increased with each subsequent younger birth cohort (P<.01). The lifetime number of sex partners was strongly correlated with a history of genital warts (odds ratio for > or =15 partners vs. 1 partner, 9.45 [95% confidence interval, 7.89-11.30]). The likelihood of reporting genital warts also increased with a history of sexually transmitted disease, use of hormonal contraceptives, use of condoms, smoking, and higher education. CONCLUSIONS: The data suggest that 1 in 10 women in the Nordic countries experience genital warts before the age of 45 years, with an increasing occurrence in younger birth cohorts. These data are important for developing and evaluating strategies (e.g., human papillomavirus [HPV] vaccination) to control and prevent HPV infection and disease in the population.

Cancer incidence in blood transfusion recipients.

BACKGROUND: Blood transfusions may influence the recipients' cancer risks both through transmission of biologic agents and by modulation of the immune system. However, cancer occurrence in transfusion recipients remains poorly characterized. METHODS: We used computerized files from Scandinavian blood banks to identify a cohort of 888,843 cancer-free recipients transfused after 1968. The recipients were followed from first registered transfusion until the date of death, emigration, cancer diagnosis, or December 31, 2002, whichever came first. Relative risks were expressed as ratios of the observed to the expected numbers of cancers, that is, standardized incidence ratios (SIRs), using incidence rates for the general Danish and Swedish populations as a reference. All statistical tests were two-sided. RESULTS: During 5,652,918 person-years of follow-up, 80,990 cancers occurred in the transfusion recipients, corresponding to a SIR of 1.45 (95% confidence interval [CI] = 1.44 to 1.46). The SIR for cancer overall decreased from 5.36 (95% CI = 5.29 to 5.43) during the first 6 months after transfusion to 1.10 or less for follow-up periods more than 2 years after the transfusion. However, the standardized incidence ratios for cancers of the tongue, mouth, pharynx, esophagus, liver, and respiratory and urinary tracts and for squamous cell skin carcinoma remained elevated beyond 10 years after the transfusion. CONCLUSIONS: The marked increase in cancer risk shortly after a blood transfusion may reflect the presence of undiagnosed occult cancers with symptoms that necessitated the blood transfusion. The continued increased risk of tobacco- and alcohol-related cancers suggests that lifestyle and other risk factors related to conditions prompting transfusion rather than transfusion-related exposures per se are important to the observed cancer occurrence in the recipients.

Improving health profile of blood donors as a consequence of transfusion safety efforts.

BACKGROUND: Transfusion safety rests heavily on the health of blood donors. Although they are perceived as being healthier than average, little is known about their long-term disease patterns and to which extent the blood banks' continuous efforts to optimize donor selection has resulted in improvements. Mortality and cancer incidence among blood donors in Sweden and Denmark was investigated. STUDY DESIGN AND METHODS: All computerized blood bank databases were compiled into one database, which was linked to national population and health data registers. With a retrospective cohort study design, 1,110,329 blood donors were followed for up to 35 years from first computer-registered blood donation to death, emigration, or December 31, 2002. Standardized mortality and incidence ratios expressed relative risk of death and cancer comparing blood donors to the general population. RESULTS: Blood donors had an overall mortality 30 percent lower (99% confidence interval [CI] 29%-31%) and cancer incidence 4 percent lower (99% CI 2%-5%) than the background population. Mortality rates and cancer incidence were lowest for outcomes that are recognized as being related to lifestyle factors such as smoking or to the selection criteria for blood donation. Blood donors recruited in more recent years exhibited a lower relative mortality than those who started earlier. CONCLUSION: Blood donors enjoy better than average health. Explicit and informal requirements for blood donation in Scandinavia, although mostly of a simple nature, have successfully refined the selection of a particularly healthy subpopulation.

Condom use and its correlates among female sex workers in Hanoi, Vietnam.

Knowledge of female sex workers' (FSW) condom use behaviors in Vietnam is important for predicting the epidemic and designing interventions. Four hundred FSWs in Hanoi were studied in 2002. Consistent condom use in the past month was higher with irregular clients (62%), less with regular clients (41%), and lowest with "love mates" (5%). Reasons for not using condoms were partner objection, condom unavailability, and belief of partner's disease-free status. Twenty-seven percent reported not always having a condom available. Thirty-five percent reported increasing condom use in the previous 6 months. Reluctance to ask clients to use condoms and condom unavailability were independently associated with inconsistent condom use with both irregular and regular clients. Older age was also associated with inconsistent condom use with irregular clients. Condom promotion should focus on FSWs and their partners. Negative attitudes toward FSWs and condom promotion need to be changed to reduce stigmatization of FSWs and to make condom use a norm in the society.

HIV infection and risk characteristics among female sex workers in Hanoi, Vietnam.

The prevalence of HIV/sexually transmitted diseases (STDs) was determined, the risk characteristics examined, and factors associated with HIV infection identified among noninstitutionalized female sex workers (FSWs), using a cross-sectional survey with 2-stage cluster sampling. Four hundred FSWs were interviewed face to face using a structured questionnaire and tested for HIV, syphilis, Chlamydia infection, and gonorrhea. HIV seroprevalence was 12%, syphilis 17% (using the treponemal pallidum hemagglutination assay), Chlamydia infection 3.8% (using polymerase chain reaction [PCR]), and gonorrhea 6.3% (PCR). Lower-class FSWs averaged 2 clients per day, and middle-class FSWs about 1.2. Median duration in sex work was 2.3 years. Consistent condom use was 63% with irregular clients, 41% with regular clients, and only 4.8% with "love mates." Fifty-five percent had had sex with a drug user(s). Thirty-eight percent used drugs, of whom 83% injected. Factors associated with HIV included being young, having a low level of education, longer residence in Hanoi, being a lower-class FSW, having higher income compared with peers, perception of self being at low risk for HIV, poor knowledge of HIV, and sharing injecting equipment. Intervention strategies should include reduction of both stigmatization and sharing of drug paraphernalia, promotion of nonstigmatizing voluntary testing and counseling, and aggressive marketing and promotion of condoms.