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Tattoos 'Strong Risk Factor for HCV Transmission' - new study
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"We believe that having a tattoo is a strong risk factor for transmission of hepatitis C.....we found the strongest association between tattooing and risk of hepatitis C for samples derived from non-injection drug users"
"Results of our systematic review indicate an increase in the risk of hepatitis C infection among those who have tattooed. The strength of our review is mainly in the large number of studies and multinational nature of the study participants.....When seeking tattooing services, clients should be advised to be alert to the use of equipment that has not been adequately sterilized or disinfected......current tattooing regulations and policies need to be updated to enforce infection control measures among tattoo artists.....education programs for tattoo artists must be implemented to stress the importance of proper hygiene, as well as the potential for spread of blood-borne infections by tattoo needles.....parlor owners and tattoo artists should be required to keep records of their clients, to inform tattoo recipients about possible risks related to tattooing, and to report any adverse event related to tattooing to the health authorities."
Tattoos Increase Risk of Hepatitis C - full text below, publication pdf attached
publication pdf attached, figure 5 is very useful
MedPage Today
Published: August 09, 2010
The global fad for tatoos, particularly among young people, is growing -- and along with it the risk of acquiring hepatitis C, according to a multinational study.
A systematic review and meta-analysis of 124 published studies from 30 countries, found that people with tattoos were almost three times more likely to have hepatitis C as those without tattoos, according to Jane Buxton, MD, of the British Columbia Centre for Disease Control in Vancouver, and colleagues.
But in some subgroups -- particularly non-injection drug users -- the odds of having the virus were almost six-fold higher, Buxton and colleagues wrote online in the International Journal of Infectious Diseases.
Action Points
* Discuss with patients that tattooing is associated with a higher risk of hepatitis C infection.
* Point out that one limitation of this analysis is the observational nature of the included studies -- and that such studies can neither prove nor disprove causality.
In recent years, tattoos have become increasingly popular. An estimated 36% of Americans under 30 have the skin designs, the researchers wrote. In Canada, they added, around 8% of high school students have at least one tattoo and among those without a tattoo, 21% are eager to get one.
Since tattoo instruments come in contact with blood and bodily fluids, infection is possible if instruments are used on more than one person without being sterilized or without proper hygiene, the researchers noted. Additionally, tattoo dyes are not kept in sterile containers and may also transmit infections, they wrote
To help quantify the risks, the researchers reviewed and analyzed 124 studies from 30 countries -- including Canada, Iran, Italy, Brazil and the U.S. Of those, 83 cross-sectional, case-control, and cohort studies were included in the meta-analysis.
The pooled odds ratio for hepatitis C -- comparing those with and without tattoos -- was 2.74 (95% CI 2.38 to 3.15), they found.
However, in sub-group analyses, the risk could go much higher, they found. For example, in samples derived from non-injection drug users the OR was 5.74 (95% CI 1.98 to 16.66).
In other groups, the odds ratios were:
* 3.73, for blood donors (95% CI 2.46 to 5.67).
* 3.20, for samples from hospitals (95% CI 2.25 to 4.56).
* 3.06, for injection drug users (95% CI 1.2 to 7.25).
* 2.80, in high-risk populations, (95% CI 1.63 to 4.82).
* 2.79, in community samples (95% CI 1.95 to 4.00).
* 2.56, in prison samples (95% CI 1.97 to 3.32).
Some studies had wide confidence intervals, the researchers reported, but when those were discounted there was little change in the overall effect size.
One limitation of the analysis is the observational nature of the included studies, the researchers wrote. As well, they added, studies with a non-significant effect may not have been published, which would tend to increase the observed odds ratios.
What's needed, the researchers concluded, are infection-control guidelines for tattoo artists and clients, and enforcement through inspections, reporting of adverse events and record keeping. Also, they wrote, prevention programs should focus on young people -- those most likely to get tattoos -- and among prison inmates -- who live in environments with a higher prevalence of hepatitis C.
There was no external support for the study.
The authors said they had no conflict of interest in the tattoo industry.
Primary source: International Journal of Infectious Diseases
Source reference:
Jafari S et al. "Tattooing and the risk of transmission of hepatitis C: a systematic review and meta-analysis" Int J Infect Dis 2010; DOI: 10.1016/j.ijid.2010.03.019.
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Tattooing and the risk of transmission of hepatitis C: a systematic review and meta-analysis - Review - publication pdf attached
International Journal of Infectious Diseases Aug 1 2010
Corrected Proof
Siavash Jafarib, Ray Copesa, Souzan Baharlouc, Mahyar Etminand and Jane Buxtona, Corresponding Author Contact Information, E-mail The Corresponding Author
a British Columbia Centre for Disease Control, 655 West 12th Avenue, Vancouver, British Columbia, Canada V5Z 4R4
b Community Medicine, University of British Columbia, Vancouver, British Columbia, Canada
c British Columbia Children's Hospital, Vancouver, British Columbia, Canada
d Centre for Clinical Epidemiology and Evaluation, Vancouver Hospital, Vancouver, British Columbia, Canada
Available online 1 August 2010.
Summary
Objectives
In this systematic literature review we sought to determine whether tattooing is a risk factor for the transmission of hepatitis C.
Methods
A comprehensive search was performed to identify all case-control, cohort or cross sectional studies published prior to November 2008 that evaluated risks related to tattooing or risk factors of transmission of hepatitis C infection.
Results
A total of 124 studies were included in this systematic review, of which 83 were included in the meta-analysis. The pooled odds ratio (OR) and 95% confidence interval (CI) of the association of tattooing and hepatitis C from all studies was 2.74 (2.38-3.15). In a subgroup analysis we found the strongest association between tattooing and risk of hepatitis C for samples derived from non-injection drug users (OR 5.74, 95% CI 1.98-16.66).
Conclusions
Findings from the current meta-analysis indicate that tattooing is associated with a higher risk of hepatitis C infection. Because tattooing is more common among the youth and young adults and hepatitis C is very common in the imprisoned population, prevention programs must focus on youngsters and prisoners to lower the spread of hepatitis infection.
Introduction
There has been an increase in the global prevalence of tattooing in recent years. In the USA, 36% of people under 30 have tattoos.1 Studies from Canada indicate that around 8% of high school students have at least one tattoo,[2] and [3] and among those who did not have a tattoo, 21% were eager to have one. Tattooing requires injection of pigments into the dermal layer of skin by puncturing the skin 80 to 150 times a second. Since tattoo instruments come into contact with blood and bodily fluids, viral and microbial infections may be transmitted if the instruments are used on more than one person without being sterilized or without proper hygiene techniques. Also, because tattoo dyes are not kept in sterile containers they might play a carrier role in transmitting infections. In light of the increase in the worldwide prevalence of tattoos, it has been postulated that tattooing may play an important role in the transmission of blood-borne diseases such as hepatitis B and hepatitis C.
In the USA, approximately 2.3% of adults aged 20 years or older are positive for anti-hepatitis C virus (HCV) antibody, and between 55% and 84% of these have a chronic infection;[4] and [5] however only 5% to 50% of infected adults are aware of their status.[6], [7] and [8] It is estimated that 210 000 to 275 000 people are currently infected with hepatitis C in Canada, of whom only 30% are aware of their infection.9
Tattooing among prisoners is another issue of importance. The overall prevalence of hepatitis C among inmates is estimated to be around 25.2% to 37.4%.[10], [11], [12], [13] and [14] Close to half of inmates may not know their serostatus, and the rates may vary between men and women.[10], [11], [12], [13] and 14 C. Poulin, M. Alary, G. Lambert, G. Godin, S. Landry and H. Gagnon et al., Prevalence of HIV and hepatitis C virus infections among inmates of Quebec provincial prisons, CMAJ 177 (2007), pp. 252-256. View Record in Scopus | Cited By in Scopus (7)[14] Reusing and sharing tattoo needles is reported to be a common practice among almost 45% of inmates.13 Given that the annual cost of each new case of hepatitis C for the healthcare system is estimated at around US$25 000 to US$30 000,15 the number of new cases of hepatitis that may arise as a result of tattooing has important clinical as well as public health implications. Because the results from epidemiological studies regarding the risk of hepatitis among tattooed individuals are conflicting, we sought to systematically review the literature in order to quantify the risk of hepatitis in tattooed individuals.
Discussion
Results of our systematic review indicate an increase in the risk of hepatitis C infection among those who have tattooed. The strength of our review is mainly in the large number of studies and multinational nature of the study participants. In light of the observational nature of the studies in this review, the association between tattooing and hepatitis was strong in all subgroups and consistent across all study designs. We believe that having a tattoo is a strong risk factor for transmission of hepatitis C for two reasons. First, several studies have reported an association between tattooing and other infections including HIV,20 hepatitis B,21 leprosy,22 and methicillin-resistant Staphylococcus aureus.23 Secondly, some studies have shown that the risk of hepatitis infection increases with the increase in the surface area covered by a tattoo, as well as the number of tattoos received by an individual. For example, a study found that the RR (95% CI) for the association between tattooing and risk of hepatitis C for tattoos that covered a surface area of 1-4 cm2 was 5.0 (2.6-9.6), whereas the RR for tattoos that covered an area of 20 cm2 was 12.2 (4.6-32.2) (Ref. W98, Appendix B). Also, the incidence of hepatitis C after tattooing has been shown to have a direct association with the number of tattoo experiences (Ref. W44, Appendix B).
HCV has become the most common chronic blood-borne infection in the USA and the leading indication for liver transplantation.24 Given that hepatitis C can spread through percutaneous[25] and [26] or mucous membrane exposure to blood,27 M. Sartori, G. La Terra, M. Aglietta, A. Manzin, C. Navino and G. Verzetti, Transmission of hepatitis C via blood splash into conjunctiva. (Letter), Scand J Infect Dis 25 (1993), pp. 270-271. View Record in Scopus | Cited By in Scopus (83)27 needle-stick injury,28 and tattooing using non-sterile equipment,29 several measures should be implemented to prevent the transmission of hepatitis C among tattoo recipients. First, education programs for tattoo artists must be implemented to stress the importance of proper hygiene, as well as the potential for spread of blood-borne infections by tattoo needles. Second, parlor owners and tattoo artists should be required to keep records of their clients, to inform tattoo recipients about possible risks related to tattooing, and to report any adverse event related to tattooing to the health authorities. Third, because most tattoo recipients are young adults, education efforts should focus on this age group to promote tattoo-related risk awareness. When seeking tattooing services, clients should be advised to be alert to the use of equipment that has not been adequately sterilized or disinfected. HCV and other blood-borne pathogens can be transmitted if tools are not sterile or if the tattoo artist does not follow proper infection-control procedures (e.g., washing hands, using latex gloves, and cleaning and disinfecting surfaces and instruments). Fourth, clinicians should consider screening for hepatitis C among those who have recently received tattoos or have a history of receiving a tattoo. And last, current tattooing regulations and policies need to be updated to enforce infection control measures among tattoo artists.
The risk from tattooing may depend on the background prevalence of hepatitis C in the population. For instance, our results indicate that the OR/RR for the association between tattooing in prison and the risk of transmission of hepatitis C is lower compared to that from community samples. However, results of prior research indicate that the prevalence of hepatitis C among inmates in some countries is more than 20 times higher than that in the general population, which indicates that tattooing in prison presents a higher risk compared to tattooing outside prison.30 We calculated the population attributable fraction for the association between tattooing and the risk of hepatitis C for tattoos done in prison and out of prison based on a tattooing prevalence of 11% to 27%14 among inmates and 8% in the general population.[2] and [3] Results indicate that in countries with data close to these assumptions, 12% to 25% of hepatitis C infections in prison and 6% of the hepatitis C infections in the community are related to tattooing. These findings indicate that there is a clear need for establishing comprehensive programs that provide safer tattooing practices in prisons. One such program was initiated in Canada in 2006, but the program was terminated before the potential benefits could be evaluated. Similar programs may be able to prevent not only the transmission of hepatitis C, but also the transmission of other blood-borne infections.
Our study is subject to several limitations, mainly because of the observational nature of the studies included in the review. First, although some studies were published relatively recently, information on the history of tattooing was taken in the past, which may not reflect the current population risk of hepatitis infection. Second, publication bias in this study indicates a lack of publication of some studies with non-significant effects, which may amplify the OR/RR towards a higher association. However the association between tattooing and risk of transmission of hepatitis C was so strong in seven out of eight subgroups that this leaves no place for doubt in considering tattooing as an important risk factor in the transmission of hepatitis C. To lower the spread of hepatitis infection, prevention programs must focus on the youth and young adults, the populations most likely to get tattoos, and prisoners, the population that faces the higher prevalence of hepatitis C.
Conflict of interest: None of the authors in this study have any conflict of interest in the tattoo industry. There was no source of funding for this study.
Results
Figure 1 shows the results of our search strategy and step-by-step inclusion and exclusion of the retrieved papers. Appendix A represents the search strategy used in this study. We identified a total of 1299 citations related to risk factors of hepatitis. A total of 272 studies were excluded as duplicates, 717 studies were excluded after reviewing titles, 170 excluded after reviewing abstracts, and 16 were excluded after reviewing the full text. A final number of 124 papers from 30 countries that reported an association between tattooing and the risk of transmission of hepatitis C were included in this systematic review (Appendix B).
Characteristics of the 83 studies (45 cross-sectional, 30 case-control, and eight cohort) with a total of 132 145 participants that were included in the meta-analysis are represented in Table 1.
A total of 41 studies were not included in the meta-analysis. The reasons for not including these studies in the meta-analysis are explained in Table 2.
Tattoo and hepatitis
Results of the current meta-analysis indicate a strong association between tattooing and the risk of hepatitis C when all studies are combined (pooled OR 2.24, 95% CI 2.01-2.50). In a subgroup analysis we found the strongest association between tattooing and the risk of hepatitis C for samples derived from non-IDUs (OR 5.74, 95% CI 1.98-16.66), followed by blood donors (OR 3.73, 95% CI 2.46-5.67), hospital samples (OR 3.20, 95% CI 2.25-4.56), IDUs (OR 3.06, 95% CI 1.29-7.25), high-risk populations (OR 2.80, 95% CI 1.63-4.82), community samples (OR 2.79, 95% CI 1.95-4.00), prison samples (OR 2.56, 95% CI 1.97-3.32), and drug users (OR 1.46, 95% CI 0.93-2.30) ([Figure 2] and [Figure 3]).
We conducted a subgroup analysis to investigate the effect of the country where the study had been conducted, study design, and professional parlor vs. non-professional parlor on the transmission of hepatitis C. We combined data from community samples, blood donors, and hospital samples in a single group (group 1) and data from IDUs, non-IDUs, drug users (any), prisoners, and high-risk populations in a second group (group 2) (Table 3). The association between tattooing and hepatitis C was the strongest in group 2 studies in Australia (OR 5.90, 95% CI 2.62-13.30), followed by group 1 studies in Iran (OR 5.61, 95% CI 2.31-13.62) and Canada (OR 5.15, 95% CI 2.65-9.98). The association between tattooing and hepatitis C was the strongest among case-control studies, followed by cross-sectional and cohort studies (Table 3). Also, the association between tattooing and hepatitis C was significant for tattoos done in non-professional parlors or done by friends (OR 2.80, 95% CI 1.29-6.08).
We conducted a sensitivity analysis to review the effects of 11 studies with wide confidence intervals (References W37, W45, W53, W64, W71, W82, W85, W90, W101, W106, W113; Appendix B) on the pooled OR (95% CI). The analysis was conducted multiple times; first all 11 studies were removed from the analysis, and then one study was removed from the analysis at a time. We did not find a significant difference between pre- and post-sensitivity OR (95% CI) when all 11 studies were removed from the analysis (OR 2.12, 95% CI 1.91-2.36). We also found no significant difference between the pooled pre-sensitivity effect size (OR 2.74, 95% CI 2.38-3.15) and post-sensitivity effect size after removing any of these studies - Ref. W37, OR 2.22, 95% CI 2.00-2.48; Ref. W45, OR 2.24, 95% CI 2.01-2.49; Ref. W53, OR 2.21, 95% CI 1.98-2.46; Ref. W64, OR 2.24, 95% CI 2.01-2.50; Ref. W71, OR 2.24, 95% CI 2.01-2.49; Ref. W82, OR 2.23, 95% CI 2.00-2.49; Ref. W85, OR 2.23, 95% CI 2.00-2.49; W90, OR 2.23, 95% CI 2.00-2.48; Ref. W101, OR 2.24, 95% CI 2.01-2.50; Ref. W106, OR 2.24, 95% CI 2.01-2.50; and Ref. W113, OR 2.23, 95% CI 2.01-2.49, from the analysis (for references see Appendix B).
We examined the heterogeneity by excluding studies that did not report adjusted OR/relative risk (RR) from the analysis. Post-sensitivity pooled OR and I2 of heterogeneity did not change significantly (pre-sensitivity OR 2.74, 95% CI 2.38-3.15, I2 = 81%; post-sensitivity OR 2.41, 95% CI 1.86-3.14, I2 = 75%). We also examined the source of heterogeneity in all subgroups and attempted to identify the studies that introduced heterogeneity and their effect on the pooled OR (95% CI). Table 4 presents the pre- and post-sensitivity pooled OR (95% CI) and the studies that were identified as a source of heterogeneity. As represented in Table 4, I2 of heterogeneity improved to a non-significant level in all subgroups, however the pooled OR (95% CI) did not change significantly.
We scored all the studies based on a 0-9 scale developed from MOOSE guidelines.16 The mean score from all the studies was 7 with a range of 6 to 9. We found no association between study quality scores and the pooled measure of effect. However, results of our assessment indicate there is a possibility of publication bias for the outcome hepatitis C for studies of small effect size showing negative results (Figure 4). We believe that this is unlikely to change the overall results, since the majority of included studies were of high quality and precision. However this should be interpreted with caution in the face of heterogeneity in studies.
Methods
Search strategy
We identified relevant studies and abstracts by searching MEDLINE (1966 to November 2008), EMBASE (1980 to November 2008), Database of Abstracts of Reviews of Effects (DARE; 1991 to November 2008), ACP Journal Club (1991 to November 2008), International Pharmaceutical Abstracts (1970 to November 2008), BIOSIS Previews (1969 to November 2008), Web of Science (1961 to November 2008), and Pubmed. There was no language restriction in selecting the studies. The initial search strategy was developed from the MeSH subject headings 'hepatitis' and 'tattoo' in MEDLINE. Titles were reviewed for relevance from this search, and subject headings and abstracts were then examined. Appropriate subject headings and keywords were added to the search strategy. The scope notes in MEDLINE and EMBASE were also examined to ensure the correct subject headings were used based on their definitions; other subject headings were included based on previous indexing and the inclusion of keywords based on synonyms used in the scope notes. Consequently, broader MeSH subject headings such as 'tattooing', 'hepatitis', and 'hepatitis C' were included. Proceedings and conference abstracts were searched through the databases PapersFirst (1993) and ProceedingsFirst (1993) up to October 2008. Author names and year of published work from key papers were entered into the cited reference search in the Web of Science. We screened the references of retrieved studies and review articles for any potentially missed articles. In addition, we hand-searched the reference lists of retrieved studies as well as journals related to 'hepatitis', 'hepatology', 'blood', 'infection', 'epidemiology', and 'gastroenterology', and abstracts and books related to hepatitis. We contacted authors to ensure there was no overlap in the sample included in their studies whenever needed.
Selection criteria
We considered all observational studies that assessed the association between tattooing and hepatitis. Observational studies were included if they (1) clearly defined hepatitis C as either the primary or secondary outcome; (2) clearly defined tattoos as either primary or secondary exposure; (3) presented relative risks or odds ratios and their corresponding confidence intervals or provided enough data to compute these parameters. In the case of a study published in different phases or if data from a study were duplicated in more than one study, we only included the most recent study.
Data extraction
We created a spreadsheet and recorded study characteristics including author names, publication year, country of study, study design, sample size, study population type, mean age or range, gender of participants, type of risk factors or confounders adjusted for, outcome of interest (hepatitis C), and adjusted odds ratio (OR) and 95% confidence interval (CI). Included articles were reviewed in full by two independent reviewers (SJ and SB). In studies that provided several levels of exposure, each exposure was categorized and analyzed in the designated subgroup. To assess the quality of studies we created a quality assessment scale (0 to 9 points) based on Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines.16 The scale includes reporting the inclusion/exclusion criteria, outcome definition, exposure definition, risk adjustment, possible sources of confounding, assessment of data, crude OR (95% CI) report, and adjusted OR (95% CI) report.
Statistical analysis
We performed several subgroup analyses to investigate the association between tattooing and hepatitis C among different populations. We conducted subgroup analyses based on the study population and study design (case-control, cohort, and cross-sectional). We also grouped studies into eight main mutually exclusive subgroups including: community samples, blood donors, hospital samples, injection drug users (IDUs), non-injection drug users (non-IDUs), drug users, prisoners, and high-risk population (street youth, HIV patients, tattooed in non-professional shops, and reused tattoo needles).
For all analyses, we weighted the study-specific adjusted log ORs by the inverse of their variances. Both fixed and random effect models were used to estimate the pooled adjusted OR. Statistical heterogeneity between studies was evaluated with Cochran's Q test and the I2 statistic.17 A sensitivity analysis was carried out to assess the individual influence of studies, and the analysis repeated excluding the studies with the largest weights. We used a funnel plot18 and Egger's test19 to assess the presence of publication bias. Statistical analyses and graphs were performed with RevMan 5 (Review Manager, version 5.0., The Cochrane Collaboration, 2008) and HEpiMA (Compute Methods Programs Biomed).
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