Jafari from the University of British Columbia School of Population
and Public Health and colleagues performed a systematic literature
review to determine whether tattooing is a risk factor for the
hepatitis C transmission.
Tattoos have become increasingly popular in recent years, the
study authors noted as background. In the U.S., an estimated
36% of people under age 30 have tattoos. In Canada, approximately
8% of high school students have at least one tattoo, while 21%
of those who don't have one want one. Among prisoners, an estimated
25%-35% have tattoos.
Tattooing involves injection of pigments into the dermal layer
of skin. This is typically done using a machine with multiple
needles that puncture the skin 80-150 times per second, but
amateur tattoos may also be done by hand using a single needle
or other sharpened implement.
"Since tattoo instruments come in contact with blood and
bodily fluids, infections may be transmitted if instruments
are used on more than one person without being sterilized or
without proper hygiene techniques," Jafari said in a University
of British Columbia press release.
Tattoo needles and other equipment can potential transmit HCV,
hepatitis B virus (HBV), HIV, and other blood-borne pathogens.
Professional tattooists in the U.S. today use single-use needles,
sterilized or single-use ink holders, and inks formulated specially
for tattooing, as well as employing universal blood-borne pathogen
precautions such as wearing latex gloves; do-it-yourself tattoos
and those done in settings such as prisons, however, often do
not follow such precautions.
The investigators searched medical literature databases including
MEDLINE, PUBMED, and EMBASE to identify all case-control, cohort,
and cross-sectional studies published prior to November 2008
that evaluated risks related to tattooing or risk factors for
A total of 124 studies from more than 30 countries -- including
Canada, the U.S., Australia, Brazil, Italy, and Iran -- were
included in the systematic review. Of these, 83 studies (45
cross-sectional, 30 case-control, and 8 cohort) were used for
the meta-analysis, representing a total 132,145 participants.
was associated with nearly a 3-fold increased likelihood
of HCV infection overall (pooled odds ratio [OR] 2.74).
sub-group analysis showed that the strongest association
between tattooing and HCV risk was seen among people who
do not inject drugs (OR 5.74).
was also associated with elevated HCV risk in other sub-groups:
donors: OR 3.73;
patients: OR 3.20;
drug users: OR 3.06;
populations: OR 2.80;
samples: OR 2.79;
of any type of drugs: OR 2.30.
association between tattoos and HCV infection was seen for
both professionally done tattoos and those done in non-professional
facilities or by friends (OR 2.80).
association held in another analysis that excluded 11 studies
with the widest confidence intervals, indicating more uncertainty
about whether the results were due to chance.
from the current meta-analysis indicate that tattooing is associated
with a higher risk of hepatitis C infection," the study
authors concluded. "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."
"The strength of our review is mainly in the large number
of studies and multinational nature of the study participants,"
they elaborated in their discussion. "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," they
continued. "First, several studies have reported an association
between tattooing and other infections including HIV, hepatitis
B, leprosy, and methicillin-resistant Staphylococcus aureus
[MRSA]. 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
The authors also noted other potential risks of tattooing besides
blood-borne pathogens, including bacterial and fungal infections,
allergic reactions, toxic ingredients in tattoo inks, unknown
risks of new glow-in-the-dark or black-light inks, and risks
associated with tattoo removal.
In addition to prevention awareness efforts for tattoo recipients,
the researchers called for risk-reduction education for tattoo
artists, infection-control guidelines enforced through inspections,
and better adverse event reporting and record-keeping. They
also suggested that clinicians might consider HCV screening
for their patients with tattoos.
Investigator affiliations: British Columbia Centre for Disease
Control; Community Medicine, University of British Columbia;
British Columbia Children's Hospital; Centre for Clinical Epidemiology
and Evaluation, Vancouver Hospital, Vancouver, British Columbia,
S Jafari, R Copes, S Baharlou, and others. Tattooing and the
risk of transmission of hepatitis C: a systematic review and
meta-analysis. International Journal of Infectious Diseases.
July 31, 2010 (Epub ahead of print).
University of British Columbia. Tattooing linked to higher risk
of hepatitis C: UBC study. Press release. August 6, 2010.