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.
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.
source: International Journal of Infectious Diseases