numerous publications present anti - hcv prevalence in particular groups : blood or plasma donors , hemodialyzed and post - transfusion subjects , intravenous drug users , subjects with high - risk behaviour , health care workers , and patients with liver diseases . among these groups only data from studies of blood donor volunteers can more or less be treated as a reflection of anti - hcv prevalence in the general population .
such studies were conducted in many european countries shortly after hcv discovery [ 117 ] .
taking into account risk groups , blood donors studies gave a picture of anti - hcv prevalence and routes of hepatitis c virus ( hcv ) spread in various parts of europe .
a systematic review by esteban et al summarized those data up to 2007 . according to this comprehensive review , in general european population the lowest anti - hcv prevalence occurs in northern ( 0.11.0% ) and central europe ( 0.21.2% ) . in southern europe and spain anti - hcv prevalence
the authors stressed that up to now there were no sufficient data about anti - hcv prevalence in eastern europe .
naoumov ( 1999 ) reviewed and summarized data from eastern european studies of blood donors , medical personnel and hemodialysed patients .
it was ascertained with reference to blood donor studies that the eastern european population has a high prevalence of hcv infection  from 0.68% in czech republic to 4.9% in romania .
later publications from this european region have confirmed this conclusion , but there are still no population - based studies published from eastern european countries [ 2022 ] .
prevalence of hcv infection in lithuania has been studied in small groups of first - time blood donors , acute viral hepatitis patients and in risk groups ( 2.2% in first - time blood donors , 7.9% in commercial donors , 13.9% in commercial plasma donors , 48.3% in hemodialysed patients , 29.4% in prisoners , 9.4% in elderly nursing home residents , and 7.9% in hemodialysis staff ) .
these data did not provide a clear picture of anti - hcv prevalence in the general population , but it allowed estimation of prevalence at from 2% to 3% .
we present a descriptive epidemiological study , prepared according to consort   and strobe   recommendations , aimed at assessing age - specific risk factors for hcv acquisition and prevalence of anti - hcv in the general population of lithuania .
an observational analytical cross - sectional study design was conducted to clarify the prevalence of anti - hcv and hcv transmission routes in the general population .
cross - sectional survey of random anonymous volunteers and testing them for anti - hcv was conducted may 1722 , 2010 in 5 cities of lithuania ( vilnius , kaunas , klaipda , iauliai , and panevys ) and corresponding rural regions where 75% of the population live ( 2 513 313 out of 3 329 039 , according to the lithuanian statistical department ; http://www.stat.gov.lt/lt/ ) . according to data on anti - hcv prevalence in eastern europe and the study by ambrozaitis et al . on lithuanian blood donors and some risk groups , we expected the prevalence of anti - hcv in lithuania to be approximately p=3%1% .
after calculation of an adequate sample size with precision 1% ( d=0.01 ) and level of confidence of 95% ( z=1.96 ) , a cohort of n=1118 subjects was estimated by the formula n=(zp(1p))/d .
people over age 18 who were willing to be tested for anti - hcv were voluntarily enrolled into the study by a convenience sampling of shoppers at one of the biggest supermarkets in vilnius , kaunas , klaipda , iauliai and panevys .
the only eligibility criteria were age 18 and residence in the selected cities and/or corresponding rural regions . during this study ,
anti - hcv testing was wrongly performed or questionable for 14 ( 0.9% ) participants or a tested person refused or could not repeat it .
anti - hcv tests was suitable for evaluation in a total of 1514 ( 99.1% ) subjects ( 572 men and 942 women )  651 ( 241 men and 410 women in vilnius ) , 266 ( 128 men and 138 women in kaunas ) , 313 ( 115 men and 198 women in klaipda ) , 148 ( 55 men and 93 women ) in panevys , and 136 ( 33 men and 103 women ) in iauliai ( figure 1 ) .
the study was performed according to the world medical association declaration of helsinki , and all procedures were approved by the lithuanian bioethics committee .
all volunteers who wanted to know their anti - hcv status signed informal consent and answered an anonymous questionnaire with demographic data ( age , sex , education , occupation , residence ) and exposure to hcv risk factors ( intravenous drug use , blood transfusions , blood donations , hemodialysis , tattooing , piercing , open trauma , surgery , multiple and the long - term hospitalizations , hcv infection among family members , dentistry , tooth removal , childbirth , abortions , and risky sexual behaviour ) .
screening for anti - hcv was performed on the peripheral capillary blood using rapid lateral flow immunochromatography test ( core hcv - wb ; core diagnostics , birmingham b2 5hg , uk ) with 99.99% diagnostic specificity and 100% sensitivity .
all anti - hcv - positive subjects were admitted for further testing at the centre of hepatology , gastroenterology and dietetics of vilnius university hospital  santariki klinikos  , where anti - hcv were confirmed with 2-step chemiluminescent microparticle immunoassay ( architect system anti - hcv ; abbott , 65205 wiesbaden , germany ) .
the following limitations of such data collection are : free anonymous testing for anti - hcv might be more attractive for having exposure to hcv risk ( for example : intravenous drug users , subjects having family member infected with hcv ) rather than for persons without suspected exposure .
that is why detected anti - hcv prevalence can occur been higher than it really is .
such subjects could also be not fully overt in indication of possible risk factors , although the questionnaire used was fully anonymous .
that is why in a study cohort we had 37.8% men and 62.2% women ; although in the general population we have 45% men and 55% women . in the study cohort
the anti - hcv rate was calculated separately for men and women on age - dependent strata .
crude rate in age - dependent strata and in the study population overall were calculated as a mean of rates among men and women .
age- and sex - dependent standardized anti - hcv rate in the general population was calculated using the direct standardization method and separate calculation of standard vectors for men and women in age - dependent strata ( wj = nj /
n where nj  number of males or females on age - depended stratum , n  population overall ) .
for every statistically significant ( .05 ) hcv route , an odds ratio was estimated using univariate logistic regression analysis with 95% confidence interval .
differences in anti - hcv positivity between men and women on age - dependent strata were evaluated with fisher s exact test .
an observational analytical cross - sectional study design was conducted to clarify the prevalence of anti - hcv and hcv transmission routes in the general population .
cross - sectional survey of random anonymous volunteers and testing them for anti - hcv was conducted may 1722 , 2010 in 5 cities of lithuania ( vilnius , kaunas , klaipda , iauliai , and panevys ) and corresponding rural regions where 75% of the population live ( 2 513 313 out of 3 329 039 , according to the lithuanian statistical department ; http://www.stat.gov.lt/lt/ ) .
according to data on anti - hcv prevalence in eastern europe and the study by ambrozaitis et al . on lithuanian blood donors and some risk groups , we expected the prevalence of anti - hcv in lithuania to be approximately p=3%1% .
after calculation of an adequate sample size with precision 1% ( d=0.01 ) and level of confidence of 95% ( z=1.96 ) , a cohort of n=1118 subjects was estimated by the formula n=(zp(1p))/d .
people over age 18 who were willing to be tested for anti - hcv were voluntarily enrolled into the study by a convenience sampling of shoppers at one of the biggest supermarkets in vilnius , kaunas , klaipda , iauliai and panevys .
the only eligibility criteria were age 18 and residence in the selected cities and/or corresponding rural regions . during this study ,
anti - hcv testing was wrongly performed or questionable for 14 ( 0.9% ) participants or a tested person refused or could not repeat it .
anti - hcv tests was suitable for evaluation in a total of 1514 ( 99.1% ) subjects ( 572 men and 942 women )  651 ( 241 men and 410 women in vilnius ) , 266 ( 128 men and 138 women in kaunas ) , 313 ( 115 men and 198 women in klaipda ) , 148 ( 55 men and 93 women ) in panevys , and 136 ( 33 men and 103 women ) in iauliai ( figure 1 ) .
the study was performed according to the world medical association declaration of helsinki , and all procedures were approved by the lithuanian bioethics committee . all volunteers who wanted to know their anti - hcv status signed informal consent and answered an anonymous questionnaire with demographic data ( age , sex , education , occupation , residence ) and exposure to hcv risk factors ( intravenous drug use , blood transfusions , blood donations , hemodialysis , tattooing , piercing , open trauma , surgery , multiple and the long - term hospitalizations , hcv infection among family members , dentistry , tooth removal , childbirth , abortions , and risky sexual behaviour ) . screening for anti -
hcv was performed on the peripheral capillary blood using rapid lateral flow immunochromatography test ( core hcv - wb ; core diagnostics , birmingham b2 5hg , uk ) with 99.99% diagnostic specificity and 100% sensitivity .
all anti - hcv - positive subjects were admitted for further testing at the centre of hepatology , gastroenterology and dietetics of vilnius university hospital  santariki klinikos  , where anti - hcv were confirmed with 2-step chemiluminescent microparticle immunoassay ( architect system anti - hcv ; abbott , 65205 wiesbaden , germany ) .
the following limitations of such data collection are : free anonymous testing for anti - hcv might be more attractive for having exposure to hcv risk ( for example : intravenous drug users , subjects having family member infected with hcv ) rather than for persons without suspected exposure .
that is why detected anti - hcv prevalence can occur been higher than it really is .
such subjects could also be not fully overt in indication of possible risk factors , although the questionnaire used was fully anonymous .
that is why in a study cohort we had 37.8% men and 62.2% women ; although in the general population we have 45% men and 55% women . in the study cohort
the anti - hcv rate was calculated separately for men and women on age - dependent strata .
crude rate in age - dependent strata and in the study population overall were calculated as a mean of rates among men and women .
age- and sex - dependent standardized anti - hcv rate in the general population was calculated using the direct standardization method and separate calculation of standard vectors for men and women in age - dependent strata ( wj = nj / n where nj  number of males or females on age - depended stratum , n  population overall ) .
comparison of different routes of exposure was evaluated with fisher s exact test . for every statistically significant ( .05 ) hcv route
, an odds ratio was estimated using univariate logistic regression analysis with 95% confidence interval .
differences in anti - hcv positivity between men and women on age - dependent strata were evaluated with fisher s exact test .
among 1514 tests , 37 ( 2.44% ) anti - hcv - positive subjects were detected ( 23 men , 14 women ) , of these there were 3 ( 8.1% ) people ( 2 from vilnius region and 1 from klaipda ) who knew their anti - hcv status because hcv infection had been diagnosed previously and/or they were treated for chronic hepatitis c , and 34 ( 91.9% ) had never been tested for anti - hcv ( table 1 ) . in our cohort , anti - hcv positivity did not depend on age ( p=.7216 ) , but more men than women had been exposed to hcv ( crude rates : 4.02% vs 1.49% , p=.0030 ) .
the mean of anti - hcv rates was 2.76% and was similar to the rate in the general population ( 2.78% ) .
after direct standardization of sex - adjusting rates by age distribution of standard european population prevalence of anti - hcv , a rate of 2.85% was obtained .
we did not standardize the anti - hcv rate of our cohort to the world population because the population of lithuania is older and anti - hcv prevalence dependence on age was not ascertained . in the study cohort
rural lithuanian regions are less affected by hcv infection than the capital and bigger cities ( table 2 ) . after analyzing the questionnaire data
, we found that intravenous drug use is the most important risk factor for hcv spread in our population ( table 3 ) .
blood transfusions , tooth removal , childbirth , and long - term or multiple hospitalizations can be assigned to hcv acquisition risks ( table 3 ) . statistically , other healthcare procedures ( blood donation , hemodialysis , surgery , dentistry , abortions ) are not associated with hcv acquisition .
people who had a single surgery had generally similar rates of infection to the general population , but people having more than 2 surgeries were more often anti - hcv positive ( table 4 ) .
among the 5 ( 19.2% ) anti - hcv - positive people , 2 had hcv - infected brothers , 1 had an hcv - infected sister , 1 had an hcv - infected wife , and 1 had an hcv - infected husband . among the 4 ( 1.4% ) anti - hcv - negative people , 2 had hcv - infected fathers , 1 had an hcv - infected brother , and 1 had an hcv - infected sister .
being rather often declared , piercing was ascertained as a safe procedure concerning hcv spread , but the tattoo is not safe .
among 1514 tests , 37 ( 2.44% ) anti - hcv - positive subjects were detected ( 23 men , 14 women ) , of these there were 3 ( 8.1% ) people ( 2 from vilnius region and 1 from klaipda ) who knew their anti - hcv status because hcv infection had been diagnosed previously and/or they were treated for chronic hepatitis c , and 34 ( 91.9% ) had never been tested for anti - hcv ( table 1 ) . in our cohort , anti - hcv positivity did not depend on age ( p=.7216 ) , but more men than women had been exposed to hcv ( crude rates : 4.02% vs 1.49% , p=.0030 ) .
the mean of anti - hcv rates was 2.76% and was similar to the rate in the general population ( 2.78% ) .
after direct standardization of sex - adjusting rates by age distribution of standard european population prevalence of anti - hcv , a rate of 2.85% was obtained .
we did not standardize the anti - hcv rate of our cohort to the world population because the population of lithuania is older and anti - hcv prevalence dependence on age was not ascertained . in the study cohort
rural lithuanian regions are less affected by hcv infection than the capital and bigger cities ( table 2 ) .
after analyzing the questionnaire data , we found that intravenous drug use is the most important risk factor for hcv spread in our population ( table 3 ) .
blood transfusions , tooth removal , childbirth , and long - term or multiple hospitalizations can be assigned to hcv acquisition risks ( table 3 ) .
statistically , other healthcare procedures ( blood donation , hemodialysis , surgery , dentistry , abortions ) are not associated with hcv acquisition .
people who had a single surgery had generally similar rates of infection to the general population , but people having more than 2 surgeries were more often anti - hcv positive ( table 4 ) .
nine people had hcv - infected relatives . among the 5 ( 19.2% ) anti - hcv - positive people
, 2 had hcv - infected brothers , 1 had an hcv - infected sister , 1 had an hcv - infected wife , and 1 had an hcv - infected husband . among the 4 ( 1.4% ) anti - hcv - negative people , 2 had hcv - infected fathers , 1 had an hcv - infected brother , and 1 had an hcv - infected sister .
being rather often declared , piercing was ascertained as a safe procedure concerning hcv spread , but the tattoo is not safe .
based on the results of this study we estimate that the anti - hcv prevalence in lithuania is 2.78% , and adjusted to the standard european population the anti - hcv rate is 2.85% .
perhaps the free anonymous testing provided by our study was more attractive for people possibly having exposure to hcv ( eg , intravenous drug use , having a family member with hcv infection ) than for those without such risks .
our estimated anti - hcv prevalence is similar to that in russia , but it is higher than in poland , estonia and latvia .
however , the conclusion related to anti - hcv prevalence in eastern european countries was based on studies of blood donors , as in case of poland , or on the basis of personally communicated data , as in case of the baltic states .
we could not find a single observational study presenting anti - hcv prevalence in the general populations of estonia , latvia , poland or in other neighbouring countries ( russia , byelorussia or ukraine ) . in lithuania blood donors , some small risk groups and chronic hepatitis c patients were investigated [ 23,3134 ] .
similar data are obtainable in latvia and estonia [ 3539 ] . the data on anti - hcv prevalence from a large cohort of 4216 healthy people from various regions of russia and mongolia were presented in 1996 . according to this study , anti - hcv prevalence in those regions varied from 0.7% in central russia to 10.7% in mongolia .
there is no current data about hcv infection spread in russia including the kaliningrad region where an explosion of intravenous drug abuse was observed during the last decade .
a study of northern ukrainian schoolchildren and blood donors found a 0.8% anti - hcv prevalence for schoolchildren and 2.3% for blood donors ; anti - hcv prevalence directly correlated with the age 
people ages 4049 years had 4.0% positivity , while those older than 60 years had 6.25% .
those data were published in 1993 and do not reflect the present situation of hcv infection in ukraine .
in addition , the correlation of anti - hcv prevalence with age was not reported anywhere in the literature , nor did we find such correlation in our cohort . in byelorussia , 1.26% anti - hcv prevalence was reported without reference to the source . on the basis of the above - mentioned publications , esteban and co - authors presented anti - hcv prevalence in eastern europe ( figure 1 in review ) .
however , these data are not sufficient to provide a true picture of anti - hcv prevalence or the number of hcv carriers in this region .
those authors presumed that anti - hcv prevalence could be higher not only in eastern europe , but also in the general european population because there are not sufficient current data .
epidemiological studies of the general population would be useful in order to clarify the situation of hcv infection in europe in light of increasing intravenous drug abuse .
according to the obtained data , the main hcv infection route in lithuania is currently intravenous drug use ( or=42.5 ) . in our country about 80% of intravenous drug users are infected with hcv and men more often than women engage in this behavior .
this could explain the higher rate of anti - hcv positivity found in men of our cohort .
intravenous drugs are more accessible in cities ( especially in the capital ) ; accordingly , we found lower anti - hcv prevalence in rural regions .
observations and data of other investigators taken together reinforce the fact that intravenous drug use is now the principal route of hcv spread in the european population .
former nosocomial routes such as blood donations , surgeries , and hemodialysis seem to be well controlled in our country
. nevertheless , blood transfusion can still be a source of hcv ( or=6.4 ) . in lithuania
every donor s blood has been tested for anti - hcv since 1994 and since 2004 for hcv rna .
hcv rna is tested separately in every donation , not in pools , and nat sensitivity is 3.01 iu / ml .
safety of donor s blood is still a worldwide health care problem which could be partially solved by introducing more sensitive nat methods .
however , it will not be solved completely , especially in the case of paid donations .
the possibility of hcv transmission through saliva is questionable , but it can not be ruled out . taking into consideration the hcv rna presence in saliva of 3555% of chronic hepatitis c patients , there is a possibility to transmit hcv to dentists and others [ 4449 ] .
childbirth , being a risk factor for hcv acquisition , was an unexpected finding for us .
anti - hcv prevalence among pregnant women and mother - to - child hcv transmission have been discussed in the literature [ 5054 ] .
the number of anti - hcv - positive women in our cohort was only 14 and only 10 answered the question about childbirth  7 ( 70% ) had children  and 171 anti - hcv - negative women , answered a question about childbirth  54 ( 32% ) had children .
so , the small group of anti - hcv - positive women in our cohort may indicate why childbirth became statistically significant as an hcv risk factor .
we failed to find a single study of anti - hcv prevalence in women before and after childbirth .
such a study would be useful to confirm or deny our controversial finding and clarify a possible source of hcv infection if this exists in the maternity clinic . confirming that multiple and long - term hospitalization is an hcv risk factor raises the question of the specific route of transmission in hospitals .
the possible infection source can be asymptomatic hcv carriers who are admitted for surgery or conservative treatment , for example , heart disease , and they are not tested for hcv by diagnostic algorithm . a health care worker infected with hcv but not diagnosed
there were only 2 patients in the study cohort who underwent hemodialysis : 1 was anti - hcv positive and the other one was not .
such limited data does not allow us to draw conclusions , but studies before 1995 indicated to a high prevalence of anti - hcv in hemodialyzed patients .
it is necessary to pay attention to a new risk factor for hcv acquisition in our population 
nine people ( 5 anti - hcv - positive and 4 anti - hcv - negative ) indicated presence of hcv infection in family members ( usually it is sister or brother , but also it can be a spouse or parent ) ; it confirmed a possibility of household and/or sexual hcv acquisition .
however , risky sexual behaviour was not proved to be an hcv acquisition route . still , intrafamilial hcv spread is not well elucidated ,
it was only recognized that family members of hcv - infected patients had a 3- to 5-fold higher prevalence of anti - hcv than the general population and are often infected with the same hcv strain [ 6164 ] .
open traumas with a big blinding area can be considered as a risk for hcv acquisition but its reasons are unclear ( or=3.7 ) . receiving a tattoo is a risk factor for hcv infection ( or=4.4 ) , possibly because of violation of sanitary norms during the procedure .
our previous study of chronic hepatitis c cohort   found a changing trend in hcv transmission , from nosocomial to less controlled intravenous drug use or hcv infection in family member .
we found that older patients often get hcv during surgeries or long - term and multiple hospitalizations , while younger ones get it through intravenous drug use and tattooing .
considering the asymptomatic course of infection , a high hcv rate in intravenous drug users and existence of their  trusted networks  , a new peak of hcv infection can be expected in the near future .
this is important not only for lithuania , but also for other european countries where intravenous drug use is becoming a core of the hcv epidemic .
hcv spread through intravenous drug use is not only a healthcare problem ; it is a social problem as well .
it can not be resolved only with prevention or other healthcare tools , especially in the absence of effective immunization .
only a complex of coordinated means directed to intravenous drug use prevention , public education and preventive efforts can be effective in prevention of hcv spread .
in our population , anti - hcv prevalence is 2.78% ; adjusted to the standard european population , prevalence is 2.85% . this rate is higher in vilnius and kaunas in comparison with other regions of lithuania .
the main hcv transmission route is intravenous drug use ; intrafamilial transmission is significant as well .
blood transfusions , tattooing , open trauma , tooth removal , uncertain nosocomial transmission during multiple and long - term hospitalizations and childbirth are also hcv infection routes . despite active prevention of nosocomial hcv transmission ,
the incidence of hcv infection does not decrease , due to virus spread in  trusted networks  of intravenous drug users .
nowadays , hcv transmission control can not be carried out without controlling intravenous drug use and active prevention educational tools .
 summarybackgroundthe aim of this study was to assess risk factors for hcv acquisition and prevalence of anti - hcv in the general population of lithuania.material/methodsthe study enrolled 1528 randomly selected adults from the 5 biggest cities of lithuania and its rural regions . 
 screening for anti - hcv was performed by analysis of peripheral capillary blood with lateral flow immunochromatography and confirmation of positive cases by peripheral venous blood testing with 2-step chemiluminescent microparticle immunoassay.resultsanti-hcv prevalence in lithuania is 2.78% and according to the standard european population the adjusted anti - hcv rate is 2.85% . 
 it is more prevalent among men ( crude rates : 4.02% males vs. 1.49% females , p=.0030 ) and this does not depend on age . 
 vilnius and kaunas regions have higher infection rates than smaller rural regions ( 2.92% and 3.01% vs. 2.24% , 0.74% and 1.35% ) . nowadays among 
 our population hcv infection spreads mainly via intravenous drug use ( or=42.5 , p<.0001 ) . 
 hcv transmission occurs through blood transfusions ( or=6.4 , p=.0002 ) , tooth removal ( or=4.1 , p=.0048 ) , childbirth 
 ( or=5.0 , p=.0224 ) , multiple and a long - term hospitalization ( or=3.0 , p=.0064 ) , tattooing ( or=4.4 , p=.0013 ) , open traumas ( or=3.7 , p=.0009 ) and intrafamilially ( or=11.3 , p=.0002).conclusions2.78% of the population is anti - hcv - positive . 
 the anti - hcv rate is higher in vilnius and kaunas in comparison with other regions . 
 hcv spreads mainly through intravenous drug use , but intrafamilial and some nosocomial routes are also important . 
 the anti - hcv prevalence did not depend on age . despite active prevention of nosocomial hcv transmission 
 , the incidence of hcv infection does not decrease due to virus spread mostly in  trusted networks  of intravenous drug users . 
Background
Material and Methods
Study design
Study population
Data collection
Statistical evaluation
Results
Anti-HCV positivity
HCV infection routes
Discussion
Conclusions