Comparison of risk factors among blood donors, volunteers and replacement individuals, infected or not by hepatitis C virus

ORIGINAL PAPER

Comparison of risk factors among blood donors, volunteers and replacement individuals, infected or not by hepatitis C virus

Felippe MJDB^I; Meira DA^II

^IBauru State Hospital, Botucatu Medical School, São Paulo State University, UNESP, Bauru, São Paulo State, Brazil

^IIDepartment of Tropical Diseases, Botucatu Medical School, São Paulo State University, UNESP, Botucatu, São Paulo State, Brazil

^{Correspondence to}

ABSTRACT

Hepatitis C is transmitted primarily parenterally by contaminated blood and is often associated with: intravenous drug abuse, invasive procedures, blood transfusions, acupuncture, tattooing, and alcohol and tobacco use. This study aimed to quantify and evaluate the risk factors among blood donors, volunteer blood donors and replacement individuals, infected or not by the C virus. The main transmission routes of C virus were identified in 55 men and 25 women (GI) monitored by the Ambulatory Unit of the Department of Tropical Diseases, Botucatu Medical School, and in 24 men and 26 women (GII), all active blood donors at the Bauru State Hospital Transfusional Agency. Both groups were similar in: tobacco and alcohol consumption, sexual behavior, tattooing and illicit drug use. The duration of alcohol and tobacco consumption and blood transfusions in GI were longer, whereas the option for steady partners, condom use, disposable materials and piercings were predominant in GII. In conclusion, the risk factors for hepatitis C demonstrate the necessity of health policies that act on the primary and secondary prevention levels (respectively, reduction of infection incidence and hepatopathy risk).

Key words: hepatitis C, risk factors, blood donors, injectable drugs, tobacco, alcohol, marijuana, sexual behavior.

INTRODUCTION

There are many risk factors involved in hepatitis C virus penetration into the host body, mainly parenterally, in which there is a rupture on skin or mucous membrane continuity (1-23). This type of acquisition is related to invasive hospital treatments and occurs by use of non-disinfected or incorrectly sterilized materials and equipment. Risky procedures include use of the following: surgical instruments, contaminated needles and syringes, endoscopic equipment, acupuncture, hemodialysis, as well as organ transplants (currently in a significant low incidence) and hemocomponent transfusions (2, 15, 23-25). Hepatitis C virus is also transmitted through illicit parenteral and intra-nasal drug users, mirrors and inhalation straws contaminated by nasal and intranasal secretions, through shared use of personal devices such as razors and other blades, toothbrushes, cuticle nippers, as well as permanent tattoo applicators (1, 2, 23-26).

The virus may also be transmitted by sexual contact, the manner reported in 6 to 10% of the cases (18). The abuse of alcohol and tobacco is also related to the high incidence of hepatitis C. Both substances cause harmful effects on the liver of infected individuals and their chronic use may also result in immunosuppressive action that may lead to the evolution of hepatocellular carcinoma (19, 23). The present study aimed to identify, quantify and evaluate the risk factors among blood donors, volunteers and replacement individuals, infected or not by the C virus, specifically, its main transmission routes, epidemiology and prevalence in a specific group.

MATERIALS AND METHODS

The non-randomized, transversal clinical study was conducted from March 2003 to May 2004, among eighty volunteer blood donors, found to be infected by hepatitis C virus, monitored by the Tropical Diseases Outpatient Unit, Botucatu Medical School, UNESP. Three individuals that presented serological evidence of anti-HCV antibodies, determined by the Blood Bank of the Botucatu Medical School, were also grouped into GI. The risk factors for fifty normal individuals not infected by hepatitis C virus, were also analyzed. They were donors at the Bauru State Hospital Transfusional Agency - managed by Botucatu Medical School - and grouped into GII.

The research approach included male and female individuals over 18 years old, randomly inserted into each group, according to their previous medical records or blood donations. A demographic data instrument was employed to evaluate socioeconomic conditions, hepatitis C risk factors, epidemiology as well as occurrences with needles, injections, syringes or other non-disposable material, including any transfusions received up to 1989 (see ^{Annex 1}) (25).

Source Characterization

The individuals were distributed according to the estimated population of their city of origin. Population data were supplied by IBGE (Brazilian Institute of Geography and Statistics), Census 2004 (27). The number of inhabitants per city was divided into five categories: 1 - cities with up to 20,000 inhabitants; 2 - from 20,000 to 40,000; 3 - 40,000 to 100,000; 4 - from 100,000 to 200,000; and 5 - over 200,000 inhabitants.

Risk Factors

Parenteral infection may be due to blood transfusions, injections with non-disposable needles and syringes, use of injectable drugs, permanent tattooing or piercings. Sexual components - including condom use, number of sexual partners, promiscuity (homo- or heterosexuality) and sexually transmitted diseases (STD) - are also risk factors for hepatitis C infection. "Habits" refer to duration of tobacco use and daily consumption were taken into account. The weekly amount of alcohol ingested was converted into units: 600 mL of beer corresponded to 4 units/alcohol; 100 mL of sugarcane rum to 4 units/alcohol; 200 mL of mixed drink (gin, vodka, vermouth or other component) to 4 units/alcohol; a 100 mL dose of whiskey to 4 units/alcohol; and one glass of wine (150 mL) was equivalent to 1 unit/alcohol (28).

Diagnosis Confirmation

The diagnosis of hepatitis C infection was confirmed through ELISA serological test, at three different stages: the first before patients were sent to Outpatient Unit, according to routine procedures, and the other two during ambulatory monitoring. Polymerase chain reaction (PCR) was performed, and prior HCV positive serologies were confirmed.

Statistical Analysis

For quantitative variables, the mean (χ²) and standard deviation were calculated for each group. Group comparisons were carried out using a t-test, calculating t and p statistics, for independent samples. Mann-Whitney nonparametric test was also employed in cases of high standard deviation. In these comparisons, whenever both tests had the same result the t-test was performed.

Regarding variables classified into more than two categories, the number of occurrences was recorded for each in GI, GII and in the juxtaposition of both groups. Comparison among groups was made by: chi-square test (χ²) and calculation of p values. When classification reached ordinal scale, the number of occurrences was calculated in each group and in the juxtaposition of both, and comparison between GI and GII was performed through Mann-Whitney nonparametric test, for large samples, by calculating z and p. For binary variables ("Yes" or "No"; "Male" or "Female", among others), the number of occurrences of each class ("Yes", for example), its dimension and the total group frequency were registered. In both groups, the dimension of "Yes or No" occurrence was calculated by chi-square test (χ²). Fisher's exact test was applied to some of the variables, with the direct calculation of p values, for data comparison. In all analyses, comparisons between GI and GII were significant when p < 0.05 (29).

All patients who took part in the present study had authorized the use of their data, and signed terms of free and informed consent. This study was approved by the Research Ethics Committee of the Botucatu Medical School on January 9^th, 2003.

RESULTS

From March 2003 to May 2004, eighty individuals (GI) were studied, including 55 males and 25 females, between 18 and 70 years old (χ² 40.21 ± 12.47), mostly from urban areas. Seventy of them (87.50%) resided in cities with less than 40,000 inhabitants and had tested positive for hepatitis C virus.

In GII, the fifty normal, volunteer blood donors investigated, mostly from the VI Regional Health Department, presented negative serology for hepatitis B and C viruses. Gender distribution was similar. Most GII subjects were from urban areas, living in cities with over 100,000 inhabitants.

GI presented most of the elderly individuals, with predominance of male gender and persons living in cities with fewer inhabitants. Urban area origin presented no statistical difference between the two groups.

Table 1 shows "Study Period", "Schooling" and "Family Income" variables for both groups. The statistical analyses revealed that GI had less formal education and a lower schooling level than GII. Family income presented no difference between the groups.

The variables "Consumed Tobacco Amount" in units per day and "Tobacco Consumption Duration" in years are expressed in Table 2. There was no statistical difference for tobacco consumption between the two groups whereas GI individuals had consumed it longer. "Alcohol Consumption", expressed in units per week, and "Alcohol Consumption Duration", in years; presented no difference. However, the consumption duration was longer in GI.

The overwhelming majorities of GI and GII were heterosexuals, respectively 95% and 96% (Table 3). "Steady Partners" was higher in GII. Comparing single partners, statistics revealed similar values, with condom use predominant in GII. Sexually transmitted diseases (STD) were more frequent in GI than in GII. Among STD, gonorrhea and syphilis were predominant in the first group. Comparison of "Use of Disposable Material in Invasive Procedures", including piercings and tattoos, verified that GII individuals always made use of disposable materials. Piercings were also more frequent in this group, while tattooing presented similar values.

Concerning drug abuse, Table 4 shows no difference between both groups. Hemocomponent transfusion was predominant in GI.

DISCUSSION

The prevalence of male individuals infected by C virus agrees with the literature (1, 3, 30). In the normal volunteer blood donor group, gender proportions were similar. The divergence found in the infected group may be due to campaigns to collect hemocomponents, accomplished by blood banks. When there is a shortage of blood derivatives in these institutions, young men recruited for the military are encouraged to donate blood and most of them maintain this practice afterwards. Some of the studied population may have participated in a blood donation campaign held in November 2003, on the occasion of the first anniversary of the Bauru State Hospital (31).

Comparison revealed no significant statistical difference between urban or rural origin and no reference was found in the literature concerning this feature. Elderly individuals were more predominant in the infected group. This finding agrees with demographic studies on volunteer blood donors, in which age presented similar figures among individuals infected by C virus (41 to 50 years old), while control the group was younger (from 21 to 30 years old) (23, 30, 32, 33). The current study showed that the control group had a more formal education than the infected one. Data from the southern Brazilian population also revealed that lower schooling level was directly related to higher for hepatitis C (34).

The two groups were socioeconomically homogeneous, although lower salaries limit access to better health assistance, and these individuals are less worried about diseases dissemination, treatment or prevention. Furthermore, exposure to the virus is higher, due to ignorance about its contamination routes and risk factors, which is consistent with data about C virus world prevalence, that compare population purchasing power (22, 25, 35, 36). GI individuals lived in smaller cities, compared to controls, who came from larger cities with better health services.

GI individuals were mostly technical professionals. On the other hand, infected individuals were more associated with domestic tasks that require no specialized knowledge. The literature, so far, does not mention any relation between C virus incidence and professional activity, nor does it report any virus transmission among construction workers or maids. Risk factors for these professions are hypothetically taken into account. A more detailed study on connecting these risk factors to C virus transmission is necessary. HCV incidence is low even among health workers, although their infection risk is significantly higher (37). Accidents with sharp instruments and professional exposure to materials containing C virus, as well as invasive procedures, may be related to the high prevalence of HCV seroconversion (16). Data also reveal possible unreported cases of cutting accidents involving health workers, a phenomenon that demands awareness and prevention campaigns as well.

Tobacco consumption duration was relevant among infected individuals, and expressive when time of use was over 10 years. Many studies relating severe steatosis and cirrhosis due to excessive tobacco use, reported that individuals infected by hepatitis C virus present higher prevalence of these diseases than non-tobacco users (11, 25, 38). Pessione et al. (11) observed that cigarette smokers, mostly young ones, had presented a significant augmentantion in damaged liver functions caused by chronic hepatitis.

Tobacco's harmful effects, including its carcinogenicity to humans, were monitored in studies on causative factors of hepatocellular carcinoma (39). This occurred because the liver is highly susceptible to cigarette components and these compounds also affect the response to interferon treatment in individuals infected by the C virus (38). Even low concentrations of nicotine and other cigarette compounds do not minimize cytotoxic effects on the liver after long-term consumption (12).

Statistical data on alcohol consumption demonstrated homogeneity between the groups. The same results were found by Yu and Yuan (38), in which the amount of alcohol ingested, from "1 to 3 doses/day" - equivalent to 7 to 21 weekly units of alcohol - was not considered relevant. Alcohol consumption duration differed statistically, since most infected individuals had consumed alcohol for over 10 years. About alcohol's damaging effects on the liver, especially of HCV-infected individuals, many authors were unanimous on its aggravating aspects (7, 11, 24, 25, 38).

No significant statistical difference regarding sexual orientation was registered. The probability of C virus transmission through sexual intercourse is considered low according to Strauss (15). However, Alter et al. (40) found a contamination incidence of 20% through sex when studying hepatitis C in blood donors. This type of transmission is considered uncommon, given that most infected individuals present more than one risk factor that can never be separately identified (5, 41). GII partners were less steady than the control group. According to Hepburn and Lawitz (42), the greater the number of sexual partners, the higher the probability of C virus transmission. Bosia et al. (43) suggested that having more than one sexual partner is not directly related to HCV infection.

Only a small portion of the infected individuals had used some kind of protective barrier during sexual intercourse whereas most of the controls had utilized condoms. On the correlation between severity of hepatic lesions and sexual transmission of hepatitis C virus, Drawan et al. (36) mentioned the need to train persons on sexual protection methods, not only concerning hepatitis prevention, but also contraception.

In the present study, most GII subjects presented STD, with a high incidence of gonorrhea and syphilis. However, Henderson (41) found contrary results in his meta-analysis on epidemiology and transmission routes of hepatitis C virus, in which the occurrence of these diseases was inversely proportional to C virus infection. The current data agrees with Oliveira et al. (8), who studied the virus prevalence and risk factors in drug users from Rio de Janeiro. Wejstal (20) took into account the infrequent occurrence through hepatitis C sexual transmission, and suggested further research on the main STD and their relation to hepatitis C virus.

Use of disposable materials in invasive procedures presented statistical difference between the studied groups. Bibliographical data showed that, before 1990, injectable medicines were administrated via non-disposable materials, boiled before reutilization. According to Labedzka, Simon and Gladysz (1), invasive surgical procedures are the main risk factors studied in clinical and epidemiological research of hepatitis C virus in volunteer blood donors. Any cutting or perforating procedure deserves attention to pathogen transmissibility (1, 14, 34, 44). Henderson (41) notes that health institutions should develop efficient preventive mechanisms against professional accidents that would lead to risk factors. The availability of individual protective equipment is legally guaranteed, so that health organizations who do not provide them may face legal sanctions.

In the current work, tattooing presented no statistical difference between GI and GII, a finding that contradicts the literature, in which tattooing is considered a risk factor for HCV infection (3, 13, 40, 45). This relevance may be due to obsolate techniques, when tattoos were applied with non-disposable non-sterilized equipment in inappropriate parlors, by persons who were not aware of disease epidemiology (3, 40). According to Haley and Fischer (44), the US Centers for Disease Control and Prevention do not recommend inspection in tattoo clinics, in view of previous studies conducted in such establishments, by this organization, that did not identify any virus presence.

Piercings were predominant in the control group. Only a few studies characterize piercings as risk factors for hepatitis C transmission, although they use perforating materials and their invasive application breaks the natural barrier against pathogens (1, 46, 47). The Hepatitis C Section of the Public Health Agency of Canada reported that only 4% of the nation's youth, from 12 to 29 years old, who used this type of adornment, had contracted HCV (48).

No statistical difference was observed herein between the two groups regarding use of illicit drugs. Data presented by US National Institutes of Health on management of hepatitis C showed that this type of risk factor must be distinguished from other manners of C virus dissemination, not only by parenteral transmission, but also by inhalation through nasal catheters (6). According to McMahon et al. (4), in a study on the virus presence in nasal secretions of drug users, substances commonly inhaled intranasally - such as cocaine, methamphetamine and heroin - may cause tissue deterioration or nasal membrane necrosis. Inhalation implements inserted in a damaged nasal cavity can transmit the virus, especially when used by many individuals including a infected person.

Injectable drugs constitute the major risk factor for hepatitis C in the United States (23). In Rio de Janeiro, Brazil, Oliveira et al. (8) reported high rates of cocaine consumption among injectable drug users, and high prevalence of hepatitis C infection in these individuals. Many authors affirm that illicit drug abuse is related to hepatitis C (8, 10, 17, 25). They recommend health programs directed to chemical dependence and control strategies to stop the virus dissemination.

Post-transfusion hepatitis used to be more frequent before 1989, when the C virus was discovered (13, 17, 24, 26). Until then, infected individuals could donate blood without knowing they were transmitting the disease. As technologies improved, new studies revealed that serological and control tests were extremely important to prevent this type of transmission (21). Nowadays, control rules established by governmental organizations have inhibited HCV transmission through blood transfusion by defining specific recommendations to donors (9). In the current study, even after adoption of such guidelines for blood donation, post-transfusion hepatitis was registered in GI individuals.

CONCLUSIONS

It was possible to verify that risk factors identified in blood donors infected by hepatitis C virus were similar to the literature, except for illicit drug use, which demands some attention to local customs and habits. Judicious donor selection, including precise serological tests, is also very important; given that risk factors are routinely present in general population, especially in the youngest portion. Thus, orientation campaigns are essential to prevent dissemination of the C virus, through health policies that act on the primary and secondary prevention levels (respectively, reduction of infection incidence and hepatopathy risks).

Received: May 19, 2008

Accepted: September 09, 2008

Abstract published online: September 18, 2008

Full paper published online: February 28, 2009

Conflicts of interest: There is no conflict.

UNESP São Paulo State University

Botucatu Medical School Hospital - Tropical Diseases Outpatient Unit

COMPARISON OF RISK FACTORS AMONG BLOOD DONORS, VOLUNTEERS AND REPLACEMENT INDIVIDUALS, INFECTED OR NOT BY C VIRUS

1. IDENTIFICATION

Name: _________________________________________ ID ________________

Address: _________________________________________________, N. _______

Quarter: _____________________________________ City: ___________________

ZIP Code: ______________________ Telephone: __________________________

2. SOCIODEMOGRAPHIC CHARACTERISTICS

Sex: ____________ Age: _______________ Civil state: ______________________

Schooling: _______________________ Study period (years): ______________

Area of origin: _______________________ Occupation: _____________________

Family income: _____________ /person - Number of people in the house: ________

3. RISK FACTORS - HABITS

Tobacco consumer: ______ Units/day _______ Duration (years): _________

Alcohol consumer: ________ Units/week _____ Duration (years): _________

Sexual activity:

Steady sexual partners: _______ With/without ____________ Time: ______

Single partner: Yes/No: ___________ Lifetime? _________________

Condom use: Yes/No: _________________ Consistently? _____________

Sexuality - Heterosexual: ______ Homosexual: _______ Bisexual: ________

Sexually transmitted diseases: Yes/No: ______Which? __________________

Use of disposable materials in invasive procedures: Yes/No: _________________

Use of piercing: Yes/No: _________________ Use of tattooing: Yes/No: _______

Use of illicit drug: Yes/No: _______ Injectable: Yes/No: ______Which? ___________

Intranasal: Yes/No: ______ Which? _____________ Crack: Yes/No: ____________

Another drug: Yes/No: ______Which? _____________

4. EPIDEMIOLOGICAL AND CLINICAL DATA

Clinical history

Hepatits C. Yes/No: ____

Jaundice: Yes/No: ____ Hepatocellular carcinoma: Yes/No: ____

Hemocomponent transfusion: Yes/No: _____ Why? __________________

How many bags? ________

HIV (infection or illness): Yes/No: _____

Familial antecedents

Hepatitis: Yes/No: ___ Which? _____ Who? _____________ (relationship)

Jaundice: Yes/No: ____ Who? ________________ (relationship)

Hepatocellular carcinoma: Yes/No: ____ Who? ______________ (relationship)

5. DIAGNOSTIC CONFIRMATION

ELISA

1^st result:___/___/___ - 2^nd result:___/___/___ - 3^rd result:___/____/__

Reagent confirmed (anti-HCV): Yes/No: _____ Why? ____________________

PCR

Qualitative: Yes/No: _____ Quantitative: Yes/No: _____

Genotype: Yes/No: ___ Which? _____

Biopsy: Yes/No: _____ Result: _______________________________________

6. DESCRIPTION OF THE ILLNESS

Isolation of the virus: Where? ______________________________________

Blood donor: Yes/No: _____ Where? __________________________________

For how long: _________ How many times: _________

7. OTHER OBSERVATIONS: _________________________________________

___________________________________________________________________

___________________________________________________________________

Free and Informed Consent Term: Yes/No: _____

Date: ____________________ Signature: _____________________

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ANNEX 1 

Publication Dates

• Publication in this collection
  16 Mar 2009
• Date of issue
  2009

History

• Accepted
  09 Sept 2008
• Received
  19 May 2008