Age-specific frequency of screen-detected hepatitis C virus seropositivity in men from the Punjab province of Pakistan

Abstract

Pakistan is a South Asian country with a high population seroprevalence of anti-hepatitis C virus (anti-HCV) antibody. In administrative districts of its most populous province, Punjab, the frequency of seropositivity for HCV in different age groups of adult men, the usual bread winners for their families, is not known. This study describes the frequency and age-distribution of seropositivity for anti-HCV antibodies in 58,680 clinically healthy, adult men, from nine districts of the Punjab province in Pakistan, undergoing pre-employment health screening. Laboratory records belonging to these men, screened by enzyme-linked immunosorbent assay 3 for antiHCV antibodies in serum, were analysed and frequencies were calculated. A total of 4034 (6.9%) were seropositive for HCV. The highest frequency of HCV seropositivity was noted in men from Multan (9.6%), followed by Lahore (9.4%) district. The lowest (5.0%) was noted among men residing in Bahawalpur district. There was a progressive increase in seroprevalence with increasing age in men from all districts. Further research needs to be initiated to describe differential HCV risk factor distribution in various districts and sustainability of relatively low seroprevalence noted in younger men.

INTRODUCTION

The South Asian developing nation of Pakistan ranks among countries with a high prevalence of chronic hepatitis C virus (HCV) infection. A recent nation-wide population screening, the Pakistan Medical Research Council (PMRC) hepatitis survey, found an overall frequency of 4.9% seropositivity for anti-HCV antibody. ¹ In Punjab province, the most populous region of Pakistan with over 73 million people, ² anti-HCV antibodies were found in 6.7% of all screened samples. ¹

The Punjab is a patriarchal society, and adult males play a key role as the traditional breadwinners for the family. ³ Published data from the PMRC survey does not elaborate on prevalence of anti-HCV antibody among this group in the Punjab province. There have been other, albeit smaller, studies on adult males in Punjab; most notably in young army recruits, which a recently published review summarized, describing 3.6% of recruits having anti-HCV antibodies. ⁴ Studies screening men of all ages in individual cities in Punjab inevitably suffer from bias due to self-selection of those screened, and have found remarkably high sero-prevalence figures (up to 24%). ^5,6

The existing gap in literature concerns sero-prevalence in men of different ages from various administrative districts in Punjab province, described using a single sampling criteria and consistent serological methods. This information on district- and age group wise prevalence is vital for public health experts designing targeted interventions to reduce the burden of HCV in this large population, and potential employers in Pakistan and overseas seeking to employ men from this region of the world.

The present study describes the frequency and age-distribution of seropositivity for anti-HCV antibodies in 58,680 clinically healthy, adult men, from nine, predominantly eastern, administrative districts of the Punjab province in Pakistan, undergoing pre-employment health screening.

METHODS

These men underwent screening for work visas to the Arabian Gulf region from June 2007 to June 2009, at a privately owned laboratory, contracted for serological testing subsequent to a clinical examination, by the concerned representative embassies issuing visas in Pakistan. Hepatitis C serological screening was performed by enzyme-linked immunosorbent assay (ELISA) 3 for anti-HCV antibody. The laboratory database included age and district of present residence as reported by the embassy. An administrative district in Pakistan is a geographical area that contains one, or occasionally more, large cities, and a number of towns and villages, somewhat similar to a ‘county’ in the USA and the UK.

Only those labelled ‘reactive’ on the assay results are considered sero-positive.

Frequency of HCV seropositivity was generated according to district of current residence and age category.

RESULTS

For the 58,680 screened individuals, median age was 26 years (range 16–59 years). The overall frequency of HCV seropositivity was 6.9% (n = 4034).

Table 1 presents the results for all screened men, by age-group. Readers interested in district-wise frequency, by age-group, are referred to the online-only supplementary table accompanying this report.

Table 1

Frequency of seropositivity for HCV with ELISA 3 in all screened men, by age categories

No. of men from all districts	Overall frequency (%)	Frequency in various age ranges, % (n)
		16–19 years	20–24 years	25–29 years	30–34 years	35–39 years	40–44 years	45–49 years	>50 years
58, 680	6.9	4.9 (796)	5.1 (1156)	6.8 (1152)	8.4 (651)	8.9 (463)	11.2 (352)	11.3 (161)	7.3 (60)

http://www.pmrc.org.pk/Hepatitis-Survey-Data.ppt

DISCUSSION

Among healthy adult men, from various districts of Punjab, the frequency of sero-positivity for anti-HCV antibody was 5% or greater. Frequency of sero-positivity of anti-HCV antibodies increased with age.

Strengths of the present study are that unlike studies on army recruits, who are always young men aged between 16 and 22 years, ^7,8 older male individuals were also included (median age 28 years, range 16–59 years). Uniform serological testing procedures using third-generation ELISA for all the specimens were used, providing better serological testing accuracy as compared with the PMRC survey (rapid diagnostic kits) and several other studies reviewed by Ali et al. ⁹

There is remarkable variability in frequency of seropositivity noted for various cities and districts in Punjab, Pakistan by this study and previous publications. ^1,8 Only the PMRC survey provides figures from a true population screening using uniform methodology in the districts that the present study covers. The frequency of sero-positivity of HCV noted by the present study in only one district, Faisalabad, was within 0.5 percentage points of the sero-prevalence for the whole population of the district noted by the PMRC survey, while for five other districts: Gujranwala, Gujrat, Sargodha, Multan, Lahore, in ascending order, frequency of sero-positivity noted in men by the present study was 1 to 2.6 percentage points greater than the PMRC survey noted for all screened individuals in the same districts. Three districts, Rawalpindi, Sialkot and Bahawalpur, showed the frequency of HCV sero-positivity to be 0.6 to 5.1 percentage points lower than the prevalence in corresponding districts noted by PMRC.

Increasing frequency of seropositivity with age as shown in Table 1 may be explained by more lifetime exposure in older men to unsafe injections, a major risk factor for HCV transmission in Pakistan. ^4,10 This is of concern from a public health perspective because if left untreated, a significant proportion of older men would develop liver cirrhosis in the coming decades, increasing morbidity, decreasing economic productivity and greatly burdening the already fragile health-care system of the country. Future research should explore whether the reduced frequency of seropositivity in younger men is due to less life-time exposure to unsafe injections, or due to introduction of safer injection and donor blood screening practices. Long-term follow-up studies would be ideal for this purpose. Another critical area, needing exploration, is the differential distribution of risk factors for transmission of HCV in various districts of Punjab.

This study found that up to 9.6% of clinically healthy men from districts of Punjab Province in Pakistan undergoing pre-employment screening were sero-positive for HCV. Frequency of seropositivity for HCV increased with increasing age among men from all the districts. Further research needs to be initiated to describe differential HCV risk factor distribution in various districts and sustainability of relatively low sero-prevalence noted in younger men.