Prevalence of HIV and syphilis infections among long-distance truck drivers in China: a data synthesis and meta-analysis

International Journal of Infectious Diseases 17 (2013) e2–e7

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Prevalence of HIV and syphilis infections among long-distance truck drivers in China: a data synthesis and meta-analysis Xiaohu Zhang a, Eric P.F. Chow b, David P. Wilson b, Xiaoshu Sun a, Rui Zhao a, Jun Zhang a, Jun Jing a, Lei Zhang b,* a b

Comprehensive AIDS Research Center, Tsinghua University, Beijing, China The Kirby Institute, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia

A R T I C L E I N F O

S U M M A R Y

Article history: Received 27 April 2012 Received in revised form 23 July 2012 Accepted 29 July 2012

By 2009, 46 national sentinel surveillance sites had been established for long-distance truck drivers (LDTDs) in China, but the overall disease burden of HIV and syphilis among LDTDs has remained unclear. This study aimed to summarize the prevalence levels of these infections from available published peerreviewed studies through a comprehensive systematic review and meta-analysis. Forty-six eligible articles were selected in this review. The pooled prevalence estimates of HIV and syphilis among Chinese LDTDs during 1995–2010 were 0.19% (95% confidence interval (CI) 0.15–0.24%) and 0.86% (95% CI 0.70– 1.06%), respectively, corresponding to a 3.33 (95% CI 2.40–4.62) and 1.65 (95% CI 1.35–2.03) times higher risk of infection among LDTDs than the general Chinese population. However, these infection risks were much lower than those of LDTDs in other developing country settings and at-risk groups in China. Current surveillance resources have been disproportionately focused on LDTDs and should be diverted to other at-risk groups. ß 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Corresponding Editor: Mark Holodniy, California, USA Keywords: China Long-distance truck drivers HIV Meta-analysis Syphilis

1. Introduction By the end of 2011, approximately 780 000 (95% confidence interval (CI) 620 000–940 000) people were living with HIV/ AIDS in China,1 corresponding to a national prevalence of 0.058% (95% CI 0.046–0.070%).1 In 2011, the majority (81.6%) of people newly diagnosed with HIV (n = 48 000) were infected through sexual means, including 52.2% through heterosexual exposure and 29.4% through homosexual exposure.1 Of those infected through heterosexual exposure, approximately threequarters were infected through a non-spousal pathway, indicating that extra-marital relationships are an important factor contributing to HIV transmission. In addition, the diagnosis of syphilis among the general Chinese population increased 3.55-fold from 6.5 cases per 100 000 individuals in 1999 to 23.1 cases per 100 000 individuals in 2009,2,3 reaching a prevalence level of between 0.33% and 0.71% among sexually active young Chinese adults.4 It has long been perceived that male clients of female sex workers (FSWs) can act as a potential bridge for HIV and other sexually transmitted infections (STIs) to their regular female

* Corresponding author. Tel.: +61 2 9385 0900; fax: +61 2 9385 0920. E-mail address: [email protected] (L. Zhang).

partners.5 Long-distance truck drivers (LDTDs) – in the Chinese context defined as truck drivers who have undertaken at least three overnight trips in the past 3 months6 – typically have frequent sexual encounters with FSWs during their trips7–9 and are often regarded as a proxy group for male clients in many international settings.7–10 Due to extensive time away from their families, it has been suggested that LDTDs in China are more likely to solicit FSWs,11–13 and they often patronize ‘low-tier’ FSWs from roadside settlements/hotels, who are generally poorly educated with limited knowledge and awareness of HIV, with a relatively high prevalence of HIV.14 The previous literature has reported an HIV prevalence among ‘low-tier’ FSWs of about 14.2–20.9%,15–17 much higher than that among ‘high-tier’ FSWs (0.8–2.9%).17–19 Levels of condom use among LDTDs are low with both FSWs (48.2%)20 and their regular female partners (24.7–35%)21–23 in the last sexual act. The Chinese LDTDs have been regarded as a population with a high risk of acquiring, as well as spreading, HIV and syphilis through sexual contacts, both locally and in distant areas.24 HIV and STI epidemic markers among LDTDs have been monitored in China through its established sentinel surveillance system since 1995.25 However, these surveillance results have not been published in a systematic manner and the overall disease burden of HIV and syphilis among LDTDs remains unclear. This study aimed to collate and summarize the

1201-9712/$36.00 – see front matter ß 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijid.2012.07.018

X. Zhang et al. / International Journal of Infectious Diseases 17 (2013) e2–e7

prevalence of HIV and syphilis among LDTDs in China from available published peer-reviewed studies through a comprehensive systematic review and meta-analysis. This analysis will provide important evidence that directs effective surveillance efforts and strategies for HIV in China.

2. Methods 2.1. Search strategy Two investigators (XZ, EPFC) performed a systematic review of published research articles by searching the Chinese and English databases independently. Electronic databases used in this review included PubMed, China National Knowledge Infrastructure (CNKI), Wanfang Data, and CQVIP (Chinese Scientific Journals Fulltext Database) for the period 1995 to August 2011. Keywords used in the database search included ‘‘Long-distance truck driver’’ AND (‘‘HIV’’ OR ‘‘AIDS’’ OR ‘‘STI’’ OR ‘‘sexually transmitted infections’’ OR ‘‘syphilis’’) AND ‘‘China’’. This review was conducted and reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement issued in 2009.26 2.2. Study selection Studies were eligible for inclusion in the systematic review if they met the following criteria: (1) study published in Chinese or English language; (2) study reported the prevalence level of HIV and/or syphilis among LDTDs in China; (3) reported infections had to have been diagnosed in a laboratory using a qualified serologic testing method; (4) study design and sample size had to be reported. We excluded review papers, non-peer-reviewed local/government reports, conference abstracts, presentations, and studies with a small sample size (n < 30). If the same study data were published in both English and Chinese databases, the articles published in Chinese were excluded from the review. Disagreements with regard to the study criteria were decided by a third investigator (LZ). The quality of studies was assessed using a validated quality assessment tool.27 2.3. Data abstraction We extracted the following information from all eligible studies: first author and year published, study location, study period, sample size, percentage of male respondents in the study, testing method for syphilis and HIV infection, and the prevalence of HIV and syphilis infection. Data were stored in Microsoft Access 2007. 2.4. Statistical analysis Meta-analyses were carried out using the Comprehensive Meta-Analysis software (v2.0, Biostat, Englewood, NJ, USA). Heterogeneity was tested by Cochran Q-test (p < 0.10 represents statistically significant heterogeneity) and the I2 statistic (I2 = 25, 50, and 75 represents low, medium, and high heterogeneity, respectively). Since all meta-analyses in this study showed low and insignificant heterogeneities, a fixedeffect model was used to calculate the effect rate of pooled prevalence estimates and 95% CI. Publication bias was measured by the Begg and Mazumdar rank correlation (p < 0.05 represents statistically significant publication bias). Odd ratios and their 95% CI for the prevalence of the diseases were calculated to compare the risk of infection between Chinese LDTDs and the general adult population.

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3. Results Our search identified 336 articles from four electronic databases (PubMed = 1; CQVIP = 29; CNKI = 177; Wanfang = 129). We excluded 177 articles due to a lack of relevance or duplicated titles from different databases. We screened the abstracts of the remaining 159 articles and excluded a further 55 articles (49 articles were qualitative research and six were review papers). Full-text screening was conducted of the 104 articles and 58 were excluded due to the absence of any prevalence data reported (n = 55) and duplicated studies based on the same data source (n = 3). The remaining 46 studies20,21,28–71 (two in English and 44 in Chinese) were eligible for the quantitative synthesis. Metaanalyses were performed to estimate the prevalence of HIV (46 articles, 74 prevalence estimates) and syphilis (23 articles, 33 prevalence estimates) infections among LDTDs. The selection process is illustrated in the Supplementary Material (Figure S1) and the details of each study are shown in Table 1. 3.1. Study characteristics Among 46 eligible articles, all reported the study location, covering 14 Chinese provinces. The study sampling size ranged from 47 to 12 119 (median 402, interquartile range 366–711). Only one-quarter of the studies (12/46) reported the gender composition of the respondents, among which 11 studies reported 100% male respondents and one reported 99.3% male respondents. Types of studies on HIV prevalence included national sentinel studies (n = 15), cross-sectional studies (n = 28), cohort studies (n = 2), and a baseline survey from an intervention study (n = 1). Among 22 articles reporting the prevalence of syphilis infection, five were national sentinel studies and 17 were cross-sectional studies. 3.2. Prevalence of HIV and syphilis Correlation analysis showed that there was no significant association between HIV infection and the study period (r = 0.165, p = 0.167). The pooled estimate of HIV prevalence among Chinese LDTDs was 0.19% (95% CI 0.15–0.24%) during 1995–2010 (Table 2). Significant publication bias (Begg rank correlation, p = 0.005) and low heterogeneity (I2 = 0, p = 0.941) were found across studies. In comparison, the prevalence of syphilis infections was 0.86% (95% CI 0.70–1.06%) among LDTDs, with a significant publication bias (p < 0.001) and medium heterogeneity (I2 = 46.053; p = 0.002). Similarly, there was no significant correlation between the study period and the prevalence of syphilis infection (r = 0.228, p = 0.218). In contrast, the prevalence levels of HIV and syphilis among the general population were 0.057% (95% CI 0.042–0.071%)3 and 0.52% (95% CI 0.33– 0.71%),4,72 respectively (Table 2). LDTDs were found to be 3.33 (95% CI 2.40–4.62) and 1.65 (95% CI 1.35–2.03) times more at risk of being infected with HIV and syphilis, respectively. 4. Discussion Chinese LDTDs are one of the at-risk populations regularly monitored by the national HIV sentinel surveillance in China.25 However, this practice is not based on sound scientific evidence within China, but relies purely on findings from other developing countries, where LDTDs have been found to be particularly vulnerable to HIV.5,7,8,10 In contrast to the high HIV prevalence reported in Africa (56% in South Africa,73 17.8% in Kenya,74 and 10.0% in Nigeria24) and other Asian countries (15.9% in India75,76 and 5.3–7.0% in Guinea77), Chinese LDTDs sustained a relatively low HIV prevalence (0.19%, 95% CI 0.15–0.24%) throughout 1995– 2010. Similarly, the prevalence of syphilis infection among LDTDs

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Table 1 Studies reporting the prevalence of HIV and syphilis infection among Chinese long-distance truck drivers Prevalence of HIV infection First author, published year

Language

Study period

Study location

Type of study

Laboratory test for HIV infection

Sample size

Number of HIV infections

HIV prevalence

Quality assessment score

Cai, 200728 Chen, 200829 Chen, 200630 Cheng, 200931 Cheng, 200931 Cheng, 200931 Cheng, 200931 Cheng, 200931 Deng, 200932 Deng, 200533 Deng, 201134 Feng, 200836 Feng, 200836 Feng, 200836 Guo, 201037 He, 200638 Qu, 200035 Qu, 200035 Ji, 201039 Ji, 201039 Jia, 200240 Ke, 200841 Leng, 201042 Li, 201043 Li, 199944 Li, 200245 Li, 201046 Liao, 200647 Liao, 200848 Lin, 200249 Liu, 200650 Liu, 200651 Liu, 200651 Liu, 200651 Liu, 200552 Lu, 200753 Lu, 200954 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Osman, 200556 Peng, 200957 Peng, 200957 Peng, 200957 Peng, 200957 Peng, 200957 Peng, 200957 Qiu, 200820 Shi, 201058 Shi, 201058 Shi, 201058 Wang, 199859 Wang, 200760 Wei, 200061 Wen, 201062 Xi, 200863 Xu, 201164 Yan, 201065 Yang, 200966 Yang, 200966 Yang, 200966 Yao, 200967 Zhan, 200968 Zhan, 200968 Zhan, 200968 Zhan, 200968 Zhang, 200821 Zhang, 200469

Chinese Chinese English Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese English Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese

2005–2006 2005 02/2000–05/2000 2003 2004 2005 2006 2007 2002–2007 2000–2002 N/A 1997–2006 2001 2005 04/2010–05/2010 10/2004–11/2004 1997 1998 2009 2008 1995–2000 2004–2007 2009 1997–2006 1995–1997 2000 04/2009–06/2009 2002–2005 2007 01/2000–09/2002 2004 2002 2003 06/2004 2004 07/2004–08/2004 07/2008–07/2008 09/2004–11/2004 09/2005–11/2005 09/2006–11/2006 09/2007–11/2007 04/2008–06/2008 04/2009–06/2009 04/2010–06/2010 2000–2003 2002 2003 2004 2005 2006 2007 08/2007–09/2007 2007 2008 2009 09/1996 01/2006–12/2006 1996–1998 2004–2009 04/2007 2009 04/2009–05/2009 2006 2005 2007 01/2007–12/2007 2007 2006 2005 2008 2005 2003

Ningbo (Zhejiang) Ningbo (Zhejiang) Tongling (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Anlu (Hubei) Huangshi (Hubei) Kunming (Yunnan) Golmud (Xinjiang) Golmud (Xinjiang) Golmud (Xinjiang) Lanzhou (Gansu) Guangxi Urumqi (Xinjiang) Urumqi (Xinjiang) Qilihe (Gansu) Qilihe (Gansu) Jiangsu Huangshi (Hubei) Zhoukou (Henan) Hebei Nanning, Pingxiang (Guangxi) Huaian and Ganyu (Jiangsu) Shangluo (Shaanxi) Yulin (Guangxi) Shandong Keramay (Xinjiang) Shandong Henan Henan Henan Yingcheng (Hubei) Huaibei (Anhui) Kunming (Yunnan) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Urumqi (Xinjiang) Hubei Hubei Hubei Hubei Hubei Hubei Guixi (Xinjiang) Suizhou (Hubei) Suizhou (Hubei) Suizhou (Hubei) Ili (Xinjiang) N/A Shihezi (Xinjiang) Xingshan (Xinjiang) Hangzhou (Zhejiang) Hohhot (Inner Mongolia) Lanzhou (Gansu) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Shanghai Hubei Hubei Hubei Hubei Tianmen (Hubei) Hubei

Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional National sentinel study National sentinel study Cohort Cohort Cohort Cross-sectional Cross-sectional Cross-sectional Intervention (baseline) Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional National sentinel study National sentinel study National sentinel study Cross-sectional N/A Cross-sectional National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study Cross-sectional National sentinel study National sentinel study National sentinel study Cross-sectional National sentinel study National sentinel study National sentinel study Cross-sectional National sentinel study Cross-sectional National sentinel study National sentinel study National sentinel study Cross-sectional National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study

ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA N/A N/A ELISA ELISA ELISA N/A N/A ELISA ELISA ELISA ELISA ELISA N/A ELISA N/A ELISA ELISA ELISA N/A N/A N/A ELISA ELISA N/A ELISA ELISA ELISA ELISA ELISA ELISA ELISA N/A N/A N/A N/A N/A N/A N/A ELISA N/A N/A N/A ELISA N/A ELISA N/A N/A ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA ELISA

708 303 550 387 409 420 418 422 670 436 400 4193 417 401 400 368 400 400 400 284 765 695 400 6322 364 565 403 1453 377 526 720 500 761 1193 47 406 360 368 370 386 403 400 400 400 1096 287 227 279 248 257 285 314 367 1415 1468 254 305 863 12 119 270 400 400 411 94 423 455 1600 1604 761 1200 303 2309

0 0 0 0 0 1 0 1 0 0 3 3 2 1 0 0 1 2 1 0 1 0 0 0 0 1 0 1 0 0 0 0 1 4 0 0 3 0 0 1 1 1 0 0 4 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

0.00% 0.00% 0.00% 0.00% 0.00% 0.20% 0.00% 0.20% 0.00% 0.00% 0.75% 0.07% 0.48% 0.25% 0.00% 0.00% 0.30% 0.50% 0.25% 0.00% 0.13% 0.00% 0.00% 0.00% 0.00% 0.18% 0.00% 0.07% 0.00% 0.00% 0.00% 0.00% 0.13% 0.34% 0.00% 0.00% 0.83% 0.00% 0.00% 0.26% 0.25% 0.25% 0.00% 0.00% 0.36% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.32% 0.00% 0.00% 0.00% 0.39% 0.00% 0.00% 0.00% 0.00% 0.00% 0.25% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

6 6 8 5 5 5 5 5 5 6 7 7 7 7 5 7 6 6 4 4 5 5 7 6 1 3 7 2 6 6 3 6 6 6 6 6 5 6 6 6 6 6 6 6 3 5 5 5 5 5 5 7 4 4 4 5 4 4 3 4 5 6 6 6 6 7 5 5 5 5 5 5

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Table 1 (Continued ) Prevalence of HIV infection First author, published year

Language

Study period

Study location

Type of study

Laboratory test for HIV infection

Zhou, 200970 Zou, 200571

Chinese Chinese

N/A 04/2004–11/2004

Ningbo (Zhejiang) Zhejiang

Cross-sectional Cross-sectional

N/A ELISA

Sample size 805 113

Number of HIV infections

HIV prevalence

Quality assessment score

0 0

0.00% 0.00%

6 6

Syphilis prevalence

Quality assessment score

0.14% 0.33% 0.70% 1.00% 0.20% 0.70% 0.20% 1.18% 0.50% 1.00% 1.09% 0.25% 0.66% 0.00% 0.00% 0.19% 0.00% 0.28% 1.09% 0.27% 0.26% 0.74% 1.50% 0.75% 3.00% 0.16% 0.66% 0.46% 1.11% 1.75% 0.25% 0.88% 0.30%

6 6 8 5 5 5 5 5 7 5 7 7 1 7 6 6 3 5 6 6 6 6 6 6 6 3 4 4 4 5 6 7 6

Prevalence of syphilis infection Sample Number size of syphilis infection

First author, Published year

Language Study period

Study location

Type of study

Laboratory test for syphilis infection

Cai, 200728 Chen, 200829 Chen, 200630 Cheng, 200931 Cheng, 200931 Cheng, 200931 Cheng, 200931 Cheng, 200931 Deng, 201134 Guo, 201037 He, 200638 Leng, 201042 Li,199944 Li, 201046 Liao, 200848 Lin, 200249 Liu, 200650 Lu, 200954 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Nong, 201155 Osman, 200556 Wang, 200760 Wei, 200061 Xi, 200863 Xu, 201164 Yan, 201065 Yao, 200967 Zhou, 200970

Chinese Chinese English Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese English Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese Chinese

Ningbo (Zhejiang) Ningbo (Zhejiang) Tongling (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Anqing (Anhui) Kunming (Yunnan) Lanzhou (Gansu) Guangxi Zhoukou (Henan) Nanning, Pingxiang (Guangxi) Shangluo (Shaanxi) Shandong Keramay (Xinjiang) Shandong Kunming (Yunnan) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Pingxiang (Guangxi) Urumqi (Xinjiang) Dangyang (Hubei) Shihezi (Xinjiang) Hangzhou (Zhejiang) Hohhot (Inner Mongolia) Lanzhou (Gansu) Shanghai Ningbo (Zhejiang)

Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional Intervention (baseline) Cross-sectional Cross-sectional Cross-sectional Cross-sectional Cross-sectional National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study National sentinel study Cross-sectional National sentinel study Cross-sectional Cross-sectional Cross-sectional

RPR/TPPA 708 RPR/TPPA 303 RPR/TPHA 550 TRUST 387 TRUST 409 TRUST 420 TRUST 418 TRUST 422 RPR/TPPA 400 N/A 400 ELISA/TPPA 368 RPR/TPPA 400 RPR/TPHA 364 RPR 403 N/A 377 RPR/TPHA 526 ELISA 720 N/A 360 TRUST 368 TRUST 370 TRUST 386 TRUST 403 TRUST 400 TRUST 400 TRUST 400 N/A 1096 N/A 305 RPR 863 N/A 270 ELISA/WB 400 RPR 400 RPR 455 N/A 805

2005–2006 2005 02/2000–05/2000 2003 2004 2005 2006 2007 N/A 12/2010–20/2010 10/2004–11/2004 2009 1995–1997 04/2009–06/2009 2007 01/2000–09/2002 2004 07/2008–07/2008 09/2004–11/2004 09/2005–11/2005 09/2006–11/2006 09/2007–11/2007 04/2008–06/2008 04/2009–06/2009 04/2010–06/2010 2000–2003 01/2006–12/2006 1996–1998 04/2007 2009 04/2009–05/2009 01/2007–12/2007 N/A

1 1 4 4 1 3 1 5 2 4 4 1 2 0 0 1 0 1 4 1 1 3 6 3 12 2 2 4 3 7 1 4 3

ELISA, enzyme-linked immunosorbent assay; N/A, laboratory test method not mentioned in the study; RPR, rapid plasma reagin; TPHA, Treponema pallidum hemagglutination assay; TPPA, Treponema pallidum particle agglutination assay; TRUST, toluidine red unheated serum test; WB, Western blot.

is as high as 21% in India,75,76 but we estimate only 0.86% (95% CI 0.7–1.06%) among Chinese LDTDs. This indicates that Chinese LDTDs experience a much lower risk of HIV infection than the level originally perceived during the early phase of the HIV epidemic in China. This could be due to several reasons. First, China has maintained a low-level concentrated epidemic of HIV and syphilis.24,78 Second, it is reported that LDTDs in other developing countries are more likely to solicit FSWs (68.5–86%)24,79,80 in comparison to those in China (19–30%),34,37,81 with consistently lower condom use (15–32%)24,73,79,82 than in China (53– 64%).22,34,64,67 In addition, LDTDs also demonstrate a much lower

risk of HIV and syphilis infections than other at-risk populations in China. For example, the current HIV and syphilis prevalences among Chinese men who have sex with men (MSM) are 5.3% and 13.5%,2,83 representing a 27.9 and 15.7 times higher odds of infection risk than LDTDs, respectively. The prevalences of HIV and syphilis among FSWs are 0.6% and 6.9%, respectively,84 and the risks of infection are 3.16 and 8.02 times higher than in LDTDs. Both MSM and FSW are populations defined according to their high risk sexual behaviors, whereas the term LDTD refers to an occupation that may potentially include individuals with diversified sexual behaviors. However, surveillance resources and efforts

Table 2 Relative risk and 95% confidence intervals for the prevalence of HIV/STIs among long-distance truck drivers in comparison with the general population in China Infection

Pooled prevalence estimate in LDTDs from meta-analysis, % (95% CI)

Reported prevalence mean in general population, % (range)

Relative risk of infection (95% CI)

HIV

0.19 (See 0.86 (See

0.057 (0.042–0.071)3

3.33 (2.40–4.62)

Syphilis

(0.15–0.24) Supplementary Material, Figure S2) (0.70–1.06) Supplementary Material, Figure S3)

CI, confidence interval; LDTD, long-distance truck driver; STI, sexually transmitted infection.

4,72

0.52 (0.33–0.71)

1.65 (1.35–2.03)

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have been invested at a disproportionately high level to LDTDs. The latest statistics indicate that 46 national HIV sentinel sites had been designated to monitor LDTDs countrywide but only 25 for MSM in 2009.85 As LDTDs mostly acquire HIV from FSWs, extra surveillance resources should be prioritized and directed to strengthen the surveillance of HIV transmission among FSWs while maintaining regular monitoring and effective interventions among LDTDs. Chinese LDTDs have traditionally been regarded as a proxy group for male clients of FSWs. A recent large survey among 1840 male clients conducted in five Chinese cities reported the prevalence of HIV and syphilis infections to be 0.11% and 1.6%, respectively.86 Consistent with this, other past studies have also reported similar HIV and syphilis disease burdens among male clients.87–90 However, despite these similarities, Chinese LDTDs were found mostly to engage with roadside FSWs, who represent a subgroup of ‘low-tier’ FSWs with greater risk behaviors than the average FSW population.16–18 Previous studies have indicated a substantially lower level of condom usage and higher HIV/STI prevalence among roadside FSWs than in those of high-class entertainment establishments.14,91,92 Additionally, Chinese LDTDs have low levels of knowledge and awareness of HIV/AIDS and are less likely to use condoms with their regular and commercial sexual partners.22,23,28,29,93 Further, the fact that only 19–30% of LDTDs reported having sex with FSWs in the last 12 months,34,37,81 suggests that a large proportion of LDTDs is not sexually exposed to HIV/STIs. In addition, with the large expansion of the inter-provincial road network, the previous main traffic routes for long-distance transportation are rapidly being replaced by national motorways that enable high traffic flow and restricted access for pedestrians.94 This may have resulted in a reduction in the likelihood of truck drivers patronizing roadside FSWs. The limited proportion of patronizing LDTDs but greater risk behaviors with low-tier FSWs provides a probable explanation for the comparable HIV/STI prevalence levels between LDTDs and male clients. However, the substantial differences in their risk behaviors indicate considerable limitations in seeing LDTDs as a proxy group for male clients from the perspective of surveillance. Several limitations should be noted in our study. Out of 31 provinces in China, our review only covers the prevalence of the diseases in 14 provinces. Two provinces with a high HIV prevalence (Sichuan and Guangdong), which have more than 50 000 people were living with HIV/AIDS, have no published data. This may have led to the significant publication biases detected in the meta-analyses on HIV and syphilis prevalence. Additionally, due to the limited number of available studies, we were unable to stratify and investigate the geographical and temporal trends in the epidemics of the burden of diseases among Chinese LDTDs. In conclusion, the risks of HIV and syphilis infections are significantly higher among Chinese LDTDs than the general Chinese adult population, but much lower than LDTDs in other developing country settings and at-risk groups in China. LDTDs in China may not be a good proxy for male clients in general as only a small proportion of LDTDs bought sex from FSWs. This indicates that the current surveillance resources have been disproportionately allocated to LDTDs. More resources should be directed to other at-risk groups in China while sustaining the current level of surveillance efforts in LDTDs. Funding source: This study was supported by the Australian Government Department of Health and Ageing, the University of New South Wales, the Endeavour Awards (Award ID: 2744_2012), the World Bank Global HIV/AIDS Program, grant number 2008ZX10001–003 from the Ministry of Science and technology

in China, and grant number FT0991990 from the Australian Research Council. Ethical approval: No ethical approval was needed for this study. Conflict of interest: No conflict of interest to declare.

Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.ijid.2012.07.018.

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