Introduction India's large HIV epidemic and the potential for epidemic HIV spread in some areas demands a full understanding of HIV transmission. Factors associated with HIV infection in India include: commercial sex work, sexually transmitted infections (STI), numbers of sex partners and male circumcision. We wished to quantify effects of the above risk factors, roughly estimating their size, for each gender and in high- and low-HIV risk populations.

Methods Meta-analysis of risk factors for HIV from 34 studies identified through literature search of multiple on-line databases. Risk factors were: male circumcision/religion, biologically confirmed infection with Herpes Simplex Virus 2, syphilis or gonorrhoea, self-reported genital ulcer, multiple sexual partners and paid sex work. Random-effects meta-analysis of effects was conducted.

Results Each of the seven risk factors were significantly associated with HIV status in both men and women. The strongest effect size among men was HSV-2 infection (OR: 4.68; 95% CI 2.40 to 5.43) while the strongest effect among women was ever being paid for sex (OR: 5.06; 95% CI 3.69 to 6.95). The effect of multiple sexual partners was similar among men (2.80; 95% CI 2.09 to 3.77,) and women (3.00; 95% CI 1.88 to 4.79) and was similar when further stratified by HIV-risk group. Syphilis and multiple sexual partners as risk factors for HIV were significantly associated with lower HIV-risk study populations.

Conclusions The risk factors examined in our analysis should remain targets of HIV prevention programs. Our results confirm that sexual risk factors for HIV infection remain an important part of the HIV epidemic in India.