Degree and correlates of sexual mixing in female sex workers in Karnataka, India.

UNLABELLED Background The degree of sexual mixing plays an important role in understanding disparities in sexually transmissible infections and HIV across social groups. This study examines the degree of sexual age mixing, and explores its individual and partnership level correlates among female sex workers (FSWs) in Karnataka, India. METHODS Data were drawn from special behavioural surveys conducted in 2006-07 among 577 FSWs in two districts of Karnataka: Belgaum and Bangalore. Sexual mixing in age was assessed as the difference in age between FSWs and their sexual partners, and the degree of assortativeness in sexual mixing was assessed using Newman's assortativity coefficient. RESULTS A total of 577 FSWs were interviewed; 418 of whom reported two or more partnerships, resulting in 942 partnerships. In about half (52%) of these partnerships, the age difference between the FSW and her sexual partner was 5 years or more. The degree of assortativity in age mixing was 0.098, indicating minimally assortative mixing. The disassortativeness in age mixing was positively associated with young age and no formal education, and negatively with duration in sex work. Partnerships which were of a commercial nature were more likely to be disassortative than noncommercial partnerships. CONCLUSION The minimally assortative age mixing indicates sexually transmissible infections can transfer from members of one age group to another. Efforts are required to limit the transmission of infection from one group to other by promoting safer sexual behaviour.