Background: The extent of the differential spread of HIV around the world remains incompletely explained. This paper examines the extent to which five explanatory variables (circumcision prevalence, condom usage, STI ...Background: The extent of the differential spread of HIV around the world remains incompletely explained. This paper examines the extent to which five explanatory variables (circumcision prevalence, condom usage, STI treatment coverage, number of sex partners, partner concurrency) are correlated with peak HIV prevalence rates at a country level. Methods: We performed linear regression analysis to measure the association between each of the independent variables and the national peak HIV prevalence rates for 15 - 49 years old. Results: Our analysis shows a strong positive association between peak HIV prevalence and the prevalence of partner concurrency (rho = 0.853;P = 0.001). There was no association between peak HIV prevalence and circumcision prevalence (rho = 0.118;P = 0.161), condom usage (rho = 0.048;P = 0.794), STI treatment coverage (rho = 0.143;P = 0.136) and number of sex partners (rho = 0.134;P = 0.298) at a global level. There was however a strong negative association between peak HIV prevalence and circumcision prevalence when the analysis was limited to countries within sub Saharan Africa (rho = -0.659;P = 0.000). Sub Saharan Africa had the second and third highest circumcision rates in the world when the circumcision prevalence thresholds were set at 80% and 20% respectively. Conclusions: Differences in the prevalence of circumcision likely influence differential peak HIV prevalence within sub Saharan Africa but are implausible causes for the higher HIV prevalence in this region. The close association found between concurrency and HIV prevalence requires replication in further studies.展开更多
Objective: The prevalence of syphilis differs considerably between different populations and indi-vidual level risk factors such as number of sex partners seem unable to completely explain these differences. The effec...Objective: The prevalence of syphilis differs considerably between different populations and indi-vidual level risk factors such as number of sex partners seem unable to completely explain these differences. The effect of network level factors, such as the prevalence of partner concurrency, on syphilis prevalence has not hitherto been investigated. Study design: Linear regression was per-formed to assess the relationship between the prevalence of male concurrency and prevalence of syphilis in each of 11 countries for which we could obtain comparable data. The data for concur-rency prevalence was taken from the WHO/Global Programme on AIDS (GPA) sexual behavioural surveys. Syphilis prevalence rates were obtained from antenatal syphilis serology surveys done in the same countries. In addition, we used linear regression to assess if there was a relationship between syphilis and concurrency prevalence of various racial and ethnic groups within the United States and South Africa. Results: In the international study, we found a strong relationship between the prevalence of male concurrency and syphilis prevalence (r = 0.79, P = 0.003). In the subnational studies, the relationship between concurrency and syphilis prevalence was positive in all cases but was only statistically significant so in the case of South Africa’s racial groups (r = 0.98, P = 0.01). Conclusions: The findings of an ecological-level association between syphilis and partner concurrency need to be replicated but suggest that efforts directed towards decreasing partner concurrency may reduce syphilis prevalence.展开更多
文摘Background: The extent of the differential spread of HIV around the world remains incompletely explained. This paper examines the extent to which five explanatory variables (circumcision prevalence, condom usage, STI treatment coverage, number of sex partners, partner concurrency) are correlated with peak HIV prevalence rates at a country level. Methods: We performed linear regression analysis to measure the association between each of the independent variables and the national peak HIV prevalence rates for 15 - 49 years old. Results: Our analysis shows a strong positive association between peak HIV prevalence and the prevalence of partner concurrency (rho = 0.853;P = 0.001). There was no association between peak HIV prevalence and circumcision prevalence (rho = 0.118;P = 0.161), condom usage (rho = 0.048;P = 0.794), STI treatment coverage (rho = 0.143;P = 0.136) and number of sex partners (rho = 0.134;P = 0.298) at a global level. There was however a strong negative association between peak HIV prevalence and circumcision prevalence when the analysis was limited to countries within sub Saharan Africa (rho = -0.659;P = 0.000). Sub Saharan Africa had the second and third highest circumcision rates in the world when the circumcision prevalence thresholds were set at 80% and 20% respectively. Conclusions: Differences in the prevalence of circumcision likely influence differential peak HIV prevalence within sub Saharan Africa but are implausible causes for the higher HIV prevalence in this region. The close association found between concurrency and HIV prevalence requires replication in further studies.
文摘Objective: The prevalence of syphilis differs considerably between different populations and indi-vidual level risk factors such as number of sex partners seem unable to completely explain these differences. The effect of network level factors, such as the prevalence of partner concurrency, on syphilis prevalence has not hitherto been investigated. Study design: Linear regression was per-formed to assess the relationship between the prevalence of male concurrency and prevalence of syphilis in each of 11 countries for which we could obtain comparable data. The data for concur-rency prevalence was taken from the WHO/Global Programme on AIDS (GPA) sexual behavioural surveys. Syphilis prevalence rates were obtained from antenatal syphilis serology surveys done in the same countries. In addition, we used linear regression to assess if there was a relationship between syphilis and concurrency prevalence of various racial and ethnic groups within the United States and South Africa. Results: In the international study, we found a strong relationship between the prevalence of male concurrency and syphilis prevalence (r = 0.79, P = 0.003). In the subnational studies, the relationship between concurrency and syphilis prevalence was positive in all cases but was only statistically significant so in the case of South Africa’s racial groups (r = 0.98, P = 0.01). Conclusions: The findings of an ecological-level association between syphilis and partner concurrency need to be replicated but suggest that efforts directed towards decreasing partner concurrency may reduce syphilis prevalence.
