A population's higher-risk sexual behaviour is associated with its average sexual behaviour-An ecological analysis of subpopulations in Ethiopia, Kenya, South Africa, Uganda and the United States.
Given the large variation in the prevalence of sexually transmitted infections between populations it is important to characterize how sexual vary between populations. In this paper we assess how the distribution of lifetime sexual partners varies between populations. We ask: do populations with higher mean lifetime sexual partners merely differ by virtue of the presence of a core-group with increased number of partners or do the population distributions move as more coherent wholes?



We defined those in the top decile of lifetime sex partners in each country as constituting the higher-risk behaviour group (HRB). Spearman's correlation was used to evaluate the relationship between mean lifetime partners and prevalence of those in the HRB by ethnic group within Ethiopia, Kenya, South Africa, Uganda and the United States. In each case, data from nationally representative surveys were used. Two-sample Wilcoxon rank-sum were applied to test if there was a difference in the number of lifetime partners between the highest and lowest-risk subpopulations, separately for men and women. To account for autocorrelation, all analyses were conducted using means/medians excluding those in the HRB. A P-value of <0.05 was considered statistically significant.



In each country, a positive correlation existed between subpopulations' mean lifetime partners and the prevalence of the HRB. Spearman's correlation varied from 0.20 to 0.99 for men and 0.74 to 1.0 for women. This association was statistically significant in 6 out of 10 comparisons. There was a statistically significant difference in the number of lifetime partners between the highest and lowest-risk ethnic groups in all countries except South Africa, where the difference was only significant for women.



Our results suggest that sexual behaviours vary coherently between different populations. As such, sexually transmitted infection control efforts would benefit from including both targeted campaigns focusing on the HRB and population-strategies that seek to address factors responsible for high mean risk behaviour.
HIV/STI Unit, Institute of Tropical Medicine, Antwerp, Belgium. Electronic address: ckenyon@itg.be.
Chris R
CR
Kenyon
HIV/STI Unit, Institute of Tropical Medicine, Antwerp, Belgium. Electronic address: atsoumanis@itg.be.
Achilleas
A
Tsoumanis
Department of Medical Microbiology, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, MB, Canada; Department of Epidemiology and Social Medicine, Faculty of Health Sciences, University of Antwerp, Antwerp, Belgium. Electronic address: ilan.steven.schwartz@gmail.com.
Ilan Steven
IS
Schwartz
D000293:Adolescent; D000328:Adult; D000351:Africa, Eastern; D000368:Aged; D044383:Black People / Q000523:psychology / Q000706:statistics & numerical data*; D005006:Ethnicity / Q000523:psychology / Q000706:statistics & numerical data*; D005260:Female; D000073599:Health Risk Behaviors; D006801:Humans; D008297:Male; D008875:Middle Aged; D012725:Sexual Behavior / Q000208:ethnology* / Q000706:statistics & numerical data; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000208:ethnology* / Q000523:psychology; D013019:South Africa; D014481:United States; D055815:Young Adult; D001741:Black or African American
Distribution; Ethnicity; HIV; High-risk strategy; Lifetime sex partners; STI