Gasasira et al. BMC Public Health 2012, 12:134 http://www.biomedcentral.com/1471-2458/12/134 Sampling Frame Page 3 of 8 1 2 3 4 5 6 • National level : The survey meant to cover the whole country. • Five Provinces (Eastern, Northern, Southern , Western and the City of Kigali) • The data collection was carried out in 29 districts. • Systematic probability proportional to size sampling method to select the Primary Sampling Unit ( Villages) based on the size of each district. • In total, 279 Villages were selected and visited. • The selection of the households used a probability proportional to the size of the village, based on the existing list of households used during the malaria surveys in Rwanda. • From each household selected, all eligible male household members and those who spent the night before age 15 - 59 years were interviewed after giving their consent • A total of 1098 participants completed the interviews. Figure 1 Sampling frame. consent was obtained from all the study participants after describing to them all the issues related to the study in details. Results Background characteristics of the study population The questionnaire in the study was administrated to 1098 men. Table 1 presents the socio-demographic characteris- tics of the study population by provinces. The distribution of the study population by province was as follows: The City of Kigali with 101 (9.2%), Southern Province with 290 (26%), Western Province with 294 (27%), Northern Pro- vince with 214 (20%) and Eastern Province with 199 (18%). Prevalence of male circumcision The prevalence of MC was estimated at 17% [95% Confidence interval (CI): 14%-19%] in the general population, varying from 100% among Muslim com- munity to 14% among non Muslim. The MC preva- lence was 13%, 17%, 15%, and 13% of those in the age groups of > 39, 30-39, 20-29 and less than 19 years. Adolescent are 66% less likely to be circumcised com- pared to adults aged 40 and above [Adjusted Odd Ratio (aOR): 0.34; (95% CI: 0.13, 0.85) (P ≤ 0.05)]. The City of Kigali had the highest prevalence with 53% and the Southern province had the lowest (4%). Compared to men in Kigali, men in the North province had the lowest likelihood to be circumcised [aOR: 0.09; (95% CI: 0.04, 0.22) (P ≤ 0.001)]. Men who lived in urban settings (44%) were more circumcised than those who lived in rural areas (10%). There was no significant dif- ference of MC prevalence among non Muslims. The MC prevalence was 10%, 20% and 11% among Catho- lics, Protestants and Adventists respectively. Eighteen