Although age at first sex is considered a measure of sexual risk and vulnerability for HIV infection, there is a dearth of literature on age at sexual debut in the Canadian context. This study examined time variations to first sex among heterosexual African, Caribbean, and Black (ACB) men in four Ontarian cities. A population-based retrospective survey (n = 879) on timing to first sexual intercourse was conducted between 2018 and 2019 among self-identified heterosexual ACB men 16 years or older and residing in London, Ottawa, Toronto or Windsor. We used the lognormal survival analysis technique to examine variations in time to first sexual intercourse among age cohorts and between cities. The findings showed a generational shift in the pattern of sexual initiation, with younger heterosexual ACB men initiating sexual intercourse earlier compared with those currently older than 50 years. We observed those between 16 and 19 years, 20 and 29 years, and 30 and 39 years of age to have significantly higher risk ratios of TR = 0.852, TR = 0.869, and TR = 0.855, respectively. At city level, the results show marked spatial variations, with youth in cities of Toronto, Ottawa, and London at the highest risk of early sexual debut relative to those in Windsor. Early initiation of first sexual intercourse among heterosexual ACB youth was observed with those in the larger cities being at a relatively higher risk. There is the need for programs aimed at delaying sexual debut among youth in general. It is, however, important to recognize the relative risk of those in the larger cities.

尽管第一次性行为的年龄被认为是衡量艾滋病毒感染的性风险和脆弱性的指标，但在加拿大的背景下，关于首次性行为年龄的文献却很少。这项研究调查了安大略省四个城市的非洲、加勒比海和黑人 (ACB) 异性恋男性第一次性行为的时间变化。一项基于人群的回顾性调查 ( n = 879) 在 2018 年至 2019 年期间，在居住在伦敦、渥太华、多伦多或温莎的 16 岁或以上的自称异性恋 ACB 男性中进行了首次性交时间。我们使用对数正态生存分析技术来检查不同年龄段和城市之间第一次性交时间的变化。研究结果表明，性开始模式发生了代际转变，与目前年龄超过 50 岁的男性相比，年轻的异性恋 ACB 男性开始性交的时间更早。我们观察到 16 至 19 岁、20 至 29 岁以及 30 至 39 岁的人的风险比分别显着较高，分别为 TR = 0.852、TR = 0.869 和 TR = 0.855。在城市层面，结果显示出显着的空间差异，多伦多、渥太华、与温莎相比，伦敦的早期性行为风险最高。观察到异性恋 ACB 青年早期开始第一次性交，大城市的人风险相对较高。有必要制定旨在延迟一般青年的首次性行为的计划。然而，重要的是要认识到大城市的相对风险。