MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, St. Mary's Hospital Campus, Norfolk Place, London, W2 1PG, UK.
BMC Public Health. 2022 Jun 4;22(1):1120. doi: 10.1186/s12889-022-13451-y.
Debuting sexual intercourse marks exposure to pregnancy or fatherhood and sexually transmitted infections (STIs), including HIV. In sub-Saharan Africa (SSA), sexual debut varies according to cultural, religious, and economic factors, and encouraging delay has been a longstanding component of behavioural HIV prevention strategies. Age at first sex (AFS) is routinely collected in national household surveys, but data are affected by reporting biases, limiting utility to monitor trends and guide sexual health interventions.
We collated individual-level data from nationally-representative household surveys to analyse timing and national trends in AFS in 42 SSA countries. We used a log-skew-logistic distribution to characterize the time to AFS in a Bayesian spatio-temporal model, providing estimates of the sexual debut rate by sex, age, time, and country. We statistically adjusted for reporting biases by comparing AFS reported by the same birth cohorts in multiple survey rounds, allowing different reporting biases by sex and country.
Median AFS in 2015 ranged from 15.8 among Angolan women to 25.3 among men in Niger. AFS was younger for women than men in 37/40 countries. The gap was largest for Sahel region countries and minimal in southern African countries. The distribution of female AFS was asymmetric with half debuting sex in an age range of 3.9 years [IQR 3.4-5.0 across countries]. Median AFS increased slightly between 1985 and 2020, ranging 0.84 years [IQR 0.11-1.55] and 0.79 [IQR -0.23-1.98] for females and males, respectively. The gender gap changed little over time in most countries. Female teens often reported higher AFS compared to when asked in their late twenties while male teens reported lower AFS; both sexes recalled a higher AFS in older ages compared to their thirties.
AFS increased slightly in most SSA countries, but changes were modest relative to large and persistent variation between countries and sexes, indicating relatively entrenched socio-cultural practices around sexual debut. Sexual health, family planning, and HIV/STI prevention services should adapt to local practices rather than focusing interventions to change AFS. These estimates for rates of sexual debut provide data to guide programmatic prioritization and implementation of sexual health services.
首次性行为标志着怀孕或为人父母以及性传播感染（STIs）的风险，包括 HIV。在撒哈拉以南非洲（SSA），首次性行为的时间因文化、宗教和经济因素而异，鼓励延迟首次性行为一直是行为 HIV 预防策略的重要组成部分。首次性行为年龄（AFS）通常在国家家庭调查中收集，但数据受到报告偏倚的影响，限制了其用于监测趋势和指导性健康干预的用途。
我们整理了来自具有代表性的国家家庭调查的个人层面数据，以分析 42 个撒哈拉以南非洲国家首次性行为的时间和国家趋势。我们使用对数偏斜逻辑分布来描述首次性行为的时间，在贝叶斯时空模型中提供了按性别、年龄、时间和国家划分的首次性行为率估计。我们通过比较多个调查轮次中同一出生队列报告的 AFS 来统计调整报告偏倚，允许按性别和国家存在不同的报告偏倚。
2015 年，安哥拉女性的 AFS 中位数为 15.8 岁，尼日尔男性的 AFS 中位数为 25.3 岁。在 40 个国家中的 37 个国家中，女性的 AFS 比男性年轻。在萨赫勒地区国家中差距最大，在南部非洲国家中最小。女性 AFS 的分布呈不对称分布，一半的人在 3.9 岁的年龄范围内首次发生性行为[各国范围为 3.4-5.0]。1985 年至 2020 年间，女性 AFS 中位数略有增加，分别为 0.84 岁[各国范围为 0.11-1.55]和 0.79 岁[各国范围为-0.23-1.98]；男性分别增加 0.79 岁[各国范围为-0.23-1.98]和 0.79 岁[各国范围为-0.23-1.98]。大多数国家的性别差距随时间变化不大。与二十多岁时相比，十几岁的女性通常报告更高的 AFS，而十几岁的男性报告的 AFS 则较低；与三十多岁相比，所有年龄段的人都回忆起更高的 AFS。
大多数撒哈拉以南非洲国家的 AFS 略有增加，但与国家和性别之间的巨大且持续的差异相比，变化相对较小，表明首次性行为的社会文化习俗相对根深蒂固。性健康、计划生育和 HIV/性传播感染预防服务应适应当地做法，而不是将干预重点放在改变 AFS 上。这些关于首次性行为率的估计为指导方案优先事项和实施性健康服务提供了数据。
