Wringe A, Cremin I, Todd J, McGrath N, Kasamba I, Herbst K, Mushore P, Zaba B, Slaymaker E
Centre for Population Studies, London School of Hygiene and Tropical Medicine, London, UK.
Sex Transm Infect. 2009 Apr;85 Suppl 1(Suppl_1):i56-63. doi: 10.1136/sti.2008.033423.
To assess inconsistencies in reported age at first sex (AFS) and age at first marriage (AFM) in three African cohorts, and consider their implications for interpreting trends in sexual and marital debut.
Data were analysed from population-based cohort studies in Zimbabwe, Uganda and South Africa with 3, 10 and 4 behavioural survey rounds, respectively. Three rounds over a similar time frame were selected from each site for comparative purposes. The consistency of AFS and AFM reports was assessed for each site by comparing responses made by participants in multiple surveys. Respondents were defined as unreliable if less than half of all their age-at-event reports were the same. Kaplan-Meier functions were used to describe the cumulative proportion (1) having had sex and (2) married by age, stratified by sex, birth cohort and site, to compare the influence of reporting inconsistencies on these estimates.
Among participants attending all three comparable rounds, the percentage with unreliable AFS reports ranged from 30% among South African women to 56% among Zimbabwean men, with similar patterns observed for AFM. Inclusion of unreliable reports had little effect on estimates of median age-at-event in all sites. There was some evidence from the 1960-9 birth cohort that women in Uganda and both sexes in South Africa reported later AFS as they aged.
Although reporting quality is unlikely to affect comparisons of AFS and AFM between settings, care should be taken not to overinterpret small changes in reported age-at-event over time within each site.
评估三个非洲队列中首次性行为年龄（AFS）和初婚年龄（AFM）报告的不一致性，并考虑其对解释性初次登场和婚姻初次登场趋势的影响。
分析了来自津巴布韦、乌干达和南非基于人群的队列研究的数据，分别进行了3次、10次和4次行为调查。为了进行比较，从每个地点选择了在相似时间范围内的三轮调查。通过比较参与者在多次调查中的回答，评估每个地点AFS和AFM报告的一致性。如果参与者所有事件发生年龄报告中少于一半相同，则定义为不可靠。使用Kaplan-Meier函数按性别、出生队列和地点分层，描述按年龄计算的（1）发生性行为和（2）结婚的累积比例，以比较报告不一致对这些估计值的影响。
在参加所有三轮可比调查的参与者中，AFS报告不可靠的百分比从南非女性的30%到津巴布韦男性的56%不等，AFM也观察到类似模式。纳入不可靠报告对所有地点事件发生年龄中位数的估计影响不大。有证据表明，在1960 - 1969年出生队列中，乌干达女性和南非两性随着年龄增长报告的AFS较晚。
虽然报告质量不太可能影响不同环境之间AFS和AFM的比较，但应注意不要过度解读每个地点随时间报告的事件发生年龄的微小变化。
