BACKGROUND Rapid urbanisation and population growth in sub-Saharan Africa has increased the incidence of asthma in children and adolescents. One major barrier to achieving good asthma control in these adolescents is obtaining a clinical diagnosis. To date, there are scant data on prevalence and severity of asthma in undiagnosed yet symptomatic adolescents. We therefore aimed to assess symptom prevalence and severity, the effect of symptoms on daily life, and objective evidence of asthma in young adolescents from sub-Saharan Africa with and without a clinical diagnosis of asthma by spirometry and fractional exhaled nitric oxide (FeNO). METHODS We designed a two-phase, multi-country, school-based, cross-sectional study to assess symptom prevalence and severity in sub-Saharan African adolescents. In phase 1 we surveyed young adolescents aged 12-14 years who were attending selected primary and secondary schools in Blantyre in Malawi, Durban in South Africa, Harare in Zimbabwe, Kampala in Uganda, Kumasi in Ghana, and Lagos in Nigeria. The adolescents were screened for asthma symptoms using the International Study of Asthma and Allergies in Children (ISAAC) questionnaire. Then, after opt-in consent, symptomatic adolescents were invited to complete a detailed survey on asthma severity, treatment, and exposure to environmental risk factors for phase 2. Adolescents performed the European Respiratory Society's diagnostic tests for childhood asthma. A positive asthma test was classified as a forced expiratory volume in 1 sec (FEV1) predicted under 80%, a FEV1 under the lower limits of normal, or FEV1 divided by forced vital capacity (FEV1/FVC) under the lower limits of normal; positive bronchodilator responsiveness or reversibility was defined as either an increase in absolute FEV1 of 12% or more, or an increase of 200 mL or more, or both, after 400 μg of salbutamol (shortacting β2 agonist) administered via a metered-dose inhaler and spacer, or FeNO of 25 parts per billion or higher, or any combination of these. The study was registered with ClinicalTrials.gov (NCT03990402) and is complete. FINDINGS Between Nov 1, 2018, and Nov 1, 2021, we recruited 149 schools from six regions in six sub-Saharan countries to participate in the study. We administered phase 1 asthma questionnaires from Jan 20, 2019 to Nov 11, 2021, and from 27 407 adolescents who were screened, we obtained data for 27 272 (99·5%). Overall, 14 918 (54·7%) adolescents were female and 12 354 (45·3%) adolescents were male, and the mean age was 13 years (IQR 12-13); nearly all recruited adolescents were of black African ethnicity (26 821 [98·3%] of 27 272). In phase 1, a total of 3236 (11·9% [95% CI 11·5-12·3]) reported wheeze in the past 12 months, and 644 (19·9%) of 3236 had a formal clinical diagnosis of asthma. The prevalence of adolescents with asthma symptoms ranged from 23·8% in Durban, South Africa to 4·2% Blantyre, Malawi. Using ISAAC criteria, severe asthma symptoms were reported by 2146 (66·3%) of 3236 adolescents, the majority of whom (1672 [77·9%] of 2146) had no diagnosis of asthma by a clinician. Between July 16, 2019, and Nov 26, 2021, we administered the phase 2 questionnaire to the 1654 adolescents who had asthma symptoms in phase 1 and consented to proceed to the second phase. In the phase 2 cohort, 959 (58·0%) were female and 695 (42·0%) were male, and the mean age was 13 years (IQR 12-14). One or more diagnostic tests for asthma were obtained in 1546 (93·5%) of 1654 participants. One or more positive asthma tests were found in 374 (48·8%) of 767 undiagnosed adolescents with severe symptoms, and 176 (42·4%) of 415 of undiagnosed adolescents with mild-to-moderate symptoms. Of the 392 adolescents in phase 2 with clinician-diagnosed asthma, 294 (75·0%) reported severe asthma symptoms, with 94 (32·0%) of those with severe symptoms not using any asthma medication. In general, findings in both phases 1 and 2 were consistent across sub-Saharan African countries. INTERPRETATION A large proportion of adolescents in sub-Saharan Africa with symptoms of severe asthma do not have a formal diagnosis of asthma and are therefore not receiving appropriate asthma therapy. To improve the poor state of asthma control in sub-Saharan Africa, potential solutions such as educational programmes, better diagnosis, and treatment and screening in schools should be considered. FUNDING UK National Institute for Health and Care Research and UK Medical Research Council.

中文翻译：

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撒哈拉以南非洲青少年早期有和没有哮喘临床诊断的哮喘症状、严重程度和控制：一项多国、以学校为基础的横断面研究。


背景 撒哈拉以南非洲的快速城市化和人口增长增加了儿童和青少年哮喘的发病率。在这些青少年中实现良好哮喘控制的主要障碍之一是获得临床诊断。迄今为止，关于未确诊但有症状的青少年哮喘患病率和严重程度的数据很少。因此，我们旨在评估来自撒哈拉以南非洲的年轻青少年的症状患病率和严重程度、症状对日常生活的影响以及哮喘的客观证据，这些青少年通过肺活量测定和呼出气一氧化氮 （FeNO） 临床诊断为哮喘。方法 我们设计了一项两阶段、多国、以学校为基础的横断面研究，以评估撒哈拉以南非洲青少年的症状患病率和严重程度。在第一阶段，我们调查了在马拉维布兰太尔、南非德班、津巴布韦哈拉雷、乌干达坎帕拉、加纳库马西和尼日利亚拉各斯的选定小学和中学就读的 12-14 岁青少年。使用国际儿童哮喘和过敏研究 （ISAAC） 问卷筛查青少年的哮喘症状。然后，在选择同意后，邀请有症状的青少年完成关于第 2 阶段哮喘严重程度、治疗和环境风险因素暴露的详细调查。青少年进行了欧洲呼吸学会 （European Respiratory Society） 的儿童哮喘诊断测试。 哮喘试验阳性被归类为 1 秒用力呼气容积 （FEV1） 预测低于 80%，FEV1 低于正常下限，或 FEV1 除以用力肺活量 （FEV1/FVC） 低于正常下限;支气管扩张剂阳性反应性或可逆性定义为绝对 FEV1 增加 12% 或更多，或增加 200 mL 或更多，或两者兼而有之，通过定量吸入器和垫片给药 400 μg 沙丁胺醇（短效 β2 激动剂），或 FeNO 为十亿分之 25 或更高，或这些的任意组合。该研究已在 ClinicalTrials.gov （NCT03990402） 注册并已完成。结果 在 2018 年 11 月 1 日至 2021 年 11 月 1 日期间，我们招募了来自 6 个撒哈拉以南国家 6 个地区的 149 所学校参与这项研究。我们从 2019 年 1 月 20 日至 2021 年 11 月 11 日进行了 1 期哮喘问卷调查，从接受筛查的 27 407 名青少年中，我们获得了 27 272 名 （99·5%） 的数据。总体而言，14 918 （54·7%） 青少年为女性，12 354 （45·3%） 青少年为男性，平均年龄为 13 岁 （IQR 12-13）;几乎所有招募的青少年都是非洲黑人（27 272 人中的 26 821 [98·3%]）。在第 1 阶段，共有 3236 例 （11·9% [95% CI 11·5-12·3]） 报告在过去 12 个月内出现喘息，3236 例中有 644 例 （19·9%） 有哮喘的正式临床诊断。有哮喘症状的青少年患病率从南非德班的 23·8% 到马拉维布兰太尔的 4·2% 不等。使用 ISAAC 标准，3236 名青少年中有 2146 名 （66·3%） 报告了严重的哮喘症状，其中大多数 （2146 名中的 1672 名 [77·9%]）没有被临床医生诊断为哮喘。 在 2019 年 7 月 16 日至 2021 年 11 月 26 日期间，我们对 1654 名在第一阶段出现哮喘症状并同意进入第二阶段的青少年进行了第 2 阶段问卷调查。在 2 期队列中，959 名 （58·0%） 为女性，695 名 （42·0%） 为男性，平均年龄为 13 岁 （IQR 12-14）。在 1654 名参与者中，有 1546 名 （93·5%） 获得了一项或多项哮喘诊断测试。在 767 名未确诊的严重症状青少年中，有 374 名 （48·8%） 被发现一种或多种哮喘检测呈阳性，在 415 名未确诊的轻度至中度症状青少年中，有 176 名 （42·4%） 被发现阳性。在第 2 阶段经临床诊断为哮喘的 392 名青少年中，294 名 （75·0%） 报告了严重的哮喘症状，其中 94 名 （32·0%） 有严重症状的人没有使用任何哮喘药物。一般来说，第 1 阶段和第 2 阶段的结果在撒哈拉以南非洲国家是一致的。解释 在撒哈拉以南非洲，很大一部分有严重哮喘症状的青少年没有正式的哮喘诊断，因此没有接受适当的哮喘治疗。为了改善撒哈拉以南非洲地区哮喘控制不佳的状况，应考虑可能的解决方案，例如教育计划、更好的诊断以及学校的治疗和筛查。资助 英国国家健康与护理研究所和英国医学研究委员会。