The Wingate Institute of Neurogastroenterology, Centre for Neuroscience, Trauma and Surgery, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 26 Ashfield Street, Whitechapel, London, E1 2AJ, UK.
Department of Respiratory Medicine, Royal Free Hospital, Royal Free NHS Foundation Trust, Pond Street, Hampstead, London, NW3 2QG, UK.
BMC Infect Dis. 2021 Feb 25;21(1):210. doi: 10.1186/s12879-021-05899-x.
Pakistan ranks amongst the top 20 highest burden tuberculosis (TB) countries in the world. Approximately 369,548 cases of TB (all forms) were notified in 2018, with an estimated incidence of 265 per 100,000 people per year. In other settings, TB has been shown to demonstrate seasonal variation, with higher incidence in the spring/summer months and lower incidence in the autumn/winter; the amplitude of seasonal variation has also been reported to be higher with increasing distance from the equator.
Notifications of newly-diagnosed pulmonary and extrapulmonary TB cases were obtained for 139 districts in Pakistan from 2011 to 2017. Data were provided by the Pakistan National TB Control Programme, Islamabad, Pakistan. Statistical analyses were performed to determine whether there was seasonal variation in TB notifications in Pakistan; whether the amplitude of seasonal variation in TB notifications varied according to latitude; whether the amplitude of seasonal variation of TB in Pakistan differed between extrapulmonary TB vs. pulmonary TB. To assess the quarterly seasonality of TB, we used the X-13-ARIMA-SEATS seasonal adjustment programme from the United States Census Bureau. The mean difference and corresponding 95% confidence intervals of seasonal amplitudes between different latitudes and clinical phenotype of TB were estimated using linear regression.
TB notifications were highest in quarter 2, and lowest in quarter 4. The mean amplitude of seasonal variation was 25.5% (95% CI 25.0 to 25.9%). The mean seasonal amplitude of TB notifications from latitude 24.5°N- < 26.5°N was 29.5% (95% CI 29.3 to 29.7%) whilst the mean seasonal amplitude of TB notifications from latitude 34.5°N - < 36.5°N was 21.7% (95% CI 19.6 to 23.9%). The mean seasonal amplitude of TB notifications across Pakistan between latitudes 24.5°N to 36.5°N reached statistically significant difference (p < 0.001). The amplitude of seasonal variation was greater for extrapulmonary TB (mean seasonal amplitude: 32.6, 95% CI 21.4 to 21.8%) vs. smear positive pulmonary TB mean seasonal amplitude: 21.6, 95% CI 32.1 to 33.1%), p < 0.001.
TB notifications in Pakistan exhibit seasonal variation with a peak in quarter 2 (April-June) and trough in quarter 4 (October-December). The amplitude of seasonality decreases with increasing latitude, and is more pronounced for extrapulmonary than for pulmonary TB.
巴基斯坦是全球结核病(TB)负担最重的 20 个国家之一。2018 年报告了约 369548 例结核病(所有类型)病例,估计发病率为每年每 10 万人 265 例。在其他环境中,已经证明结核病具有季节性变化,春季/夏季发病率较高,秋季/冬季发病率较低;据报道,随着与赤道距离的增加,季节性变化的幅度也会增加。
从 2011 年到 2017 年,从巴基斯坦的 139 个地区获得了新诊断的肺和肺外结核病病例的通知。数据由巴基斯坦伊斯兰堡的巴基斯坦国家结核病控制规划提供。进行了统计分析,以确定巴基斯坦的结核病通知是否存在季节性变化;结核病通知季节性变化的幅度是否随纬度而变化;巴基斯坦肺外结核病与肺结核之间的结核病季节性变化幅度是否不同。为了评估结核病的季度季节性,我们使用了美国人口普查局的 X-13-ARIMA-SEATS 季节性调整程序。使用线性回归估计不同纬度和结核病临床表型之间季节性幅度的平均差异和相应的 95%置信区间。
结核病通知在第二季度最高,第四季度最低。季节性变化幅度的平均幅度为 25.5%(95%CI 25.0 至 25.9%)。纬度 24.5°N-<26.5°N 的结核病通知的平均季节性幅度为 29.5%(95%CI 29.3 至 29.7%),而纬度 34.5°N-<36.5°N 的结核病通知的平均季节性幅度为 21.7%(95%CI 19.6 至 23.9%)。巴基斯坦纬度 24.5°N 至 36.5°N 之间的结核病通知季节性幅度差异具有统计学意义(p<0.001)。肺外结核病的季节性变化幅度较大(平均季节性幅度:32.6,95%CI 21.4 至 21.8%),而涂阳肺结核的平均季节性幅度为 21.6,95%CI 32.1 至 33.1%),p<0.001。
巴基斯坦的结核病通知存在季节性变化,高峰期在第二季度(4 月至 6 月),低谷期在第四季度(10 月至 12 月)。随着纬度的增加,季节性的幅度会减小,而且肺外结核病比肺结核更为明显。