Department of Epidemiology, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, Portugal.
Centro de Investigação em Saúde Pública, Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisboa, Portugal.
Am J Epidemiol. 2018 Dec 1;187(12):2541-2549. doi: 10.1093/aje/kwy164.
Although the impact of deaths occurring during the 1918-1919 influenza pandemic has been assessed in many archeo-epidemiologic studies, detailed estimates are not available for Portugal. We applied negative binomial models to monthly data on respiratory-related and all-cause deaths at the national and district levels from Portugal for 1916-1922. Influenza-related excess mortality was computed as the difference between observed and expected deaths. Poisson regression was used to estimate the association of geographic and sociodemographic factors with excess mortality. Two waves of pandemic influenza-July 1918 to January 1919 and April to May 1919-were identified, for which the excess all-cause death rate was 195.7 per 10,000 persons. All districts of Portugal were affected. The pandemic hit earlier in southeastern districts and the main cities, but excess mortality was highest in the northeast, in line with the high death burden experienced by northern Spanish provinces. During the period of intense excess mortality (fall/winter 1918-1919), population density was negatively associated with pandemic impact. This pattern changed during the March 1919 to June 1920 wave, when excess mortality increased with population density and in northern and western directions. Portuguese islands were less and later affected. Given the geographic heterogeneity evidenced in our study, subnational sociodemographic characteristics and connectivity should be integrated in pandemic preparedness plans.
虽然在许多考古流行病学研究中评估了 1918-1919 年流感大流行期间死亡的影响，但葡萄牙没有详细的估计数。我们应用负二项式模型，对葡萄牙 1916-1922 年全国和地区层面的呼吸相关和全因死亡的月度数据进行分析。流感相关超额死亡率计算为实际死亡人数与预期死亡人数的差值。泊松回归用于估计地理和社会人口因素与超额死亡率的关联。确定了 1918 年 7 月至 1919 年 1 月和 1919 年 4 月至 5 月的两波大流行流感，全因超额死亡率为每 10000 人 195.7 人。葡萄牙所有地区都受到了影响。东南部地区和主要城市的疫情爆发得更早，但东北部的超额死亡率最高，与西班牙北部省份的高死亡负担一致。在高超额死亡率期间（1918 年秋季至冬季），人口密度与大流行的影响呈负相关。在 1919 年 3 月至 1920 年 6 月的波期间，这种模式发生了变化，当时超额死亡率随人口密度增加，在北部和西部方向增加。葡萄牙岛屿受到的影响较小且较晚。鉴于我们研究中证据表明的地理异质性，应在大流行防范计划中纳入国家以下社会人口特征和连通性。
