Nielsen Bibi Uhre, Byberg Stine, Aaby Peter, Rodrigues Amabelia, Benn Christine Stabell, Fisker Ane Baerent
Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark.
Trop Med Int Health. 2017 Jul;22(7):846-856. doi: 10.1111/tmi.12889. Epub 2017 Jun 6.
In many African countries, child mortality is higher in the rainy season than in the dry season. We investigated the effect of season on child mortality by time periods, sex and age in rural Guinea-Bissau.
Bandim health project follows children under-five in a health and demographic surveillance system in rural Guinea-Bissau. We compared the mortality in the rainy season (June to November) between 1990 and 2013 with the mortality in the dry season (December to May) in Cox proportional hazards models providing rainy vs. dry season mortality rate ratios (r/d-mrr). Seasonal effects were estimated in strata defined by time periods with different frequency of vaccination campaigns, sex and age (<1 month, 1-11 months, 12-59 months). Verbal autopsies were interpreted using InterVa-4 software.
From 1990 to 2013, overall mortality was declined by almost two-thirds among 81 292 children (10 588 deaths). Mortality was 51% (95% ci: 45-58%) higher in the rainy season than in the dry season throughout the study period. The seasonal difference increased significantly with age, the r/d-mrr being 0.94 (0.86-1.03) among neonates, 1.57 (1.46-1.69) in post-neonatal infants and 1.83 (1.72-1.95) in under-five children (P for same effect <0.001). According to the InterVa, malaria deaths were the main reason for the seasonal mortality difference, causing 50% of all deaths in the rainy season, but only if the InterVa included season of death, making the argument self-confirmatory.
The mortality declined throughout the study, yet rainy season continued to be associated with 51% higher overall mortality.
在许多非洲国家，儿童死亡率在雨季高于旱季。我们研究了几内亚比绍农村地区季节对不同时间段、性别和年龄儿童死亡率的影响。
班迪姆健康项目在几内亚比绍农村的一个健康与人口监测系统中跟踪五岁以下儿童。我们在Cox比例风险模型中比较了1990年至2013年雨季（6月至11月）和旱季（12月至5月）的死亡率，得出雨季与旱季死亡率比值（r/d-mrr）。在由不同疫苗接种活动频率、性别和年龄（<1个月、1 - 11个月、12 - 59个月）定义的时间段分层中估计季节效应。使用InterVa - 4软件对死因推断进行解读。
1990年至2013年期间，81292名儿童中有10588人死亡，总体死亡率下降了近三分之二。在整个研究期间，雨季的死亡率比旱季高51%（95%置信区间：45 - 58%）。季节差异随年龄显著增加，新生儿的r/d-mrr为0.94（0.86 - 1.03），新生儿期后的婴儿为1.57（1.46 - 1.69），五岁以下儿童为1.83（1.72 - 1.95）（相同效应的P值<0.001）。根据InterVa软件分析，疟疾死亡是季节性死亡率差异的主要原因，导致雨季所有死亡的50%，但前提是InterVa软件纳入了死亡季节，这使得该论点具有自我验证性。
在整个研究期间死亡率有所下降，但雨季总体死亡率仍高出51%。
