摘要：Objectives. To improve our understanding of climate variability and diarrheal disease at the community level and inform predictions for future climate change scenarios, we examined whether the El Niño climate pattern is associated with increased rates of diarrhea among Peruvian children. Methods. We analyzed daily surveillance data for 367 children aged 0 to 12 years from 2 cohorts in a peri-urban shantytown in Lima, Peru, 1995 through 1998. We stratified diarrheal incidence by 6-month age categories, season, and El Niño, and modeled between-subject heterogeneity with random effects Poisson models. Results. Spring diarrheal incidence increased by 55% during El Niño compared with before El Niño. This increase was most acute among children older than 60 months, for whom the risk of a diarrheal episode during the El Niño spring was nearly 100% greater (relative risk = 1.96; 95% confidence interval = 1.24, 3.09). Conclusions. El Niño–associated climate variability affects community rates of diarrhea, particularly during the cooler seasons and among older children. Public health officials should develop preventive strategies for future El Niño episodes to mitigate the increased risk of diarrheal disease in vulnerable communities. The effect of weather on disease transmission is well recognized for many infectious diseases that exhibit seasonal patterns, 1 including diarrhea, 2,3 respiratory infections, 4 malaria, 5 and dengue. 6 There is growing concern that severe weather changes resulting from El Niño episodes and global climate change directly affect human health. 7 Diarrheal illnesses are among the highest disease burdens in children younger than 5 years of age worldwide 8 and are predicted to increase with climate change. However, specific estimates for the magnitude of this increase in the community setting remain uncertain, in part because epidemiological data on the relationship between community rates of diarrhea and extreme weather variability are scarce. 9 Although the relationship between specific weather variables and infectious disease has been examined extensively with retrospective, hospital-based data, 10–14 data from prospective population-based cohort studies are limited. Determining the effects of El Niño on rates of diarrhea with a cohort study would greatly improve our understanding of climate variability and diarrheal disease at the community level and inform predictions for other extreme weather episodes or future climate change scenarios. 15 The El Niño southern oscillation (ENSO) is a main driver of global interannual weather variation. Occurring every 3 to 7 years, the ENSO phenomenon leads to extreme worldwide weather events, such as heavy flooding and drought. 16 The ENSO provides health researchers with an opportunity to model effects of local climate anomalies on infectious disease dynamics, 17 and it has been linked to changes in rates of cholera, 18–21 diarrhea, 11,22,23 malaria, 10 dengue, 24 hantavirus, 25 viral pneumonia, 26 and Rift Valley fever. 27 The 1997–1998 El Niño episode altered weather conditions around the world—particularly severely along the Peruvian coastline. This El Niño episode has been described as the strongest yet recorded. 28 Previously, we found that the number of pediatric hospital admissions for diarrheal diseases in Lima, Peru, increased substantially during this episode, especially during the winter months. 11 A separate study found similar results for adults. 22 In this study, we sought to examine the effects of the 1997–1998 El Niño episode on rates of childhood diarrhea and several parasitic agents in a peri-urban Peruvian community with cohort studies conducted between June 1995 and August 1998.
