Temperature in summer and children's hospitalizations in two Mediterranean cities.
Children are potentially vulnerable to hot ambient temperature. However, the evidence on heat-related children's morbidity is still scarce. Our aim was to examine the association between temperatures in summer (May to September) and children's hospitalizations in two Mediterranean cities, Rome and Valencia, during the period 2001-2010.



Quasi-Poisson generalised additive models and distributed lag non-linear models were combined to study the relationship between daily mean temperature and hospital admissions for all natural, respiratory and gastrointestinal diseases in children under 15 years of age. Associations were summarised as the percentage of change (Ch%) in admissions at 50th, 75th, 90th, 95th and 98th percentiles of temperature in summer compared to 1.) the 50th percentile in the whole year (50th(y)) and 2.) the preceding percentile in the previous series. Cumulated risks were obtained for groups of lags showing a similar pattern: 0-1, 2-7, 8-14 and 15-21 days.



Almost whatever increase of temperature from 50th(y) was significantly associated with an increase of paediatric hospitalizations by all natural diseases at short term (lag 0-1), while small increases at high temperatures only had a delayed effect on this outcome. The same pattern was observed in Rome for respiratory admissions, while in Valencia only a delayed association (days 8-14) was observed. The increase of temperature from 50th to 75th percentiles was associated at short time to an increase of gastrointestinal admissions in both cities.



Children's hospitalizations rose with heat in Rome and Valencia. Patterns of delays and critical windows of exposure mainly varied according the outcome considered.
FISABIO - Universitat Jaume I - Universitat de València Epidemiology and Environmental Health Joint Research Unit, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain. Electronic address: inyiguez_car@gva.es.
Carmen
C
Iñiguez
Department of Epidemiology Lazio Regional Health Service, Italy.
Patrizia
P
Schifano
Department of Epidemiology Lazio Regional Health Service, Italy.
Federica
F
Asta
Department of Epidemiology Lazio Regional Health Service, Italy.
Paola
P
Michelozzi
Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
Ana
A
Vicedo-Cabrera
FISABIO - Universitat Jaume I - Universitat de València Epidemiology and Environmental Health Joint Research Unit, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain.
Ferran
F
Ballester
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002947:Cities; D005767:Gastrointestinal Diseases / Q000453:epidemiology* / Q000209:etiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012140:Respiratory Tract Diseases / Q000453:epidemiology* / Q000209:etiology; D012384:Rome / Q000453:epidemiology; D012621:Seasons; D013030:Spain / Q000453:epidemiology
Children's health; Environmental health; Hot temperature; Mediterranean region