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Seasonal variation of febrile convulsion in Japan
Insights
Febrile convulsions occurred in 8.2% of 3-year-olds, with higher rates in boys. Seasonal illness patterns, not birth season, influenced convulsion risk.
Area of Science:
- Pediatrics
- Epidemiology
- Neurology
Background:
- Febrile convulsions are common in young children.
- Understanding incidence and risk factors is crucial for public health.
- Previous studies suggest seasonal influences on febrile illnesses.
Purpose of the Study:
- To determine the incidence of febrile convulsions in 3-year-old children.
- To investigate the influence of sex, birth season, and seasonal illness patterns on febrile convulsion risk.
Main Methods:
- A 6-year prospective study in Fuchu, Japan.
- Inclusion of 17,044 children, representing 95% of the target population.
- Analysis of incidence rates by sex, month/year of birth, and seasonal variations.
Main Results:
- Overall 6-year incidence was 8.2%, higher in boys (9.0%) than girls (7.5%).
- Slight variations observed with month and year of birth.
- Two seasonal peaks for first febrile convulsion: Nov-Jan (winter respiratory infections) and Jun-Aug (summer gastrointestinal infections).
Conclusions:
- Febrile convulsion liability is influenced by child's age and seasonal febrile illnesses.
- Seasonal patterns of infection, particularly respiratory and gastrointestinal, correlate with convulsion occurrences.
- Birth season does not appear to be a significant risk factor for febrile convulsions.
Abstract:
The 6-year incidence rates of febrile convulsions in all 3-year-old children in Fuchu (covering 95% of children, number examined 17,044) was 8.2%. The incidence was higher in boys than in girls (9.0%: 7.5%, P less than 0.001). The incidence rates varied with the month and year of birth, but the variations observed were slight. Two peak appearances of seasonal variation of the first febrile convulsion were found in November-January and in June-August. The former could be interpreted as a tendency to winter virus infection of the upper respiratory tract in children. The other peak in summer could be explained as a tendency to gastrointestinal infection. Liability to febrile convulsion was influenced by the age of children and by the seasonal variations of febrile illness, but not by the season of birth.