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A summertime peak of Down's syndrome in Franklin County, Ohio
Insights
An unusual number of infants with Down syndrome were born in Franklin County, Ohio, during the summer of 1984. This observed increase was statistically significant, though the overall yearly incidence remained within expected ranges.
Area of Science:
- Epidemiology
- Genetics
- Public Health
Background:
- Down syndrome (a genetic disorder) is typically associated with a relatively stable incidence rate.
- Environmental or temporal factors potentially influencing Down syndrome births are of public health interest.
Purpose of the Study:
- To investigate a reported increase in Down syndrome births in Franklin County, Ohio, during summer 1984.
- To determine if the observed number of cases was statistically significant compared to expected rates.
Main Methods:
- A direct physician survey was conducted to identify infants born with Down syndrome.
- Chromosome reports were reviewed for confirmation.
- Chi-squared analysis was used to assess statistical significance.
Main Results:
- Eleven infants with Down syndrome were identified as born during June, July, and August 1984.
- The observed number (11) was significantly higher than the expected number (5) based on statistical analysis.
- Despite the summer peak, the overall annual incidence rate of 1.09 per 1000 live births was within the expected range.
Conclusions:
- A statistically significant increase in Down syndrome births occurred during the summer of 1984 in Franklin County, Ohio.
- While a seasonal pattern was observed, the yearly incidence did not deviate from the established norm.
Abstract:
In June, July, and August of 1984, more infants than usual were born with Down's syndrome in Franklin County, Ohio. A direct physician survey was done, and chromosome reports were reviewed, resulting in the identification of 11 infants with Down's syndrome born during that period. Using a chi 2 analysis, the expected number of affected newborns was five, making the actual number of 11 significant. Although a summertime peak was observed, the yearly incidence of 1.09 per 1000 live births was within the expected range.