Immersion events in residential swimming pools. Evidence for an experience effect
G. J. Wintemute, C. Drake and M. Wright
Department of Family Practice, University of California, Davis, Sacramento.
BACKGROUND.--Drowning and near-drowning in residential swimming pools are
leading causes of morbidity and mortality for young children. We tested the
hypothesis that the period immediately after a pool is acquired is a time
of high risk for these events. This study was also designed to provide
population-based data on swimming pool immersion events, regardless of
severity. METHODS.--We conducted a mail survey of a probability sample of
Sacramento County, California, households with in-ground swimming pools in
January 1988; 80% of eligible subjects responded. Onset of exposure to a
pool was defined as the month in which (1) the responding household had a
pool installed, or (2) the responding household first occupied a residence
with a pool. Exposures began in 1959 through 1987. RESULTS.--The home
swimming pool immersion event rate was 11 per 1000 pool-years. The rate per
1000 pool-years was higher for the first 6 months of exposure than
thereafter (0 to 6 months, 44; 7 to 24 months, 14; greater than 24 months,
seven), but 77% of events occurred outside the high-risk period. For
households whose exposures began in 1984 through 1987, the immersion event
rate was 51 per 1000 pool-years overall and 123 per 1000 pool-years for the
first 6 months of pool exposure; these increases probably represent
underreporting of earlier events. In this group, 48% of events occurred
outside the high-risk period. The family swimming pool accounted for 91% of
immersion events at the respondents' homes. CONCLUSIONS.--The residential
swimming pool is an important hazard for pool-owning households. The first
6 months of exposure constitute a high-risk period, but many immersion
events occur later. Pool drowning prevention programs may focus on newly
acquired swimming pools and their owners but should be as broad as possible
to maximize their effectiveness.
