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Drowning Interventions, Pool Fencing
Background
Over the last decade, many communities have passed laws requiring
the fencing of private and public pools. In fact, much of the evidence that pool
fencing reduces the risk of drowning among children comes from studies examining
before and after rates of drowning for fenced and unfenced pools. Even after these
pioneering studies had been done, the favorable attitude toward pool fencing did
not necessarily translate into actual changes in pool fencing.6
More recently, studies have examined whether the type of fence surrounding
a pool makes a difference. Comparison studies7 of perimeter fencing (property barrier)
versus isolation fencing (around immediate pool area) show isolation fencing to
be much more effective in reducing the risk of drowning. Adding to this finding
are studies8,9 examining children’s ability to climb certain types of fences. In particular,
chain-link fences, while allowing visibility of the pool area, are the most easily
scaled by children as young as 2 years old. Ornamental iron bar fences were advocated
as a better barrier, with reduced ‘climability’ while retaining the visibility
factor.
Fence height makes little difference if the child is able to climb
it; one study8 showed the median time for four-year-olds to climb a 5-foot fence was seventeen
seconds. For a fence that is not scaleable, the most important element of fencing
is a secure, self-closing gate.
Taking these and other findings into account, the U.S. Consumer
Product Safety Commission has compiled a list of minimum recommendations10 for residential pool fencing; recent
legislation passed in Seattle11 requires a fence height of at least 5 feet, and an inter-bar spacing of
no more than 4 inches.
Here we review the relevant studies which have examined the effect
of pool fencing on drowning. These studies are time series, case-control, or non-equivalent
control group comparisons. No randomized controlled studies have been conducted.
Review of pool fencing intervention studies:
Author | Morgenstern et al., 2000 |
Study design and target population | Retrospective cohort study of pool
drownings in Los Angeles County, CA. (Stage 1), case
control study.
(Stage 2), cases-all pools where drownings occurred, 1990-95;
controls-randomly selected pools matched by geographic & ecological areas.
|
Intervention | Presence of pool fencing ordinance
when pool built or upgraded. |
Outcomes | Residential pool drownings in children
under 10 years of age. |
Results | 146 deaths in 6 years. 1.77
per 100,000 children per year; rate 9-10 times higher in 1-4 year old children
than in infants or school age kids.
81% of all drownings occurred in pools that were regulated
by pool-fencing ordinances.
OR=1.27 (95% CI=0.72, 2.25) comparing presence of fencing
ordinance to absence of fencing ordinance. |
Study quality and conclusions | Implies that laws governing fencing
are ineffective.
Study couldn't distinguish between above-ground and in-ground pools.
Local ordinances did not require 4-sided fencing.
Inadequate enforcement of ordinance and poor maintenance of
pool barriers.
Future studies should include exposure data (person-time at
risk). |
Author | Pitt & Balanda, 1998 |
Study design and target population | Time series; Queensland Australia. |
Intervention | Uniform pool fence requirements, 1992. |
Outcomes | Drowning in residential pools, children
1-4 years of age. |
Results | Deaths decreased from 12/year (1982-1991)
to 2/year (1992-1994) but increased 11/year (1995-1997). Increased exposure, 70,000 additional pools added between 1991 and
1997.
33 of 38 pools (87%) where children drowned did not comply
with fencing legislation. |
Study quality and conclusions | Good surveillance databases &
investigation of cases.
Recommend policing to improve compliance with legislation and public
education campaign. |
Author | Pitt et al., 1991 |
Study design and target population | Population-based case-control study
All children 0-13 years old with immersion injury in Brisbane
(n=139) from 1984 to 1989.
Cases: Children with immersion injury from unintentional access
to domestic pools
Controls: Random sample of households with pools |
Intervention | Pool fencing stratified by type (isolation,
three-sided, none) |
Outcomes | Comparison of drowning and near-drowning
rates for fenced and unfenced pools. (Because all children
gaining unintentional access to pool from three-sided fencing did so through
the house door, both no fencing and three-sided fencing comprise the ‘unfenced’
category.) |
Results | Significantly decreased risk of drowning
in isolation-fenced pool compared to unfenced pool (OR=0.27, 0.15-0.49).
Similar, significantly decreased risks when stratified by pool type
(inground, above-ground, spa).
Eighty-three percent of all immersions occurred in children
less than 3 years of age. |
Study quality and conclusions | All analyses restricted to immersions
with unintentional access to pool. |
Author | Intergovern-mental Working Party on swimming pool safety (Australia),
1988 |
Study design and target population | Population based case-control study
Preschoolers aged 0-4 years in Metropolitan Perth, Australia,
1975-Feb. 1988.
Cases: Deaths from immersion
Controls: Pool fencing type among households with children
0-4 years |
Intervention | Perimeter fencing v. isolation fencing. |
Outcomes | Incidence rates for drowning for specific
fencing types; AR%s. Swimming Pool Drowning Index (SPDI),
adjusting for population distribution and home pool installation changes (i.e.,
exposure to pools) over time. |
Results | Significantly decreased risk of drowning
in isolation-fenced pool compared to perimeter-fenced pool (OR=0.16, 0.05-0.49);
AR%=0.84. |
Study quality and conclusions | Good ascertainment of drownings.
SPDI for near-drownings more important from public health
view, but difficult to ascertain number of private pools outside city limits. |
Author | Present, 1987 |
Study design and target population | Case-control study Reported
drownings and near-drownings to children under age five in eight selected
U.S. counties
Cases: Children with immersion injury in domestic pools
Controls: Non-random population survey of households with
pools |
Intervention | Isolation fencing v. three-sided fencing
(access from house or no fencing). |
Outcomes | Comparison of drowning cases by fencing
type |
Results | Logistic regression showed a non-significant,
negative relationship between isolation fencing and drowning (data not presented). |
Study quality and conclusions | Controls matched on household income
and type, and age of proxy interviewee. Controls self-selected. Incomplete case
ascertainment. |
Author | Nixon et al., 1986 |
Study design and target population | Interrupted time series study
Reported drownings of children in Brisbane from 1967 to 1981.
All near-drownings from 1971-1981. |
Intervention | Broad assessment of educational and
public awareness programs (daily newspaper articles, letters to the editor,
news reports). Brief mention of legislative safety
intervention requiring pool fencing (type not specified). |
Outcomes | Comparison of drowning and near-drowning
annual incidences. |
Results | Safety legislation appears to decrease
drowning incidence by about one-third. Media campaigns
may affect whole drowning spectrum.
Actual decrease in survival rate after safety campaign. |
Study quality and conclusions | Type of safety legislation not stated.
Combined drowning and near-drowning rates did not show as much decline as drowning
rates did. No adjustments made for age, population distribution changes over
time, or number of pools. |
Author | Fergusson et al., 1984 |
Study design and target population | Case-control study Drownings
in fenced and unfenced pools estimated from available New Zealand-based data
Cases: Domestic drownings where fencing type was known
Controls: Estimates of domestic pool fencing types |
Intervention | Pool fencing versus no fencing (type
not specified). |
Outcomes | Risk of drowning in unfenced pool
and attributable risk percent calculated using Bayes’ Theorem. |
Results | Risk of drowning in fenced pool significantly
lower than for unfenced pool (OR range=0.21–0.48) Reduction in risk, expressed as attributable risk percent, ranges
from 41% to 67%. |
Study quality and conclusions | "Cases" derived from probabilities
cited in previous studies and personal communication. Quality
of previous studies unknown. Relatively small numbers may make risk estimates
unstable.
No definition of fenced/unfenced pools. |
Author | Milliner et al., 1980 |
Study design and target population | Ecological (case series) study
Children 0-14 years old. |
Intervention | Legislation requiring pool fencing
(apparently isolation fencing, defined as barriers between pool and house, but
unclear in article); enforcement of pool-fencing law. |
Outcomes | Comparison of drowning, near-drowning
requiring admission or ED care in Mulgrave (with law) to Cairns (without law). |
Results | Fatality rate using mid-survey population
is 7.7/100,000 in Mulgrave (with law), compared to 14.3/100,000 in Cairns (without
law). RR=0.54 Near-drowning rate is 15.4/100,000 in
Mulgrave, compared to 14.3/100,000. RR=1.08 |
Study quality and conclusions | Population estimates are for all ages;
drownings and near-drownings for children 0-15 years old. Near-drowning rates
include rivers. All 10 drownings in Cairns Shire occurred
in unfenced pools. One drowning in unfenced pool (previously exempted) in
Mulgrave Shire. |
Author | Pearn et al., 1979 |
Study design and target population | Ecological comparison study (no before/after
comparison of legislation) Children and adolescents
under 16 years old. |
Intervention | Regulation requiring swimming pool
fencing (type not specified). |
Outcomes | Swimming pool fatality rate. |
Results | Fatality rate is 0.9/100,000 in Honolulu
(with law) compared to 2.6/100,000 in Brisbane (without law). RR=0.35 |
Study quality and conclusions | No controlling for exposure. |
Odds ratio summary table (image)
Summary of pool fencing studies
Early studies of pool fencing compare drowning rates in communities
with and without fencing legislation, revealing significantly higher drowning incidences
in those areas without any pool fencing laws. However, this evidence is gathered
from ecological studies or case series, rendering the preventive association between
fencing and drowning tentative at best. Subsequent case-control studies are able
to examine pool fencing intervention (within and between communities), showing that
pool fencing significantly reduces the risk of drowning. Case control studies evaluating
fencing type indicate that isolation fencing (enclosing pool only) is superior to
perimeter fencing (enclosing property and pool) because perimeter fencing allows
access to the pool area through the house. The two recent studies evaluating pool
fencing ordinances in Los Angeles County and Queensland, Australia indicate that
the mere passage of legislation is not sufficient to reduce drownings.
To reference the complete Cochrane Review on
Pool Fencing click here.
Recommendations on effectiveness of pool fencing
and regulations requiring pool fencing
There is no reason to believe that a particular fencing type shown
to be effective in preventing toddlers from climbing it should not translate to
the real world. Because three-sided pool fencing still allows for unintentional
access through the house, we therefore strongly recommend isolation pool fencing
as an effective strategy in preventing submersion injuries. Legislation requiring
fencing does increase the percentage of pools that are fenced. However, many children
and toddlers gain access to pools from a poorly-latched gate or from the house itself
if the fence is three-sided. Pool fencing that serves merely as a barrier to trespassers
will not prevent drownings for those allowed access to the property. Pool fences
should have a dynamic and secure gate and isolate (i.e., four-sided fencing) the
pool from the house. Most unintentional accesses to private pools with isolation
fences occur because of a poorly-working or poorly-designed latch, or because a
toddler follows older children inside the pool fencing. Legislation should require
isolation fencing with secure, self-latching gates. Legislation should require retrofitting
of existing pools and include enforcement provisions in order to be effective.
Recommendations for future research
Studies examining fencing enforcement might lead to
better fencing legislation. Specifically, case-control study comparing types of
fencing legislation and their policies (fines, periodic inspections, etc.) would
be important in determining the most effective and practical means of enforcement
for a given community. Future studies should examine the effect of adding a multifaceted
educational campaign to legislation. Creating, updating, and maintaining surveillance
databases of drownings are essential in order to evaluate the effectiveness of fencing
type or the effectiveness of any other intervention. These databses should include
near-drownings, information on circumstances of drowning, number of private and
public pools, person-time exposure measures, fencing types, and regulations.
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