Use of Shade in U.S. and Australian City Parks

This study is designed to understand the value of shade development in skin cancer prevention
and test predictions from social ecologic models that health behavior results from the
interplay among the built environment, social environment, and setting features. Use of shade
is recommended by health authorities worldwide. However, shade provision requires expensive
physical environment changes and may be effective only when health education has created a
social environment (e.g., norms) that motivates its use. A multi-national research team will
explore the use of built shade in passive recreation areas (i.e., areas for sitting/ standing
while socializing, preparing/eating a meal, watching/coaching sports, watching a concert,
taking a class, or waiting, or areas where people stroll for sightseeing, while observing
outdoor displays, or shopping) within public parks and compare use between the United States
(i.e., Denver, Colorado) and Australia (i.e., Melbourne, Victoria) to prospectively test the
moderating influence of social environment on the built environment. Pilot studies confirmed
that adults in Melbourne had stronger sun protection habits and norms than adults in Denver.
The specific aims of the project are to: a) introduce built shade structures (i.e., shade
sails) in public parks in Denver and Melbourne; b) compare the use of passive recreation
areas with and without built shade; c) compare the change in use of the passive recreation
areas in Denver and Melbourne after introduction of built shade, and d) examine the
relationship among social environment and physical features of the environment and built
shade.The research team will build shade sails at passive recreation areas in public parks
and compare use of the passive recreation areas to unshaded passive recreation areas in a
randomized pretest-posttest controlled design. Passive recreation areas will be enrolled in
one of three annual sample waves and stratified by location (72 in Denver and 72 in
Melbourne). In each wave, passive recreation areas will be pretested in a first summer,
further stratified based on baseline use, and randomized following pretest to construction of
a shade sail or an untreated control group in a 1:3 ratio. Posttesting will occur the
following summer, after construction of the shade sails. In total, 36 passive recreation
areas will be randomized to the intervention group with shade sail construction (18 per city)
and 108 passive recreation areas to the untreated control group with no shade sails (54 per
city). The primary outcome measure will be use of the passive recreation areas, observed by
trained research assistants. The secondary outcome measure will be the potential ultraviolet
radiation exposure, assessed by hand-held meters during the observations of the passive
recreation areas. Data collection will occur during 30-minute periods between 11 am and 3 pm
on on 4 weekend days over 20-weeks in the summer. Primary analyses will be performed on the
probability the passive recreation areas are in use when observed and secondary analysis, on
estimated standard erythemal dose of ultraviolet radiation during 30 minutes, using
intent-to-treat methods.

Inclusion Criteria:

- Passive recreation areas had to be located in public parks in Denver, Colorado USA or
Melbourne, Victoria Australia metropolitan area.

- Parks had to contain at least two unshaded PRAs and be administered by the study
municipalities,

- Passive recreation areas had to meet the definition of a passive recreation area,
i.e., areas for sitting/standing while socializing, preparing/eating a meal, watching
or coaching sports, watching a concert, taking a class, or waiting, or areas where
people stroll (walk slowly) for sightseeing while observing outdoor displays (e.g.,
festivals, gardens, zoo exhibits).

- Passive recreation areas had to be in full sun (i.e. no shade) at pretest.

- Passive recreation areas had to contain a space where a shade sail could be
constructed, i.e., free from underground or above ground obstructions, relatively
level, and large enough to accommodate the shade sail.

- Passive recreation areas had to be approved by parks department staff for shade sail
construction.

- Adults had to appear to be 18 years of age or older.

- Adults had to be in the public parks.

Exclusion Criteria:

- Passive recreation areas where major construction/ redevelopment of the parks was
planned within the study period.