Table 4.

Moderators and mediators examined in relation to outdoor time.

Author (Year)	Moderators or Mediators Examined	Results
Avol (1998) [50]	Asthma status (healthy, “wheezy”, or asthmatic) as potential moderator	Asthma status did not moderate the relationship between peak hourly ambient ozone (O3) concentration and OT (all p > 0.10).
French (2013) [83]	Gender and ethnicity as potential moderators	Gender and ethnicity did not moderate the relationship between age and outdoor time (all p ≥ 0.2).
Händel (2017) [38]	Sex, age, mother’s BMI, mother’s education, and mother’s PA level were examined as potential moderators of the effect of the intervention.	No significant interactions were found (all p ≥ 0.2).
Handy (2008) [61]	The presence of children aged 6 to 12 was examined as a potential moderator between 12 perceived neighbourhood characteristics ((1) nearby amenities; (2) neighbourhood upkeep; (3) large back yard; (4) large front yard; (5) living in a cul-de-sac rather than on a through street; (6) low traffic on neighbourhood streets; (7) parks and open spaces nearby; (8) sidewalks through neighbourhood; (9) lots of interaction among neighbours; (10) lots of people out and about in the neighbourhood; (11) low crime rate in neighbourhood; (12) safe neighbourhood for children to play) and weekly frequency of OP.	The only significant interaction in longitudinal analyses was between the change in cul-de-sac and the presence of children aged 6–12 in the household (β = 0.170; p = 0.014), suggesting that the presence of cul-de-sacs is supportive of OP for younger children.
Li (2021) [63]	Child age, sex, and household income as potential moderators	The effect of limiting the number of visitors on OT was significant in children < 5 years (β = −9.94, 95% CI = −17.18, −2.71, p = 0.01), but not in older children. The effect of practising physical distancing was significant for children for families earning ≥ CAD 80,000 (β = −5.00, 95% CI: −9.47, −0.53, p = 0.03), but not in those earning less. Age, sex, and household income did not moderate any other associations.
Miller (2017) [86]	Gender and parental monitoring as potential moderators	The effect of youth-perceived neighbourhood danger at Time 1 on OT at Time 2 was moderated by both gender (coefficient = −0.0718, SE = 0.1392, t = −0.5157) and parental monitoring at Time 1 (coefficient = −0.0157, SE = 0.0195, t = −0.8077). The effect of youth-perceived neighbourhood support at Time 1 on OT at Time 2 was also moderated by parental monitoring (coefficient = −0.1153, SE = 0.1130, t = −1.0200) and gender (coefficient = −0.9064, SE = 0.8646, t = −1.0484). The author reported that “youth with lower levels of parental monitoring perceived their neighbourhood to be more supportive and spent more time outside. In contrast, youth with high parental monitoring, who perceived their neighbourhood to be more dangerous, spent less time outside”. The author did not clearly discuss the moderating effect of gender.
Remmers (2014a) [70]	Perceived responsibility regarding child PA as potential moderator	Perceived responsibility moderated the effect of perceived functionality on OP (Table 3). When stratified, functionality was related to more OP in children of parents with high perceived responsibility (β = 0.04; 95% CI = −0.07, 0.15), while among parents with low responsibility, functionality was related to less OP (β = −0.03; 95% C = −0.09, 0.04). Traffic safety interacted with perceived responsibility, but this effect was only significant after adjustment for main effects (Model 3) and became non-significant after adjustment for the other interaction (Model 4). Stratification showed that the association between traffic safety and OP was marginally stronger when parents perceived high (β = 0.10; 95% CI = −0.03, 0.23) vs. low responsibility (β = 0.06; 95% CI = −0.003, 0.12).
Schneor (2021) [74]	Full vs. partial COVID-19 lockdown as potential moderator	A larger reduction in OT was observed with a full lockdown vs. a partial lockdown (−93 vs. −30 min/day; p = 0.008).
Shah (2017) [46]	Age as potential moderator	Age moderated the association between future risk of myopia and OT (p = 0.002), such that, before the age of 4, there was little difference in OT between children who later became myopic and those who remained non-myopic. Between the ages of 4 and 8.5 years, children who later became myopic spent progressively less time outdoors than their peers who remained non-myopic (0.1 SD unit per day difference in OT by age 8.5 years).
van Grieken (2014) [77]	Sex as potential moderator	The interaction between sex and group was significant (p = 0.019). Males in the intervention group had a change in OP of −13.99 min/day (95% CI: −46.11, 18.13) vs. 31.65 min/day for females (95% CI: 4.32, 58.98).
Van Stralen (2012) [78]	This study investigated several hypothesized personal and environmental mediators, which included perceived pros and cons, social pressure, social support, social modelling, self-efficacy, planning skills, perceived barriers, enjoyment, and habit strength related to OP.	No statistically significant intervention effects on potential mediators were seen at Time 2; thus, criteria for mediation were not satisfied.
Watowicz (2012) [87]	Length of time since parental weight loss surgery as potential moderator	There were no differences in reported lifestyle behaviours (including OP) in an analysis of the subset of subjects (n = 33) for whom length of time since surgery was available (by Watowicz et al.).
Xu (2016) [49]	Time as a potential moderator of sleep patterns (bedtime, sleep duration, sleep latency, sleep > 10 h/day, and waking at night)	Interactions were excluded from the final model, as they were not statistically significant (p > 0.05).

Note: OP: outdoor play; OT: outdoor time; PA: physical activity.