Table 3.

Multivariable relative risks (95% confidence intervals)^a for time spent outdoors from high school to age 24 years by residence at age 15 years and family history in relation to the risks of exfoliation glaucoma or exfoliation glaucoma suspect in women only (1980-2010)

	Time spent outdoors (hours per week)
By residence at age 15years	1-5	6-10	≥11	P for interaction
<42° north (middle or southern tier)b	1.00 (reference)	2.11 (1.28, 3.47)	2.36 (1.21, 4.60)
≥ 42°north (northern tier) b	2.35 (1.41, 3.90)	2.48 (1.36, 4.53)	4.08 (2.03, 8.22)	0.07
By family history of glaucoma
Without family history	1.00 (reference)	1.63 (1.11, 2.38)	2.21 (1.33, 3.67)
With family history	3.20 (2.17, 4.73)	3.04 (1.62, 5.73)	4.61 (2.07, 10.29)	0.17

^aMultivariable analyses were adjusted for the same covariates as listed in ^b footnote of Table 2.

^bStates in each geographic tier of the United States are listed in footnote ^b of Table 2.