Table 3. Association between season-specific quintile of serum 25(OH)D at baseline and mortality among men diagnosed with prostate cancer, ATBC Study.

Season-Specific Quintile of Serum 25(OH)D	# Prostate Cancer Deaths	Person-Years	HR (95% CI)*	HR (95% CI)†
Q1	69	875	1.0 (ref)	1.0 (ref)
Q2	79	1,231	0.81 (0.59 – 1.12)	0.84 (0.61 – 1.17)
Q3	76	1,433	0.69 (0.50 – 0.96)	0.71 (0.51 – 0.99)
Q4	55	1,368	0.52 (0.37 – 0.75)	0.54 (0.38 – 0.77)
Q5	83	1,629	0.69 (0.50 – 0.95)	0.72 (0.52 – 0.99)
p-trend			0.003	0.006

^*Adjusted for age at prostate cancer diagnosis

^†Adjusted for age at prostate cancer diagnosis, cigarettes smoked per day, physical activity, and family history of prostate cancer