Table 3.

Serum 25(OH)D and fibroid incidence, 1230^a participants from the Study of Environment, Lifestyle & Fibroids, Detroit, Michigan, 2010–2018

Categories of 25(OH)D ng/ml	Incident Case	Person-Years	Hazard Ratio (95% Confidence Interval)
Categories of 25(OH)D ng/ml	Incident Case	Person-Years	Unadjusted^b	Fully adjusted^c
<12	88	1717	REF	REF
12–<20	119	2213	1.06 (0.81, 1.40)	1.03 (0.78, 1.37)
20–<30	71	1075	1.23 (0.90, 1.68)	1.15 (0.83, 1.58)
≥30	16	303	0.91 (0.53, 1.55)	0.83 (0.48, 1.42)
<20	207	3930	REF	REF
≥20	87	1377	1.11 (0.87, 1.43)	1.05 (0.81, 1.36)
<30	278	5004	REF	REF
≥30	16	303	0.84 (0.51, 1.39)	0.78 (0.47, 1.30)

Note: 25(OH)D = 25-hydroxyvitamin D

Incidence analyses were conducted among 1230 participants who were fibroid-free at enrollment and had at least one follow-up ultrasound.

Cox model with age as time scale (starting at age of enrollment), with no further adjustment.

Cox model with age as time scale further adjusted for time varying parity (0, 1–2 births, ≥3 births), years since last birth (within 4 years, ≥4 years ago including no births), years since last use of injection contraceptive (<2 years, ≥2 years/never), body mass index kg/m² (<25, 25–<30, 30–<35, 35–<40, ≥40), current smoking (yes, no), household income (<$20,000, ≥$20,000). Twelve observations excluded from analyses due to missing data on at least one covariate.