Table 2.

Associations of 25-hydroxyvitamin D (25(OH)D) with menstrual cycle characteristics among women from the Uterine Fibroid Study

	N	Model 1 a OR (CI) per 10 ng/mL decrease in 25(OH)D	p-value	N	Model 2 b OR (CI), per 10 ng/ml decrease in 25(OH)D	p-value
Short cycles (≤25 days)	135	1.10 (0.82, 1.49)	0.51	133	1.08 (0.79, 1.48)	0.64
Long cycles (≥32 days)	22	1.28 (0.69, 2.38)	0.43	22	1.31 (0.66, 2.60)	0.44
Irregular cycles	48	2.17 (1.23, 3.83)	0.008	46	1.87 (1.03, 3.39)	0.04
		Model 1 a OR(CI) for insufficient versus sufficient 25(OH)D			Model 2 b OR(CI) for insufficient versus sufficient 25(OH)D
Short cycles (≤25 days)	135	1.01 (0.60, 1.72)	0.96	133	0.95 (0.55, 1.67)	0.87
Long cycles (≥32 days)	22	1.07 (0.40, 2.84)	0.89	22	1.02 (0.35, 2.96)	0.97
Irregular cycles	48	3.09 (1.02, 9.42)	0.05	46	2.44 (0.77, 7.69)	0.13

^aResults of the polytomous logistic regression model adjusted for age (linear) and race. The referent category is women who reported regular menstrual cycles and a usual cycle length between 26 and 31 days (N = 431).

^bResults of the polytomous logistic regression model adjusted for: age, race, BMI, education, age of menarche, current smoking, alcohol use, and physical activity. The referent category is women who reported regular menstrual cycles and a usual cycle length between 26 and 31 days (N = 426).