Table 2.

Age-Adjusted Associations of Reproductive Factors and Hormone Use With Risk of Glioma Among 225,355 Women in the NIH-AARP Diet and Health Study

	Gliomas (N = 174)	Person-years	HRa (95% CI)
Age at menarche (yrs)
<13	77	790,914	1.00 (reference)
13–14	70	669,902	1.06 (0.74, 1.46)
≥15	23	151,592	1.53 (0.96, 2.44)
Missing	4	17,108
P for trend			0.16
Age at first live birth (yrs)
Nulliparous	28	235,516	1.00 (reference)
<20	32	284,450	0.95 (0.57, 1.58)
20–24	68	699,601	0.79 (0.51, 1.23)
≥30	41	383,175	0.87 (0.54, 1.40)
Missing	5	26,775
Parous/nulliparous
Nulliparous	30	248,161	1.00 (reference)
Parous	140	1,363,196	0.83 (0.56, 1.23)
Missing	4	18,159
Parity
Nulliparous	30	248,161	1.00 (reference)
1	19	169,685	0.93 (0.52, 1.65)
2	41	422,117	0.80 (0.50, 1.28)
≥3	80	771,394	0.83 (0.54, 1.26)
Missing	4	2,548
History of hysterectomy
No	81	919,284	1.00 (reference)
Yes	87	687,972	1.42 (1.05, 1.92)
Missing	6	22,259
History of oophorectomy
No	109	1,117,365	1.00 (reference)
Both ovaries removed	48	376,483	1.01 (0.58, 1.76)
Other surgery	12	103,557	0.78 (0.47, 1.31)
Missing	5	32,112
Menopausal status
Premenopausal	7	70,842	1.14 (0.52, 2.49)
Postmenopausal	164	1,537,075	1.00 (reference)
Missing	3	21,600
Type of menopauseb
Natural	87	880,004	1.00 (reference)
Surgery/radiation/chemo	77	643,657	1.23 (0.90, 1.67)
Missing	6	66,956
Age at menopauseb
≥50	56	608,858	1.00 (reference)
45–49	43	386,466	1.17 (0.80, 1.72)
<45	65	541,751	1.27 (0.91–1.79)
Missing	3	21,500
Oral contraceptive use
Never	117	970,560	1.00 (reference)
Ever	53	633,935	0.74 (0.53, 1.05)
Missing	4	25,021
Duration of OC use
Never	117	970,560	1.00 (reference)
1–4 yrs	23	282,728	0.73 (0.46, 1.15)
5–9 yrs	17	198,153	0.77 (0.45, 1.29)
≥10 yrs	13	153,054	0.75 (0.42, 1.34)
Missing	4	25,021
P for trend			0.22
Hormone therapy
Never	87	770,682	1.00 (reference)
Ever	87	858,834	0.94 (0.72, 1.23)
Hormone therapy
Never	87	770,682	1.00 (reference)
Former	17	161,149	1.16 (0.75, 1.78)
Current	70	695,008	1.05 (0.94, 1.18)
Duration of hormone use
Never	80	728,152	1.00 (reference)
<5 yrs	33	312,649	1.17 (0.82, 1.67)
5–9 yrs	22	214,010	0.91 (0.58, 1.41)
≥10 yrs	32	329,564	0.83 (0.57, 1.20)
Missing	7	6,318
P for trend			0.23

Abbreviations: HR, hazard ratio; CI, confidence interval.

^aAdjusted for age at entry as a continuous variable.

^bRestricted to postmenopausal women.

Missing values: age at menarche (4 cases/2397 non-cases); age at first live birth (5 cases/3738 non-cases); parity (4 cases/2544 non-cases); hysterectomy status (6 cases/3120 non-cases); oophorectomy status (5 cases/4494 non-cases); menopausal status (3/3012), age at menopause (3 cases/3012 non-cases); oral contraceptive use (4 cases/3499 non-cases); duration of oral contraceptive use (4 cases/3499 non-cases); ever hormone use (0 cases/0 non-cases); hormone status (0 cases/374 non-cases); years of hormone therapy (7 cases/6311 non-cases).