Table 5.

Multivariate hazard ratios (HR) and 95% confidence intervals (CI) according to low/high^* joint intake of nitrite or nitrate and vitamin C and glioma risk

Joint intake Nitrite and/or nitrate/vitamin C	Low/high	Low/low	High/high	High/low	p-joint interaction
Nitrite, total, median intake†	0.55	0.55	0.77	0.77
Dietary vitamin C, median intake†	116	53	116	53
Number of cases	133	155	175	122
Multivariate HR‡	1.00	0.85	1.01	0.88	0.88
95% CI	(ref)	0.67–1.08	0.81–1.27	0.69–1.13
Nitrite, plant sources, median intake†	0.32	0.32	0.54	0.54
Dietary vitamin C, median intake†	116	53	116	53
Number of cases	125	164	183	113
Multivariate HR‡	1.00	0.77	0.93	0.91	0.16
95% CI	(ref)	0.61–0.98	0.74–1.18	0.71–1.18
Males
Number of cases	87	129	118	85
Multivariate HR‡	1.00	0.78	1.00	0.97	0.29
95% CI	(ref)	0.59–1.03	0.76–1.32	0.72–1.31
Nitrate, total, median intake†	27.4	27.4	63.5	63.5
Dietary vitamin C, median intake†	116	53	116	53
Number of cases	100	174	208	103
Multivariate HR‡	1.00	0.89	1.17	1.07	0.87
95% CI	(ref)	0.69–1.14	0.92–1.49	0.81–1.41
Nitrite plus nitrate, animal sources, median intake†	2.2	2.2	3.7	3.7
Dietary vitamin C, median intake†	116	53	116	53
Number of cases	173	132	135	145
Multivariate HR‡	1.00	0.82	0.90	0.83	0.50
95% CI	(ref)	0.65–1.03	0.72–1.13	0.66–1.03
Nitrite plus nitrate, processed meat sources, median intake†	0.25	0.25	0.87	0.87
Dietary vitamin C, median intake†	116	53	116	53
Number of cases	182	114	126	163
Multivariate HR‡	1.00	0.89	0.93	0.79	0.80
95% CI	(ref)	0.70–1.13	0.74–1.17	0.64–0.99

^*Low-high distinctions based on median intake values.

^†mg/1,000 kcal per day.

^‡Adjusted for sex, age (continuous), race (non-Hispanic White, non-Hispanic Black, other, and missing), energy intake (continuous), education (<high school, high school graduate, post-high school other than college, some college, college graduate, postgraduate, and missing), height (8 pre-specified categories and missing), and history of cancer at baseline (yes, no, and missing).