Table 2.

Association between total antioxidant index (TAI) and survival in population-based glioblastoma multiforme patients from the San Francisco Bay Area, 1991–2004

Model: TAI variable	Hazard Ratio (95% Confidence Interval Limits)
	All	Series I (1991–1994)	Series II (1997–1999)	Series III (2001–2004)
1:TAI (Trolox equivalent)a	0.98 (0.94, 1.02)	1.07 (0.98, 1.16)	1.01 (0.95,1.07)	0.88 (0.82, 0.94)
2: Log (TAI)	1.01 (0.90, 1.13)	1.30 (1.07, 1.58)	1.06 (0.83, 1.35)	0.58 (0.46, 0.74)
3:TAI categories:b TAI < 1500	reference level	reference level	reference level	reference level
1500 ≤ TAI ≤ 2999	1.06(0.84, 1.33)	1.29 (0.94, 1.79)	1.07(0.63, 1.81)	0.54 (0.34, 0.85)
3000 ≤ TAI ≤ 4499	1.13 (0.87, 1.45)	1.51 (1.00, 2.27)	1.32 (0.76, 2.27)	0.48 (0.30, 0.77)
TAI ≥ 4500	0.99 (0.75, 1.31)	1.39 (0.80, 2.40)	1.22 (0.69, 2.14)	0.42 (0.26, 0.69)
4: TAI and vitamin/supplement intake:
Low TAI (no regular vitamin/supplements)c	reference level	reference level	reference level	reference level
Low TAI + regular vitamin/supplements	0.90 (0.673, 1.10)	0.97 (0.70, 1.34)	0.64 (0.42, 0.99)	0.94 (0.63, 1.39)
High TAI (no regular vitamin/supplements)	0.99 (0.79, 1.24)	1.20 (0.77, 1.86)	1.07 (0.71, 1.60)	0.70 (0.47, 1.04)
High TAI + regular vitamin/supplement	0.94 (0.77, 1.16)	1.01 (0.76, 1.59)	0.94 (0.64, 1.37)	0.66 (0.46, 0.96)

^aTAI scaled such that HR represents a 1000 unit change.

In Models 1–3 – covariates included age, gender, ethnicity, series, proxy-reporting, treatment (resection, radiation, temodar, and other chemotherapy), total calorie intake, and regular vitamin/supplement use (yes/no);

In Model 4 - covariates included all the covariates used in Models 1–3 except regular vitamin/supplement use (yes/no), which was part of the main exposure.

^b1500 TAI units correspond approximately to 1 cup of green (~800) or black (~900) tea plus 1 serving of Brussels sprouts (~500) plus 1 serving of carrots (~150).

^cHigh TAI is above median, low TAI is equal or below median.