Table 2.

Associations of green tea and catechin intakes with the biomarkers of glucose metabolism

		The first season (winter)a				The four seasonsa
		β	95% CI		pb	β	95% CI		pb
			2.5%	97.5%			2.5%	97.5%
Fasting blood glucose
Green tea		6.20 × 10−3	− 2.89 × 10−3	1.53 × 10−2	0.18	− 4.89 × 10−3	− 9.64 × 10−3	− 1.33 × 10−4	0.04
Season	Spring					− 3.38 × 10−1	− 1.98	1.30	0.69
(Ref: winter)	Summer					− 3.81 × 10−1	− 2.05	1.29	0.65
	Autumn					− 1.78	− 3.46	− 1.01 × 10−1	0.04
Catechins		7.75 × 10−3	− 1.12 × 10−2	2.67 × 10−2	0.42	− 8.05 × 10−4	− 9.58 × 10−3	7.97 × 10−3	0.86
Season	Spring					− 1.54 × 10−1	− 1.80	1.49	0.85
(Ref: winter)	Summer					− 1.28 × 10−1	− 1.81	1.56	0.88
	Autumn					− 1.61	− 3.31	8.95 × 10−2	0.06
EGCG		2.32 × 10−2	− 3.36 × 10−2	8.01 × 10−2	0.42	4.23 × 10−3	− 2.52 × 10−2	3.36 × 10−2	0.78
Season	Spring					− 1.27 × 10−1	− 1.79	1.53	0.88
(Ref: winter)	Summer					− 1.21 × 10−1	− 1.81	1.57	0.89
	Autumn					− 1.65	− 3.36	5.06 × 10−2	0.06
HbA1c
Green tea		7.57 × 10−6	− 2.74 × 10−4	2.89 × 10−4	0.96	9.82 × 10−5	− 5.00 × 10−5	2.46 × 10−4	0.19
Season	Spring					6.83 × 10−3	− 3.57 × 10−2	4.93 × 10−2	0.75
(Ref: winter)	Summer					− 2.06 × 10−2	− 6.53 × 10−2	2.42 × 10−2	0.37
	Autumn					− 1.98 × 10−2	− 6.59 × 10−2	2.63 × 10−2	0.40
Catechins		− 5.55 × 10−4	− 1.13 × 10−3	2.21 × 10−5	0.06	9.79 × 10−5	− 1.57 × 10−4	3.53 × 10−4	0.45
Season	Spring					3.33 × 10−3	− 3.90 × 10−2	4.57 × 10−2	0.88
(Ref: winter)	Summer					− 2.59 × 10−2	− 7.11 × 10−2	1.94 × 10−2	0.26
	Autumn					− 2.46 × 10−2	− 7.07 × 10−2	2.16 × 10−2	0.30
EGCG		− 1.65 × 10−3	− 3.39 × 10−3	8.06 × 10−5	0.06	1.76 × 10−4	− 6.28 × 10−4	9.80 × 10−4	0.67
Season	Spring					3.97 × 10−3	− 3.86 × 10−2	4.66 × 10−2	0.85
(Ref: winter)	Summer					− 2.53 × 10−2	− 7.06 × 10−2	1.99 × 10−2	0.27
	Autumn					− 2.41 × 10−2	− 7.03 × 10−2	2.21 × 10−2	0.30
Insulin
Green tea		2.83 × 10−4	− 2.50 × 10−4	8.15 × 10−4	0.29	− 4.43 × 10−4	− 7.98 × 10−4	− 8.82 × 10−5	0.01
Season	Spring					− 2.56 × 10−2	− 1.59 × 10−1	1.08 × 10−1	0.71
(Ref: winter)	Summer					− 7.68 × 10−2	− 2.11 × 10−1	5.75 × 10−2	0.26
	Autumn					− 3.66 × 10−2	− 1.74 × 10−1	1.01 × 10−1	0.60
Catechins		6.74 × 10−5	− 1.03 × 10−3	1.16 × 10−3	0.90	− 4.53 × 10−4	− 1.17 × 10−3	2.64 × 10−4	0.21
Season	Spring					− 1.01 × 10−2	− 1.45 × 10−1	1.25 × 10−1	0.88
(Ref: winter)	Summer					− 5.27 × 10−2	− 1.88 × 10−1	8.24 × 10−2	0.44
	Autumn					− 1.43 × 10−2	− 1.55 × 10−1	1.27 × 10−1	0.84
EGCG		1.53 × 10−4	− 3.15 × 10−3	3.45 × 10−3	0.93	− 7.06 × 10−4	− 2.93 × 10−3	1.52 × 10−3	0.53
Season	Spring					− 1.14 × 10−2	− 1.48 × 10−1	1.26 × 10−1	0.87
(Ref: winter)	Summer					− 5.49 × 10−2	− 1.91 × 10−1	8.11 × 10−2	0.43
	Autumn					− 1.75 × 10−2	− 1.59 × 10−1	1.24 × 10−1	0.81
HOMA-IR
Green tea		3.36 × 10−4	− 2.15 × 10−4	8.87 × 10−4	0.27	− 1.17 × 10−4	− 5.55 × 10−4	3.21 × 10−4	0.60
Season	Spring					− 1.69 × 10−2	− 1.58 × 10−1	1.24 × 10−1	0.81
(Ref: winter)	Summer					− 7.53 × 10−2	− 2.17 × 10−1	6.65 × 10−2	0.30
	Autumn					− 3.06 × 10−2	− 1.80 × 10−1	1.19 × 10−1	0.69
Catechins		1.49 × 10−4	− 9.85 × 10−4	1.28 × 10−3	0.79	− 5.90 × 10−5	− 8.16 × 10−4	6.98 × 10−4	0.88
Season	Spring					− 1.25 × 10−2	− 1.52 × 10−1	1.28 × 10−1	0.86
(Ref: winter)	Summer					− 6.89 × 10−2	− 2.08 × 10−1	7.04 × 10−2	0.33
	Autumn					− 2.52 × 10−2	− 1.72 × 10−1	1.22 × 10−1	0.74
EGCG		4.01 × 10−4	− 3.00 × 10−3	3.80 × 10−3	0.81	8.41 × 10−4	− 1.87 × 10−3	3.55 × 10−3	0.54
Season	Spring					− 7.52 × 10−3	− 1.48 × 10−1	1.33 × 10−1	0.92
(Ref: winter)	Summer					− 6.80 × 10−2	− 2.07 × 10−1	7.08 × 10−2	0.34
	Autumn					− 3.29 × 10−2	− 1.79 × 10−1	1.13 × 10−1	0.66

CI, confidence interval; EGCG, epigallocatechin-3-gallate; HbA1c, glycated hemoglobin A1c; HOMA-IR, homeostatic model assessment index of insulin resistance

^aBeta coefficients, confidence intervals, and p values from the linear regression model for the first season and from the linear mixed-effects model for the four seasons

^bp values shown in bold are statistically significant (p < 0.05)