Table 5.

Subgroup analysis of association of energy-adjusted dietary vitamin B6 intake with all-cause mortality in SWHS (1997–2014)

	Quintiles of dietary vitamin B6 intake a
	Q1	Q2	Q3	Q4	Q5	P for trend	P for interaction
Age at baseline							0.542
Age <60 y
No. of deaths	305	336	331	320	331
HR (95%CIs)	1.00 (reference)	1.05 (0.89,1.22)	0.97 (0.83,1.14)	0.94 (0.80,1.11)	0.94 (0.80,1.10)	0.216
Age>=60 y
No. of deaths	1864	1362	1081	919	706
HR (95%CIs)	1.00 (reference)	0.88 (0.82,0.94)	0.87 (0.80,0.94)	0.87 (0.81,0.95)	0.82 (0.75,0.89)	<0.001
Body mass index							0.057
BMI<24 kg/m2
No. of deaths	885	774	649	520	394
HR (95%CIs)	1.00 (reference)	0.94 (0.85,1.03)	0.94 (0.85,1.04)	0.86 (0.77,0.96)	0.80 (0.71,0.91)	<0.001
BMI>=24 kg/m2
No. of deaths	1284	924	763	719	643
HR (95%CIs)	1.00 (reference)	0.88 (0.80,0.95)	0.84 (0.77,0.92)	0.88 (0.81,0.97)	0.85 (0.77,0.94)	0.001
Energy intake							0.015
<Median
No. of deaths	1101	1140	921	736	434
HR (95%CIs)	1.00 (reference)	0.89 (0.82,0.97)	0.86 (0.79,0.94)	0.85 (0.78,0.94)	0.77 (0.68,0.86)	<0.001
>=Median
No. of deaths	1068	558	491	503	603
HR (95%CIs)	1.00 (reference)	0.90 (0.81,1.00)	0.90 (0.80,1.00)	0.90 (0.81,1.00)	0.89 (0.80,0.98)	0.024
History of chronic							0.002
No
No. of deaths	1512	1155	991	902	745
HR (95%CIs)	1.00 (reference)	0.92 (0.85,0.99)	0.90 (0.83,0.97)	0.91 (0.84,0.99)	0.83 (0.76,0.91)	<0.001
Yes
No. of deaths	657	543	421	337	292
HR (95%CIs)	1.00 (reference)	0.86 (0.77,0.97)	0.85 (0.75,0.96)	0.80 (0.70,0.91)	0.85 (0.74,0.98)	0.004
Vitamin B supplements use							0.015
No
No. of deaths	1951	1491	1246	1066	904
HR (95%CIs)	1.00 (reference)	0.90 (0.84,0.97)	0.90 (0.84,0.97)	0.89 (0.82,0.96)	0.86 (0.79,0.93)	<0.001
Yes
No. of deaths	218	207	166	173	133
HR (95%CIs)	1.00 (reference)	0.87 (0.71,1.05)	0.72 (0.59,0.89)	0.78 (0.64,0.96)	0.65 (0.52,0.81)	<0.001
Menopause status							0.983
No
No. of deaths	221	229	234	222	237
HR (95%CIs)	1.00 (reference)	0.96 (0.79,1.16)	0.91 (0.75,1.10)	0.86 (0.71,1.04)	0.88 (0.73,1.06)	0.102
Yes
No. of deaths	1948	1469	1178	1017	800
HR (95%CIs)	1.00 (reference)	0.89 (0.84,0.96)	0.88 (0.82,0.95)	0.89 (0.82,0.96)	0.83 (0.76,0.90)	<0.001

Abbreviation: Q, quintiles; SWHS, Shanghai Women’s Health Study; HR, hazards ratio; CI, confidence interval.

^aHR: Adjusted for age, energy intake, education, income, occupation, smoke, alcohol, body mass index, waist-hip ratio, physical activity, history of diabetes, hypertension, coronary heart disease and stroke, vitamin B supplements use, menopausal status, and hormone replacement therapy.