Table 1

Percentage of subjects in each plasma vitamin C group by gender, gender/age, gender/smoking habit and gender/social class

		Number		Plasma vitamin C group		χ²
		Number		% Low	% Marginal	χ²		% Optimal
All	1267	20	24	56
By gender
Men	632	26	26	48
Women	635	14	22	64	^***
By age
Men:
25–34	101	15	19	66
35–44	125	14	24	62
45–54	129	31	30	39
55–64	142	30	29	41
65–74	135	36	25	38	^***
Women:
25–34	135	9	19	72
35–44	127	11	26	62
45–54	117	10	23	67
55–64	125	15	27	58
65–74	131	24	15	60	^**
By smoking
Men:
smokers	321	36	30	34
non-smokers	308	15	22	63	^***
Women:
smokers	271	23	30	48
non-smokers (including ex)	361	8	16	76	^***
By social class
Men:
manual	447	30	28	42
non-manual	150	12	21	67	^***
Women:
manual	278	17	24	59
non-manual	242	10	16	74	^**

Plasma vitamin C groups are Low <11.4 μmol/l, Marginal 11.4–22.7 μmol/l, and Optimal 22.7 μmol/l and above. ^***p<0.001,^**p<0.01.