Table 3. Symptom prevalence of the diary panel sub-cohort, by zone and year (n = 380)^a.

	Reduced exposure zone			Increased exposure zoneb			Eastern stack zoneb			Control zone
	2006	2007	2008	2006	2007	2008	2006	2007	2008	2006	2007	2008
N c (% of 2006)	86	76 (88)	70 (81)	82	57 (70)	52 (63)	85	69 (81)	62 (73)	81	57 (70)	46 (57)
%
Symptom days d
At least once	99	96	94	96	93	98	95	97	94	94	91	98
10% of days	93	84	79	89	70	77	82	78	89	84	72	76
>20% of days	69	67	60	73	53	62	62	64	66	63	60	61
Day-time symptoms d
At least once	79	72	70	84	70	69	67	65	63	63	58	65
>10% of days	52	43	53	63	42	48	49	46	48	41	40	43
>20% of days	36	33	37	39	26	37	33	32	31	23	25	30
Night-time symptoms d
At least once	64	61	59	73	44	50	66	59	65	54	42	52
>10% of days	36	30	27	38	25	29	34	32	40	30	26	28
>20% of days	19	13	13	21	12	15	18	22	21	15	19	17
Wheeze d
At least once	28	24	20	35	21	23	22	28	35	35	28	33
>10% of days	9	7	9	17	4	10	11	9	5	15	14	7
>20% of days	3	7	3	10	4	4	6	4	0	11	9	4
Bronchodilator use d
At least once	12	16	10	21	11	12	6	7	8	12	12	13
>10% of days	3	7	6	12	7	10	2	3	2	6	11	4
>20% of days	2	1	1	5	5	4	0	0	0	5	9	4
Cough d
At least once	71	68	60	77	53	56	66	64	58	57	46	63
>10% of days	43	33	39	48	32	35	40	38	45	36	32	37
>20% of days	26	18	23	32	12	21	21	23	26	20	25	30
Upper resp. symptoms d
At least once	50	50	53	60	44	44	48	49	53	40	44	50
>10% of days	19	17	29	24	11	21	18	23	18	9	14	26
>20% of days	5	8	13	12	7	10	6	9	3	5	11	15
Lower resp symptomse f	37	44	33	26	57	51	38	32	44	31	38	39
Severe lower resp sympe f	6	7	8	12	16	13	5	7	6	9	7	12
Upper resp. symptoms e f	12	18	18	5	27	33	11	22	15	8	26	20
Mouth symptoms f	12	14	22	9	18	15	7	22	21	8	14	9

^aEach subject contributed up to 63 days of data in the diary study.

^bParticipants in overlapping area of increased exposure zone and stack zone, diary panel cohort (2006 = 6(4); 2007 = 5(2); 2008 = 5(3)), contributed data to both zones. n =  subjects in overlapping area with spirometry; (n) = subjects in overlapping area taking part in peak flow and symptom diary.

^cPanel sub-cohort participants who took part in peak flow/symptom diary.

^dSymptoms recorded by diary. % represents proportion of subjects experiencing those symptoms a) at least one day during the study period; b) >10% of days during the study period; c) >20% of days during the study period.

^eComposite variables derived from variables measured in questionnaire (See Table S1, Supporting Information).

^fAttributes measured by questionnaire.