Table 1

Selected characteristics of AHS spouses at enrolment with valid OP use information (n=29 325*), stratified by ever use of OP insecticides

			Any OP use
	Total		No		Yes
	N=29 325		N=21 736		N=7589
	N	Per cent	N	Per cent	N	Per cent	p Value†
Age at enrolment
≤35	5740	19.6	4743	21.8	997	13.1	<0.01
36–45	8829	30.1	6465	29.7	2364	31.2
46–55	7493	25.6	5172	23.8	2321	30.6
56+	7263	24.8	5356	24.6	1907	25.1
State
Iowa	19 880	67.8	14 323	65.9	5557	73.2	<0.01
North Carolina	9445	32.2	7413	34.1	2032	26.8
Race
White	28 757	98.1	21 208	97.6	7549	99.5	<0.01
Other	520	1.8	489	2.3	31	0.4
Missing	48	0.2	39	0.2	9	0.1
Cigarette smoking (pack-years)
Never smoker	20 607	70.3	15 304	70.4	5303	69.9	0.06
Q1: ≤1.5	1894	6.5	1361	6.3	533	7.0
Q2: 1.51–6.625	1973	6.7	1456	6.7	517	6.8
Q3: 6.626–18	2049	7.0	1551	7.1	498	6.6
Q4: >18	1802	6.1	1311	6.0	491	6.5
Missing	1000	3.4	753	3.5	247	3.3
Educational attainment
High school or less	11 983	40.9	9117	41.9	2866	37.8	<0.01
Some college	8010	27.3	5914	27.2	2096	27.6
College graduate	6302	21.5	4623	21.3	1679	22.1
Other/missing	3030	10.3	2082	9.6	948	12.5
Alcohol use
Never	13 135	44.8	10 095	46.4	3040	40.0	<0.01
Less than once/month	7799	26.6	5667	26.0	2132	28.1
1–3 times/month	4579	15.6	3321	15.3	1258	16.6
1 time/week or more	3480	11.9	2401	11.0	1079	14.2
Missing	332	1.1	252	1.2	80	1.1
Body mass index
≤25	12 853	43.8	9514	43.8	3339	44.0	<0.01
25.1–30	8285	28.3	5936	27.3	2349	31.0
>30	4795	16.4	3491	16.1	1304	17.2
Missing	3392	11.6	2795	12.9	597	7.9
Family history of cancer
No	14 356	49.0	10 943	50.4	3413	45.0	<0.01
Yes	14 426	49.2	10 343	47.6	4083	53.8
Missing	543	1.9	450	2.1	93	1.2
Menopause at enrolment
No	14 841	50.6	11 130	51.2	3711	48.9	<0.01
Yes, before age 50	7086	24.2	5022	23.1	2064	27.2
Yes, after age 50	4101	14.0	2870	13.2	1231	16.2
Missing	3297	11.2	2714	12.5	583	7.7
Number of live births
0	1554	5.3	1149	5.3	405	5.3	<0.01
1	2194	7.5	1711	7.9	483	6.4
2	8625	29.4	6347	29.2	2278	30.0
3	6961	23.7	4944	22.8	2017	26.6
4+	5585	19.1	3949	18.2	1636	21.6
Missing	4406	15.0	3636	16.7	770	10.2
Oral contraceptive use
Never	6838	23.3	5049	23.2	1789	23.6	<0.01
Ever	19 124	65.2	13 938	64.1	5186	68.3
Missing	3363	11.5	2749	12.7	614	8.1
Apply pesticides in home
No	21 164	72.2	16 833	77.4	4331	57.1	<0.01
Yes	8161	27.8	4903	22.6	3258	42.9
Apply pesticides on lawn/garden
No	26 158	89.2	20 417	93.9	5741	75.7	<0.01
Yes	3167	10.8	1319	6.1	1848	24.4

*Excluded n=678 women missing information on any OP use. The overall study population included 30 003 women, as there were some women who had valid exposure information for a single OP but were missing data for overall OP use.
†χ² Test for homogeneity.
AHS, Agricultural Health Study; OP, organophosphates.