Table 1.

Characteristics of subjects with synovial sarcoma and controls, California, 1978–2015.

	Synovial sarcoma		Control group
	n = 244		n = 12,200
	Number of participants	%	Number of participants	%	Pa
Overall	244		12,200
Sex
Female	106	43.4	5,940	48.7	0.10
Male	138	56.6	6,260	51.3
Race/ethnicity
White	93	38.1	4,834	39.6	0.45
Black	17	7.0	1,097	9.0
Hispanic	112	45.9	4,965	40.7
Asian	20	8.2	1,139	9.3
Other	2	0.8	165	1.4
Birth weight (grams)
250–2,499	15	6.1	721	5.9	0.76
2,500–2,999	32	13.1	1,928	15.8
3,000–3,499	95	38.9	4,480	36.7
3,500–3,999	71	29.1	3,674	30.1
4,000+	31	12.7	1,397	11.5
Gestational age (weeks)
37–41	19	7.8	1,118	9.2	0.56
22–36	183	75.0	8,820	72.3
42–44	20	8.2	1,268	10.4
Unknown	22	9.0	994	8.1
Birth plurality
Singleton	239	98.0	11,927	97.8	0.84
Multiple	5	2.0	273	2.2
Birth order
1st	128	52.5	4,873	39.9	<0.01
2nd	66	27.0	3,932	32.2
3rd and higher	50	20.5	3,395	27.8
Mode of delivery
Vaginal	193	79.1	9,630	78.9	0.95
Cesarean section	51	20.9	2,570	21.1
Year of birth
1978–1982	47	19.3	2,350	19.3	1.00
1983–1987	66	27.0	3,300	27.0
1988–1992	66	27.0	3,300	27.0
1993–2013	65	26.6	3,250	26.6
Maternal education
Up to 8 years	10	4.1	981	8.0	0.20
9–11 years	23	9.4	1,171	9.6
12 years	47	19.3	2,079	17.0
13–15 years	31	12.7	1,365	11.2
16 or more years	24	9.8	1,114	9.1
Unknown	109	44.7	5,490	45.0
Mother’s place of birth
United States	157	64.3	7,668	62.9	0.63
Foreign	87	35.7	4,532	37.1
Miscarriage/stillbirth
Never	205	84.0	10,114	82.9	0.60
Ever	38	15.6	2,060	16.9
Unknown	1	0.4	26	0.2
Maternal complication during pregnancy
Never	196	80.3	9,872	80.9	0.79
Ever	37	15.2	1,775	14.5
Unknown	11	4.5	553	4.5
Previous cesarean section
Never	221	90.6	10,735	88.0	0.23
Ever	15	6.1	1,004	8.2
Unknown	8	3.3	461	3.8
Maternal age (years)
<20	30	12.3	1,484	12.2	0.44
20–24	76	31.1	3,373	27.6
25–29	60	24.6	3,591	29.4
30–34	56	23.0	2,532	20.8
≥35	22	9.0	1,220	10.0
Paternal age (years)
<25	66	27.0	2,938	24.1	0.11
25–29	78	32.0	3,421	28.0
30–34	42	17.2	2,901	23.8
35–39	31	12.7	1,484	12.2
≥40	22	9.0	865	7.1
Unknown	5	2.0	591	4.8

^aP values were derived from χ² tests.