Table 2.

Associations between demographic/prognostic factors and highest level of education.

Characteristic	Highest level of education achieved								χ2(df), p	p
	Incomplete high school		High school		University		Total
	%	No.	%	No.	%	No.	%	No.
Age at diagnosis
<35 years	9.7	27	21.2	114	17.8	38	17.4	179
35-39 years	20.9	58	31.0	167	37.6	80	29.6	305
40-49 years	28.5	79	24.7	133	31.5	67	27.1	279
50-59 years	40.8	113	23.2	125	13.1	28	25.9	266	67.19(6), <0.001	N/A
Tumour size
<20 mm	70.8	196	66.8	360	70.0	149	68.5	705
>20 mm	28.9	80	32.7	176	30.0	64	31.1	320	1.43(2), 0.49	0.89
Unknown	0.4	1	0.6	3	0	0	0.4	4
Tumour grade score
1	14.4	40	14.1	76	14.1	30	14.2	146
2	37.5	104	35.4	191	35.2	75	36.0	370
3	43.0	119	44.9	242	48.8	104	45.2	465	0.99(4), 0.91	0.45
Unknown	5.1	14	5.6	30	1.9	4	4.7	48
Number of involved nodes
0	58.1	161	51.6	278	58.2	124	54.7	563
1 to 3	25.6	71	28.4	153	28.6	61	27.7	285
>4	13.7	38	15.8	85	10.8	23	14.2	146	5.24(4), 0.26	0.67
Unknown	2.5	7	4.3	23	2.3	5	3.4	35
Obese in year prior to diagnosis
No	82.3	228	87.6	472	93.0	198	87.3	898
Yes	15.5	43	11.9	64	7.0	15	11.9	122	8.82(2), 0.01	0.03
Unknown	2.2	6	0.6	3	0	0	0.9	9
Years since last pregnancy
Nulliparous	18.4	51	23.4	126	29.6	63	23.3	240
<2 years	4.3	12	7.6	41	5.6	12	6.3	65
2-4 years	6.9	19	13.9	75	20.2	43	13.3	137
>5 years	70.4	195	55.1	297	44.6	95	57	587	40.91(6), <0.001	0.004

N/A indicates the test was not applicable. The χ² test statistic, associated degrees of freedom (df), and p-value are shown for the unadjusted tests. p-values for the age-adjusted test as also presented.

Note: a) Adjusted for age at diagnosis Individuals with missing data were excluded from all tests of association.