Table 2.

The association between grand-paternal and grand- maternal age and risk of schizophrenia

Grandparent age (years)	Count of cases	%	Count of controls	%	Adjusted Odds Ratio	Lower 95% CI	Upper 95% CI
Maternal GF age
<20	31	1.23	188	1.20	1.06	0.71	1.59
20–24	327	13.02	2124	13.60	Reference
25–29	628	25.01	4277	27.38	0.96	0.83	1.12
30–34	618	24.61	4088	26.17	1.00	0.85	1.19
35–39	454	18.08	2786	17.84	1.09	0.90	1.32
40–44	265	10.55	1353	8.66	1.33	1.07	1.66
45–49	115	4.58	550	3.52	1.47	1.12	1.94
50–54	46	1.83	186	1.19	1.76	1.21	2.58
≥ 55	27	1.08	67	0.43	2.79	1.71	4.56
Maternal GM age
<20	155	6.17	970	6.21	1.06	0.86	1.29
20–24	628	25.01	4166	26.67	Reference
25–29	700	27.88	4499	28.80	1.01	0.89	1.15
30–34	551	21.94	3408	21.82	0.97	0.84	1.13
35–39	346	13.78	1859	11.90	1.00	0.83	1.20
40–44	118	4.70	670	4.29	0.83	0.64	1.08
≥ 45	13	0.52	47	0.30	1.12	0.58	2.15
Paternal GF age
<20	27	1.08	132	0.85	1.19	0.77	1.84
20–24	334	13.30	1964	12.57	Reference
25–29	655	26.09	4219	27.01	0.90	0.78	1.05
30–34	699	27.84	4169	26.69	0.96	0.82	1.14
35–39	412	16.41	2787	17.84	0.86	0.71	1.04
40–44	247	9.84	1521	9.74	0.91	0.73	1.14
45–49	84	3.35	566	3.62	0.80	0.59	1.08
50–54	35	1.39	189	1.21	0.99	0.65	1.49
≥ 55	18	0.72	72	0.46	1.40	0.80	2.44
Paternal GM age
<20	142	5.66	814	5.21	1.06	0.86	1.30
20–24	624	24.85	3987	25.53	Reference
25–29	760	30.27	4596	29.43	1.07	0.95	1.22
30–34	552	21.98	3507	22.45	1.04	0.90	1.21
35–39	295	11.75	2020	12.93	0.99	0.82	1.19
40–44	132	5.26	655	4.19	1.36	1.06	1.76
≥ 45	6	0.24	40	0.26	0.94	0.39	2.30

^*Adjusted for age of spouse, birth year and sex of proband

GM -= grandmother; GF = grandfather. Significant results shown in bold