Table 2

Cox proportional HRs for risk of PTSD in veterans by age at recruitment, overall and by birth cohort, compared with all matched non-veterans

Age at entry (years)	≤17			18–19			≥20
Age at entry (years)	HR	95% CI	P value	HR	95% CI	P value	HR	95% CI	P value
Birth cohort
Overall	1.84	1.64 to 2.07	<0.001	2.17	1.93 to 2.43	<0.001	2.35	2.03 to 2.73	<0.001
1945–1949	1.43	0.94 to 2.18	0.096	1.92	1.32 to 2.78	0.001	2.40	1.66 to 3.48	<0.001
1950–1954	1.59	1.16 to 2.19	0.004	2.14	1.60 to 2.85	<0.001	1.98	1.40 to 2.78	<0.001
1955–1959	1.83	1.41 to 2.38	<0.001	1.54	1.09 to 2.15	0.013	3.15	2.31 to 4.29	<0.001
1960–1964	1.59	1.22 to 2.08	0.001	1.74	1.29 to 2.34	<0.001	1.26	0.84 to 1.88	0.268
1965–1969	1.26	0.82 to 1.94	0.294	1.87	1.33 to 2.62	<0.001	2.07	1.50 to 2.87	<0.001
1970–1974	2.10	1.29 to 3.43	0.003	2.42	1.63 to 3.61	<0.001	1.91	1.16 to 3.16	0.012
1975–1984	2.95	1.24 to 7.04	0.015	2.17	0.91 to 5.24	0.082	2.80	1.22 to 6.42	0.015

1985–1995 cohort: insufficient numbers.