Table 3.

Temporal evolution of mortality risk by study era

Era	No. of Studies	Participants	SMR	95% CI	I² (%)	τ²	Prediction Interval	Q (df), p-value (subgroup test)
1974–1987	3	6,802	3.95	2.88–5.41	65.1	0.184	1.87–8.37
1988–2003	6	41,203	2.76	2.31–3.29	48.3	0.077	1.90–4.01
2004–2019	5	41,242	2.18	1.85–2.57	31.2	0.041	1.63–2.92	Q = 12.7 (2), p = 0.002