Table 3. Results of the leave-one-out analysis.

Study left out (first author, year of publication)	RR	95% confidence interval
Correia et al., 2013 (18)	1.0097	[0.9940; 1.0258]
Frerichs et al.,1980 (20– 22)	1.0152	[0.9994; 1.0313]
Gan et al., 2012 (23)	1.0130	[0.9957; 1.0306]
Hansell et al., 2013 (4)	1.0118	[0.9968; 1.0270]
Héritier et al., 2017 (2, 5)	1.0137	[0.9901; 1.0378]
HYENA study (3, 24– 31, e14)	1.0130	[0.9975; 1.0288]
NORAH study on health risks (32, 33)	1.0165	[1.0007; 1.0324]

RR: risk ratio