Table 3.

Quality assessment

Author	Selection bias	Study design	Confounders	Blinding	Data collection methods	Withdrawals and drop-outs	Global rating
Buurman et al24	Moderate	Strong	Strong	Strong	Strong	Weak	Moderate
Chow et al22	Moderate	Strong	Strong	Moderate	Strong	Strong	Strong
Courtney et al25	Moderate	Strong	Strong	Moderate	Strong	Moderate	Strong
Finlayson et al23	Weak	Strong	Strong	Weak	Weak	Moderate	Weak
Koehler et al26	Weak	Strong	Strong	Weak	Strong	Weak	Weak
Lin et al31	Strong	Moderate	Weak	Weak	Weak	Strong	Weak
Nielsen et al28	Strong	Strong	Strong	Weak	Strong	Weak	Weak
Robinson et al32	Strong	Moderate	Strong	Weak	Strong	Strong	Moderate
Rottman-Sagebiel et al29	Weak	Strong	Strong	Weak	Weak	Weak	Weak
Sahota et al27	Strong	Strong	Strong	Weak	Strong	Moderate	Moderate
Voss et al30	Weak	Strong	Strong	Weak	Strong	Weak	Weak