“…Known confounders, such as BMI, smoking status, and diabetes, were often not controlled for or reported on in the studies. BMI was reported in 31 studies ( 7–9 , 11 , 12 , 25–35 , 40 , 42–44 , 46–49 , 53 , 56 , 57 , 59 , 60 , 63 ), smoking status was reported in 26 studies ( 8 , 9 , 12 , 25 , 27 , 29–32 , 34–36 , 40 , 42–44 , 46–50 , 54 , 59 , 60 , 63 , 64 ), and diabetes was reported in 10 studies ( 25 , 30 , 38 , 40 , 42 , 49 , 57 , 59 , 63 , 64 ).…”