[1] Kazan State Med Univ, Cent Res Lab, Kazan, Russia
[2] Kazan State Med Univ, Epidemiol & Evidence Based Med Dept, Kazan, Russia
[3] Univ Bristol, MRC Integrat Epidemiol Unit, Bristol, Avon, England
[4] Univ Bristol Sch Med, Populat Hlth Sci, Bristol, Avon, England
[5] Cardiff Univ, Sch Optometry & Vis Sci, Cardiff, Wales