Table 1.
Characteristics of Eligible Studies.
| Author year | Country | Study design | Age, year | DR diagnosis | DR definication | No. of case/control | Diabetes | Adjustment/matched | Exposure Definition |
|---|---|---|---|---|---|---|---|---|---|
| Yang JY 2013 | Korean | CS | ≥19 | Fundus examination | ETDRS | 112/866 | Mix | Age, gender, smoking status, regular exercise, BMI, Serum total cholesterol, Serum triglyceride, Serum HDL-cholesterol, Anti-lipid drug use | ≥4 alcoholic drinks/week, <3 drinks/week |
| Xu L 2009 | China | Cohort | ≥40 | Fundus photographs | NR | 366/3775 | General | BMI, high-density lipoprotein, low-density lipoprotein, arterial hypertension | Consumers, Non-consumers |
| Moss SE 1994 | USA | Cohort | ≥21 | Fundus photographs | ETDRS | 238/678 | Mix | Age, sex, glycosylated, hemoglobin, retinopathy | Average loz/day increase |
| Lee CC 2010 | Whole world | Cohort | 55–81 | Retinal photography | ETDRS | 640/599 | T2DM | age, sex, HbA1c, systolic blood pressure, duration of diabetes, BMI, cigarette smoking, ethnicity | 0, drinks ⁄week 1–14, drinks ⁄week >14 drinks ⁄week |
| Kohner EM 1998 | UK | CC | 25–65 | Retinal photography | ETDRS | 1102/1862 | T2DM | NR | None, occasional, regular, heavy |
| Hirai FE 2007 | USA | CS | 45.3 ± 9.9 | Retinal photography | ETDRS | 309/228 | T1DM | NR | Alcohol/No alcohol |
| Harjutsalo V 2014 | Finnish | CS | 28.9–46.8 | Retinal photography | NR | 1191/2417 | T1DM | None | Heavy drinker light drinker |
| Fenwick EK 2015 | Australia | CS | ≥18 | Fundus photography | ETDRS | 235/160 | T2DM | Education, income, language spoken at home, country of birth, lipid-lowering medication, hypertension medication | None, moderate, high |
| Young RJ 1984 | UK | Cohort | 20–59 | Fundoscopic | Four Grades | 230/62 | Mix | NR | ≤10 measures/week, >10 measures/week |
| Beulens JW 2008 | European | CS | 15–60 | Retinal photographs | Three grades | 304/2946 | T1DM | Age, sex, centre, duration of illness, systolic BP, physical activity, smoking, BMI, presence of cardiovascular disease and HbA | 0 g/week, 0.0–4.9 g/week, 5.0–29.9 g/week, 30.0–69.9 g/week, 70.0–209.9 g/week, ≥210 g/week |
| Rasmidatta S 1998 | Thailand | CC | 60.5 ± 7.4 | Fundoscopic examinations | Three grades | 63/135 | T2DM | Glycosylated hemoglobin (%), cholesterol (mg/dL), triglyceride (mg/dL), HDL (mg/dL), BP (mmHg) | Nondrinker, drinker, not regular drinker |
| Jongsareejit A 2013 | Thailand | CS | 59.5 | Indirect ophthalmoscope | International scalesa | 214/719 | type 2 | Gender, age, diastolic BP, waist, total cholesterol HDL, ccular perfusion pressure | No, ever, current |
| Martín-Merino E 2016 | UK | CC | NR | Computerized records | NR | 7735/9395 | T2DM | Sex; age at index date; diabetes duration; primary care practitioner visits; referrals and hospitalizations; smoking; alcohol consumption; first HbA1c; systolic blood pressure; glaucoma; cataracts, or lens extraction; high-density lipoprotein and triglycerides; and hypoglycaemic agents, including oral hypoglycaemic drugs and insulin | 0–1 units/week 2–21 units/week 22–34 units/week ≥35 units/week |
| Giuffrè G 2004 | Italy | CC | ≥40 | Fundus examination | ETDRS | 45/86 | Mix | NR | None 1–19 years 20 years or more |
| Tseng ST 2015 | China | Cohort | 58.9 | Funduscopic | Three grades | 91/482 | T2DM | NR | Drinker no-drinker |
NR: not reported; CC: case-control study; CS: cross-sectional study; T1DM: type 1 diabetes mellitus; T2DM: type 1 diabetes mellitus; HDL: high-density lipoprotein; BMI: body mass index; BP: blood pressure; ETDRS: Early Treatment Diabetic Retinopathy Study.
aInternational clinical diabetic retinopathy and diabetic macular edema disease severity scales.