Table 1.
Characteristics of the individual studies included in this meta-analysis.
| Reference | Location | Age years | Gender | Sample Size | Study design | Adjustments | Exposure assessment | Category of exposure | Effect Estimates (RR or SMD) | Diagnostic criteria of MetS | NOS |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Ford (17) | US | >20 | Both | 8,808 | Cross-sectional | NA | FFQ and HPLC | Control subjects MetS subjects Control subjects MetS subjects |
Dietary vitamin E 9.9 (9.5, 10.3) 9.4 (8.8, 10.0) Circulating vitamin E 25.9 (25.5, 26.4) 30.1 (29.2, 30.9) |
NCEP ATP III | 8 |
| Kim (18) | Korea | >60 | Both | 404 | Cross-sectional | Age, BMI, energy intake, smoking status, alcohol, physical activity, vitamin, and mineral supplements | 24 h recall and HPLC | Male Control subjects MetS subjects |
Dietary vitamin E 8.6 (7.0, 10.2) 7.0 (5.6, 8.4) |
NCEP ATP III | 7 |
| Female Control subjects MetS subjects |
Dietary vitamin E 8.6 (7.6, 9.6) 6.7 (5.9, 7.5) |
||||||||||
| Dietary vitamin E Male Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 0.71 (0.25, 2.1) 0.94 (0.33, 2.67) 0.54 (0.18, 1.62) |
||||||||||
| Female Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 1.0 (0.52, 1.93) 0.52 (0.43, 1.58) 0.50 (0.26, 0.98) |
||||||||||
| Control subjects MetS subjects |
Circulating vitamin E 11.7 (10.5, 12.9) 10.8 (10.0, 11.6) |
||||||||||
| Circulating vitamin E Male Tertiles 1 Tertiles 2 Tertiles 3 |
RR 1.0 1.3 (0.2, 7.3) 3.5 (0.7, 17.7) |
||||||||||
| Female Tertiles 1 Tertiles 2 Tertiles 3 |
RR 1.0 1.1 (0.5, 2.9) 0.8 (0.3, 1.9) |
||||||||||
| Kim (19) | Korea | Middle-aged | Both | 688 | Cross-sectional | NA | FFQ | Male Control subjects MetS subjects |
Dietary vitamin E 7.9 (7.5, 8.3) 7.7 (7.3, 8.2) |
NCEP ATP III | 6 |
| Female Control subjects MetS subjects |
Dietary vitamin E 8.7 (8.1, 9.3) 8.1 (7.6, 8.6) |
||||||||||
| Czernichow (20) | France | 49 | Both | 5,520 | Cohort | Age, sex, intervention group, educational level, smoking status, physical activity and alcohol consumption | HPLC | Circulating vitamin E Tertiles 1 Tertiles 2 Tertiles 3 |
RR 1.0 0.94 (0.64, 1.38) 1.02 (0.70, 1.49) |
NCEP ATP III | 9 |
| Cho (21) | Korea | >20 | Male | 163 | Cross-sectional | NA | HPLC | Control subjects MetS subjects |
Circulating vitamin E 1,153.3 (1,100.7, 1,206.0) 1,315.7 (1,148.8, 1,482.5) |
NCEP ATP III | 6 |
| Bruscate (22) | Brazil | 69.3 | Female | 284 | Cross-sectional | Age, smoking, education, physical activity and dietary fiber | 24 h recall | Control subjects MetS subjects |
Dietary vitamin E 17.8 (16.7, 18.9) 17.4 (15.7, 19.1) |
IDF | 7 |
| Dietary vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 0.52 (0.25, 1.08) 0.65 (0.32, 1.33) 0.70 (0.34, 1.42) |
||||||||||
| Beydoun (23) | US | 20–85 | Both | 3,202 | Cross-sectional | Age, sex, race/ethnicity, marital status, educational level, PIR, smoking status, total energy intake, alcohol, caffeine, b-carotene, vitamin C, vitamin E, and dietary supplement use, serum levels of folate, tHcy, vitamin B12, 25(OH)D, total cholesterol, and TG | 24 h recall and HPLC | Male Control subjects MetS subjects |
Dietary vitamin E 8.2 (7.8, 8.6) 8.0 (7.6, 8.4) |
NCEP ATP III | 8 |
| Female Control subjects MetS subjects |
Dietary vitamin E 6.6 (6.4, 6.8) 6.1 (5.7, 6.5) |
||||||||||
| Male Control subjects MetS subjects |
Circulating vitamin E 28.5 (27.5, 29.5) 33.8 (32.0, 35.6) |
||||||||||
| Female Control subjects MetS subjects |
Circulating vitamin E 28.2 (27.2, 29.2) 35.3 (33.5, 37.1) |
||||||||||
| Circulating vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 0.79 (0.41, 1.52) 1.54 (0.84, 2.84) 1.09 (0.44, 2.67) |
||||||||||
| Kouki (24) | Finland | 57–78 | Both | 1,334 | Cross-sectional | Age, alcohol consumption, smoking, education and VO2 max | 4-day food record | Male Control subjects MetS subjects |
Dietary vitamin E 11.1 (10.6, 11.6) 9.9 (9.0, 10.8) |
NCEP ATP III | 8 |
| Female Control subjects MetS subjects |
Dietary vitamin E 9.8 (9.2, 10.4) 9.5 (8.6, 10.4) |
||||||||||
| Dietary vitamin E Male <10 mg/d >10 mg/d |
RR 1.0 0.99 (0.96, 1.03) |
||||||||||
| Female <10 mg/d >10 mg/d |
RR 1.0 1.01 (0.98, 1.05) |
||||||||||
| Beydoun (25) | US | 12–19 | Both | 1,339 | Cross-sectional | NA | 24 h recall and HPLC | Control subjects MetS subjects |
Dietary vitamin E 6.4 (6.2, 6.6) 5.9 (4.3, 7.5) |
IDF | 7 |
| Control subjects MetS subjects |
Circulating vitamin E 18.6 (18.2, 19.0) 20.2 (18.0, 22.4) |
||||||||||
| de Oliveira Otto (26) | US | 45–84 | Both | 3,828 | Cohort | Energy intake, age, sex, race-ethnicity, education, study center, alcohol intake, physical activity, BMI, fiber intake, cigarette smoking, dietary supplement use, the ratio of polyunsaturated fat intake and saturated fat intake, Mg, Zn, heme iron, non-heme iron, and antioxidant intake | FFQ | Dietary vitamin E Quintiles 1 Quintiles 2 Quintiles 3 Quintiles 4 Quintiles 5 |
RR 1.0 1.00 (0.79, 1.26) 1.03 (0.81, 1.31) 0.84 (0.65, 1.09) 0.76 (0.56, 1.03) |
AHA | 8 |
| Odum (27) | Nigeria | 50 | Both | 192 | Case-control | NA | HPLC | Control subjects MetS subjects |
Circulating vitamin E 30.8 (29.6, 32.0) 16.9 (15.9, 17.9) |
NCEP ATP III | 7 |
| Al-Daghri (28) | Saudi Arabia | 19–60 | Both | 185 | Cross-sectional | Age, BMI and physical activity | 24 h recall | Control subjects MetS subjects |
Dietary vitamin E 2.3 (2.1, 2.5) 2.0 (1.8, 2.2) |
IDF | 7 |
| Dietary vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 0.20 (0.07, 0.60) 0.14 (0.05, 0.40) 0.17 (0.06, 0.51) |
||||||||||
| Motamed (31) | Iran | 35–65 | Both | 3,800 | Cross-sectional | Sex, age, physical activity level, smoking, past medical history, energy intake, and BMI | 24 h recall | Male Control subjects MetS subjects |
Dietary vitamin E 14.8 (14.2, 15.4) 16.6 (15.9, 17.3) |
IDF | 7 |
| Female Control subjects MetS subjects |
Dietary vitamin E 14.7 (14.3, 15.1) 13.8 (13.4, 14.2) |
||||||||||
| Dietary vitamin E Quintiles 1 Quintiles 2 Quintiles 3 Quintiles 4 Quintiles 5 |
RR 1.0 0.96 (0.70, 1.10) 0.86 (0.60, 1.00) 1.06 (0.80, 1.30) 0.90 (0.70, 1.10) |
||||||||||
| Bian (29) | China | 30–70 | Both | 258 | Cross-sectional | NA | 24 h recall | Control subjects MetS subjects |
Dietary vitamin E 29.9 (28.4, 31.4) 27.5 (25.9, 29.1) |
NCEP ATP III | 8 |
| Li (30) | China | 18–65 | Both | 550 | Cross-sectional | Age and sex | 3-day food record and HPLC | Control subjects MetS subjects |
Dietary vitamin E 45.7 (43.2, 48.2) 45.1 (42.1, 48.1) |
NCEP ATP III | 8 |
| Dietary vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 Control subjects |
RR 1.0 0.65 (0.37,1.04) 0.85 (0.51–1.41) 0.62 (0.37–1.04) Circulating vitamin |
||||||||||
| MetS subjects | E 12.1 (11.7, 12.5) 12.9 (12.2, 13.6) |
||||||||||
| Circulating vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 0.44 (0.15,1.25) 0.88 (0.32–2.44) 1.58 (0.55–4.54) |
||||||||||
| Mah (32) | US | 24–40 | Both | 20 | Case-control | NA | HPLC | Control subjects MetS subjects |
Circulating vitamin E 22.2 (19.5, 24.9) 23.9 (21.9, 25.9) |
JIS | 5 |
| Wei (33) | China | 18–84 | Both | 2,069 | Cross-sectional | Age, sex, cigarette smoking, alcohol, drinking, nutritional supplementary, activity level, dietary energy intake, fiber intake and protein intake | FFQ | Control subjects MetS subjects |
Dietary vitamin E 29.8 (29.1, 30.6) 30.7 (28.8, 32.6) |
AHA | 7 |
| Dietary vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 1.07 (0.77, 1.50) 0.98 (0.67, 1.41) 1.20 (0.77, 1.87) |
||||||||||
| Godala (34) | Poland | 30–65 | Both | 273 | Case-control | NA | 3-day food record and spectrophotometric method | Control subjects MetS subjects |
Dietary vitamin E 9.33 (8.27, 10.39) 8.85 (8.03, 9.67) |
IDF | 7 |
| Control subjects MetS subjects |
Circulating vitamin E 25.49 (24.86, 26.12) 12.47 (12.08, 12.86) |
||||||||||
| Lim (36) | Korea | Middle-aged | Both | 143 | Cross-sectional | Not mentioned | 3-day food record | Control subjects MetS subjects |
Dietary vitamin E 12.6 (11.5, 13.7) 12.7 (11.3, 14.1) |
NCEP ATP III | 6 |
| Ahn (35) | Korea | 30–60 | Both | 614 | Cross-sectional | Age, smoking, alcohol consumption and physical activity | 3-day food record | Male Control subjects MetS subjects |
Dietary vitamin E 3.5 (3.3, 3.7) 3.3 (3.2, 3.4) |
NCEP ATP III | 7 |
| Female Control subjects MetS subjects |
Dietary vitamin E 3.5 (3.3, 3.7) 3.8 (3.5, 4.1) |
||||||||||
| ‘Dietary vitamin E Male Tertile 1 Tertile 2 Tertile 3 |
RR 1.0 1.00 (0.56, 1.76) 0.52 (0.30, 0.92) |
||||||||||
| Female Tertile 1 Tertile 2 Tertile 3 |
RR 1.0 1.16 (0.65, 2.09) 1.70 (0.94, 3.08) |
||||||||||
| Ahn (37) | Korea | 19–64 | Both | 10,351 | Cross-sectional | Age, BMI, alcohol consumption, smoking, physical activity, household income, education level and energy intake | 24 h recall | Dietary vitamin E Male Tertile 1 Tertile 2 Tertile 3 |
RR 1.0 0.88 (0.71, 1.11) 0.76 (0.60, 0.96) |
NCEP ATP III | 8 |
| Female Tertile 1 Tertile 2 Tertile 3 |
RR 1.0 0.87 (0.67, 1.14) 1.02 (0.79, 1.31) |
||||||||||
| Godala (38) | Poland | 57 | Both | 332 | Cross-sectional | NA | 24 h recall and HPLC | Control subjects MetS subjects |
Dietary vitamin E 9.31 (8.26, 10.35) 9.01 (8.37, 9.66) |
IDF | 7 |
| Control subjects MetS subjects |
Circulating vitamin E 23.67 (22.88, 24.46) 14.22 (13.93, 14.51) |
||||||||||
| Kim (39) | Korea | 47.1 | Both | 5,885 | Cross-sectional | Age, sex, residence, household income, education, alcohol consumption, smoking status, physical activity, hs-CRP and BMI | HPLC | Circulating vitamin E Quartiles 1 Quartiles 2 Quartiles 3 Quartiles 4 |
RR 1.0 1.30 (0.97, 1.74) 1.71 (1.30, 2.25) 2.56 (1.95, 3.35) |
NCEP ATP III | 9 |
| Peng (40) | China | >99 | Both | 992 | Cohort | Aex, marital status, physical activity, smoking status, alcohol intake, family history of chronic diseases and daily total energy intake | 24 h recall | Control subjects MetS subjects |
Dietary vitamin E 17.74 (10.45, 25.03) 12.18 (9.00, 15.36) |
NCEP ATP III | 7 |
| Zaeemzadeh (41) | Iran | 30 | Both | 42 | Case-control | NA | FFQ | Control subjects MetS subjects |
Dietary vitamin E 17.21 (14.49, 19.93) 6.17 (2.01, 10.33) |
NCEP ATP III | 6 |