Table 1. Main characteristics of studies included in the review.
| Author (year) | Country of origin | Children*, adults or both | Gender | n, cases | n, total | Type of control | Method of vitamin E determination | Subsets of vitamin E | Skin disease | Method of Skin diseases determination | Matching or adjustment factors |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Oh et al., 2010 [17] | Korea | Young children | Patients: 54.7% boys, 45.3% girls; Control: 50.8% boys, 49.2% girls | 180 | 422 | Non- atopic Dermatitis | HPLC | alpha tocopherol | Atopic Dermatitis | SCORAD | Gender, Age |
| Sivaranjani et al., 2013 [32] | India | An average age of 35 years (10–60 years) | NA | 25 | 50 | Healthy controls of same age group | Spectrophotometry | alpha tocopherol | NA | Age | |
| Daniluk et al., 2019 [16] | Poland | Children aged from 1 to 15 years | Patients: 41.4% boys, 58.6% girls; Control: 63.6% boys, 36.4% girls | 29 | 51 | Healthy controls with negative history of allergy | HPLC | alpha tocopherol | SCORAD | Age | |
| Hozyasz et al., 2004 [25] | Poland | Children with DA (age: 1–9 years). | NA | 25 | 43 | Healthy controls | HPLC | alpha tocopherol | Clinically diagnosed | Age | |
| Ines et al.,2006 [18] | Tunisia | 18–66 years old | Patients: 38.9% male, 61.1% female; Control: 37.5% male, 62.5% female | 36 | 76 | Healthy controls | HPLC | NA | Vitiligo | Clinically diagnosed | Age |
| Khan et al., 2009 [19] | India | 22–41 years old aldult | Patients: 23.3% male, 76.7% female; Control: matched | 30 | 60 | Healthy controls | Fluorometery | alpha tocopherol | Clinically diagnosed | Gender, Age | |
| Agrawal et al., 2014 [22] | Nepal | <15 years old | Patients: 48% male, 52% female; Control: 45% male, 55% female | 80 | 160 | Healthy controls | Spectrophotometric assay | alpha tocopherol | Clinically diagnosed | Age | |
| Jain et al., 2008 [26] | India | 11–20 years old | Patients: 50% male, 50% female; Control: 50% male, 50% female | 40 | 80 | Healthy controls | Rapid determination of vitamin E | NA | Clinically diagnosed | Gender, age | |
| Dell’Anna et al., 2001 [23] | Italy | 18–53 years old | Patients: 50% male, 50% female; Control: 50% male, 50% female | 40 | 80 | Healthy controls | Gas Chromatography Mass Spectrometry (GC-MS) | NA | Clinically diagnosed | Gender, age | |
| Agrawal et al., 2004 [22] | India | 5–45 years old | Patients: 37.5% male, 62.5% female; Control: 37.5% male, 62.5% female | 63 | 123 | Healthy controls | Spectrophotometry | NA | Clinically diagnosed | Age | |
| Picardo et al., 1994 [29] | Italy | 19–45 years old | Patients: 40.3% male, 59.7% female; Control: 40.3% male, 59.7% female | 62 | 122 | Healthy controls | GC-MS | alpha tocopherol | Clinically diagnosed | Age | |
| Kökçam et al., 1999 [28] | Turkey | 9 to 76 years old | Patients: 58.8% male, 41.2% female; Control: matched | 34 | 68 | Healthy controls | HPLC | alpha tocopherol | Psoriasis | Clinically diagnosed | Gender, age |
| Pereira et al., 2004 [21] | Portugal | Patients:47.4 ± 13.3 years old;Control:45.9 ± 12.2 years old | Patients: 57% male, 43% female; Control: 55% male, 45% female | 70 | 110 | Healthy controls | HPLC | alpha tocopherol | Clinically diagnosed | Gender, age, BMI | |
| Jain, et al., 1988 [27] | India | Both sexes from various age groups | Both sexes | 20 | 40 | Healthy controls | By method of Baker and Frank | NA | Clinically diagnosed | Gender, age | |
| Demir et al., 2013 [24] | Turkey | Patients:39.23 ± 15.32 years old; control: 38.46 ± 10.32 years old | Patients: 32.3% male, 67.7% female; Control: 35.1% male, 64.9% female | 31 | 68 | Healthy controls | HPLC | alpha tocopherol | Biopsy-proven diagnosed | Gender, age | |
| Pujari et al., 2014 [30] | India | Aged 20–60 years | NA | 90 | 180 | Healthy controls | α-α dipyridyl antioxidant assay | NA | Clinical diagnosed | Gender, age | |
| Severin et al., 1999 [31] | Germany | NA | NA | 33 | 69 | Healthy controls | HPLC | alpha tocopherol | Clinical diagnosed | NA | |
| El-akawi et al., 2006 [35] | Jordan | Patients: 21.0 ± 5.4 years old; controls: 21.3 ± 5.3 years old | NA | 100 | 200 | Healthy controls | HPLC | NA | Acne | GAGS | Age |
| Ozuguz et al., 2013 [33] | Turkey | Patients: 28.54±8.30 years old | Patients: 35.1% male, 64.9% female; Control: 21.4% male, 78.6% female | 94 | 150 | Healthy controls | HPLC | alpha tocopherol | Clinical diagnosed | Gender, age | |
| Tunçez Akyürek | Turkey | Patients:18.67 ± 3.36 years old; controls: 19.7 ± 2.49 years old | NA | 90 | 120 | Healthy controls | HPLC | alpha tocopherol | GAGS | NA |
*Children defined as <18 years of age.
HPLC: High-performance liquid chromatography.
SCORAD: Scoring Atopic Dermatitis index.
GAGS: Global Acne Grading System.