| No. | Name of Lifestyle | Third Class | Second Class | First Class | Type | No. of Studies |
|---|---|---|---|---|---|---|
| 1 | Serum β-carotene+Family history | β-carotene+Family medical history | Vitamin A+Family medical history | Joint effect | Risk factor No statistical significance factor | 1 |
| 2 | β-carotene+Family history | β-carotene+Family medical history | Vitamin A+Family medical history | Joint effect | Risk factor | 1 |