Table 2. EMBASE search strategy.
| No. | Search strategy1 |
| 1 | exp tobacco/ OR exp smoking/ |
| 2 | (smok* OR tobacco OR cigarette OR nicotiana* OR lifestyle*).mp |
| 3 | 1 OR 2 |
| 4 | Exp dry eye/ OR exp xerophthalmia/ OR exp meibomian gland/ |
| 5 | (Dry eye* OR xerophthalmi* OR meibomian gland dysfunction OR MGD).mp |
| 6 | 4 OR 5 |
| 7 | Exp case control study/ OR exp cohort analysis/ OR exp cross-sectional study/ |
| 8 | (Case control OR case comparison OR case compeer OR case referrent* OR case base OR retrospective stud* OR cohort OR concurrent stud* OR incidence OR longitudinal stud* OR follow up OR prospective stud* OR cross sectional OR disease frequency OR prevalence).mp |
| 9 | 7 OR 8 |
| 10 | 3 AND 6 AND 9 |
1Database: EMBASE (OvidSP) (1974 to 2015 December).