Table 3

Logistic regression analysis of the association between dry eye symptom prevalence and demographic and clinical variables before and after adjustment for confounding factors

 CrudeModel 1
OR95% CIOR95% CI
Age (years) (continuous)1.001(0.993 to 1.008)0.964(0.874 to 1.064)
 <30referencereference
 30–390.831(0.617 to 1.119)0.798(0.589 to 1.079)
 40–490.876(0.654 to 1.173)0.809(0.588 to 1.113)
 50–590.904(0.649 to 1.260)0.811(0.547 to 1.201)
 60–691.092(0.799 to 1.493)0.923(0.608 to 1.402)
 ≥702.032(1.155 to 3.576)1.570(0.767 to 3.210)
Gender
 Menreferencereference
 Women2.502(2.005 to 3.124)2.378(1.676 to 3.372)
Education status (years)
 <6referencereference
 6–90.564(0.361 to 0.881)0.720(0.415 to 1.169)
 10–120.645(0.463 to 0.900)0.824(0.538 to 1.263)
 >120.629(0.489 to 0.942)0.862(0.554 to 1.340)
Household income
 1Qreferencereference
 2Q0.695(0.483 to 1.002)0.800(0.530 to 1.207)
 3Q0.733(0.507 to 1.060)0.879(0.577 to 1.337)
 4Q0.841(0.579 to 1.223)0.956(0.625 to 1.463)
Smoking status
 Non-smokerreferencereference
 Ex-smoker0.698(0.532 to 0.915)1.124(0.797 to 1.585)
 Current smoker0.527(0.400 to 0.694)0.900(0.622 to 1.304)
Heavy alcohol drinking
 Noreferencereference
 Yes0.564(0.414 to 0.768)0.945(0.643 to 1.391)
Sleep time (h)
 ≥6referencereference
 <61.338(0.978 to 1.831)1.141(0.815 to 1.597)
Perceived stress status
 Noreferencereference
 Yes1.357(1.071 to 1.719)1.330(1.046 to 1.692)
Cholesterol (mg/dL)
 <240referencereference
 ≥2401.129(0.836 to 1.524)1.055(0.768 to 1.450)
Atopy history
 Noreferencereference
 Yes0.848(0.457 to 1.574)0.777(0.415 to 1.453)
Anaemia
 Noreferencereference
 Yes1.215(0.830 to 1.778)0.803(0.430 to 1.499)
Blood mercury levels
 <Medianreferencereference
 ≥Median1.303(1.056 to 1.607)1.324(1.059 to 1.655)
  • Italics indicate that the variable was inserted in the survey logistic regression as a continuous variable.

  • The data from Model 1 are after adjusting for age, gender, education, total household income, smoking status, heavy alcohol status, sleep time, perceived stress status, cholesterol levels and atopy history.

  • Anaemia was defined as follows; for males with a haemoglobin level <13 g/dL, pregnant females with a haemoglobin level <11 g/dL, and non-pregnant females with a haemoglobin level <12 g/dL.

  • The median cut-off levels that discriminated between participants with ‘low’ and ‘high’ blood mercury levels were 4.26 and 2.89 µg/L for males and females, respectively.