Table 3 Odds ratio and 95% confidence interval for GERD in the multivariate ordinal logistic regression (N = 2368)

 29≥

Ref

Ref

Ref

 30–39

1.02(0.83–1.25)

1.02(0.83–1.26)

1.05(0.85–1.30)

 40≤

1.04(0.76–1.42)

1.06(0.77–1.45)

1.17(0.85–1.61)

 3-year college

Ref

Ref

Ref

 4-year college

0.92(0.77–1.09)

0.93(0.77–1.11)

.93(0.78–1.12)

 Master’s degree or higher

0.88(0.63–1.23)

0.90(0.65–1.26)

.91(0.65–1.27)

 Single

Ref

Ref

Ref

 Married

0.99(0.80–1.22)

0.98(0.79–1.22)

1.04(0.84–1.30)

 Divorced or widowed

0.96(0.37–2.50)

1.03(0.39–2.69)

1.05(0.40–2.76)

 20,000≥

Ref

Ref

Ref

 20,000–29,999

0.69(0.41–1.19)

0.70(0.41–1.21)

0.76(0.44–1.31)

 30,000–39,999

0.70(0.41–1.21)

0.71(0.41–1.22)

0.76(0.44–1.32)

 40,000–49,999

0.63(0.35–1.12)

0.63(0.35–1.12)

0.68(0.38–1.23)

 50,000≤

0.71(0.38–1.32)

0.72(0.38–1.34)

0.79(0.42–1.48)

 No

Ref

Ref

Ref

 Yes

0.92(0.76–1.11)

0.92(0.76–1.11)

0.87(0.72–1.06)

 Non-smoker

Ref

Ref

 Former smoker

1.93^*(1.12–3.35)

1.89^* (1.08–3.28)

 Current smoker

2.31 (0.94–5.66)

2.01(0.82–4.98)

 Non-drinker

Ref

Ref

 Below 1/month

1.11(0.84–1.48)

1.11(0.84–1.48)

 2–4/month

1.23(0.91–1.66)

1.25(0.92–1.69)

 Over 2/week

1.11(0.78–1.58)

1.11(0.78–1.58)

 Normal

Ref

Ref

 Underweight

1.38^**(1.10–1.73)

1.38^**(1.10–1.74)

 Overweight

1.31^*(1.06–1.64)

1.32^*(1.06–1.64)

 Minimal

Ref

 Mild

1.33^**(1.08–1.63)

 Moderate

1.67^**(1.28–2.17)

 Moderately severe

1.97^**(1.39–2.80)

 Severe

1.97^**(1.19–3.26)

Stress

1.01(0.97–1.05)

Nagelkerke R²

0.003

0.016

0.033

χ²/df

1.597/8

10.229/8

6.802/8