Table 3 The association between body mass index as a categorical variable and oesophageal pH adjusting for waist circumference as a continuous variable (n = 204, two outliers excluded).

	BMI 25.0–29.9 kg/m2			BMI <30 kg/m2
	PE	SE	p Value	PE	SE	p Value
Acid reflux episodes
Total	32.82	17.36	0.060	57.65	25.57	0.025
Postprandial	17.26	9.53	0.072	39.52	14.04	0.005
Upright	24.92	13.09	0.058	45.92	19.28	0.018
Supine	8.74	8.16	0.285	11.57	12.01	0.337
Long acid reflux episodes
Total	0.92	0.77	0.232	1.75	1.13	0.124
Postprandial	0.59	0.47	0.215	1.05	0.70	0.136
Upright	0.28	0.56	0.609	0.22	0.82	0.785
Supine	0.64	0.43	0.143	1.40	0.64	0.029
Time with pH >4
Total	31.85	19.38	0.102	52.87	28.55	0.066
Postprandial	15.38	10.17	0.132	31.08	14.98	0.039
Upright	15.98	11.28	0.158	21.64	16.62	0.194
Supine	16.58	12.36	0.181	31.14	18.20	0.089
% Time with pH >4 (%)
Total	2.36	1.45	0.103	3.88	2.13	0.070
Postprandial	2.88	2.28	0.208	4.67	3.36	0.167
Upright	1.80	1.38	0.194	2.61	2.03	0.200
Supine	2.51	2.22	0.259	2.76	3.27	0.400

BMI, body mass index; PE, parameter estimate.