Table 1 Associations between several anthropometric measurements treated as continuous variables and several parameters of oesophageal acid exposure measured at the distal probe.

	BMI			Waist circumference
	PE*	SE	p Value	PE*	SE	p Value
Acid reflux episodes
Total	4.07	1.35	0.003	1.23	0.53	0.022
Postprandial	2.76	0.69	<0.001	0.85	0.28	0.002
Upright	2.76	1.00	0.006	0.76	0.39	0.055
Supine	1.29	0.56	0.023	0.45	0.22	0.042
Long acid reflux episodes
Total	0.08	0.05	0.121	0.03	0.02	0.185
Postprandial	0.06	0.03	0.050	0.02	0.01	0.074
Upright	0.04	0.03	0.287	0.01	0.01	0.337
Supine	0.04	0.03	0.229	0.01	0.01	0.306
Time with pH <4 (min)
Total	3.02	1.37	0.028	1.08	0.54	0.046
Postprandial	1.89	0.68	0.006	0.61	0.27	0.022
Upright	1.40	0.73	0.056	0.44	0.29	0.127
Supine	1.59	0.89	0.074	0.63	0.35	0.074
% Time with pH <4 (%)
Total	0.23	0.10	0.024	0.08	0.04	0.039
Postprandial	0.38	0.15	0.015	0.14	0.06	0.020
Upright	0.26	0.09	0.006	0.09	0.04	0.020
Supine	0.23	0.15	0.123	0.11	0.06	0.057

BMI, body mass index; PE, parameter estimate.

Results of unadjusted linear regression models.

*The magnitude of change in the outcome variable (eg, total reflux episodes) in response to one unit change in the predictor variable (eg, 1 kg of weight).