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Table 2 Predictors of irritable bowel syndrome (IBS)

From: Prevalence and predictors of irritable bowel syndrome in patients with morbid obesity: a cross-sectional study

    Adjusted for center only Adjusted for all significant predictors
  Patients without IBS Patients with IBS Odds ratio (95% CI) p-value Odds ratio (95% CI) p-value
Gender (%male) 84 (28%) 6 (11%) 0.35 (0.14–0.87) 0.02 0.57 (0.18–1.82) 0.34
Age (years) 44 (21–61) 41 (23–61) 0.97 (0.94–1.00) 0.07   
Body mass index (kg/m2) 42 (33–62) 42 (36–53) 0.98 (0.92–1.06) 0.64   
Ethnicity (% Caucasian) 281/296 (95%) 53/54 (98%) 1.34 (0.17–10.82) 0.51   
Smoking 68/291 (23%) 12/52 (23%) 1.24 (0.60–2.59) 0.56   
Diabetes mellitus 72/296 (24%) 7/54 (13%) 0.51 (0.22–1.20) 0.12   
Hypothyroidism 29/296 (10%) 7/53 (13%) 1.27 (0.51–3.16) 0.61   
Fibromyalgia 33/295 (11%) 12/54 (22%) 1.86 (0.86–4.00) 0.12   
Self-reported psychiatric disorder 47/296 (16%) 18/54 (33%) 2.61 (1.33–5.13) 0.005 2.39 (1.12–5.08) 0.02
Hemoglobin (g/dl) 14.3 (1.1) 14.0 (1.1) 0.65 (0.49–0.88) 0.004 0.68 (0.45–1.02) 0.07
White-cell count (×109/l) 7.5 (2.8–16.1) 7.3 (2.4–11.3) 0.85 (0.72–1.00) 0.05   
Platelet count (×109/l) 275 (112–519) 294 (131–939) 1.00 (1.00–1.01) 0.14   
C-reactive protein (mg/l) 6 (0–50) 5 (1–23) 0.97 (0.92–1.03) 0.33   
Cholesterol (mmol/l) 4.9 (1.0) 5.4 (0.8) 1.73 (1.23–2.43) 0.002   
High-density lipoprotein (mmol/l) 1.1 (0.4–2.2) 1.1 (0.7–2.0) 1.02 (0.39–2.67) 0.97   
Low-density lipoprotein (mmol/l) 3.1 (0.9) 3.6 (0.7) 1.85 (1.27–2.70) 0.001 2.10 (1.34–3.29) 0.001
Thyroid stimulating hormone (mIE/l) 1.5 (0.0–7.9) 1.7 (0.2–14.6)   0.02   0.08
Free T4 (pmol/l) 15 (10–28) 15 (11–23) 0.97 (0.85–1.10) 0.17   
Vitamin B1 (nmol/l) 155 (62–239) 142 (91–246) 0.98 (0.97–1.00) 0.008 0.99 (0.98–1.01) 0.21
Vitamin B6 (nmol/l) 26 (5–231) 26 (6–113) 0.99 (0.98–1.01) 0.36   
Vitamin B12 (pmol/l) 346 (158–1480) 342 (173–712) 1.00 (1.00–1.00) 0.52   
Folic acid (nmol/l) 18 (6–46) 16 (7–46) 0.98 (0.94–1.02) 0.28   
Use of statins 52/295 (18%) 2/54 (4%) 0.18 (0.04–0.78) 0.02 0.31 (0.07–1.47) 0.14
Use of thyroid substitution therapy 26/296 (9%) 6/54 (11%) 1.30 (0.49–3.46) 0.60   
Center      5.22 (2.48–10.99) <0.001
  1. The results are given as number (proportion in percent) for categorical variables, mean (standard deviation) for continuous variables with normal distribution and median (range) for other continuous variables. In the column “Adjusted for center only”, comparisons between patients with and without IBS were performed with logistic regression adjusted for center. In total, 48 potential predictors were examined. The 25 predictors presented in the tables are all predictors with significant associations with IBS and a selection of other potential predictors of clinical interest. In the column “Adjusted for all significant predictors”, gender, self-reported psychiatric disorders, hemoglobin, low-density lipoprotein, thyroid stimulating hormone, vitamin B1, use of statins and center were included in the final logistic regression analysis with 342 patients. Cholesterol is not included in the final analysis due to high correlation with LDL. No odds ratio for thyroid stimulating hormone is available as the variable is transformed with fractional polynomials