Baseline characteristics, biochemical parameters and dietary intakes of study participants were shown based on case and control group (Table 1). Individuals in the case group as compared to those in the control group were higher in total energy intake and prevalence of type-2 diabetes and lower in physical activity, protein intake, dietary cholesterol, and dietary fiber (p-value < 0.05).
Table 1
Baseline characteristics, biochemical parameters and dietary intakes of study participants based on the patients with biliary stone disease and control group
| Cases (n = 110) | Controls (n = 230) | P valuea |
Age (yr), mean ± SD | 57.66 ± 16.39 | 56.00 ± 10.64 | 0.072 |
Male n (%) | 53 (48.2) | 129 (56.1) | 0.172 |
BMI (kg/m2), mean ± SD | 27.04 ± 5.46 | 26.70 ± 4.01 | 0.884 |
Physical activity (MET), mean ± SD | 29.47 ± 3.33 | 40.00 ± 9.35 | < 0.001 |
Current smokers, n (%) | 29 (26.4) | 41 (17.8) | 0.069 |
Drank alcohol in past year, n (%) | 6 (5.2) | 5 (2.2) | 0.190 |
Diabetes type 2, n (%) | 18 (16.4) | 20 (8.7) | 0.036 |
Total energy (kcal), mean ± SEM | 2448.28 ± 61.48 | 2302.27 ± 38.11 | 0.034 |
Carbohydrate (% of total energy) , mean ± SEM | 48.27 ± 0.80 | 49.00 ± 0.44 | 0.079 |
Protein (% of total energy), mean ± SEM | 12.59 ± 0.25 | 13.19 ± 0.14 | 0.004 |
Fat (% of total energy), mean ± SEM | 41.53 ± 0.86 | 40.91 ± 0.46 | 0.682 |
Dietary cholesterol (mg/d), mean ± SEM | 203.30 ± 8.50 | 236.99 ± 6.58 | 0.001 |
Saturated fat (g/d), mean ± SEM | 25.49 ± 0.85 | 24.42 ± 0.38 | 0.142 |
Monounsaturated fat (g/d) (mg/d), mean ± SEM | 29.22 ± 1.21 | 29.74 ± 0.56 | 0.376 |
Polyunsaturated fat (g/d) (mg/d), mean ± SEM | 21.95 ± 0.93 | 22.79 ± 0.44 | 0.201 |
Dietary fiber (g/d), mean ± SEM | 36.08 ± 2.01 | 40.33 ± 0.74 | 0.001 |
T test for quantitative variables and χ 2 test for qualitative variables. Dietary intakes (except total energy) were adjusted for total energy intake. BMI: Body mass index; MET: Metabolic equivalent task. |
Dietary intake of animal and plant protein base on case and control group for men, women and both sex were shown in Table 2. Men in the case group as compared to men in control group consumed higher animal protein and lower plant protein (p-value < 0.05). for women there was no significant differences between case and control groups. When both sex considered, case group as compared to control group consumed lower plant protein (p-value < 0.05).
Table 2
Animal and plant protein dietary intakes of study participants based on the patients with biliary stone disease and control group
| Men | P value | Women | P value | Both sex | P value |
| Cases (n = 53) | Controls (n = 129) | | Cases (n = 101) | Controls (n = 57) | | Cases (n = 110) | Controls (n = 230) | |
Animal protein intake (g/day) | 52.12 ± 34.84 | 40.37 ± 14.16 | 0.02 | 38.43 ± 19.51 | 39.45 ± 14.79 | 0.32 | 45.03 ± 28.67 | 39.96 ± 14.42 | 0.44 |
Plant protein intake (g/day) | 28.44 ± 36.19 | 38.56 ± 15.39 | 0.03 | 34.01 ± 21.35 | 32.97 ± 12.38 | 0.54 | 31.33 ± 29.44 | 36.10 ± 14.39 | 0.03 |
Table 3 shows the odds ratios for the biliary stone disease for male, female and both sex together in four models. In the crude model, there was a significant relationship between biliary stone disease and animal protein intake for male (OR: 1.03, 95% CI = 1.01–1.05) and both sex together (OR: 1.01, 95% CI = 1.00 -1.01). In fact, patients with higher consumption of animal protein intake were significantly more likely to have the biliary stone disease. In model 2 (adjusted for energy intake and physical activity), model 3 (further controlled for, body mass index and history of diabetes), and model 4 which were adjusted for (additionally adjusted for dietary cholesterol and dietary fiber), these relationships were significant for men, women, and both sex (Table 3).
Table 3
Odds ratios of biliary stone disease for animal and plant protein intakea
| Men | Women | Both sexes |
Animal protein intake | OR | 95% CI | OR | 95% CI | OR | 95% CI |
Crude | 1.03* | 1.01–1.05 | 0.99 | 0.98–1.02 | 1.01* | 1.00–1.02 |
Model 2 | 1.04* | 1.01–1.08 | 1.04* | 1.01–1.08 | 1.03* | 1.01–1.06 |
Model 3 | 1.04* | 1.00–1.08 | 1.04* | 1.00–1.08 | 1.03* | 1.01–1.06 |
Model 4 | 1.05* | 1.01–1.10 | 1.07* | 1.01–1.13 | 1.05** | 1.02–1.08 |
| Men | Women | Both sexes |
Plant protein intake | OR | 95% CI | OR | 95% CI | OR | 95% CI |
Crude | 0.98* | 0.96–0.99 | 1.00 | 0.98–1.02 | 0.99 | 0.98–1.01 |
Model 2 | 0.96* | 0.92–0.99 | 0.94* | 0.89–0.98 | 0.96* | 0.94–0.99 |
Model 3 | 0.96 | 0.92–1.01 | 0.93* | 0.88–0.98 | 0.96* | 0.94–0.99 |
Model 4 | 0.96 | 0.92–1.01 | 0.94* | 0.89–0.99 | 0.96* | 0.93–0.99 |
A: Crude model; B: Model 2, multivariate adjusted for energy intake and physical activity; C: Model 3, further controlled for, body mass index and history of diabetes; D: Model 4, additionally adjusted fordietary cholesterol and dietary fiber. Data are presented as the odds ratio (95%CI). (* significant P value < 0.05, ** significant P value < 0.01) |
In the case of the plant protein intake, there was a significant relationship between biliary stone disease and plant protein intake for male in crude model (OR: 0.98, 95% CI = 0.96–0.99) and model 2 (OR: 0.96, 95% CI = 0.92–0.99). After adjustment for body mass index and history of diabetes in model 3 and dietary cholesterol and dietary fiber in model 4, this relationship was not significant. For women and both sex, although there was no significant relationship in crude and model 2, there was a significant relationship between biliary stone disease and plant protein intake in model 3 and model 4. Persons with higher consumption of plant protein intake were significantly less likely to have the biliary stone disease (for women: OR: 0.94, 95% CI = 0.89–0.99, for both sex:OR: 0.96, 95% CI = 0.93–0.99) (Table 3).