Demographic information of enrolled households and Helicobacter pylori infection risk factors
| Categories | Total no. of household (10,735), n (%) | Infected household* (n=7636) | Uninfected household† (n=3099) | Household infection rate (%)‡ | Crude OR (95% CI) | P value§ | Adjusted OR (95% CI) | P value |
| Demographic and socioeconomic characteristics | ||||||||
| Geographical areas | ||||||||
| Southwest | 2176 (20.27) | 1392 | 784 | 63.97 | Reference | Reference | ||
| North | 1739 (16.20) | 1204 | 535 | 69.24 | 1.26 (1.10 to 1.45) | 0.001 | 1.25 (1.08 to 1.43) | 0.002¶ |
| Central | 748 (6.97) | 535 | 213 | 71.52 | 1.39 (1.15 to 1.67) | <0.001 | 1.38 (1.14 to 1.66) | 0.001¶ |
| East | 2791 (26.00) | 2042 | 749 | 73.16 | 1.55 (1.37 to 1.76) | <0.001 | 1.45 (1.28 to 1.65) | <0.001¶ |
| South | 1025 (9.55) | 766 | 259 | 74.73 | 1.67 (1.41 to 1.97) | <0.001 | 1.51 (1.27 to 1.79) | <0.001¶ |
| Northeast | 857 (7.89) | 633 | 224 | 73.86 | 1.67 (1.40 to 2.00) | <0.001 | 1.50 (1.25 to 1.80) | <0.001¶ |
| Northwest | 1399 (13.03) | 1064 | 335 | 76.05 | 1.86 (1.60 to 2.17) | <0.001 | 1.83 (1.57 to 2.13) | <0.001¶ |
| Annual household income (thousand yuan) | ||||||||
| <100 | 6639 (61.84) | 4691 | 1948 | 70.66 | Reference | |||
| 100–300 | 3265 (30.41) | 2352 | 913 | 72.04 | 1.03 (0.94 to 1.13) | 0.547 | ||
| >300 | 831 (7.74) | 593 | 238 | 71.36 | 0.97 (0.82 to 1.14) | 0.668 | ||
| Resident location | ||||||||
| City | 7961 (74.16) | 5679 | 2282 | 71.34 | Reference | |||
| Rural | 2774 (25.84) | 1957 | 817 | 70.55 | 1.03 (0.93 to 1.13) | 0.614 | ||
| Household living area (m2) | ||||||||
| <60 | 1261 (11.75) | 866 | 395 | 68.68 | Reference | Reference | ||
| 60–120 | 6296 (58.65) | 4462 | 1834 | 70.87 | 1.09 (0.96 to 1.25) | 0.182 | 1.03 (0.90 to 1.18) | 0.660 |
| >120 | 3178 (29.60) | 2308 | 870 | 72.62 | 1.18 (1.02 to 1.36) | 0.028 | 1.07 (0.92 to 1.25) | 0.359 |
| Family size (n) | ||||||||
| 2 | 5305 (49.42) | 3339 | 1966 | 62.94 | Reference | Reference | ||
| 3 | 2909 (27.10) | 2195 | 714 | 75.46 | 1.84 (1.66 to 2.04) | <0.001 | 1.97 (1.76 to 2.21) | <0.001¶ |
| 4 | 1461 (13.61) | 1162 | 299 | 79.53 | 2.39 (2.07 to 2.74) | <0.001 | 2.53 (2.17 to 2.95) | <0.001¶ |
| 5 | 680 (6.33) | 588 | 92 | 86.47 | 3.96 (3.15 to 4.97) | <0.001 | 4.25 (3.32 to 5.43) | <0.001¶ |
| 6 | 257 (2.39) | 233 | 24 | 90.66 | 6.25 (4.09 to 9.56) | <0.001 | 6.29 (4.07 to 9.71) | <0.001¶ |
| Seven and above | 123 (1.15) | 119 | 4 | 96.75 | 18.83 (6.94 to 51.13) | <0.001 | 19.51 (7.15 to 53.20) | <0.001¶ |
| Family size (n) (when adjusted for variables excluding ‘generations in household’ in multivariate logistic analysis) | ||||||||
| 2 | 5305 (49.42) | 3339 | 1966 | 62.94 | Reference | Reference | ||
| 3 | 2909 (27.10) | 2195 | 714 | 75.46 | 1.84 (1.66 to 2.04) | <0.001 | 1.80 (1.62-2.60)** | <0.001** |
| 4 | 1461 (13.61) | 1162 | 299 | 79.53 | 2.39 (2.07 to 2.74) | <0.001 | 2.26 (1.97-2.60)** | <0.001** |
| 5 | 680 (6.33) | 588 | 92 | 86.47 | 3.96 (3.15 to 4.97) | <0.001 | 3.75 (2.99-4.72)** | <0.001** |
| 6 | 257 (2.39) | 233 | 24 | 90.66 | 6.25 (4.09 to 9.56) | <0.001 | 5.60 (3.66-8.56)** | <0.001** |
| Seven and above | 123 (1.15) | 119 | 4 | 96.75 | 18.83 (6.94 to 51.13) | <0.001 | 17.31 (6.38-46.99)** | <0.001** |
| Generations in household | ||||||||
| 1 | 3814 (35.53) | 2556 | 1258 | 67.02 | Reference | Reference | ||
| 2 | 4878 (45.44) | 3477 | 1401 | 71.28 | 1.21 (1.10 to 1.33) | <0.001 | 0.82 (0.74 to 0.91) | <0.001¶ |
| 3 | 2043 (19.03) | 1603 | 440 | 78.46 | 1.81 (1.59 to 2.05) | <0.001 | 0.79 (0.68 to 0.92) | <0.001¶ |
| Generations in household (when adjusted for variables excluding ‘family size’ in multivariate logistic analysis) | ||||||||
| 1 | 3814 (35.53) | 2556 | 1258 | 67.02 | Reference | Reference | ||
| 2 | 4878 (45.44) | 3477 | 1401 | 71.28 | 1.21 (1.10 to 1.33) | <0.001 | 1.21 (1.10-1.32)†† | <0.001†† |
| 3 | 2043 (19.03) | 1603 | 440 | 78.46 | 1.81 (1.59 to 2.05) | <0.001 | 1.77 (1.56-2.01)†† | <0.001†† |
| Premeal factors | ||||||||
| Dishwashing | ||||||||
| Tap water | 9022 (84.04) | 6437 | 2585 | 71.35 | Reference | |||
| In a basin | 1713 (15.96) | 1199 | 514 | 69.99 | 0.95 (0.84 to 1.06) | 0.341 | ||
| Tableware sterilisation | ||||||||
| No sterilisation | 6999 (65.20) | 4997 | 2002 | 71.40 | Reference | |||
| Disinfection cabinet | 1791 (16.68) | 1268 | 523 | 70.80 | 0.94 (0.84 to 1.06) | 0.289 | ||
| Other disinfection methods | 1945 (18.12) | 1371 | 574 | 70.49 | 0.94 (0.84 to 1.05) | 0.250 | ||
| Sources of drinking water | ||||||||
| Boiled water | 8034 (74.84) | 5730 | 2304 | 71.32 | Reference | |||
| Tap water | 854 (7.96) | 620 | 234 | 72.60 | 1.08 (0.92 to 1.26) | 0.378 | ||
| Bottled water | 1469 (13.68) | 1027 | 442 | 69.91 | 0.94 (0.83 to 1.06) | 0.302 | ||
| Purified water | 291 (2.71) | 198 | 93 | 68.04 | 0.89 (0.69 to 1.14) | 0.354 | ||
| Well water | 87 (0.81) | 61 | 26 | 70.11 | 0.92 (0.58 to 1.47) | 0.732 | ||
| Mid-meal factors | ||||||||
| Individual dining | ||||||||
| No | 9289 (86.53) | 6633 | 2656 | 71.41 | Reference | |||
| Yes | 1446 (13.47) | 1003 | 443 | 69.36 | 0.91 (0.80 to 1.02) | 0.111 | ||
| Dish sharing | ||||||||
| No | 1704 (15.87) | 1207 | 497 | 70.83 | Reference | |||
| Yes | 9031 (84.13) | 6429 | 2602 | 71.19 | 1.04 (0.93 to 1.17) | 0.505 | ||
| Serving chopsticks and spoons | ||||||||
| No | 8484 (79.03) | 6070 | 2414 | 71.55 | Reference | Reference | ||
| Yes | 2251 (20.97) | 1566 | 685 | 69.57 | 0.89 (0.81 to 0.99) | 0.034 | 0.92 (0.83 to 1.02) | 0.129 |
| Post-meal factors | ||||||||
| Water cup sharing | ||||||||
| No | 8014 (74.65) | 5687 | 2327 | 70.96 | Reference | |||
| Yes | 2721 (25.35) | 1949 | 772 | 71.63 | 1.06 (0.97 to 1.17) | 0.210 | ||
| Dental mouthwash cup sharing | ||||||||
| No | 9719 (90.54) | 6931 | 2788 | 71.31 | Reference | |||
| Yes | 1016 (9.46) | 705 | 311 | 69.39 | 0.91 (0.79 to 1.05) | 0.202 | ||
| Dental appliances sharing | ||||||||
| No | 10 263 (95.60) | 7294 | 2969 | 71.07 | Reference | |||
| Yes | 472 (4.40) | 342 | 130 | 72.46 | 1.06 (0.86 to 1.30) | 0.600 | ||
| Others | ||||||||
| Family history of diseases | ||||||||
| None | 9018 (84.01) | 6386 | 2632 | 70.81 | Reference | Reference | ||
| Peptic ulcers | 1447 (13.48) | 1043 | 404 | 72.08 | 1.06 (0.94 to 1.20) | 0.337 | 1.02 (0.90 to 1.16) | 0.724 |
| Gastric cancer | 270 (2.52) | 207 | 63 | 76.67 | 1.35 (1.02 to 1.80) | 0.037 | 1.28 (0.96 to 1.71) | 0.099 |
| Pets in household | ||||||||
| No | 9526 (88.74) | 6775 | 2751 | 71.12 | Reference | |||
| Yes | 1209 (11.26) | 861 | 348 | 71.22 | 0.98 (0.86 to 1.12) | 0.768 | ||
| Poultry in household | ||||||||
| No | 10 359 (96.50) | 7365 | 2994 | 71.10 | Reference | |||
| Yes | 376 (3.50) | 271 | 105 | 72.07 | 1.12 (0.89 to 1.41) | 0.337 | ||
| Livestock in household | ||||||||
| No | 10 525 (98.04) | 7491 | 3034 | 71.17 | Reference | |||
| Yes | 210 (1.96) | 145 | 65 | 69.05 | 0.96 (0.71 to 1.29) | 0.796 | ||
*Infected household is defined as a household with at least one H. pylori-infected family member.
†Uninfected household is defined as a household without any H. pylori-infected family member.
‡Household infection rate is defined as percentage of infected household among all households.
§P value was calculated by univariate logistic regression, p<0.05 indicates that infection risk increase/decrease significantly compared with the reference groups.
¶These are independent risk/protective factors for household H. pylori infection compared with reference group. P value was calculated by multivariate logistic regression, and was adjusted with items of p<0.1 in univariate logistic regression.
**These were results when ‘family size’ was adjusted for variables excluding ‘generations in household’ in multivariate logistic analysis, all other variable adjustment did not change this result and conclusion.
††These were results when ‘generations in household’ was adjusted for variables excluding ‘family size’ in multivariate logistic analysis, all other variable adjustment did not change this result and conclusion.