Table 1. Characteristics of case–control and cohort studies included in the meta-analysis.
| Study | Year/location | Population/age M(SD) | Duration (yrs) | H. pylori detection | Outcome |
| Cohort studies | |||||
| Baudron [17] | 2013, France | N=603 H. pylori positive 73.1(6.4) H. pylori negative 74.3(6.5) |
20 | Serum H. pylori IgG antibodies | all-cause dementia |
| Huang [21] | 2014, Chian | N=83965 H. pylori positive 63.2 (13.5) H. pylori negative 63.6 (13.4) |
12 | H. pylori infection (ICD-9 code 041.86) | all-cause dementia; AD; non-AD |
| Fani [15] | 2018, Netherlands | N=4275 H. pylori positive 69.3 (8.6) H. pylori negative 67.5 (8.5) |
10.4 | Serum H. pylori IgG antibodies | all-cause dementia; AD |
| Beydoun [13] | 2018, United States | N=5927 H. pylori positive 59.3 (0.2) H. pylori negative 62.8 (0.4) |
3 | Serum H. pylori IgG antibodies | all-cause dementia; AD |
| Von [14] | 2018, France | N=689, Age≥65 | 10 | Serum H. pylori IgG antibodies | all-cause dementia;AD |
| Case control studies | |||||
| Nagga [19] | 2003, Sweden | N=216, Age≥60 | NA | Serum H. pylori IgG antibodies | AD, VaD |
| Kountouras [18] | 2006, Greece | N=80 AD 65.0(6.9) Control 62.2(8.6) |
NA | histologic analysis | AD |
| Shiota [22] | 2011, Japan | N=482 AD74.4(10.4) Control 78.5 (6.4) |
NA | rapid urine test | AD |
| Bu [20] | 2014, Chian | N=263 AD 69(9) Control 70(10) |
NA | Serum H. pylori IgG antibodies | AD |
| Tsolaki [16] | 2015, Greece | N=61 AD 61.34(6.526) Control 62.41(4.49) |
NA | Serum H. pylori IgG antibodies and histological | all-cause dementia; AD; PD; LB; FTD |
| Study | Diagnostic criteria | OR/HR, 95%CI | Adjusting for confounders | NOS |
| Baudron [17] | NINCDS-AD-RDA | Dementia: HR 1.46 (95% CI 1.01–2.11) | Age, sex, education APOE4, basel+H4:H18ine MMSE score, obesity, CVD | 6 |
| Huang [21] | ICD-9-CM | Dementia: HR 1.51, 95%CI 1.25–1.82 AD: HR 0.66, 95%CI 0.30–1.46 Non-AD: HR 1.60, 95%CI 1.32–1.95 |
Age, sex, comorbidities hypertension, DM, depression, head injury | 6 |
| Fani [15] | DSM-III-R, NINCDS-AD-RDA |
Dementia: HR 1.03, 95%CI 0.86–1.22 AD: HR 1.06 95%CI 0.87–1.29 |
Adjusted for age, sex, study cohort, education, smoking, systolic and diastolic blood pressure, anti-hypertensive drug use, body mass index (BMI), cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, APOEε carrier status, stroke, diabetes mellitus, ethnicity, and serum lipid–reducing agents. | 7 |
| Beydoun [13] | NA | Dementia: HR1.44, 95%CI 1.05–1.98 AD: HR 1.45 (95%CI 1.03–2.04) |
Adjusted for education, poverty income ratio, smoking, weight ststus, hypertension, diabetes, and dyslipidemia | 7 |
| Von [14] | NA | Dementia: HR 1.70 (95%CI 1.05–2.74) AD: HR 2.85 (95% CI 1.58–5.12) |
NA | 8 |
| Nagga [19] | ICD-10 | H. pylori positivity: 55.3% in AD patients, 55.6% in AD with CVD, 49.2% in VaD, 62.5% in the cognitively impaired group, 50.5% in the controls | Age | 6 |
| Kountouras [18] | NINCDS-AD-AD-RDA | OR 8.4 (95% CI 2.4–28.7) | The groups were comparable regarding SES | 7 |
| Shiota [22] | NINCDS–AD-RDA | OR 0.94 (95% CI 0.56–1.58) | Age, sex | 8 |
| Bu [20] | NINCDS–AD-RDA | OR 1.39 (95% CI 0.80–2.40) | Age, sex, education, APOE, genotype, CHD, DM, hypercholesterolemia, hypertension | 6 |
| Tsolaki [16] | MMSE, FRSSD, NI | 68.33% in patients with dementia 45.16% with control | NA | 6 |
AD, Alzheimer’s Disease; DSM-III-R, Statistical Manual of Mental Disorders–3rd Edition Revised; FRSSD, Functional Rating Scale for Symptoms of Delirium; ICD-9-CM, International Classification of Diseases 9, Ninth Revision, Clinical Modification; ICD-10, International Classification of Diseases 10; MMSE, Mini Mental State Examination; M(SD), Mean (standard deviation); N, Number of population; NA, not available; NINCDS–ADRDA, National Institute of Neurological Disorders and Stroke and Alzheimer’s Disease and Related Disorders Association; NI, Neuropsychiatric Inventory.