Table 2 Summary results of the eligible studies.

Whitlock EL, 2017 [8]

Cognitive score

Continuous measure of a memory score (quantitative summary metric that combines results from several cognitive tests into a single scale).

No

Control group: 11.8.

Pain group: 8.6.

Control group: 19.9%;

Pain group: 22.1%.

RR = 0.96 (0.86-1.07)

Age, sex, race/ethnicity, education, tobacco use, comorbidities (hypertension, diabetes, cancer, chronic lung disease, heart disease, and stroke), total household financial assets, marital status, current alcohol use, depressive symptoms, and report of any limitation in activities of daily living.

Tian J, 2023 [12]

Dementia

ICD9 and ICD10; All-cause dementia and its subtypes were ascertained using hospital inpatient and death registry records.

Dementia

13.3 (12.6-14.0)

Control group: 0.5%; Pain group: 0.7%

aHR=1.02 (0.95-1.10)

Age, sex, body mass index, ethnicity, highest education level, house income, smoking status, alcohol frequency, meeting recommended moderate/vigorous physical activity, presence of comorbidity, non-steroidal anti-inflammatory medication use, opioid medication use, psychological problems and sleep duration.

Zhao W, 2023 [6]

Dementia

Dementia cases were identified using the ICD-10.

Dementia

11.8 ± 1.7

Control group: 0.98%; Pain group: 1.24%.

aHR=1.15 (1.06-1.24)

Age, gender, ethnicity, medications, Townsend deprivation index, educational attainment, BMI, smoking status, alcoholic drinking status, history of cancer, history of diabetes, history of vascular or heart problems (angina, hypertension, heart attack, and stroke), and ever seen a doctor for nervousness, anxiety, tension, or depression.

Milani SA, 2023 [14]

MMC cognitive score

Cognitive performance was measured at both waves using the Mini-Mental Cabán (MMC).

Severe cognitive impairment (unable to complete interviews independently

4

——

β = − 0.07 (SE = 0.02); OR = 0.93 (0.88-0.98)

Gender, race, education, health insurance, number of depressive symptoms, number of comorbidities, physical activity, and activities of daily living limitations.

Kao PH, 2021 [15]

Dementia

Dementia was identified using the ICD-9-CM diagnosis classifications of 290, 294.1, 294.2, or 331 with at least one hospitalization or 3 outpatient clinic visits.

Dementia

> 5

Control group: 16.6%; Pain group: 13.5%.

aHR=1.21 (1.15-1.26)

All comorbidities, including hypertension, diabetes, hyperlipidemia, depression, coronary artery disease, malignancy, stroke, congestive heart failure, chronic obstructive pulmonary disease, liver diseases, renal diseases, alcoholism, and head injury.

Rouch I, 2022 [16]

Dementia

The neuro-psychologist selected the participants who were suspected of having dementia by completing a criteria check-list for dementia using DSM-III R checklist. Then, the diagnosis of dementia and its etiology were reviewed by an independent committee of neurology experts according to current standards.

Dementia

11.3 ± 7.3

Control group: 28.3%; Pain group: 36.7%.

aHR=1.23 (0.88-1.73)

Sex, education, depressive symptomatology, antidepressant use, number of comorbidities, and number of visits.

Wang K, 2021 [17]

Dementia

Dementia was diagnosed based on the criteria of the DSM-IV, and AD was diagnosed based on the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the AD and Related Disorders Association for definite, probable, or possible AD.

Dementia

10 (6 - 13)

Control group: 6.6%; Pain group: 14.4%.

aHR=1.43 (1.06-1.92)

Age, sex, SBP, hypertension, TC, diabetes, smoking, alcohol consumption, analgesic history, depression scale, employment status, dietary fiber intake, personal income, marital status, BMI, MMSE at baseline, and education level.

Tzeng NS, 2018 [18]

Dementia

ICD-9-CM.

Dementia

10

Control group: 3.54%; Pain group: 4.09%.

aHR=2.77 (2.61-2.95)

Sex, age, monthly income, urbanization level, geographic region of residence and comorbidities.

Ezzati A, 2019 [19]

Dementia

Dementia was diagnosed according standardized criteria from the DSM-IV and required impairment in memory plus at least one additional cognitive domain, accompanied by evidence of decline from a previous level of functioning.

Dementia

4.4 ± 3.1

Over all: 10.2%

aHR=1.36 (1.07-1.73)

Demographics, pain intensity and pain interference.

Cheng YH, 2022 [20]

Dementia

ICD-9-CM.

Dementia

15

Control group: 6.4%; Pain group: 11.02%.

aHR=4.47 (3.09-6.47)

Age, sex, CCI score, comorbidities, and medications.

Bell TR, 2022 [21]

MMSE cognitive score

Cognitive status was assessed using the MMSE.

Dementia and mild cognitive impairment

10

——

β = -0.06 P = 0.006; aOR 0.94 (0.89-1.00)

Age, time (years after follow-up), race, gender, education, marital status, and depressive symptoms at baseline and over time.

Veronese N, 2018 [22]

Cognitive score

We included three domains of cognition, namely verbal fluency, memory and processing speed.

Dementia

4

——

β = 0.05 (-0.28 - 0.38); aOR 1.05 (0.75-1.36)

Age and sex, baseline values of: race; educational level; marital status; household wealth; activities of daily living score; CES-D score; body mass index; smoking habits; physical activity level; alcohol drinking (yes vs. no); presence at baseline of angina, myocardial infarction, heart failure, arrhythmia, stroke, arthritis, osteoporosis, Parkinson’s disease, lung disease, asthma, cancer, diabetes, high blood pressure; cognitive test values.

Huang SW, 2015 [23]

Dementia

ICD-9-CM.

Dementia

4

Control group: 14.7%; Pain group: 21.7%.

aHR=1.25 (1.10-1.43)

Age, sex, autoimmune disease, DM, hypertension, hyper lipidaemia, coronary heart disease, stroke, COPD, and Parkinson’s disease.

Yamada K, 2019 [24]

Dementia

Cognitive disability grade was categorized into eight levels: 0, I, IIa, IIb, IIIa, IIIb, IV, and M (0=Independent, M = Needs constant treatment in a specialized medical facility). We defined cases more than IIa as dementia development.

Dementia

3

Over all: 3.3%

aHR=1.32 (1.06-1.64)

Age, sex, body mass index, knee pain or low back pain, alcohol consumption, smoking, history of diabetes mellitus, history of hypertension, education, marital status, equivalized income, employment status, loss events, frequency of going out, frequency of social interaction, and mood or anxiety disorder.

Van der Leeuw G, 2018 [10]

Cognitive score

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

Dementia and mild cognitive impairment

2.75 ± 1.94

11% in the memory domain

aHR=0.99 (0.54-1.81)

Age, sex, ethnicity and education

Røttereng, 2015 [25]

Dementia

Dementia diagnosis registered on 2 hospitals medical records and standardized interviews to assess cognitive decline and dementia in nursing homes.

Dementia

11

Over all: 4.54%

aOR=1.24 (1.04-1.49)

Age, gender, level of education, comorbidity, smoking, and anxiety and depression.

Rist PM, 2012 [26]

Cognitive score

The assessment was composed of five separate tests: telephone interview for cognitive status, immediate and delayed recall trials of the east Boston memory test, delayed recall trial of the telephone interview for cognitive status 10 word list, and a category fluency task.

——

3.4

Over all: 8.19%

aRR=0.77 (0.46-1.28)

Age, smoking status, alcohol consumption, body mass index, educational attainment, postmenopausal hormone use, past oral contraceptive use, and comorbidities (high cholesterol levels, hypertension, and diabetes).

Rist PM, 2011 [27]

Cognitive score

MMSE; nine neuropsychological tests administered by trained psychologists.

——

5

Over all: 10.85%

aOR=0.76 (0.42-1.37)

Age, gender, education, and smoking status.

Hagen K, 2014 [28]

Dementia

ICD-10.

Dementia and mild cognitive impairment

15

Control group: 0.83%; Pain group: 0.58%.

aHR=1.3 (1.1-1.7)

Age, gender, education, total HADS score, and smoking.

Liang H, 2023 [29]

Motoric cognitive risk syndrome

The diagnosis of MCR was made based on the appearance of slow gait and subjective cognitive concerns that met the established cut points.

Dementia and cognitive impairment

4

Over all: 13.8%

aHR=1.469 (1.148-1.881)

Age, gender, and BMI, the inclusion of sleep disturbance, loneness, current drinkers, current smokers, and hypertension disease, the inclusion of social isolation, education level, marital status, and medical insurance.

Kim SJ, 2022 [30]

Dementia

ICD-10.

Dementia

7.6 ± 1.2

Pain group: 18.6%

aHR=1.16 (1.13-1.20)

Age, sex, BMI, household income, smoking status, alcohol consumption, physical exercise, blood pressure, fasting serum glucose, total cholesterol, depression, sleep disorders, Parkinson’s disease, head injury, and Charlson Comorbidity Index.

Hurh K, 2022 [31]

Dementia

ICD-10.

Dementia

7.84

Control group: 8.36%; Pain group: 10.86%.

HR = 1.30 (1.25-1.35)

——

Morton RE, 2019 [32]

Dementia

Dementia diagnoses were determined based on clinical examination, with all-cause dementia diagnosed according to DSM-IV criteria.

Dementia and mild cognitive impairment

5

Over all: 7.5%

aOR=2.97 (1.25-6.61)

Age, education, and intervening variables -stroke.

Kim, 2023 [33]

Dementia

All participants were investigated for AD development based on a positive AD diagnosis (ICD-10 code Alzheimer’s disease F00, G30) and their prescription records for anti-dementia medication.

Dementia

10

Control group: 3.7%; Pain group: 7.1%.

aHR=1.323 (1.301-1.345)

Age, sex, comorbidities (hypertension, diabetes, dyslipidemia, myocardial infarction, congestive heart failure, and stroke), eGFR, BMI, and lifestyle (smoking status, drinking status, and regular exercise).

Chuang CS, 2013 [34]

Dementia

ICD-9-CM.

Dementia

12

Control group: 2.11%; Pain group: 3.21%.

aHR=1.33 (1.22-1.46)

Age, sex and comorbidities (baseline diabetes, hypertension, coronary artery disease, head injury and depression).

Tzeng NS, 2017 [35]

Dementia

ICD-9-CM.

Dementia

10

Control group: 3.99%; Pain group: 4.7%.

aHR=2.048 (1.705-2.461)

Age, sex, comorbidities, geographical area of residence, urbanization level of residence and monthly income.

Yang FC, 2016 [36]

Dementia

ICD-9-CM.

Dementia

8.14

Control group: 2.94%%; Pain group: 4.34%.

aHR=1.15 (1.05-1.27)

Sex, age, diabetes, dyslipidemia, hypertension, IHD, AF, HF, stroke, depression, head injury, Parkinson’s disease, migraine, and COPD.

Innes KE, 2020 [37]

Alzheimer’s disease and related dementias (ADRD)

ICD-9-CM or an affirmative response to the self-reported Health Status question “Has a doctor ever told you that you had Alzheimer’s?”.

Alzheimer’s disease and related dementia

2

Control group: 5.1%; Pain group: 7.5%.

aOR=1.19 (1.02-1.38)

Sex, age, race/ethnicity, education, income, supplemental insurance, marital status, region, smoking status, BMI, chronic physical health conditions (including RA, lupus), history of stroke, joint, back, neck pain, neuropathic pain, headache, migraine.