Table 1.
Quantitative comparison of specific components of cognitive performance between osteoarthritis cohort in TILDA WAVE1 (or NACC) and age/gender matched controls.
| Controlled parameter (confounder) | OA | CONT | Compared parameter | OA | CONT | p-value |
|---|---|---|---|---|---|---|
| Males (TILDA) | 0.26 | 0.28 | Attrition (TILDA) | 0.15 | 0.18 | 0.024 |
| Age (TILDA) | 69.9 | 69.9 | MMSE average (TILDA) | 28.1 | 27.8 | 0.009 |
| Income (TILDA) | 2.97 | 2.93 | MMSE average max (NACC) | 28.55 | 27.12 | 3.8 × 10−62 |
|
Education (NACC) |
15.8 | 16.3 | MMSE average min (NACC) | 26.12 | 24.12 | 7.8 × 10−60 |
| Education (TILDA) | 3.59 | 3.48 | Cognitive Risk (TILDA) | 0.38 | 0.51 | 0.002 |
| Stroke (TILDA) | 0.018 | 0.019 | Poor short-term recall (TILDA) | 0.137 | 0.192 | 0.005 |
| Somatic Risk (TILDA) | 0.36 | 0.33 | Poor long-term recall (TILDA) | 0.07 | 0.101 | 0.057 |
| Age at baseline (NACC) | 77.2 | 71.8 | Educational underperformance (NACC) | 0.076 | 0.057 | 0.066 |
| Males (NACC) | 0.37 | 0.37 | Advanced degrees (NACC) | 2.64 | 2.82 | 0.1 |
|
Stroke (NACC) |
0.043 | 0.029 | Dementia in the baseline (NACC) | 0.14 | 0.29 | 3.8 × 10−109 |
| Somatic risk (NACC) | 2.85 | 2.02 | Dementia in the end of follow up (NACC) | 0.24 | 0.40 | 4.7 × 10−95 |
In TILDA, osteoarthritis cohort (OA, N = 820) and non-arthritic controls (CONT, N = 2300) were normalized by age, gender and somatic disease risk. Somatic comorbidity panel (Somatic Risk) included open-heart surgery, heart attack, angioplasty and stent installation, congestive heart failure, cardio-pulmonary deficiency that requires oxygen supply, cancer, stroke and diabetes. Income levels were provided as a strata of population rank.
The compared parameters in TILDA include: Attrition – fraction of patients not re-appearing in WAVE2 of TILDA after being present in WAVE1, MMSE average – is average score between WAVE1-WAVE3, Educational under-performance – completion of only elementary school, Cognitive risk – the sum of fractions for low readings of MOCA (<20), MMSE (<20), poor short and long term recalls, poor visual recognition and reasoning, high delays in performing test assignments. Recall tests were conducted according to MOCA methodology.
The compared parameters in NACC Version 3 (OA, N = 8525, CONT, N = 5250) included dementia fraction, MMSE at the beginning and the end of follow up (MMSE MAX and MMSE MIN), educational underperformance (average years of underperformance per a patient) and advanced degree presence (average years of advanced education per a patient). Educational underperformance was defined in NACC as <9 years of schooling, advanced degree as >18 years of schooling, stroke and dementia rates in NACC are provided as fractions, somatic risk as number of comorbidities per a patient in the cohort.