Table 4.

Multivariable logistic regression analyses for the association of grip strength with clinical hand OA^*

Model	Clinical hand osteoarthritis	β	Standard Error	P	Δβ%b	OR	95% CI
1	Plus sex, age, country of origin, education level (less than secondary)	1.1066	0.1282	<0.0001		3.024	2.352-3.888
2	Plus sex, age, country of origin, education level (less than secondary), and comorbidity (≥ 3 diseases)	1.0655	0.1291	<0.0001	3.9	2.902	2.254-3.738
3	Plus sex, age, country of origin, education level (less than secondary), comorbidity (≥ 3 diseases), and AUSCAN for hand OA pain subscale scorec	0.3990	0.1686	0.0180	167.0	1.490	1.071-2.074
4	Plus sex, age, country of origin, education level (less than secondary), comorbidity (≥ 3 diseases), AUSCAN for hand OA pain subscale scorec, and interaction of sex with age	0.3837	0.1678	0.0222		1.468	1.056-2.039

^*The outcome being measured was the likelihood of having less grip strength (a grip strength score in the lowest tertile of subsample distributions stratified by sex and country of origin) versus not having less grip strength (a score in the higher tertiles)

^aEstimated coefficients.

^bAmount of adjustment = 100 x (β previous Model – β Model) / β Model.

^cPossible AUStralian/CANadian Osteoarthritis Hand Index (AUSCAN) for hand osteoarthritis (OA) pain subscale scores range from 0 to 100, with 0 indicating no pain.

Controlled direct effect and natural direct effect: P = 0.0222, odds ratio (OR) 1.468 ((95% confidence interval [95% CI] 1.056-2.039); natural indirect effect: P <0.0001, OR 1.953 (95% CI 1.571-2.429); total effect P <0.0001, OR 2.867 (95% CI 2.212-3.715).