Is adult size a potential confounder of grip strength vs SF-36 associations?
Adult size was related to SF-36 scores and to grip strength. Higher weight was associated with poorer PF, RP, VT, BP and RE in men [ORs for poor SF-36 scores per standard deviation (SD) increase in weight ranged from 1.2 to 1.3, P-values = 0.01 to <0.001] and with poorer scores for all domains other than MH in women (ORs ranging from 1.2 to 1.8, P-values = 0.02 to <0.001). Shorter height was associated with increased likelihood of having poor GH scores among men (OR for poor GH score: 1.1 per SD increase in height, P = 0.02) and increased likelihood of having poor PF, VT and GH scores in women (OR = 1.1 for all, P = 0.03, P = 0.02 and P = 0.02). In addition, weight and height were positively correlated with grip strength in men (Pearson correlations and P-values: r = 0.24, P<0.001 for weight; r = 0.40, P<0.0001 for height) and women (r = 0.08, P = 0.003 for weight; r = 0.28, P<0.0001 for height). Hence, weight had the potential to mask (i.e. to negatively confound) any relationship bet
