After further adjustment for weight and height (model 2), knee extensor strength was significantly decreased in the highest versus lowest HbA 1c quartile (−4.70 ± 2.30 N · m) with a significant trend of lower knee extensor strength across higher HbA 1c quartiles ( P = 0.02).
In sensitivity analysis, using only nonimputed data, participants in the highest versus lowest HbA 1c quartile had significantly decreased muscle strength in model 3 (−6.74 N · m ± 2.59; P = 0.01) with a trend toward significance after further accounting for peripheral neuropathy (−5.68 ± 3.03 N · m; P = 0.06; model 4).
In the fully adjusted model further accounting for peripheral neuropathy, knee extensor strength was lower in the highest versus lowest HbA 1c quartile (−4.47 ± 2.32 N · m) but such difference was no longer significant, and the trend across HbA 1c categories was of only borderline significant ( P value for trend = 0.05).
Comparing highest versus lowest HbA 1c quartiles and adjusting for age, race, sex, weight, and height, strength was significantly lower (−4.70 ± 2.30 N · m; P value trend = 0.02) and results were unchanged after adjustment for physical activity ( P value trend = 0.045) but of borderline significance after additional adjustment for peripheral neuropathy ( P value trend = 0.05).