Significant J-shaped association between body mass index (BMI) and diabetic foot ulcers

Background Disagreement exists regarding the relationship between body weight and foot ulceration risk among diabetic persons. Methods We used a nested case-control design to estimate the association between body mass index (BMI) and 1-year and 5-year foot ulceration risk. We obtained data on all diabetic patients < 60 years of age who were treated in the US Department of Veterans Affairs healthcare system in 2003. Patient characteristics and co-morbidities were obtained at baseline. For each individual with an incident foot ulcer (case), up to four individuals were randomly selected who matched the case on age, sex, race, marital status, and calendar time. Results Crude 1-year and 5-year incidence rates were 1.35 and 6.22% after a mean follow-up of 11.8 +/- 1.2 months and 55.5 +/- 12.8 months, respectively. Compared with individuals with BMI 25-29.9 kg/m(2), those with BMI 40-44.9 kg/m(2) and those with BMI >= 45 kg/m(2) had 25% [adjusted odds ratio (AOR) = 1.25; 95% confidence interval (CI), 1-1.56] and 83% (AOR = 1.83; 95% CI, 1.44-2.32) higher 1-year risk and 1.4 (AOR = 1.39; 95% CI, 1.26-1.54) and 2.1 (AOR = 2.08; 95% CI, 1.86-2.32) times higher 5-year risk. BMI < 25 kg/m(2) was associated with 30% higher risk at both 1 year (AOR = 1.28; 95% CI, 1.04-1.58) and 5 years (AOR = 1.27; 95% CI, 1.15-1.40). Conclusions Our data suggest a significant J-shaped association between BMI and diabetic foot ulcers. Published 2011. This article is a US Government work and is in the public domain in the USA.