Obesity, foot pain and foot disorders in older men and women

We investigated obesity, foot pain and selected foot disorders, and determined if associations differed by foot posture or dynamic foot function.

We included 2445 men and women (4888 feet) from the Framingham Foot Study (2002-2008). A foot examination assessed presence of disorders and pain on each foot. Body mass index (BMI, kg/m²) was categorized as normal (<25), overweight (25-29.99), moderate-obesity (30-34.99) severe-obesity (35+). Foot posture (normal, cavus, planus) and dynamic foot function (normal, supinated, pronated) were defined using plantar pressure measurement system. We used sex-specific logistic regression with generalized estimating equations to account for correlation between two feet of the same person, adjusted for age and stratified by foot posture and dynamic foot function.

Average age was 68±11 years, 56% female, average BMI 28±5kg/m². 18% of feet had pain, 25% hallux valgus, 2% claw toes, 18% hammer toes, 7% overlapping toes. In men, severe-obesity was associated with foot pain (OR=2.4, p=0.002) and claw toes (OR=3.4, p=0.04). In women, overweight, moderate-obesity and severe-obesity were associated with foot pain. Women with severe-obesity were less likely to have hallux valgus. Similar patterns were evident after stratification by foot posture and dynamic foot function.

Both men and women were at increased odds of foot pain as BMI increased. Data suggested foot posture and dynamic foot function had no effect, thus are unlikely mechanisms.