Obesity and pronated foot type may increase the risk of chronic plantar heel pain: a matched case-control study

BACKGROUND: Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors. METHODS: Eighty participants with CPHP (33 males, 47 females, mean age 52.3 years, S.D. 11.7) were matched by age (+/- 2 years) and sex to 80 control participants (33 males, 47 females, mean age 51.9 years, S.D. 11.8). The two groups were then compared on body mass index (BMI), foot posture as measured by the Foot Posture Index (FPI), ankle dorsiflexion range of motion (ROM) as measured by the Dorsiflexion Lunge Test, occupational lower limb stress using the Occupational Rating Scale and calf endurance using the Standing Heel Rise Test. RESULTS: Univariate analysis demonstrated that the CPHP group had significantly greater BMI (29.8 +/- 5.4 kg/m2 vs. 27.5 +/- 4.9 kg/m2; P or = 30 kg/m2) (OR 2.9, 95% CI 1.4 - 6.1, P or = 4) (OR 3.7, 95% CI 1.6 - 8.7, P < 0.01). CONCLUSION: Obesity and pronated foot posture are associated with CPHP and may be risk factors for the development of the condition. Decreased ankle dorsiflexion, calf endurance and occupational lower limb stress may not play a role in CPHP.