BACKGROUND: Although plantar fasciitis is the most common cause of heel pain, 
little has been reported on the incidence rates of this disorder. We sought to 
determine the incidence rate and demographic risk factors of plantar fasciitis 
in an ethnically diverse and physically active population of United States 
military service members.
METHODS: A query was performed with use of the Defense Medical Epidemiology 
Database for the International Classification of Diseases, Ninth Revision, 
Clinical Modification, code for plantar fasciitis (728.71). Multivariate Poisson 
regression analysis was used to estimate the rate of plantar fasciitis per 1000 
person-years, while controlling for sex, race, rank, service, and age.
RESULTS: The overall unadjusted incidence rate of plantar fasciitis was 10.5 per 
1000 person-years. Compared with men, women had a significantly increased 
adjusted incidence rate ratio for plantar fasciitis of 1.96 (95% confidence 
interval, 1.94 to 1.99). The adjusted incidence rate ratio for black service 
members compared with white service members was 1.12 (95% confidence interval, 
1.09 to 1.12). With junior officers as the referent category, junior enlisted, 
senior enlisted, and senior officer rank groups had a significantly increased 
adjusted incidence rate ratio for plantar fasciitis: 1.20 (95% confidence 
interval, 1.18 to 1.23), 1.19 (95% confidence interval, 1.17 to 1.22), and 1.56 
(95% confidence interval, 1.52 to 1.61), respectively. Compared with service 
members in the Air Force, those in the Army and Marines had a significantly 
increased adjusted incidence rate ratio for plantar fasciitis of 1.85 (95% 
confidence interval, 1.82 to 1.87) and 1.28 (95% confidence interval, 1.25 to 
1.30), respectively. The adjusted incidence rate ratio for the age group of 
forty years old or more compared with the twenty to twenty-four-year-old group 
was 3.42 (95% confidence interval, 3.34 to 3.51).
CONCLUSIONS: Female sex; black race; junior enlisted, senior enlisted, and 
senior officer rank groups; service in the Army or Marines; and increasing age 
are all risk factors for plantar fasciitis.