Background Ankylosing Spondylitis (AS) is a chronic, inflammatory disease that primarily affects the axial skeleton, causing a progressive limitation of mobility. Some studies have highlighted the association between intake of starch and the disease activity.
Objectives The aim of this study is to confirm the association between starch intake and the parameters of disease activity, functional impact and quality of life of patients with AS.
Methods This is a prospective cohort study. Participants were patients with AS, followed in the Rheumatology Department of CHLO, Hospital de Egas Moniz. They have completed a food diary for five consecutive days, recording the ingested food and the respective amount. The measurement of the starch was based on the reference values of the Table of Food, from Institute Dr. Ricardo Jorge. The BASDAI, BASFI, BASG and SF-36 questionnaires were completed and the CRP and VS values were further analyzed. The analysis of the Pearson's Correlation Coefficient was used to evaluate the possible associations between the variables under study and the starch average ingestion. Subsequently, a Linear Regression Analysis was performed, in order to identify the statistical power of the variables, neutralizing potential confounding variables, namely the gender, age, BMI and drug therapy.
Results 12 patients (9 males and 3 females), aged between 26 and 63 years, have been evaluated. The average daily intake of starch was 185.5±64.5 mg, the average BASDAI was 2.68±2.12, the average BASFI was 3.57±2.56, the average BASG was 3.83±1.92, the average SF-36 was 74.49±9.35, the average CRP was 2.16±2.07 mg/dL and the average VS was 15.03±18.42 mmHg 1st hour. The analysis of the Pearson's Correlation Coefficient has revealed that the average starch intake was significantly associated to three factors: the disease activity (BASDAI) (p<0,05), the functional impact (BASFI) (p<0.05), and the wellness in general (BASG) (p<0.05). It was not observed any association neither with the quality of life questionnaire (SF-36), nor with the inflammation parameters (CRP and VS). By means of Linear Regression Analysis, it was verified that the average intake of starch presents a statistical power of 76.8%, 84.6% and 94.7%, for the BASDAI, BASFI and BASG variables, respectively. The Linear Regression Coefficient shows increases of 3%, 3.9% and 2.9% in BASDAI, BASFI and BASG scores, respectively, by milligram of ingested starch. The confounding variables (gender, age, BMI and drug therapy) revealed a low statistical power.
Conclusions A higher intake of starch seems to be related with an increased activity and with a greater functional impact of the disease. These results allow us to envisage the reduction of the starch content of the patient diet, as a complementary therapeutic approach to the drug therapy.
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Disclosure of Interest None declared