Association between overweight and dip osteoarthritis among middle-aged Finnish female dentists and teachers

The objective of this study was to examine associations between body mass index (BMI) and symptomatic and non-symptomatic radiographic osteoarthritis in the distal interphalangeal joints (DIP ROA). The subjects were 295 female dentists and 248 female teachers aged 45-63 years randomly selected from the registers of the Finnish Dental Association and the Finnish Teachers' Trade Union of the Helsinki metropolitan region. Radiographs of both hands were examined for the presence of osteoarthritis in each DIP joint. Information on the occurrence of pain in each DIP joint during the past 30 days and hand laterality was obtained by questionnaire. Current BMI was based on self-reported height and measured weight. BMI at the age of 25 years was based on self-reported height and weight. Overweight was defined as BMI ≥ 25.0 kg/m2. Allowing for age, occupation, hand-loading leisure-time physical activity and smoking history, the risk of symptomatic DIP ROA was increased in currently overweight women (OR 1.98, 95% CI 1.18-3.34) and in women with overweight both currently and at the age of 25 (7.55; 1.33-42.83). The OR for an increase of one standard deviation in BMI at the age of 25 was 1.20 (1.05-1.38) and that for a similar increase in current BMI 1.08 (1.01-1.16), adjusted as above. No relationship of BMI with non-symptomatic DIP ROA or joint pain only was found. The study provides evidence that the risk of symptomatic DIP ROA is increased among overweight middle-aged women. Consideration even of BMI at young adulthood further underlines the association.