Does early lifetime overweight modify the association between adult BMI and the risk of knee arthroplasty, as measures of severe knee osteoarthritis? A prospective Danish cohort study

Abstract

Abstract Background: Only few studies have explored whether BMI across life is associated with knee OA. The aim of this study was to examine if the risk of knee arthroplasty related to adult BMI is modified by early lifetime overweight.Methods: A total of 22 083 female nurses were followed from 1st of May 1999 until 10th of August 2015, date of knee arthroplasty or censoring (emigration, end of study or death). At baseline participants completed a questionnaire on different lifestyle-related factors. Knee arthroplasty events were identified through linkage to the Danish National Patient Register. The association was examined using Poisson regression of incidence rate of knee arthroplasty.Results: A direct association was found between BMI and rate of knee arthroplasty. The largest difference in the incidence rate of knee arthroplasty per unit increase in BMI was seen among women with no early lifetime overweight (IRR: 1.15, 95% CI: 1.13; 1.17), while the smallest difference was seen among women with early lifetime overweight (IRR: 1.09, 95% CI: 1.06; 1.12).Conclusion: Early lifetime overweight seems to modify the association between BMI and knee arthroplasty, suggesting a lower incidence rate for obese women with early lifetime overweight than obese women without early lifetime overweight.