The Trend of Knee Osteoarthritis Among Middle-Aged Population in the World from 1990 to 2021:Analysis by Age-Period-Cohort Model

Li Sitong; Li Bao; Wang Haofei; Li Haokun; Liu Xinwei; Zhai Shuang

Abstract：Objective To analyze the trend of the incidence of knee osteoarthritis(KOA)in the global middle-aged population from 1990 to 2021,and explore the influence of age,period and cohort factors on the incidence.Methods Data on the incidence of KOA,crude incidence of KOA and standardized incidence of KOA among the global middle-aged(40～64 years old)population were selected from the Global Burden of Disease Database 2021.The Joinpoint regression model was used to analyze the trend of the standardized incidence of KOA in the global middle-aged population from 1990 to 2021,and the annual percentage change was calculated.APC and average annual percentage change(AAPC).An age-period-cohort model was used to analyze the effects of age,period and cohort factors on the incidence of KOA in the global middle-aged population.Results From 1990 to 2021,the number of KOA cases in middle-aged people increased from 9 703 661 to 21 029 172(116.71％increase).Crude incidence rose from 900.94 × 10-5 to 985.22 × 10-5(9.35％increase),and standardized incidence increased from 907.18 × 10-5 to 976.66 × 10-5(7.66％increase).Joinpoint regression model results indicated an increasing trend in standardized KOA incidence for the global middle-aged,male,and female populations(AAPC=0.24％,P＜0.05).Age-period-cohort model analysis showed that the net drift value of KOA incidence in the global middle-aged population had a 95％CI of 0.34％(0.39％,0.29％)from 1990 to 2021.The local drift value for the 40～64 age group was＞0,initially increasing and then decreasing with age,reaching the lowest value of 0.18％in the 60～64 age group.Conclusion KOA incidence in the global middle-aged population significantly increased from 1990 to 2021,influenced by age,period,and cohort factors.Women constituted a large proportion of the increase,necessitating enhanced health education and promotion of healthy lifestyles,particularly for middle-aged women.Differentiated prevention and treatment strategies should be developed for various age groups and birth cohorts to effectively reduce KOA incidence.