Objectives:To investigate the relationships between vertebral marrow fat in lumbar spine and age and gender in adults using iterative decomposition of water and fat with echo asymmetry and least-squares estimation image quantitation(IDE AL-IQ)magnetic resonance imaging technology.Methods:The IDEAL-IQ fat fraction images from 298 subjects(Male:138,Female:160,age range:20-69 years old)were collected.All the patients were divided into 5 groups based on age,with each group spanning a range of 10 years:age range 20-29 years(Twenties):24 males,20 females;30-39 years(Thirties):47 males,39 females;40-49 years(Forties):36 males,47 females;50-59 years(Fifties):20 males,37 females;60～69 years(Sixties):11 males,17 females.The bone marrow proton density fat fration(PDFF)were measured using GE ADW4.6 processing work station.Results:In the same age group,there were differences in vertebral bone marrow PDFF between gen-ders.PDFF of L1-L5 vertebrae was significantly higher in males than females in twenties,thirties and forties(P＜0.05).In the fifties,there was no statistically significant difference in the L1-L5 vertebrae PDFF between males and females(P＞0.05);while in the sixties,the PDFF of the L1-L5 vertebrae was lower in males than that in females(P＜0.05).The PDFF of lumbar vertebral bone marrow was positively correlated with age,with a higher correlation observed in females(r=0.72,P＜0.05)than that in males(r=0.32,P＜0.05).From the age of 20 to 69,the L4 vertebra PDFF in males had the highest growth rate(21.08％),while the L1 vertebra PDFF in female had the highest growth rate(65.68％).For males,the growth of PDFF was primarily concentrated in the thirties and fifties;The PDFF of L1,L4,and L5 vertebrae showed the largest increase in the fifties,while that of L2 and L3 vertebrae had the highest increase rate in the thirties.For females,vertebral PDFF showed a slight decrease trend in the group of thirties,which gradually increased subsequently in all vertebare in the group of forties,fifties,and sixties,with the largest increase rate observed in the fifties.Conclusions:There are differences in vertebral fat distribution between males and females across different age groups,and the growth rates of vertebral PDFF also vary;the PDFF of vertebral bodies in different segments of the lumbar spine is positively correlated with age.