Effect of age on body composition in healthy Beijing women

Objective To observe the effect of ageand menstrual statuson body composition in healthy Beijing women.Methods We measured body composition with dual-energy X-ray(GE Lunar Prodigy)in 316 healthy Beijing females aged 20 to 74 years(5-7 cases per age).Parameters provided by the software were as following:total body bone mineral content,lean mass,fat mass and fat percentage(% fat).Local regions measured included arm,leg,trunk,android region and gynoid region.Body mass index (BMI),fat mass index(FMI),free fat mass index(FFMI)and A/G were calculated.Volunteers were assigned to 6 groups according age by every ten years a group.Results BMC peaked during the 4th decade,LM peaked during the 5th decade,with a decline of 18.1%and 5.2%respectively at age 74 years.Total body fat mass and % fat showed a general increase with aging throughout the studied age range.Total body fat mass increased from 16±5 kg at age 20-29 years to 24±6 kg at age 70-74 years,while % fat increased from 31.3%to 39.5%.All local region % fat increased with aging at different extents.Android region % fat showed the largest raise extent(32.2%).BMI increased gradually from 21.1 kg/m2 at age 20-29 years to 26.1 kg/m2 at age 70-74 years.FMI changed more obviously than FFMI.A/G increased from 0.85 at age 20-29years to 1.02 at age 70-74 years.Different menstrual status in women of 40-59 vears had obvious eflfect on A/G and BMC(P＜0.05),while it had no significant effect on BMI.body weight and waist circumference(P＞0.05). Conclusions Aging and menstrual status have evident effect on body composition distribution in healthy Beijing women. Key words: Body composition; Densitometry,X-ray; Age factors; Menstmation; Body weights and measures