Effect of aging on body fat.

OBJECTIVE

To examine the effects of aging on body fat.

DESIGN

Cross-sectional comparison by age and gender.

SETTING

Community health fairs, medical school, and a Department of Veterans Affairs Nursing Home Care Unit.

PARTICIPANTS

Five hundred and fourteen individuals between the ages of 29-96 attending three different community health fairs; 62 first year medical students; and 121 male residents of a nursing home.

INTERVENTION

None

MEASUREMENTS

All underwent measurements of weight, height, and percentage body fat using the RJL Spectrum Bodycomp II Bioelectrical Impedance machine.

RESULTS

Percentage body fat increased slightly between ages 20 to 39 years and 40 to 84 years. There were no significant differences noted in percentage body fat among the age groups 40-64, 65-74 and 75-84 in either males or females. There were also no significant differences noted in percentage body fat between any age groups when age-matched for body mass index. Patients over the age of 85 had significantly lower percentage body fat compared with all other age groups. Finally, nursing home patients were more likely to have a lower percentage body fat compared with the ambulatory population.

CONCLUSIONS

The percentage body fat does not appear to increase significantly after the age of 40 years. In addition, the major reason for the increase in body fat in older persons appears to be weight gain rather than a true age-related increase in percentage body fat. Previous studies suggesting a marked increase in percentage body fat with advancing age have failed to correct for the presence of an increased body mass index that commonly occurs at middle age.