[Body composition analysis among adults with different body weights].

OBJECTIVE

To explore the characteristics of body composition among male and female adults with different body weights.

METHODS

A total of 61 379 healthy adults (39 855 males and 21 527 females) were referred to our health examination center between May 2005 and February 2011. Body mass index (BMI) and body composition contents of fat, water, muscle, protein and mineral salt were measured by anthropometric measurements and bioelectrical impedance analysis (BIA). The data were analyzed among groups divided by gender, age and BMI.

RESULTS

(1) The prevalence of overweight and obesity defined by BMI was significantly higher in the male group than the female of the same age group under 70 years old (all P < 0.01). (2) Within a certain age range (< 60 in males, < 70 in females), the prevalence of both overweight and obesity defined by BMI increased with age (all P < 0.01). (3) The fat mass percentage was significantly higher in females than in males of the same age group. The difference became more and more significant with advancing age. And the most significant difference was found in the upper 70 years old group (fat mass rate of males vs females, 24% ± 7% vs 36% ± 6%, P < 0.01). (4) Body fat mass percentage progressively elevated with increases of BMI while there was a decreasing trend of other body composition contents. The total male subjects had higher percentage of muscle, water and mineral salt than females (percentage of muscle, water and mineral salt of males vs females, 0.708 ± 0.066 vs 0.664 ± 0.063, 0.520 ± 0.044 vs 0.474 ± 0.042, 0.040 ± 0.004 vs 0.036 ± 0.004, all P < 0.01) while the percentage of protein was higher in the total female group (P < 0.01).

CONCLUSIONS

Females has more fat mass than males under the same BMI. So it is more reasonable to introduce adiposity for the evaluation of obesity, especially in females.