Does body mass index reflect adequately the body fat content in perimenopausal women?
OBJECTIVE
To test whether BMI cut-off points for obesity, reflect adequately the actual obesity status, in a sample of perimenopausal women. For study's purposes, a new bioelectrical impedance analysis (BIA) equation was estimated.


METHODS
115 Greek, middle-aged women were tested. Body composition was estimated by dual X-ray absorptiometry and BIA method. Waist (WC) and hip circumference (HC) and skinfolds were also measured.


RESULTS
The BIA equation predicted fat free mass (FFM) from height, weight, age and resistance (R(2)=0.88, S.E.E.=1.89 kg). The bias was not significant and the limits of agreement +/-3.6 kg. BMI, FFM, body fat percentage (BF%), waist-to-hip ratio (WHR), WC and HC did not differ between pre (N=37) and postmenopausal (N=48) women (at p=0.05). Both BF% and BMI correlated with WHR and WC (r(BF%-WHR)=0.287, p=0.009; r(BMI-WHR)=0.355, p=0.001 and r(BF%-WC)=0.72, p<0.0001; r(BMI-WC)=0.81, p<0.0001). The mean values for BF%, WC and WHR for women with normal BMI were 36.15% (+/-4.19), 72.53 cm (+/-3.64) and 0.749 (+/-0.05), whereas values for overweight women were 41.42% (+/-3.16), 83.06 cm (+/-7.55) and 0.787 (+/-0.05) and for obese these were 47.40% (+/-3.67), 95.10 cm (+/-8.52) and 0.814 (+/-0.05), respectively.


CONCLUSIONS
The body composition analysis of the study sample revealed undesirably high BF%, even in subjects with BMI below 25, in whom BMI did not reflect the body fat content. However, BF was mainly distributed at the lower part of the body. Whether BMI or BF% is a more sensitive index for obesity related diseases, in perimenopausal period, remains to be defined.
Department of Dietetics and Nutritional Science, Harokopio University, 17671, Kallithea, El. Venizelou 70, Athens, Greece.
Meropi D
MD
Kontogianni
Demosthenes B
DB
Panagiotakos
Fotini N
FN
Skopouli
D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D047648:Perimenopause / Q000502:physiology*