[Vertebral and femoral bone mineral density of 724 caucasian Brazilian women: influence of age and body weight].
OBJECTIVE
To study the vertebral (L2-L4) and femoral (neck) bone mineral density (BMD) of normal white women.


METHODS
We measured the BMD of 724 women (40-79 kg; 20-69 years-age) by dual-energy X-ray absorptiometry. Data were analysed as a function of age and body weight (BW).


RESULTS
Thinner women (40-49 kg) attained maximal vertebral and femoral BMD (mBMD) at ages between 30-39 years, while heavier women (60-79 kg) already had the mBMD by the age of 20. At the femur, there was a significant mBMD-BW correlation (r = 0.97; p < 0.001; slope = 0.72%/kg). At the spine, only the 40-49 Kg women exhibited lower mBMD when compared to the others (p < 0.001). The decrease of the vertebral BMD was more intense (-8.3 vs. -5.7%/decade) and started earlier (fourth vs. fifth decade) in women weighting 40-59 kg, as compared to those weighting 60-79 kg. The decrease of the femoral BMD was initiated just after mBMD was achieved and, at the age of 69, heavier women showed a decrease that was 5.3% lower than those weighting 40-49 kg. The vertebral BMD of the Brazilian women was practically the same as reported for a North-American population.


CONCLUSIONS
(i) Vertebral and femoral BMD of this Brazilian population varied with age similarly to other white female populations; (ii) provided that appropriate corrections are made for BW, the BMD of Brazilian women is comparable to the BMD of North-Americans; and (iii) the BW is important both in acquisition and decline of bone mass, as it influences the relation BMD-age.
Lewin
S
S
Unidade de Diagnóstico e Densitometria Ossea, Universidade de São Paulo.
Gouveia
C H
CH
Marone
M M
MM
Wehba
S
S
Malvestiti
L F
LF
Bianco
A C
AC
D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001938:Brazil; D005260:Female; D005272:Femur Neck / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000502:physiology*; D008875:Middle Aged; D009656:North America