Changes in bone mineral density and bone turnover markers in obese women after short-term weight loss therapy during a 5-year follow-up.
BACKGROUND
The protective effect of adipocity on bone metabolism has not been confirmed during long-term follow-up. It is not known whether the rate of bone turnover and changes in mineral metabolism in obese people result from endocrine properties of the adipose tissue or merely the mechanical load.


OBJECTIVE
The aim of the study was to evaluate bone and calcium-phosphorus metabolism in obese women during a 5-year follow-up.


METHODS
The study involved 47 obese women who underwent a 3-month weight loss therapy. We evaluated changes in the serum levels of parathormone (PTH), calcidiol (25(OH)D3), collagen type I crosslinked C-telopeptide (CTx-I), osteocalcin, total calcium, inorganic phosphates, and in bone mineral density. The control group consisted of 17 healthy women with proper body weight.


RESULTS
We observed a similar decrease in bone mineral density (BMD) in the lumbar spine and femoral neck, and a comparable decrease in the serum levels of CTx-I and osteocalcin in both groups during the 5-year follow-up. Changes in serum PTH levels were not statistically significant. In obese women, a nonsignificant increase in the serum level of 25(OH)D3 was observed as early as after a 3-month weight loss therapy and during follow-up. In controls, serum 25(OH)D3 levels tended to decrease. During follow-up, the number of obese patients with disturbances in vitamin D metabolism decreased from 78.7% to 53.2% (P = 0.01). Such disturbances were observed in 35.3% of the control group. In obese patients, there was a positive correlation between the change in body mass and BMD in the proximal femur (r = 0.279, P = 0.04). In controls, there was a positive correlation between the change in body mass and BMD in the lumbar spine (r = 0.477, P = 0.05).


CONCLUSIONS
In obese women who underwent weight loss therapy, the levels of bone turnover markers decreased and abnormal vitamin D metabolism was still observed during the 5-year follow-up.
Holecki
Michał
M
Department of Internal Medicine and Metabolic Diseases, Medical University of Silesia, Katowice, Poland. holomed@poczta.onet.pl
Zahorska-Markiewicz
Barbara
B
Chudek
Jerzy
J
Wiecek
Andrzej
A
D000328:Adult; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism* / Q000628:therapy; D013997:Time Factors; D015431:Weight Loss
D015415:Biomarkers