August 19, 2011 By Jeannine Stein, Los Angeles Times
Postmenopausal women who lose weight can also lose bone mass. But a study finds that regaining that weight doesn't necessarily replace the lost bone.
The small, exploratory study included 23 overweight women who had been through menopause and were not taking any hormone therapy or drugs that might affect their bone metabolism. Women are at high risk for osteoporosis after menopause.
For six months, the women participated in a regular program of endurance exercise to encourage weight loss of about 9 to 11 pounds. After that, the women were followed for a year. They were tested for bone density at the beginning of the study as well as six and 18 months later. Almost 40% had osteoporosis at the beginning of the study.
On average, the women lost about 8.6 pounds of fat, and after 18 months — a year after they stopped exercising — they had gained back an average of 6.4 pounds, almost all of it fat.
During the six months, the women also lost bone density in their lumbar spines and hips, and there was no significant bone recovery after they regained the weight. The study authors noted that the bone loss may have been prevented or reduced had women done exercise that increased bone density, such as strength training (non-impact cardiovascular exercise typically doesn't build bone mass). They authors also speculated about whether low bone mass in some overweight and obese people may be partially blamed on repeated diet-and-weight-gain cycles.
– – – – –
A Losing Battle: Weight Regain Does Not Restore Weight Loss-Induced Bone Loss in Postmenopausal Women
Obesity , (18 August 2011) | doi:10.1038/oby.2011.263
Karen L. Villalon, Wendolyn S. Gozansky, Rachael E. Van Pelt, Pam Wolfe, Catherine M. Jankowski, Robert S. Schwartz and Wendy M. Kohrt
Previously, we reported significant bone mineral density (BMD) loss in postmenopausal women after modest weight loss. It remains unclear whether the magnitude of BMD change in response to weight loss is appropriate (i.e., proportional to weight loss) and whether BMD is recovered with weight regain. We now report changes in BMD after a 1-year follow-up. Subjects (n = 23) in this secondary analysis were postmenopausal women randomized to placebo as part of a larger trial. They completed a 6-month exercise-based weight loss program and returned for follow-up at 18 months. Dual-energy X-ray absorptiometry (DXA) was performed at baseline, 6, and 18 months. At baseline, subjects were aged 56.8 ± 5.4 years (mean ± s.d.), 10.0 ± 9.2 years postmenopausal, and BMI was 29.6 ± 4.0 kg/m2. They lost 3.9 ± 3.5 kg during the weight loss intervention. During follow-up, they regained 2.9 ± 3.9 kg.
Six months of weight loss resulted in a significant decrease in lumbar spine (LS) (?1.7 ± 3.5%; P = 0.002) and hip (?0.04 ± 3.5%; P = 0.03) BMD that was accompanied by an increase in a biomarker of bone resorption (serum C-terminal telopeptide of type I collagen, CTX: 34 ± 54%; P = 0.08).
However, weight regain was not associated with LS (0.05 ± 3.8%; P = 0.15) or hip (?0.6 ± 3.0%; P = 0.81) bone regain or decreased bone resorption (CTX: ?3 ± 37%; P = 0.73).
The findings suggest that BMD lost during weight reduction may not be fully recovered with weight regain in hormone-deficient, postmenopausal women. Future studies are needed to identify effective strategies to prevent bone loss during periods of weight loss.
– – – – – – – – – – – – – –
Appears that lumbar spine loss was -1.7 after weight loss but lumbar spine increase after weight gain was only 0.05, rather than +1.7 if spine had fully recovered
There is no reason to suspect that bone will be re-built - even if have enough vitamin D.
No way to rebuild the 'bridges' inside the bones once they are torn down - such as by weight loss