Table 2

Study	N	Follow up	Biochemical Changes				BMD
			PTH	ALP	Vit D	Ca	Femoral neck	Lumbar Spine	Total Hip
Vilrassa 2011	59 (F)	36m	Inc	--	Dec	No sig diff	-12.9%	-6.9%	--
Valderas 2009	26 (F) post-menopausal	3.5±1.1y	Inc	No sig diff	No sig diff	No sig diff	No sig diff	No sig diff	--
D de Campos 2008	30 (F)	8.5±0.7y	Inc	Inc	Dec	No sig diff	Osteoporosis in 13% Osteopenia in 40%	Osteopenia in 67%	--
Fleischer 2008	23	12m	Inc*	--	No sig diff**	No sig diff**	-9.2%	No sig diff	-8.0%
Mahdy 2008	70 (M+F)	1y	Inc	No sig diff	No sig diff**	No sig diff**	BMD by DEXA decreased by 3.198% and bone mineral content by 9.02%
diGiorgi 2007	403 (M+F) Gastric Bypass	2y	Inc	Inc	Inc**	No sig diff **	BMD not assessed, however the article suggests that with adequate supplementation the risk of bone loss can be attenuated.
diGiorgi 2007	131 (M+F) LAGB	2y	Inc***	Inc***	No sig diff **	No sig diff **
Coates 2004	25 (M+F)	11±3m		No sig diff	Inc**	No sig diff**	Urinary NTx (marker of bone resorption) increased by 288% and osetocalcin (marker of bone formation) by 53%
Parfitt 1999	21 (F)	3-14yr	Inc	Inc		Dec	Trabecular bone volume significantly reduced

* Returned to baseline by 12m
** Vit D and/or calcium supplementation
*** Values returned to or below baseline by 24h

Table 2: Selected studies of the effects of bariatric surgery and metabolic bone disease.