ABSTRACT: Low vitamin D status and hyperparathyroidism occur in obesity and may be involved in pathogenesis of obesity-associated comorbid conditions.
Our aims were to determine in obesity whether there was vitamin D insufficiency, assessed by serum 25-hydroxyvitamin D (s25D) and serum PTH (sPTH) and whether it related to comorbid conditions.
We conducted a case-control study of 48 women having bariatric surgery and 50 healthy women frequency matched for race, age, year, and season of study. Height, weight, s25D, sPTH, serum 1,25-dihydroxyvitamin D (s1,25D), serum bone alkaline phosphatase, serum cross-linked N-telopeptides of type 1 collagen, and serum calcium, phosphate, creatinine, glucose, and insulin were measured, and comorbid conditions were documented from patient files.
Weight (140 vs. 76 kg, P < 0.001), sPTH (44.4 vs. 25.6 pg/ml, P < 0.001), s1,25D (39 vs. 24 pg/ml, P < 0.001), serum bone alkaline phosphatase (19 vs. 12 ng/ml, P < 0.001), serum cross-linked N-telopeptides of type 1 collagen (9.6 vs. 7.9 nm bone collagen equivalents, P = 0.007), serum phosphate (3.45 vs. 3.24 mg/dl, P = 0.043), and serum creatinine (1.05 vs. 0.87 mg/dl, P < 0.001) were higher, and s25D (16 vs. 23 ng/ml, P <.001) was lower in bariatric-surgery women than control women. s25D was lower in bariatric-surgery women than controls in summer (17 vs. 26 ng/ml, P < 0.0001) but not winter (15 vs. 18 ng/ml, P > 0.2). Multiple regression analysis demonstrated that weight predicted s25D (P < 0.001) and sPTH (P = 0.001), but s25D did not predict sPTH or the presence of comorbid conditions except for osteoarthritis.
Women having bariatric surgery had lower s25D and higher sPTH. The major determinant of s25D and sPTH was weight. Hyperparathyroidism in obesity did not indicate vitamin D insufficiency. Low s25D was not associated with comorbid conditions, apart from osteoarthritis.
The Journal of clinical endocrinology and metabolism 02/2011; 96(5):1320-6. · 6.50 Impact Factor
ABSTRACT: The aim of the study was to examine serum markers of bone turnover at 6 and 18 months after Roux-en-Y gastric bypass surgery.
Ten women and 10 men [body mass index (BMI), 50.2 +/- 8.4 kg/m(2)] were studied at 6 months; 10 women and nine men (BMI, 47.2 +/- 6.6 kg/m(2)) were studied at 18 months after surgery.
Serum osteocalcin, bone specific alkaline phosphatase (BAP), N-telopeptide of type 1 collagen (NTX), PTH, 25-hydroxy vitamin D, and leptin were measured.
BMI was reduced 32.7 +/- 6.2% at 6 months after surgery. Serum osteocalcin (6.9 +/- 2.4 to 10.9 +/- 2.6 ng/ml; P < 0.0001), BAP (14.2 +/- 3.7 to 16.4 +/- 4.5 ng/ml; P = 0.04), and NTX (10.9 +/- 1.7 to 19.6 +/- 5.3 nm bone collagen equivalents; P < 0.0001) were increased. Calcium, phosphate, and PTH were unchanged, but 25-hydroxy vitamin D increased (16.0 +/- 8.9 vs. 26.9 +/- 10.6 ng/ml; P <0.0001). The increase in NTX correlated with reduction in serum leptin (r = 0.58; P = 0.007). BMI was reduced 40.9 +/- 7.5% at 18 months after surgery. Serum BAP (17.6 +/- 5.3 to 22.2 +/- 7.8 ng/ml; P = 0.0017) and NTX (10.8 +/- 2.7 to 16.9 +/- 5.5 nm bone collagen equivalents; P < 0.0001) were increased. Calcium, phosphate, and PTH were unchanged, but 25-hydroxy vitamin D increased (17.7 +/- 7.6 to 25.6 +/- 6.8 ng/ml; P < 0.0001). The increase in NTX correlated with reduction in BMI (r = 0.58; P = 0.009) and leptin (r = 0.45; P = 0.04) and the increase in serum 25-hydroxy vitamin D (r = 0.43; P = 0.05). In multiple regression (adjusted model R(2) 0.263; P = 0.013), reduction in leptin was a significant predictor of increase in NTX (P = 0.016), but changes in BMI and 25-hydroxy vitamin D were not.
Weight loss after bariatric surgery is associated with long-term increase in serum markers of bone turnover. The increase in NTX is related to the decrease in leptin, which may signal caloric restriction to the skeleton.
The Journal of clinical endocrinology and metabolism 10/2009; 95(1):159-66. · 6.50 Impact Factor
ABSTRACT: A cross-sectional study of 232 healthy children, with about equal numbers of boys and girls and blacks and whites, aged 4 to 16 yr, was conducted to investigate the racial differences in bone mineral. Bone mineral content (BMC) by dual x-ray absorptiometry was found to be similar between blacks and whites at the spine after controlling for age and Tanner stage. However, total body BMC was higher in blacks, compared with whites of the same age and Tanner stage. Height and weight alone reduced the racial difference in BMC from 152 g to 66 g in girls and from 163 g to 105 g in boys, in whom the difference was further reduced to 66 g after accounting for lean and fat body mass and subscapular skinfold. The only significant sex hormone was androstenedione, which explained another 4-5 g of the racial difference in total body BMC for both boys and girls. Among the biochemical variables, only 25OH vitamin D reduced the residual racial difference in total body BMC to 39 g in girls, whereas serum PTH, urine free deoxypyridinoline ratio, and 1,25(OH)(2) vitamin D reduced the residual difference to 25 g in boys. The residual racial differences in bone mass were not statistically significant.
Journal of Clinical Endocrinology & Metabolism 03/2003; 88(2):642-9. · 6.50 Impact Factor