2 Studies: osteoporosis/vit.D & PTH; hip fx & antioxidants

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Topic: OSTEOPOROSIS, BONE MINERAL DENSITY - Calcidiol, Calcitriol,

Parathyroid Hormone, PTH, Postmenopausal Women

Title: Vitamin D Status and Parathyroid Hormone are Related to Bone

Mineral Density in Postmenopausal Women

Reference: “The relationship of vitamin D status to bone mineral

density in an Italian population of postmenopausal women,” Malavolta N,

Pratelli L, et al, Osteoporos Int., 2005; 16(12): 1691-7. (Address:

Department of Internal Medicine, Policlinico S.Orsola Malpighi, Bologna,

Italy. E-Mail: malavolt@... ).

Summary: In a study involving 156 Italian postmenopausal women, bone

mineral density (BMD) was found to be positively correlated with serum

calcidiol (25-hydroxyvitaminD) and negatively correlated with

parathyroid hormone (PTH). Serum calcidiol, calcitriol

(1,25-dihydroxyvitaminD) and PTH measurements were measured according to

the current laboratory methods of analysis. BMD measurements were taken

at the lumbar spine and upper femur by dual X-ray absorptiometry. A

positive statistical correlation was found between calcidiol and BMD,

both at the hip and spine, whereas no statistically significant

correlation was found between BMD and calcitriol. A statistically

significant negative correlation was found between BMD and PTH. Logistic

regression analysis showed age, calcidiol, and PTH to be significant

predictors of low BMD. In a backward logistic regression model,

calcidiol was found to be the best predictor for femoral neck

osteoporosis, and together with age, calcidiol was found to be the best

predictor for spine osteoporosis. Thus, this study confirms that vitamin

D status is positively correlated to BMD, and PTH is negatively

correlated to BMD in postmenopausal women.

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Topic: OSTEOPOROSIS, HIP FRACTURE - Antioxidants, Vitamin C, Vitamin E,

Beta-Carotene, Selenium

Title: Antioxidant Intake may be Associated with Reduced Risk of

Osteoporotic Hip Fracture, An Effect Modified by Smoking Status

Reference: “Antioxidant intake and risk of osteoporotic hip fracture in

Utah: an effect modified by smoking status,” Zhang J, Munger RG, et al,

Am J Epidemiol., 2006; 163(1): 9-17. (Address: Department of Nutrition

and Food Sciences, Utah State University, Logan, UT, USA. E-Mail:

rmunger@... ).

Summary: In a population-based, case-control study involving 1,215 men

and women (at least 50 years old) who incurred a hip fracture during

1997-2001, and 1,349 age- and sex-matched controls from the Utah Study

of Nutrition and Bone Health, antioxidant intake was found to be

associated with a reduced risk of osteoporotic hip fracture, with the

effect being strongly modified by smoking status. Diet was assessed from

food frequency questionnaires completed by the participants. Amongst

participants classified as ‘ever smokers,’ those in the highest quintile

of vitamin E intake were found to have a lower risk of hip fracture,

after adjustment for confounders, versus those in the lowest quintile

(odds ratio 0.29). Among ‘ever smokers,’ a similar lower risk of hip

fracture was found on comparing participants in the highest quintiles of

beta-carotene intake (odds ratio 0.39) and selenium intake (odds ratio

0.27) versus those in lowest quintiles of beta-carotene and selenium

intakes. Vita min C intake did not have a significant graded association

with hip fracture risk among ‘ever smokers.’ Similar findings were

obtained with overall antioxidant intake scores (odds ratio 0.19), while

no similar associations were found among participants classified as

‘never smokers.’ Thus, this study suggests that antioxidant intake may

be associated with a reduced risk of osteoporotic hip fracture in

elderly subjects, particularly those with a history of smoking.

--

ne Holden, MS, RD < fivestar@... >

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