Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA
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Randomized Controlled Trial Clinical Trial
Wintertime vitamin D deficiency in male adolescents: effect on parathyroid function and response to vitamin D3 supplements.
The first part of this study consisted of an 18 month follow-up of the vitamin D status and parathyroid function in a group of 54 French male adolescents, aged from 13 to 16 years old and all pupils of a jockey training school. During the 18 month period four samplings were made, one every 6 months. The first was during September of the first year, the second and third during March and October of the second year, and the last in March of the third year. ⋯ In the control subjects, March 25(OH)D levels (21.0 +/- nmol/l were low, with values below 25 nmol/l in 78% of subjects, and iPTH concentrations (3.97 +/- 1.08 pmol/l) were significantly (p<0.001) higher than in September (2.91 +/- 0.81 pmol/l). The constant vitamin D wintertime deficiency and wintertime rise in iPTH in adolescent French males throughout puberty has been demonstrated. In adolescents with low dairy calcium intakes, the vitamin D3 treatment was sufficient to maintain 25(OH)D concentrations at their summer levels throughout winter and to prevent an excessive wintertime rise in iPTH levels.
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The purpose of this study was to assess whether dietary changes aimed at reducing serum cholesterol can increase the risk of osteoporosis (OP) and fracture. The study group consisted of 311 postmenopausal women with high serum cholesterol levels and following a diet low in dairy products (calcium intake estimated at less than 300 mg/day) for 27.3 +/- 29.1 months. This sample was compared with a case-control group of 622 healthy postmenopausal women paired for age and age at menopause and with a calcium intake estimated at more than 1 g/day. ⋯ No differences in further risk factors for coronary heart disease were found between the groups, but the proportion of women physically active was lower in the women with high serum cholesterol levels. A diet that severely limits calcium intake from dairy products in an attempt to correct raised serum cholesterol levels is a risk factor for postmenopausal OP and Colles' fracture. Dietary intervention methods to lower serum cholesterol in postmenopausal women should maintain an adequate calcium intake by providing calcium from low-fat dairy products or calcium supplements.