A co-twin study of the effect of calcium supplementation on bone density during adolescence

Abstract

The effect of calcium supplementation on bone mineral density (BMD) was evaluated in female twin pairs aged 10-17 years with a mean age of 14 years. Forty-two twin pairs (22 monozygotic, 20 dizygotic; (including one monozygotic pair from a set of triplets) completed at least 6 months of the intervention: 37 pairs to 12 months and 28 pairs to 18 months. BMD was measured by dual-energy X-ray absorptiometry (DXA). In a double-blind manner, one twin in each pair was randomly assigned to receive daily a 1000 mg effervescent calcium tablet (Sandocal 1000), and the other a placebo tablet similar in taste and appearance to the calcium supplement but containing no calcium. Compliance (at least 80% tablets consumed), as measured by tablet count, was 85% in the placebo group and 83% in the calcium group over the 18 months of the study, on average increasing dietary calcium to over 1600 mg/day. There was no within-pair difference in the change in height or weight. When the effect of calcium supplementation on BMD was compared with placebo at approximately 6, 12 and 18 months, it was found that there was a 0.015 +/- 0.007 g/ cm2 greater increase in BMD (1.62 +/- 0.84%) at the spine in those on calcium after 18 months. At the end of the first 6 months there was a significant within-pair difference of 1.53 +/- 0.56% at the spine and 1.27 +/- 0.50% at the hip. However, there were no significant differences in the changes in BMD after the initial effect over the first 6 months. Therefore, we found an increase in BMD at the spine with calcium supplementation in females with a mean age of 14 years. The greatest effect was seen in the first 6 months; thereafter the difference was maintained, but there was no accelerated increase in BMD associated with calcium supplementation. The continuance of the intervention until the attainment of peak bone mass and follow-up after cessation of calcium supplementation will be important in clarifying the optimal timing for increased dietary calcium and the sustained, long-term effects of this intervention.

Determinants of bone mineralization in 8 to 20 year old Finnish females

“…Average calcium intake was high (over 1000 mg daily by CaD) in all the groups, and this consistency may explain the lack of association. The benefit of calcium supplementation on bone has been found in many previous studies (Johnston et al, 1992;Lloyd et al, 1993;Lee et al, 1994;Teegarden and Weaver, 1994;Nieves et al, 1995;Nowson et al, 1995), but in all of these studies the baseline calcium intake was markedly lower than that of P a P-value for total mean difference; P b P-value for differences between the Tanner groups. P a P-value for total mean difference; P b P-value for differences between the Tanner groups.…”

“…Although genetic factors play a major role in determining peak bone mass, many environmental factors, such as calcium intake and other nutritional factors, physical activity, and some diseases, also contribute to bone accumulation. For instance, increased calcium intake and physical activity have been found to have a positive effect on bone mass accumulation in growing subjects (Johnston et al, 1992;Lloyd et al, 1993;Lee et al, 1994;Teegarden and Weaver, 1994;Cooper et al;Kannus et al, 1995;Nowson et al, 1995).…”

Girls’ Dairy Intake, Energy Intake, and Weight Status

“…There is evidence that increased intake of dairy foods and calcium may play a significant role in maintaining a healthful weight and moderating body fat (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). However, results across studies have been inconsistent (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28), and this may be attributable to major challenges in using self-reported dietary intake data. Self-reported intakes tend to be subject to underreporting bias and the underreporting of energy intake tends to be positively related to weight status.…”

Metabolismo do cálcio na fenilcetonúria

“…Nowson et al 35 , em seu trabalho, avaliaram o efeito da suplementação de cálcio na massa mineral óssea de gêmeas de faixa etária de 10 a 17 anos. Observou-se considerável aumento na densidade mineral óssea da espinha lombar.…”