Dietary Patterns and Bone Mineral Density in Postmenopausal Women with Osteoporosis

Background/Objectives:

The aim of this study was to investigate the association between dietary patterns and bone mineral density (BMD) in postmenopausal women with osteoporosis.

Subjects/Methods:

This cross-sectional study included 156 postmenopausal and osteoporotic Brazilian women aged over 45 years. BMD of lumbar spine, total femur (TF), femoral neck and of total body (TB), as well as body composition (fat and lean mass), was assessed by dual-energy X-ray absorptiometry. Body mass index and lifestyle information were also obtained. Dietary intake was assessed by using a 3-day food diary. Dietary patterns were obtained by principal component factor analysis. Adjusted multiple linear regression analysis was applied in order to evaluate the predictive effect of dietary patterns on BMD. Significance was set at P less than 0.05.

Results:

Five patterns were retained: ‘healthy’, ‘red meat and refined cereals’, ‘low-fat dairy’, ‘sweet foods, coffee and tea’ and ‘Western’. The ‘sweet foods, coffee and tea’ pattern was inversely associated with TF BMD (β=−0.178; 95% CI: −0.039 to −0.000) and with TB BMD (β=−0.320; 95% CI: −0.059 to −0.017) even after adjusting for energy and calcium intake, lean mass, age and postmenopausal time.

Conclusions:

A concomitant excessive consumption of sweet foods and caffeinated beverages appears to exert a negative effect on BMD even when the skeleton already presents some demineralization. Food and beverage intake is a modifiable factor that should not be neglected in the treatment of individuals with osteoporosis.

http://www.nature.com/ejcn/journal/vaop/ncurrent/full/ejcn201527a.html

European Journal of Clinical Nutrition (25 March 2015) | doi:10.1038/ejcn.2015.27

The Latest Dietary Reference Intakes for Vitamin D

The Institute of Medicine (IOM) released new dietary reference intakes (DRIs) for calcium and vitamin D on November 30, 2010. The IOM concluded that vitamin D plays a key role in bone health and that current evidence does not support other health benefits from vitamin D supplementation, although the IOM called for additional research targeted at other health outcomes to continue. The changes in the recommended dietary allowance (RDA) for vitamin D were based solely on bone health. The IOM raised the RDA in children (1-18 years) and adults (19-70 years) from 200 IU to 600 IU per day and raised the tolerable upper intake level (UL) for adults from 2,000 IU to 4,000 IU per day. For the elderly (>70 years), the RDA was increased to 800 IU per day. The majority of vitamin D experts were disappointed by these conservative increases, but they should be considered steps in the right direction.

The IOM also made another very important change. After reviewing the published literature, they concluded that the serum level of vitamin D sufficient for bone health is above 20 ng/ml rather than 30-32 ng/ml, a value that has been used extensively by physicians. During the press conference, they said that it was warranted by the available scientific evidence even though it had not been one of their tasks. By lowering the sufficient level, they, in effect, reduced the number of people that would be considered to have inadequate serum levels of vitamin D. This change will likely cause significant confusion for both physicians and their patients, but it should be noted that it is only relevant to bone health and may not be optimal for other health benefits that have been attributed to vitamin D.

While the new RDA may bring many people into the new sufficient range, a cut-off of 20 ng/ml is controversial in the vitamin D research community because it does not consider other areas of health that the IOM has concluded are not supported by the currently published data.

The IOM is very conservative and based their decisions on a lack of randomized controlled trials (RCTs) that demonstrate a clear benefit from taking vitamin D supplements beyond bone health, but there is overwhelming evidence that supports biological plausibility for a role of vitamin D in numerous other health outcomes. For example, most non-bone cells have receptors for vitamin D, and we know that the function of immune cells is affected by vitamin D. The IOM narrowly focused on RCTs as the “gold standard”—an almost impossible hurdle to clear when applied to micronutrients. For example, subjects in the placebo group in an RCT will still have some of the micronutrient under evaluation in their bodies—unlike an RCT testing drugs; otherwise, they would get deficiency diseases. While anecdotal reports or single studies seem to be good enough for the IOM to determine the UL, multiple RCTs demonstrating similar outcomes are required for the RDA. Clearly, this is a double standard. DRIs need to take into account the totality of evidence, not just RCTs.

Linus Pauling Institute (LPI) continues to recommend a daily intake of 2,000 IU of vitamin D. This is well below the UL of 4,000 IU set by the IOM and should ensure that individuals, particularly in areas of the world where sun exposure is limited for extended periods of the year, get enough vitamin D. Also, to adjust for individual differences and ensure adequate body vitamin D status, LPI recommends aiming for a serum 25-hydroxyvitamin D level of at least 80 nmol/l (32 ng/ml). You can find this information and the recommendations for infants and children in the LPI Micronutrient Information Center section on vitamin D.

http://lpi.oregonstate.edu/ss11/vitaminD.html

Women's Mid-Life Non-Traumatic Fracture Risk Higher With Low Vitamin D

The lower a woman's vitamin D levels as she transitions to menopause, the greater her risk of sustaining a non-traumatic fracture. 

"Women who have levels less than 20 nanograms per milliliter would need some type of vitamin D supplementation," Dr. Jane A. Cauley of the University of Pittsburgh, who worked on the study, told Reuters Health. The findings back up the Institute of Medicine's conclusion that levels lower than 20 ng/ml are insufficient for skeletal health, she added.

Bone loss is known to accelerate during the menopausal transition, and postmenopausal women require significantly more calcium to reach neutral calcium balance than perimenopausal women, Dr. Cauley and her team note in their report, online February 23 in the Journal of Clinical Endocrinology and Metabolism.

To determine if serum 25(OH)D levels would be associated with changes in bone mineral density (BMD) and fracture risk, the researchers looked at data from the Study of Women's Health Across the Nation (SWAN) on 124 women with an incident traumatic fracture, 88 with an incident non-traumatic fracture, and 1,532 who did not sustain fractures during the study's average follow-up period of 9.5 years. 

Each woman had her serum 25(OH)D level checked at her third annual visit, while her BMD was assessed annually. The women's mean age at the study's outset was 48.5.

The study participants' mean 25(OH)D levels were 21.8 ng/ml, and 43% had levels below 20 ng/mL. While multivariate analysis found no association between 25(OH)D levels and traumatic fracture risk, the risk of non-traumatic fractures decreased by 28% for every 10 ng/ml increase in serum 25(OH)D. [Referring to Table 3 of the original article, “For every 10 ng/ml increase in 25(OH)D, the hazard ratio (HR) for nontraumatic fracture was 0.72 (0.54, 0.95).”; 1.00 minus 0.72 equals 0.28, or 28%]

Women with levels of 20 ng/ml or higher had a 46% lower risk of fracture during follow-up than women with lower levels of 25(OH)D. However, there was no association between baseline 25(OH)D and changes in BMD at the lumbar spine or femoral neck across menopause.

Roughly 22% of the women in the study had vitamin D levels greater than 30 ng/ml, Dr. Cauley said, so the study lacked power to determine if these women's non-traumatic fracture risk was further reduced.
"We didn't see any relationship between 25(OH)D and these bone changes, but we were somewhat limited in that we didn't have any information on how vitamin D changed across menopause," she added.



http://www.nutrition411.com/news/womens-mid-life-non-traumatic-fracture-risk-higher-low-vitamin-d
http://www.medscape.com/viewarticle/841028?src=wnl_edit_tpal&uac=127701PY:
http://press.endocrine.org/doi/pdf/10.1210/jc.2014-4367

Strontium Prevents the Progression of Thoracic Kyphosis

Background: Thoracic kyphosis (a frequent feature in the elderly and in post menopausal osteoporosis) can be caused by vertebral fractures. This exaggerated curvature of the spine is also related to degenerative changes including intervertebral disc space narrowing, deformities of the anterior part of the vertebrae and reduced spinal muscles strength. An increase over time in thoracic kyphosis has been associated with impairment in global health due to increased body sway and risk of falls, impairments in pulmonary function, presence of esophagial hiatal hernia, and an increase in risk of mortality in older women.

Objectives: The objective of this study was to assess the effect on thoracic kyphosis progression over a 3-year treatment with strontium ranelate, a treatment against osteoporosis that reduces the risk of vertebral, nonvertebral and hip fractures.

Methods: This study was performed in women with postmenopausal osteoporosis from SOTI 1 and TROPOS 2 studies, aiming to demonstrate the efficacy of strontium ranelate against vertebral and non-vertebral fractures. Patients underwent lateral radiographs of the thoracic and lumbar spine at baseline and annually over 3 years (standardized procedures). The level of thoracic kyphosis was reflected by a kyphosis index, defined on lateral thoracic radiographs as the ratio BD/AC (AC= line from the anterior superior edge of T4 to the anterior inferior edge of T12; BD= perpendicular line from the furthest superior or inferior posterior point of T7, T8 or T9 vertebrae to AC line) expressed as a %. The highest the KI, the more severe the thoracic kyphotic curvature.

Results: The population consisted of 4055 women with postmenopausal osteoporosis (2038 patients randomised to strontium ranelate and 2017 randomised to placebo). Baseline characteristics were similar: mean age 73.5; Spine BMD T-score (L2-L4): -3.06; Femoral neck T-score: -2.97; KI: 25.4. Over 3 years, there was a significant increase from baseline in kyphotic index for all patients. However, this increase was significantly lower (p=0.003) in patients treated with strontium ranelate: +3.71±7.69% than in the placebo group:+4.70±7.32%.
The same calculations were repeated after exclusion of patients having either prevalent or incident thoracic vertebral fractures. In this subset of 1193 patients (634 in the strontium ranelate group and 559 in the placebo group), the change in the strontium ranelate group was still lower than in the placebo group (+ 2.72±7.17% versus 4.34±6.54%, respectively).



Conclusion: These prospective results demonstrate that thoracic kyphosis increases over time in postmenopausal women with osteoporosis. Strontium ranelate decreased the progression of this thoracic kyphosis over 3 years, regardless of the presence or not of vertebral fractures. This new effect of strontium ranelate possibly reflects additional benefit on spinal components besides its efficacy in decreasing vertebral fractures.

References: 1 Meunier PJ et al. N Engl J Med 2004; 2 Reginster J.Y et al. JCEM 2005

Ann Rheum Dis 2008;67(Suppl II):541
http://www.abstracts2view.com/eular/view.php?nu=EULAR08L_SAT0344

Too Much Vitamin D Can Be Bad for You

Context:

Optimal levels of vitamin D have been a topic of heavy debate, and the correlation between 25-hydroxyvitamin D [25(OH)D] levels and mortality still remains to be established.

Objective:

The aim of the study was to determine the association between all-cause mortality and serum levels of 25(OH)D, calcium, and PTH.

Design and Setting:

We conducted a retrospective, observational cohort study, the CopD Study, in a single laboratory center in Copenhagen, Denmark.

Participants:

Serum 25(OH)D was analyzed from 247,574 subjects from the Copenhagen general practice sector. In addition, serum levels of calcium, albumin-adjusted calcium, PTH, and creatinine were measured in 111,536; 20,512; 34,996; and 189,496 of the subjects, respectively.

Main Outcome Measures:

Multivariate Cox regression analysis was used to compute hazard ratios for all-cause mortality.

Results:

During follow-up (median, 3.07 yr), 15,198 (6.1%) subjects died. A reverse J-shaped association between serum level of 25(OH)D and mortality was observed. A serum 25(OH)D level of 50–60 nmol/liter was associated with the lowest mortality risk. Compared to 50 nmol/liter, the hazard ratios (95% confidence intervals) of all-cause mortality at very low (10 nmol/liter) and high (140 nmol/liter) serum levels of 25(OH)D were 2.13 (2.02–2.24) and 1.42 (1.31–1.53), respectively. Similarly, both high and low levels of albumin-adjusted serum calcium and serum PTH were associated with an increased mortality, and secondary hyperparathyroidism was associated with higher mortality (P < 0.0001).

Conclusion:

In this study from the general practice sector, a reverse J-shaped relation between the serum level of 25(OH)D and all-cause mortality was observed, indicating not only a lower limit but also an upper limit. The lowest mortality risk was at 50–60 nmol/liter. The study did not allow inference of causality, and further studies are needed to elucidate a possible causal relationship between 25(OH)D levels, especially higher levels, and mortality.

Note: 50-60 nmol/L equals 20-24 ng/ml. To convert nmol/L to ng/ml, divide by 2.5. To convert ng/ml to nmol/L, multiply by 2.5.  

The full article is available here:

http://press.endocrine.org/doi/full/10.1210/jc.2012-1176