Interaction of nutritional calcium and HRT in prevention of postmenopausal bone loss: a prospective study

Comorbidity of osteoporosis and Alzheimer's disease: Is `AKT `-ing on cellular glucose uptake the missing link?

Osteoporosis and Alzheimer's disease (AD) are both degenerative diseases. Osteoporosis often proceeds cognitive deficits, and multiple studies have revealed common triggers that lead to energy deficits in brain and bone. Risk factors for osteoporosis and AD, such as obesity, type 2 diabetes, aging, chemotherapy, vitamin deficiency, alcohol abuse, and apolipoprotein Eε4 and/or Il-6 gene variants, reduce cellular glucose uptake, and protective factors, such as estrogen, insulin, exercise, mammalian target of rapamycin inhibitors, hydrogen sulfide, and most phytochemicals, increase uptake. Glucose uptake is a fine-tuned process that depends on an abundance of glucose transporters (Gluts) on the cell surface. Gluts are stored in vesicles under the plasma membrane, and protective factors cause these vesicles to fuse with the membrane, resulting in presentation of Gluts on the cell surface. This translocation depends mainly on AKT kinase signaling and can be affected by a range of factors. Reduced AKT kinase signaling results in intracellular glucose deprivation, which causes endoplasmic reticulum stress and iron depletion, leading to activation of HIF-1α, the transcription factor necessary for higher Glut expression. The link between diseases and aging is a topic of growing interest. Here, we show that diseases that affect the same biochemical pathways tend to co-occur, which may explain why osteoporosis and/or diabetes are often associated with AD.

Dietary calcium intake and change in bone mineral density in older adults: a systematic review of longitudinal cohort studies

Many older adults do not achieve recommended intakes of calcium and there is some concern over the potential impact of this on bone health. The objective of this review was to examine evidence from cohort studies on the relationship between calcium intake and change in bone mineral density (BMD) in older adults, something not undertaken in the last two decades. Data sources included Ovid Medline, Embase, and PubMed and references from retrieved reviews and articles. The final search was performed in February 2021. We included cohort studies of calcium intake in participants aged >50 years with change in BMD over ≥1 year as an outcome. We identified 23 studies of women and 7 of men. Most studies found no association between calcium intake and change in BMD in women (71%) or men (71%). Among women, five studies reported high rates (>30% of participants) of hormone treatment or osteoporosis therapy (HT/OT) use; 80% of these studies reported a positive association between calcium intake and change in BMD, compared with 10% of studies in which HT/OT use was low. No study in women in which the mean age was >60 years reported a positive association between calcium intake and change in BMD. We conclude that calcium intake across the ranges consumed in these studies (mean intake in all but one study >500 mg/day) is not an important determinant of bone loss, particularly among women >60 years. The positive findings in studies with high rates of HT/OT use are likely to arise from confounding as a result of co-administration of calcium supplements with these medications.

Dietary Calcium Intake and Bone Loss Over 6 Years in Osteopenic Postmenopausal Women

CONTEXT

Calcium intakes are commonly lower than the recommended levels, and increasing calcium intake is often recommended for bone health.

OBJECTIVE

To determine the relationship between dietary calcium intake and rate of bone loss in older postmenopausal women.

PARTICIPANTS

Analysis of observational data collected from a randomized controlled trial. Participants were osteopenic (hip T-scores between -1.0 and -2.5) women, aged >65 years, not receiving therapy for osteoporosis nor taking calcium supplements. Women from the total cohort (n = 1994) contributed data to the analysis of calcium intake and bone mineral density (BMD) at baseline, and women from the placebo group (n = 698) contributed data to the analysis of calcium intake and change in BMD. BMD and bone mineral content (BMC) of the spine, total hip, femoral neck, and total body were measured three times over 6 years.

RESULTS

Mean calcium intake was 886 mg/day. Baseline BMDs were not related to quintile of calcium intake at any site, before or after adjustment for baseline age, height, weight, physical activity, alcohol intake, smoking status, and past hormone replacement use. There was no relationship between bone loss and quintile of calcium intake at any site, with or without adjustment for covariables. Total body bone balance (i.e., change in BMC) was unrelated to an individuals' calcium intake (P = 0.99).

CONCLUSIONS

Postmenopausal bone loss is unrelated to dietary calcium intake. This suggests that strategies to increase calcium intake are unlikely to impact the prevalence of and morbidity from postmenopausal osteoporosis.

Bone Loss Rate May Interact with Other Risk Factors for Fractures among Elderly Women: A 15-Year Population-Based Study

Aim was to investigate fracture risk (FR) according to bone loss (BL) rate. A random sample of 1652 women aged 53.5 years was measured with dual X-ray absorptiometry in femoral neck in 1989 and 1994 and divided into tertiles of annual BL rate: high >0.84%, moderate 0.13%-0.84%, and low <0.13%. Low trauma energy fractures during following 10 years were recorded. There were no differences in FR between BL tertiles in Cox regression model. Factors predicting lower FR in Cox model were in high tertile: high T-score (HR 0.71; 95% CI 0.54-0.93, P = .012), no sister's fracture (HR 0.35; 0.19-0.64, P = .001), no mother's fracture (HR 0.52; 0.31-0.88, P = .015), in moderate tertile: high T-score (HR 0.69;0.53-0.91, P = .008) and good grip strength (HR 0.98; 0.97-0.99, P = .022). In low tertile there were no predictors for FR. BL predicted FR in women with mother's fracture in univariate and multivariate model (OR 2.6; 1.15-5.7, P = .021) but with sister's fracture this was observed only in multivariate model (OR 2.66; 1.09-6.7, P = .039). Accordingly, the risk factors for postmenopausal fractures, especially mother's fracture, may interact with BL.

Agreement of self-reported estrogen use with prescription data: an analysis of women from the Kuopio Osteoporosis Risk Factor and Prevention Study

OBJECTIVE

Self-reported data are usually used for the evaluation of the effects of hormone therapy in population studies. We examined the agreement between self-reported hormone therapy use and nationwide prescription data from the Social Insurance Institution of Finland to evaluate the accuracy of self-reports.

DESIGN

The 10-year questionnaire of the population-based Kuopio Osteoporosis Study was sent in 1999 to 12,562 women aged 57 to 67 years; 11,377 women who completed questionnaires were eligible for analysis. We asked women whether they had been taking estrogen hormone therapy as a gel, plaster, or tablet for the treatment of climacteric symptoms or osteoporosis and if the answer was yes, to specify the brand and duration of treatment for each year from 1994 to 1999.

RESULTS

Among the 11,377 women, 3,105 (27.3%) reported the use of an estrogen-based preparation in 1996 to 1999, and 97.6% were confirmed by Social Insurance Institution of Finland to have been prescribed hormone therapy during that time. In these women the median duration of use was 32 months (range, 1-41), according to Social Insurance Institution of Finland data. An additional 1,738 women had been prescribed hormone therapy for short periods, but those women did not report it. The duration of self-reported hormone therapy use was compared to the duration of prescriptions. A difference of 3 months or less per year was observed in 63.4% to 77.0% of women during the years 1996-1998.

CONCLUSIONS

A postal inquiry is a reliable method of recording long-term hormone therapy use.

Protein-containing nutrient supplementation following strength training enhances the effect on muscle mass, strength, and bone formation in postmenopausal women

We evaluated the response of various muscle and bone adaptation parameters with 24 wk of strength training in healthy, early postmenopausal women when a nutrient supplement (protein, carbohydrate, calcium, and vitamin D) or a placebo supplement (a minimum of energy) was ingested immediately following each training session. At inclusion, each woman was randomly and double-blindedly assigned to a nutrient group or a placebo (control) group. Muscle hypertrophy was evaluated from biopsies, MRI, and dual-energy X-ray absorptiometry (DEXA) scans, and muscle strength was determined in a dynamometer. Bone mineral density (BMD) was measured using DEXA scans, and bone turnover was determined from serum osteocalcin and collagen type I cross-linked carboxyl terminal peptide. The nutrient group improved concentric and isokinetic (60°/s) muscle strength from 6 to 24 wk by 9 ± 3% ( P < 0.01), whereas controls showed no change (1 ± 2%, P > 0.05). Only the nutrient group improved lean body mass ( P < 0.05) over the 24 wk. BMD responded similarly at the lumbar spine but changed differently in the two groups at the femoral neck ( P < 0.05) [control: 0.943 ± 0.028 to 0.930 ± 0.024 g/mm3 (−1.0 ± 1.4%); nutrient group: 0.953 ± 0.051 to 0.978 ± 0.043 g/mm3 (3.8 ± 3.4%)] when adjusted for age, body mass index, and BMD at inclusion. Bone formation displayed an interaction ( P < 0.05), mainly caused by increased osteocalcin at 24 wk in the nutrient group. In conclusion, we report that nutrient supplementation results in superior improvements in muscle mass, muscle strength, femoral neck BMD, and bone formation during 24 wk of strength training. The observed differences following such a short intervention emphasize the significance of postexercise nutrient supply on musculoskeletal maintenance.

Calcium plus vitamin D supplementation and the risk of fractures

BACKGROUND

The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal.

METHODS

We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental [corrected] calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers.

RESULTS

Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with calcium plus vitamin D (hazard ratio, 1.17; 95 percent confidence interval, 1.02 to 1.34). Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 (95 percent confidence interval, 0.52 to 0.97). Effects did not vary significantly according to prerandomization serum vitamin D levels.

CONCLUSIONS

Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones. (ClinicalTrials.gov number, NCT00000611.).

The need for clinical guidance in the use of calcium and vitamin D in the management of osteoporosis: a consensus report

A European Union (EU) directive on vitamins and minerals used as ingredients of food supplements with a nutritional or physiological effect (2002/46/EC) was introduced in 2003. Its implications for the use of oral supplements of calcium and vitamin D in the prevention and treatment of osteoporosis were discussed at a meeting organized with the help of the World Health Organization (WHO) Collaborating Center for Public Health Aspects of Rheumatic Diseases (Liège, Belgium) and the support of the WHO Collaborating Center for Osteoporosis Prevention (Geneva, Switzerland). The following issues were addressed: Is osteoporosis a physiological or a medical condition? What is the evidence for the efficacy of calcium and vitamin D in the management of postmenopausal osteoporosis? What are the risks of self-management by patients in osteoporosis? From their discussions, the panel concluded that: (1) osteoporosis is a disease that requires continuing medical attention to ensure optimal therapeutic benefits; (2) when given in appropriate doses, calcium and vitamin D have been shown to be pharmacologically active (particularly in patients with dietary deficiencies), safe, and effective for the prevention and treatment of osteoporotic fractures; (3) calcium and vitamin D are an essential, but not sufficient, component of an integrated management strategy for the prevention and treatment of osteoporosis in patients with dietary insufficiencies, although maximal benefit in terms of fracture prevention requires the addition of antiresorptive therapy; (4) calcium and vitamin D are a cost-effective medication in the prevention and treatment of osteoporosis; (5) it is apparent that awareness of the efficacy of calcium and vitamin D in osteoporosis is still low and further work needs to be done to increase awareness among physicians, patients, and women at risk; and (6) in order that calcium and vitamin D continues to be manufactured to Good Manufacturing Practice standards and physicians and other health care professionals continue to provide guidance for the optimal use of these agents, they should continue to be classified as medicinal products.