Effect of Dietary Protein Intake on Bone Mineral Density and Fracture Incidence in Older Adults in the Health, Aging, and Body Composition Study

Identification of nutrition factors in the metabolic syndrome and its progression over time in older adults: analysis of the TUDA cohort

BACKGROUND

Nutrition is recognized as playing an important role in the metabolic syndrome (MetS), but the dietary components involved are unclear. We aimed to investigate nutrition factors in relation to MetS and its progression in older adults over a follow-up period of 5.4 years.

METHODS

Community-dwelling adults (≥ 60y) from the Trinity-Ulster-Department-of-Agriculture study, sampled at baseline (2008-12) and follow-up (2014-18; n 953), were classified as 'with MetS' by having three or more of: waist circumference (≥ 102 cm, males; ≥ 88 cm, females); HDL-cholesterol (< 1.0 mmol/L, males; < 1.3 mmol/L, females); triglycerides (≥ 1.7 mmol/L); blood pressure (systolic ≥ 130 and/or diastolic ≥ 85 mmHg); and hemoglobin A1c (≥ 39 mmol/mol).

RESULTS

MetS was identified in 67% of participants, increasing to 74% at follow-up. Predictors at baseline for the development of metabolic syndrome (MetS) at follow-up were higher waist circumference (odds ratio [95%CI]; 1.06 [1.01-1.11]), but not BMI, and increased triglyceride concentrations (2.01 [1.29-3.16]). In dietary analysis (at follow-up), higher protein (g/kg bodyweight/day) and monounsaturated fatty acid (g/day) intakes were each associated with lower risk of MetS (0.06 [0.02-0.20] and 0.88 [0.78-1.00], respectively), whilst higher protein was also associated with lower abdominal obesity (0.10 [0.02-0.51]) and hypertension (0.22 [0.00-0.80]). Furthermore, participants with, compared to without, MetS consumed less high-quality protein foods (P = 0.006) and more low-quality protein foods (P < 0.001), as defined by the protein digestibility-corrected amino acid score.

CONCLUSIONS

Dietary interventions targeting protein quantity and quality may have specific benefits in preventing or delaying the progression of MetS in at-risk older people, but this requires investigation in the form of randomized trials.

Discussion on protein recommendations for supporting muscle and bone health in older adults: a mini review

Muscle and bone tissues are interconnected, and both rely on an adequate protein intake. Recommendations for protein intake for older adults specifically vary across countries. The purpose of this narrative review is to discuss the existing evidence for protein recommendations for supporting muscle and bone health in older adults and to evaluate if a protein intake above the current population reference intake (PRI) for older adults would be scientifically justified. First, this review summarizes the protein recommendations from bodies setting dietary reference values, expert groups, and national health organizations. Next, relevant studies investigating the impact of protein on muscle and bone health in older adults are discussed. In addition, the importance of protein quality for muscle and bone health is addressed. Lastly, a number of research gaps are identified to further explore the added value of a protein intake above the PRI for older adults.

Three-Year Mortality of Older Hospitalized Patients with Osteosarcopenia: Data from the OsteoSys Study

Osteosarcopenia, the concurrent presence of sarcopenia and osteopenia/osteoporosis, poses a significant health risk to older adults, yet its impact on clinical outcomes is not fully understood. The aim of this prospective, longitudinal multicentre study was to examine the impact of osteosarcopenia on 3-year mortality and unplanned hospitalizations among 572 older hospitalized patients (mean age 75.1 ± 10.8 years, 78% female). Sarcopenia and low bone mineral density (BMD) were evaluated using Dual Energy X-ray Absorptiometry and the European Working Group on Sarcopenia in Older People (EWGSOP2) and WHO criteria, respectively. Among participants, 76% had low BMD, 9% were sarcopenic, and 8% had osteosarcopenia. Individuals with osteosarcopenia experienced a significantly higher rate of mortality (46%, p < 001) and unplanned hospitalization (86%, p < 001) compared to those without this condition. Moreover, "healthy" subjects-those without sarcopenia or low BMD-showed markedly lower 3-year mortality (9%, p < 001) and less unplanned hospitalization (53%, p < 001). The presence of osteosarcopenia (p = 0.009) increased the 3-year mortality risk by 30% over sarcopenia alone and by 8% over low BMD alone, underscoring the severe health implications of concurrent muscle and bone deterioration. This study highlights the substantial impact of osteosarcopenia on mortality among older adults, emphasizing the need for targeted diagnostic and therapeutic strategies.

The multi-faceted nature of age-associated osteoporosis

Age-associated osteoporosis (AAOP) poses a significant health burden, characterized by increased fracture risk due to declining bone mass and strength. Effective prevention and early treatment strategies are crucial to mitigate the disease burden and the associated healthcare costs. Current therapeutic approaches effectively target the individual contributing factors to AAOP. Nonetheless, the management of AAOP is complicated by the multitude of variables that affect its development. Main intrinsic and extrinsic factors contributing to AAOP risk are reviewed here, including mechanical unloading, nutrient deficiency, hormonal disbalance, disrupted metabolism, cognitive decline, inflammation and circadian disruption. Furthermore, it is discussed how these can be targeted for prevention and treatment. Although valuable as individual targets for intervention, the interconnectedness of these risk factors result in a unique etiology for every patient. Acknowledgement of the multifaceted nature of AAOP will enable the development of more effective and sustainable management strategies, based on a holistic, patient-centered approach.

Association between total and animal proteins with risk of fracture: A systematic review and dose-response meta-analysis of cohort studies

Previous cohort studies have indicated that consumption of total and animal proteins are related to fracture risk; however, results were inconclusive. This dose-dependent review sought to summarize the earlier evidence regarding the relation between total and animal proteins and fracture risk. We searched Scopus, PubMed, and Web of Science until July 2023 for original research articles examining the association of certain types of proteins and the incidence of all fractures in general adults. Summary relative risks (RRs) were calculated using random effects analysis to examine the relation between each certain amount (g/day) increment of total and animal protein and fracture risk. Twenty cohort studies with serious to moderate risk of bias involving 780,322 individuals were included. There was a non-statistically significant relation between intake of animal proteins and dairy products and all fracture risk. However, 43% and 5% decreased incidence of fracture was obtained with total protein (RR, 0.57; 95%CI, 0.36 to 0.93; per 100 g/day) and fish (RR, 0.95; 95%CI, 0.91 to 0.99; per 15 g/day) intake. Every 100 g/day total and animal protein consumption and every 15 g/day fish consumption were linked to 48%, 50%, and 5% lower hip fracture risk. Greater dietary animal protein intake might reduce risk of hip but not fracture at any site. We obtained a lower risk of any or hip fracture with greater total protein (per 100 g/day) and fish (per 15 g/day) intake. No evidence was obtained that higher intake of dairy could decrease risk of fracture.

Determinant factors of bone health after long-term of Roux-en-Y gastric bypass surgery: A cross-sectional study

OBJECTIVES

The aim of this study was to evaluate bone health and the potential influencing factors of bone metabolism disorders in adults ≥5 y after Roux-en-Y gastric bypass (RYGB) surgery.

METHODS

In this cross-sectional study, patients who were ≥5 y post-RYGB were invited. Bone health considered as bone mineral content (BMC) and bone mineral density (BMD) in this study was assessed by dual x-ray absorptiometry. We also assessed 25-hydroxy-vitamin D concentrations, individual ultraviolet B radiation levels, serum ionized calcium, alkaline phosphatase, parathyroid, anthropometric, and body composition.

RESULTS

The study evaluated 104 adults (90% women; 49.6 ± 9.1 y old; postoperative period 8.7 ± 2.2 y). Lumbar and femoral BMC and BMD were positively correlated to body mass index (BMI), appendicular lean mass (ALM), and negatively to %excess of weight loss (EWL). Femoral BMD was negatively correlated to age, and both femoral BMD and BMC were positively correlated to weekly exposed body part score. Sex, age, BMI, ALM, and weekly exposed body part score explained 35% and 54% of the total variance of femoral BMD and BMC, respectively.

CONCLUSIONS

The present findings suggested that older age, lower BMI, higher %EWL, lower ALM, and lower weekly body part exposure score are important determinants in lowering BMD and BMC parameters in long-term post-bariatric surgery individuals, rather than serum 25-hydroxy-vitamin D and parathyroid.

Protein intake and bone mineral density: Cross-sectional relationship and longitudinal effects in older adults

BACKGROUND

There are several mechanisms via which increased protein intake might maintain or improve bone mineral density (BMD), but current evidence for an association or effect is inconclusive. The objectives of this study were to investigate the association between dietary protein intake (total, plant and animal) with BMD (spine and total body) and the effects of protein supplementation on BMD.

METHODS

Individual data from four trials that included either (pre-)frail, undernourished or healthy older adults (aged ≥65 years) were combined. Dietary intake was assessed with food records (2, 3 or 7 days) and BMD with dual-energy X-ray absorptiometry (DXA). Associations and effects were assessed by adjusted linear mixed models.

RESULTS

A total of 1570 participants [57% women, median (inter-quartile range): age 71 (68-75) years] for which at least total protein intake and total body BMD were known were included in cross-sectional analyses. In fully adjusted models, total protein intake was associated with higher total body and spine BMD [beta (95% confidence interval): 0.0011 (0.0006-0.0015) and 0.0015 (0.0007-0.0023) g/cm² , respectively]. Animal protein intake was associated with higher total body and spine BMD as well [0.0011 (0.0007-0.0016) and 0.0017 (0.0010-0.0024) g/cm² , respectively]. Plant protein intake was associated with a lower total body and spine BMD [-0.0010 (-0.0020 to -0.0001) and -0.0019 (-0.0034 to -0.0004) g/cm² , respectively]. Associations were similar between sexes. Participants with a high ratio of animal to plant protein intake had higher BMD. In participants with an adequate calcium intake and sufficient serum 25(OH)D concentrations, the association between total protein intake with total body and spine BMD became stronger. Likewise, the association between animal protein intake with total body BMD was stronger. In the longitudinal analyses, 340 participants [58% women, median (inter-quartile range): age 75 (70-81) years] were included. Interventions of 12 or 24 weeks with protein supplementation or protein supplementation combined with resistance exercise did not lead to significant improvements in BMD.

CONCLUSIONS

An association between total and animal protein intake with higher BMD was found. In contrast, plant protein intake was associated with lower BMD. Research is warranted to further investigate the added value of dietary protein alongside calcium and vitamin D for BMD improvement, especially in osteopenic or osteoporotic individuals. Moreover, more research on the impact of a plant-based diet on bone health is needed.

Associations between Macronutrients Intake and Bone Mineral Density: A Longitudinal Analysis of the Health Workers Cohort Study Participants

OBJECTIVE

This study aimed to evaluate the association between macronutrient intake and bone mineral density (BMD) using non-substitution and substitution statistical approaches.

DESIGN

Longitudinal analysis.

SETTINGS AND PARTICIPANTS

1,317 adults in the Health Worker Cohort Study in Mexico.

MEASUREMENTS

These participants were assessed at baseline (2004-2006) and follow-up (2010-2012). Dietary intakes were assessed using validated food frequency questionnaires. BMD at the different sites was performed by dual-energy X-ray absorptiometry (DXA). Hybrid-mixed effects regression models were performed to evaluate the associations of interest.

RESULTS

Cross-sectional associations were found between fiber intake and higher total hip and femoral neck BMD in women and longitudinal associations with loss of femoral neck BMD in men. An increase in 5% energy intake from carbohydrate was associated with a BMD loss at several site in women and total hip and femoral neck in men. In both sexes, an increase in 5% energy intake of animal protein or fat was associated with a site-specific BMD gain after six years. Substitution analysis showed that the energy intake replacement from fat or carbohydrate by protein had an increase in BMD at different sites in women; while in men, it was only significant when replacing carbohydrate. Substitution of protein or fat by carbohydrates was associated with lower BMD in women, and only protein replacement by carbohydrates in men.

CONCLUSION

Our findings suggest that carbohydrate intake was associated with loss of BMD, while animal protein and fat intake was associated with gain of BMD among the Mexican population. Macronutrient substitutions resulted in significant associations; however, additional studies are needed to confirm these findings.