Lifetime sport and leisure activity participation is associated with greater bone size, quality and strength in older men

Introduction: It remains uncertain whether long-term participation in regular weight-bearing exercise confers an advantage to bone structure and strength in old age. The aim of this study was to investigate the relationship between lifetime sport and leisure activity participation on bone material and structural properties at the axial and appendicular skeleton in older men (>50 years).

Methods: We used dual-energy X-ray absorptiometry (DXA) to assess hip, spine and ultradistal (UD) radius areal bone mineral density (aBMD) (n=161), quantitative ultrasound (QUS) to measure heel bone quality (n=161), and quantitative computed tomography (QCT) to assess volumetric BMD, bone geometry and strength at the spine (L₁–L₃) and mid-femur (n=111). Current (>50+ years) and past hours of sport and leisure activity participation during adolescence (13–18 years) and adulthood (19–50 years) were assessed by questionnaire. This information was used to calculate the total time (min) spent participating in sport and leisure activities and an osteogenic index (OI) score for each participant, which provides a measure of participation in weight-bearing activities.

Results: Regression analysis revealed that a greater lifetime (13–50+ years) and mid-adulthood (19–50 years) OI, but not total time (min), was associated with a greater mid-femur total and cortical area, cortical bone mineral content (BMC), and the polar moment of inertia (I _p) and heel VOS (p ranging from <0.05 to <0.01). These results were independent of age, height (or femoral length) and weight (or muscle cross-sectional area). Adolescent OI scores were not found to be significant predictors of bone structure or strength. Furthermore, no significant relationships were detected with areal or volumetric BMD at any site. Subjects were then categorized into either a high (H) or low/non-impact (L) group during adolescence (13–18 years) and adulthood (19–50+ years) according to their OI scores during each of these periods. Three groups were subsequently formed to reflect weight-bearing impact categories during adolescence and then adulthood: LL, HL and HH. Compared to the LL group, mid-femur total and cortical area, cortical BMC and I _p were 6.5–14.2% higher in the HH group. No differences were detected between the LL and HL groups.

Conclusions: In conclusion, these findings indicate that long-term regular participation in sport and leisure activities categorized according to an osteogenic index [but not the total time (min) spent participating in all sport and leisure activities] was an important determinant of bone size, quality and strength, but not BMD, at loaded sites in older men. Furthermore, continued participation in weight-bearing exercise in early to mid-adulthood appears to be important for reducing the risk of low bone strength in old age.

Long-term effects of calcium-vitamin-D3-fortified milk on bone geometry and strength in older men

The long-term effects of calcium and vitamin D supplementation on bone material and structural properties in older men are not known. The aim of this study was to examine the effects of high calcium (1000 mg/day)- and vitamin-D3 (800 IU/day)-fortified milk on cortical and trabecular volumetric BMD (vBMD) and bone geometry at the axial and appendicular skeleton in men aged over 50 years. One hundred and eleven men who were part of a larger 2-year randomized controlled trial had QCT scans of the mid-femur and lumbar spine (L1–L3) to assess vBMD, bone geometry and indices of bone strength [polar moment of inertia (Ipolar)]. After 2 years, there were no significant differences between the milk supplementation and control group for the change in any mid-femur or L1–L3 bone parameters for all men aged over 50 years. However, the mid-femur skeletal responses to the fortified milk varied according to age, with a split of ≤62 versus >62 years being the most significant for discriminating the changes between the two groups. Subsequent analysis revealed that, in the older men (>62 years), the expansion in mid-femur medullary area was 2.8% (P < 0.01) less in the milk supplementation compared to control group, which helped to preserve cortical area in the milk supplementation group (between group difference 1.1%, P < 0.01). Similarly, for mid-femur cortical vBMD and Ipolar, the net loss was 2.3 and 2.8% less in the milk supplementation compared to control group (P < 0.01 and <0.001, respectively). In conclusion, calcium–vitamin-D3-fortified milk may represent an effective strategy to maintain bone strength by preventing endocortical bone loss and slowing the loss in cortical vBMD in elderly men.

Effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density in older men : a randomised controlled trial

Summary We examined the independent and combined effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density (BMD) in older men. Exercise resulted in a 1.8% net gain in femoral neck BMD, but additional calcium–vitamin D3 did not enhance the response in this group of older well-nourished men.

Introduction This 12-month randomised controlled trial assessed whether calcium–vitamin-D3-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men.

Methods Men (n  = 180) aged 50–79 years were randomised into: (1) exercise + fortified milk; (2) exercise; (3) fortified milk; or (4) controls. Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise. Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D3. Femoral neck (FN), total hip, lumbar spine and trochanter BMD and body composition (DXA), muscle strength 25-hydroxyvitamin D and parathyroid hormone (PTH) were assessed.

Results There were no exercise-by-fortified milk interactions at any skeletal site. Exercise resulted in a 1.8% net gain in FN BMD relative to no-exercise (p < 0.001); lean mass (0.6 kg, p < 0.05) and muscle strength (20–52%, p < 0.001) also increased in response to exercise. For lumbar spine BMD, there was a net 1.4–1.5% increase in all treatment groups relative to controls (all p < 0.01). There were no main effects of fortified milk at any skeletal site.

Conclusion A multi-component community-based exercise program was effective for increasing FN BMD in older men, but additional calcium–vitamin D3 did not enhance the osteogenic response.