Relationships between muscle function and bone microarchitecture in the Hertfordshire Cohort Study

KA Ward, MH Edwards, K Jameson, S Shaw, H Syddall, C Cooper, EM Dennison

MRC Lifecourse Epidemiology Unit, University of SouthamptonMRC Elsie Widdowson Laboratory, Cambridge

Musculoskeletal ageing

• By 2050 2 milliards of people aged >65 years, c.f. 600 million today

• Osteoporosis: 1 in 2 women, 1 in 5 men > 50 yrs.

• Sarcopenia: No defined consensus, IWGS, EWGSOP, FNIH.

• Healthcare costs:• OP - £2million/day, £5 billion/yr• Sarcopenia - >$18 billion in the US 2001

• Sarcopenia, falls and fracture prevention

Hertfordshire Cohort Study

• Lean mass indices – cortical area and thickness

• Fat mass indices – trabecular density, number independent of LMI

• Compartmental effects cortical vs trabecular bone, lean mass vs. fat

• Muscle strength – mass, anatomy (fibre composition, IMAT, pennation angle), force and power generating capacity

Edwards MH, PhD Thesis 2014Edwards 2015, Bone, 81 145-151

Jumping mechanography

Mus

cle C

SA (c

m3 )

Chai

r rise

(s-1)

Age (years)

JM P

ower

(W k

g-1)

Age (years)Age (years)

Rittweger, 2004, J Am J Geriatr Soc, 52:128–131

Power – functional capacity, e.g arresting a fall, walk speed Force – measure of the load to boneEfficiency – how well you utilise force to generate power

Methods

• 184 (144) men and 166 (104) women, mean (SD) age M 75.9 (2.4), F 75.9 (2.6)

• HRpQCT of the tibia and radius (X-Treme I™, Scanco Medical)

• 2-leg countermovement jump to assess jump force and power (Leonardo ™, Novotec Medical)

• Linear regression models, males and females separately• age, weight, height• social class, smoking status,

calcium intake, hormone replacement use and years since menopause in women.

Jump power

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Males (unadj)

Tot a

rea

Cor

t are

a

Trab

 are

a

Cor

t thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Jump power

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Females (103)

Tot a

rea

Cor

t are

a

Trab

 are

a

Cor

t thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Power

* * ** * *

Adjusted for age, height and weight

Jump power

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Males (142)

Tot a

rea

Cor

t are

a

Trab

 are

a

Cor

t thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Males (127)

Jump power

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Females (103)

Tot a

rea

Cor

t are

a

Trab

 are

a

Cor

t thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Females (90)

Power

* * * **

Adjusted for age, height, weight, social class, smoking status, calcium intake, hormone replacement use and years since menopause in women

Force

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Males (unadj)

Tot a

rea

Cort

 are

a

Trab

 are

a

Cort

 thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Force

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Females (103)

Tot a

rea

Cort

 are

a

Trab

 are

a

Cort

 thk

Cor

t BM

D

Cort

 por

Trab

 BM

D

Trab

 No

Trab

 thk

Force

** * * * * * ***

Adjusted for age, height and weight

Force

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Males (144)

Tot a

rea

Cort

 are

a

Trab

 are

a

Cort

 thk

Cor

t BM

D

Cor

t por

Trab

 BM

D

Trab

 No

Trab

 thk

Males (128)

Force

HRpQCT

SD p

er 1

SD

cha

nge

in p

ower

-0.5

0.0

0.5

1.0Females (103)

Tot a

rea

Cort

 are

a

Trab

 are

a

Cort

 thk

Cor

t BM

D

Cort

 por

Trab

 BM

D

Trab

 No

Trab

 thk

Females (90)

Force

*

Adjusted for age, height, weight, social class, smoking status, calcium intake, hormone replacement use and years since menopause in women

Conclusions

• In women, greater muscle power and force had more cortical and trabecular bone

• In men, consistent negative associations with porosity were found, suggesting lower turnover with greater power

• No associations between pQCT and jump parameters (data not shown) at the distal or diaphyseal sites

• LMI and FMI are more consistent predictors of bone microarchitecture in older adults (function vs. mass).

• Findings are less strong and more inconsistent than in other cohorts who are in general younger and have a wider range of ages.

AcknowledgementsCo-authors

Mark Edwards, Cyrus Cooper, Elaine DennisonKaren Jameson, Sarah Shaw, Holly Sydall

FundingMedical Research Council

Study ParticipantsHertfordshire Cohort Study

Lean mass indices: men

Unadjusted Fully adjusted

N Regression coefficient 95% CI p-value N Regression

coefficient 95% CI p-value

tibia total area135 -0.035 (-0.207, 0.136) 0.684 122 -0.041 (-0.230, 0.148) 0.667

tibia cortical area 136 0.499 (0.349, 0.648) <0.001 123 0.524 (0.358, 0.691) <0.001tibia trabecular area 137 -0.125 (-0.296, 0.046) 0.152 123 -0.137 (-0.322, 0.048) 0.146tibia apparent cortical thickness 136 0.437 (0.282, 0.593) <0.001 123 0.462 (0.295, 0.628) <0.001tibia cortical BMD 136 0.148 (-0.022, 0.318) 0.087 123 0.105 (-0.077, 0.287) 0.255tibia cortical porosity 136 0.023 (-0.141, 0.187) 0.783 123 0.082 (-0.097, 0.261) 0.365tibia trabecular density 137 0.132 (-0.035, 0.299) 0.119 123 0.172 (-0.010, 0.354) 0.064tibia trabecular number 137 0.262 (0.110, 0.415) 0.001 123 0.259 (0.088, 0.430) 0.003tibia trabecular thickness 137 -0.065 (-0.235, 0.106) 0.453 123 -0.008 (-0.191, 0.174) 0.927

Results are an SD change per one SD change in predictor

Adjusted for age, height, weight, social class, smoker status, alcohol consumption, activity, dietary calcium and HRT use and years since menopause in women

Lean mass indices: women

Unadjusted Fully adjusted

N Regression coefficient 95% CI p-value N Regression

coefficient 95% CI p-value

tibia total area100 0.134 (-0.065, 0.333) 0.184 91 0.087 (-0.143, 0.317) 0.454

tibia cortical area 100 0.489 (0.313, 0.664) <0.001 91 0.498 (0.293, 0.704) <0.001tibia trabecular area 100 0.060 (-0.140, 0.261) 0.553 91 0.012 (-0.222, 0.245) 0.921tibia apparent cortical thickness 100 0.314 (0.123, 0.505) 0.002 91 0.339 (0.115, 0.563) 0.004tibia cortical BMD 100 0.248 (0.051, 0.445) 0.014 91 0.271 (0.046, 0.496) 0.019tibia cortical porosity 100 -0.132 (-0.333, 0.070) 0.197 91 -0.143 (-0.375, 0.088) 0.221tibia trabecular density 100 0.007 (-0.194, 0.208) 0.946 91 0.051 (-0.186, 0.289) 0.668tibia trabecular number 100 0.138 (-0.063, 0.339) 0.175 91 0.155 (-0.071, 0.381) 0.177tibia trabecular thickness 100 -0.073 (-0.272, 0.126) 0.469 91 -0.025 (-0.259, 0.210) 0.835

Results are an SD change per one SD change in predictor

Adjusted for age, height, weight, social class, smoker status, alcohol consumption, activity, dietary calcium and HRT use and years since menopause in women