Prediction of Hip Fracture in Prediction of Hip Fracture in Elderly Elderly

Men and Women by Fall-related Men and Women by Fall-related Factors Factors

ND Nguyen, C Pongchaiyakul, JR Center, JA Eisman, TV Nguyen

Bone and Mineral Research Program Garvan Institute of Medical Research

Background

• Various risk factors for hip fracture, including low

bone mineral density (BMD), have been identified

in women, the situation in men remained unknown.

• Hip fracture is largely resulted from a fall.

• It is not known whether fall-related factors (muscle

strength, postural instability) predict hip fracture.

Aims

• To assess the predictiveness and

association between fall-related factors

and hip fracture in elderly men and

women

Study Design and Methods

Study design

Longitudinal population-based epidemiological

study

Setting

Dubbo city, Australia

Participants

960 women and 689 men aged 60+ (as at 1989)

of Caucasian background

Outcome measure

Incidence of hip fracture: ascertained by X-ray report

Risk factors

– Femoral neck BMD: by DEXA

– Postural sway: by sway-meter

– Quadriceps strength: maximum isometric contraction

A non-fracture case A hip fracture case

Postural sway test by the swaymeter

Data analysis

• Incidence of hip fracture was expressed per 1000

person-years assuming a the Poisson distribution.

• Cox’s proportional hazards model was used to estimate

relative risk (RR)

• Individual risk factors were dichotomized into presence

or absence. A combined risk score was derived as the

sum of all individual risk factors for each individual.

ResultsWomen

Men

Ra

tes

of

Hip

Fra

ctu

re (

pe

r 1

00

0 p

ers

on

-ye

ars

)

0

2

4

6

8

10

12

14

16

18

20

Women Men

• Duration of follow-up: 12 y (6, 13)

• 115 (86 F, 29M) hip fractures

were ascertained

Results

Incidence of hip fracture per 1000 person-yrs

* mean ± SD; ‡ n (%); † median (Q1, Q3); a significant difference between hip fracture and no fracture at P<0.001 for both sexes

Women Men

Hip fractures No fractures Hip fractures No fractures

(n=86) (n=874) (n=29) (n=660)

Age (y)* a 78.0 ± 7.7 70.3 ± 7.4 77.9 ± 7.5 69.8 ± 6.1

Height (cm)* a 155.5 ± 6.6 160.0 ± 6.2 169.5 ± 7.5 173.6 ±6.9

Weight (kg)* a 55.4 ± 11.0 66.2 ± 12.4 72.0 ± 14.2 78.9 ± 2.4

BMI (kg/m2)* a 23 ± 4 26 ± 5 25 ± 4 26 ± 4

FNBMD (g/cm2)* a 0.64 ± 0.10 0.80 ± 0.13 0.73 ± 0.17 0.93 ± 0.15

Prior fracture (yes)‡ a 18 (20.9) 85 (9.7) 9 (31.0) 39 (4.7)

Fall in the last 12 mo‡ a 55 (64.0) 407 (34.0) 13 (44.0) 191 (24. 0)Body sway (mm2)† a 2208

(1010,14840)1128 (714,1972)

3355 (1066,21700)

1036 (63,1760)

Quadriceps strength (kg)† a

14 (10, 18) 20 (14, 25) 24 (14, 30) 34 (26, 44)

Calcium intake (mg/d)† 528 (369, 791) 564 (408, 793) 483 (333, 783) 596 (412, 804)

Menarche age (y)† a 14 (13, 15) 13 (12, 14)

Menopause age (y)† 48 (41, 51) 48 (3, 51)

Table 1: Baseline characteristics of participants as at 1989

Risk factors for hip fracture after adjustment for FNBMD and sex

0 1 2 3 4 5 6 7 8 9 10

Quadriceps strength (Q1 vs others, kg)

Postural sway (Q4 vs others, mm2)

Fall in the previous year

Prior fracture

Age (+ 5y)

Risk factors:

Relative risk

Femoral neck BMD (-0.12 g/cm2)

Incidence of hip fracture by FNBMD (T-scores) and number of risk factors

0

10

20

30

40

50

60

Rat

e o

f H

ip f

ract

ure

(per

100

0 p

erso

n-y

ears

)

Num

ber o

f ris

k sc

ore

FNBMD (T-score)

3

2

1

> -1.0-2.4 to -1.1

< -2.5

50.2

32.7

6.6

11.4

4.5

1.1

0.3

0.0

3.2

Conclusions

• Falls and fall-related factors were important predictors of hip fracture in women and men.

• Individuals with multiple risk factors with or without low BMD had the highest risk of hip fracture.

• Women and men had common risk factors for hip fracture.