1. Prediction of Hip Fracture in Elderly Men and Women by Fall-related Factors ND Nguyen, C Pongchaiyakul, JR Center, JA Eisman, TV Nguyen Bone and Mineral Research Program Garvan Institute of Medical Research

2. 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.

3. Aims To assess the predictiveness and association between fall-related factors and hip fracture in elderly men and women

4. 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

5. 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

6. A non-fracture case A hip fracture case Postural sway test by the swaymeter

7. 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.

8. Results 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

9. * mean ± SD; ‡ n (%); † median (Q1, Q3); a significant difference between hip fracture and no fracture at P<0.001 for both sexes WomenMen Hip fracturesNo fracturesHip fracturesNo fractures (n=86)(n=874)(n=29)(n=660) Age (y) * a 78.0 ± 7.770.3 ± 7.477.9 ± 7.569.8 ± 6.1 Height (cm) * a 155.5 ± 6.6160.0 ± 6.2169.5 ± 7.5173.6 ±6.9 Weight (kg) * a 55.4 ± 11.066.2 ± 12.472.0 ± 14.278.9 ± 2.4 BMI (kg/m 2 ) * a 23 ± 426 ± 525 ± 426 ± 4 FNBMD (g/cm 2 ) * a 0.64 ± 0.100.80 ± 0.130.73 ± 0.170.93 ± 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 (mm 2 ) † 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

10. Risk factors for hip fracture after adjustment for FNBMD and sex

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

12. 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.