Table 3.

The main outcomes of meta-analysis and subgroup analysis

Risk factors	No. of studies	RR or WMD	LL 95% CI	UL 95% CI	P value	I2 (%)	Analysis model
Sociodemographic risk factors
Age, years	10	0.37†	0.07	0.68	0.02	85	IV, random
Age (eliminate heterogeneous sources)	7	1.83†	0.93	2.73	< 0.0001	52	IV, random
Body weight, kg	6	0.88†	0.56	1.21	< 0.00001	0	IV, fixed
Body height, cm	7	− 0.16†	− 0.40	0.08	0.20	56	IV, random
BMI (kg/m2)	9	0.34†	0.21	0.46	< 0.00001	0	IV, fixed
Age of menopause, years	5	− 0.31†	− 0.91	0.29	0.31	64	IV, random
Years since last menstruation, years	4	0.01†	− 0.15	0.16	0.94	37	IV, fixed
Exercise (yes vs. no)	4	0.97*	0.94	0.99	0.01	0	M-H, fixed
Smoking (yes vs. no)	3	0.78*	0.72	0.85	< 0.00001	0	M-H, fixed
Alcohol use, heavy use, > 30 drinks/month (yes vs. no)	2	0.98*	0.85	1.13	0.77	43	M-H, fixed
FES-I, point	2	6.60†	0.72	12.47	0.03	79	IV, random
TUG test, second	2	1.32†	− 1.21	3.86	0.31	90	IV, random
5-STS, second	3	0.30†	− 0.36	0.96	0.37	0	IV, fixed
Medical risk factors
Dietary calcium intake, mg/day	3	− 16.91†	− 25.80	− 8.01	0.0002	7	IV, fixed
Previous fracture history (yes vs. no)	3	1.21*	1.13	1.29	< 0.00001	0	M-H, fixed
Previous fallers (yes vs. no)	3	2.02*	1.91	2.14	< 0.00001	0	M-H, fixed
Hormone therapy (yes vs. no)	4	1.00*	0.98	1.03	0.80	0	M-H, fixed
Number of diseases, ˃ 2 (yes vs. no)	2	1.17*	1.11	1.23	< 0.00001	0	M-H, fixed
Number of reported chronic health disorders	2	0.30†	0.10	0.49	0.003	94	IV, random
BMD, g/cm3, neck femur	2	0.00†	− 0.02	0.02	1.00	0	IV, fixed

Note: The forest map of all risk factors is shown in Supplementary appendix 2

TUG, timed up and go; 5-STS, five-times sit-to-stand; BMI, body mass index; FES-I, Falls Efficacy Scale International; BMD, bone mineral density; RR, relative risk; WMD, standardized mean differences; LL, lower limit; UL, upper limit; M-H, Mantel Haenszel test; IV, inverse variance

*RR

^†WMD