The characteristics of the participants varied across the three consecutive waves of national surveys in 2005 and 2013 (Table 1). Characteristics that increased by survey included the proportions for those aged 80–84 years, aged ≥85 years, and using sleeping pills (from 10.9%, 12.6%, to 14.9%). Accordingly, the mean age (±SD) of respondents increased from 75.1±6.0, 75.6±6.3, to 76.4±6.5 years, respectively. The proportion of two or more comorbidities also escalated from 31.2%, 32.5%, to 39.1%. On the contrary, those characteristics that decreased by survey included the proportions for unclear vision (from 25.6%, 24.9%, to 20.3%), irregular exercise (from 6.1%, 5.0%, to 3.5%), and depressive symptoms (from 28.6%, 23.6%, to 20.4%).
Table 2 shows that the proportions of some morbidities increased in 2005 and 2013 for hypertension (from 43.1%, 49.1%, to 53.3%), diabetes (from 17.8%, 19.3%, to 22.5%), hyperlipidemia (from 23.3%, 24.0%, to 26.8%), and asthma (from 5.2%, 5.3%, to 6.3%), while the proportions of other morbidities fluctuated. With regard to the prevalence of falls, those older adults who had any of the selected chronic conditions tended to have a higher risk of falls than those who had none.
Table 3 reveals the risk of falls varied by each variable and survey. Risk of falls was higher in women and those with advanced age, with the exception of women in 2013 and those aged ≥85 years between 2005 and 2009. Older people who had urinary incontinence and depressive symptoms and used sleeping pills tended to have a higher risk of falls. Moreover, older adults were more likely to have a fall with a higher number of comorbidities and of IADL difficulty, but not with that of ADL difficulty. Notably, there was a gradient of protective effect from risk of falls by vision quality, with a moderate risk for average vision and a higher risk for unclear vision. Older people who took regular exercise had their fall risk reduced by 26% to 43% in 2005 and 2013.
Table 1 Characteristics of study subjects by number of participants and prevalence of falls during survey years
|
2005
|
2009
|
2013
|
|
Characteristics
|
No. of
participants
|
Prevalence of
falls and
p-value
|
No. of
participants
|
Prevalence of
falls and
p-value
|
No. of
participants
|
Prevalence of
falls and
p-value
|
|
N = 2722
|
%
|
n
|
%
|
N = 2900
|
%
|
n
|
%
|
N = 3200
|
%
|
N
|
%
|
Total
|
2722
|
100.0
|
579
|
21.3
|
2900
|
100.0
|
565
|
17.5
|
3200
|
100.0
|
528
|
16.5
|
Mean age (±SD, year)
|
75.1
|
±6.0
|
|
|
75.6
|
±6.3
|
|
|
76.4
|
±6.5
|
|
|
Age
|
|
|
|
0.002
|
|
|
|
0.017
|
|
|
|
0.004
|
65–69
|
868
|
31.9
|
147
|
16.9
|
877
|
30.2
|
131
|
14.0
|
852
|
26.6
|
110
|
12.1
|
70–74
|
743
|
27.3
|
161
|
20.9
|
726
|
25.0
|
141
|
18.5
|
866
|
27.1
|
135
|
16.2
|
75–79
|
619
|
22.7
|
141
|
23.2
|
653
|
22.5
|
131
|
16.4
|
654
|
20.4
|
115
|
17.9
|
80–84
|
329
|
12.1
|
88
|
28.1
|
388
|
13.4
|
96
|
23.0
|
503
|
15.7
|
99
|
18.7
|
85+
|
163
|
6.0
|
42
|
26.1
|
256
|
8.8
|
66
|
21.3
|
325
|
10.2
|
69
|
24.3
|
Sex
|
|
|
|
<0.001
|
|
|
|
<0.001
|
|
|
|
0.224
|
Male
|
1346
|
49.4
|
221
|
16.5
|
1252
|
43.2
|
198
|
14.1
|
1523
|
47.6
|
227
|
15.3
|
Female
|
1376
|
50.6
|
358
|
26.2
|
1648
|
56.8
|
367
|
20.6
|
1677
|
52.4
|
301
|
17.5
|
ADL difficulty
|
|
|
|
<0.001
|
|
|
|
<0.001
|
|
|
|
<0.001
|
None
|
2324
|
85.4
|
419
|
18.1
|
2382
|
82.2
|
399
|
15.2
|
2658
|
83.1
|
379
|
13.8
|
1 task
|
74
|
2.7
|
33
|
45.9
|
109
|
3.8
|
33
|
29.0
|
112
|
3.5
|
38
|
44.5
|
≥2 tasks
|
322
|
11.8
|
127
|
39.4
|
406
|
14.0
|
133
|
28.4
|
427
|
13.4
|
111
|
27.2
|
IADL difficulty
|
|
|
|
<0.001
|
|
|
|
<0.001
|
|
|
|
<0.001
|
None
|
1574
|
58.1
|
232
|
15.0
|
2275
|
79.4
|
371
|
14.8
|
1943
|
61.5
|
244
|
11.9
|
1 task
|
361
|
13.3
|
67
|
19.0
|
105
|
3.7
|
28
|
25.1
|
349
|
11.0
|
57
|
16.0
|
≥2 tasks
|
775
|
28.6
|
278
|
35.7
|
486
|
17.0
|
161
|
29.1
|
868
|
27.5
|
216
|
27.5
|
Use of sleeping pills use
|
|
|
|
0.005
|
|
|
|
0.022
|
|
|
|
0.009
|
No
|
2422
|
89.1
|
496
|
20.4
|
2521
|
87.4
|
468
|
16.7
|
2715
|
85.1
|
422
|
15.4
|
Yes
|
297
|
10.9
|
83
|
28.6
|
363
|
12.6
|
94
|
22.9
|
477
|
14.9
|
106
|
22.3
|
Vision
|
|
|
|
<0.001
|
|
|
|
0.002
|
|
|
|
<0.001
|
Clear
|
772
|
32.1
|
129
|
17.4
|
815
|
32.0
|
109
|
12.8
|
974
|
34.2
|
109
|
11.1
|
Average
|
1020
|
42.4
|
184
|
17.7
|
1097
|
43.1
|
206
|
17.0
|
1296
|
45.5
|
189
|
14.3
|
Unclear
|
615
|
25.6
|
166
|
28.1
|
635
|
24.9
|
159
|
22.2
|
579
|
20.3
|
146
|
27.7
|
Frequency of exercise
|
|
|
|
0.018
|
|
|
|
0.001
|
|
|
|
<0.001
|
None
|
1246
|
45.8
|
298
|
24.2
|
1370
|
50.0
|
311
|
21.2
|
1524
|
50.4
|
301
|
20.3
|
Irregular
|
167
|
6.1
|
34
|
19.3
|
138
|
5.0
|
17
|
13.0
|
107
|
3.5
|
20
|
13.4
|
Regular
|
1306
|
48.0
|
247
|
19.1
|
1233
|
45.0
|
196
|
13.8
|
1394
|
46.1
|
170
|
12.6
|
Comorbidities
|
|
|
|
<0.001
|
|
|
|
0.051
|
|
|
|
0.022
|
0
|
879
|
38.5
|
116
|
12.2
|
942
|
33.5
|
153
|
14.2
|
884
|
28.6
|
104
|
12.4
|
1
|
690
|
30.2
|
131
|
19.2
|
957
|
34.0
|
185
|
17.6
|
995
|
32.2
|
175
|
16.4
|
≥2
|
712
|
31.2
|
187
|
28.5
|
916
|
32.5
|
202
|
19.6
|
1207
|
39.1
|
218
|
18.5
|
Urinary incontinence
|
|
|
|
<0.001
|
|
|
|
0.002
|
|
|
|
<0.001
|
No
|
2066
|
76.1
|
384
|
18.8
|
2603
|
90.2
|
485
|
16.5
|
2544
|
79.9
|
367
|
14.0
|
Yes
|
649
|
23.9
|
194
|
29.6
|
284
|
9.8
|
77
|
26.0
|
640
|
20.1
|
156
|
25.5
|
Depressive symptoms
|
|
|
|
<0.001
|
|
|
|
<0.001
|
|
|
|
<0.001
|
No
|
1715
|
71.4
|
282
|
16.3
|
1999
|
76.4
|
297
|
13.6
|
2229
|
79.6
|
282
|
12.5
|
Yes
|
686
|
28.6
|
198
|
30.0
|
617
|
23.6
|
193
|
27.7
|
570
|
20.4
|
139
|
24.9
|
Note: p-value < 0.05 using the chi-square test indicates a statistically significant fall risk across each explanatory variable. The prevalence of falls was estimated by weighing according to sampling probability proportional to the population size. SD = standard deviation.
Table 2 Distribution of falls across selected chronic conditions during the year of survey
|
2005
|
2009
|
2013
|
|
Characteristics
|
No. of
participants
|
Prevalence of
falls and
p-value
|
No. of
participants
|
Prevalence of
falls and
p-value
|
No. of
participants
|
Prevalence of
falls and
p-value
|
|
N = 2722
|
%
|
n
|
%
|
N = 2900
|
%
|
n
|
%
|
N = 3200
|
%
|
N
|
%
|
Hypertension
|
|
|
|
<0.001
|
|
|
|
0.002
|
|
|
|
0.078
|
No
|
1514
|
56.9
|
277
|
17.4
|
1475
|
50.9
|
247
|
14.7
|
1482
|
46.5
|
221
|
14.7
|
Yes
|
1145
|
43.1
|
279
|
25.9
|
1421
|
49.1
|
317
|
20.3
|
1708
|
53.5
|
304
|
17.9
|
Diabetes
|
|
|
|
<0.001
|
|
|
|
0.032
|
|
|
|
0.131
|
No
|
2181
|
82.2
|
424
|
19.7
|
2337
|
80.7
|
431
|
16.5
|
2471
|
77.5
|
386
|
15.7
|
Yes
|
473
|
17.8
|
134
|
28.4
|
560
|
19.3
|
134
|
21.5
|
717
|
22.5
|
137
|
18.9
|
Hyperlipidemia
|
|
|
|
<0.001
|
|
|
|
0.979
|
|
|
|
0.014
|
No
|
1847
|
76.7
|
327
|
17.9
|
2159
|
76.0
|
421
|
17.2
|
2290
|
73.2
|
354
|
14.8
|
Yes
|
562
|
23.3
|
149
|
26.6
|
682
|
24.0
|
127
|
17.3
|
839
|
26.8
|
155
|
19.9
|
Stroke
|
|
|
|
<0.001
|
|
|
|
0.921
|
|
|
|
<0.001
|
No
|
2493
|
92.4
|
504
|
20.1
|
2687
|
92.8
|
518
|
17.4
|
2918
|
91.3
|
448
|
15.0
|
Yes
|
206
|
7.6
|
67
|
35.5
|
210
|
7.2
|
45
|
17.7
|
277
|
8.7
|
79
|
32.4
|
Transient ischemic attack
|
|
|
|
<0.001
|
|
|
|
0.037
|
|
|
|
0.008
|
No
|
2447
|
90.3
|
488
|
20.2
|
2702
|
93.7
|
514
|
16.9
|
2838
|
89.6
|
444
|
15.4
|
Yes
|
263
|
9.7
|
89
|
32.5
|
182
|
6.3
|
48
|
24.6
|
329
|
10.4
|
74
|
24.1
|
Asthma
|
|
|
|
0.050
|
|
|
|
0.001
|
|
|
|
0.648
|
No
|
2561
|
94.9
|
533
|
20.9
|
2744
|
94.7
|
519
|
16.9
|
2993
|
93.7
|
496
|
16.6
|
Yes
|
140
|
5.2
|
38
|
29.1
|
155
|
5.3
|
46
|
29.6
|
201
|
6.3
|
30
|
15.0
|
Kidney disease
|
|
|
|
<0.001
|
|
|
|
0.464
|
|
|
|
0.006
|
No
|
2375
|
91.1
|
467
|
19.5
|
2666
|
92.3
|
501
|
17.2
|
2884
|
90.4
|
456
|
15.5
|
Yes
|
232
|
8.9
|
72
|
33.9
|
223
|
7.7
|
60
|
19.7
|
308
|
9.6
|
70
|
24.3
|
* p < 0.05 using the chi-square test indicates a statistically significant fall risk across each explanatory variable. The prevalence of falls was estimated by weighing according to sampling probability proportional to the population size.
As shown in Table 1, the weighted prevalence of falls (and 95% confidence interval) over the previous year gradually dropped from 21.3% (95% CI 19.6-23.1%), 17.5% (95% CI 15.7-19.2%), to 16.5% (95% CI 14.8-18.3%) across three waves of survey. With further adjustment for age, sex, and year of survey accounting for 76% of the total variation in the multiple linear regression model (R2 = 0.76 in Additional file 2: Table S2), the age- and sex-specific prevalence of falls presented a decrease rate of 2.61% per year during the period from 2005 to 2013. In contrast to the declining trend of the prevalence rates for falls during the period from 2005 to 2013, an increasing trend was observed for the overall, sex-specific, and age-specific fall-related hospitalization rates between 2003 and 2009 [17]. This trend was especially apparent among older women and individuals aged 75–84 years (Fig 1).
The overall and sex-specific and age-specific fall-related hospitalization rates from 2003 to 2009 were adopted from Bai [17]. Bai’s fall-related data were retrieved from the inpatient expenditures by admissions (DD) of the longitudinal national health insurance research database (LHID) 2005. This database contained information on patients aged ≥65 years and hospitalized due to fall injuries with diagnostic code E880-E888 of the International Classification of Disease-Clinical Modification (ninth revision), either for external cause codes or for major diagnosis and secondary diagnosis.
Compared with the univariate logistic regression results (Table 3), Table 4 reveals that independent risk factors of falls identified in the MLR models varied with attenuation of adjusted odds ratios (OR) across these surveys. Risk of falls increased 1.4–1.6 times in women (OR 1.64, 95% CI 1.26–2.15 in 2005; OR 1.38, 95% CI 1.09–1.76 in 2009), but not with age. Those risk factors that were independently associated with a higher risk of falls included urinary incontinence (OR 1.42, 95% CI 1.04–1.94 in 2013), depressive symptoms (OR 1.51, 95% CI 1.12–2.03 in 2005; OR 1.77, 95% CI 1.35–2.31 in 2009; OR 1.45, 95% CI 1.06–1.98 in 2013), and having difficulty in performing one ADL (OR 2.39, 95% CI 1.25–4.58 in 2005; OR 2.74, 95% CI 1.55–4.86 in 2013), having difficulty in performing two or more IADLs (OR 1.45, 95% CI 1.00–2.11 in 2005), and unclear vision (OR 1.92, 95% CI 1.36–2.72 in 2013), instead of using sleeping pills. Moreover, a fall-risk gradient was found between having one (OR 1.61, 95% CI 1.16–2.24) and two or more comorbidities (OR 2.41, 95% CI 1.74–3.35) in 2005. Notably, both regular and irregular exercises were not associated with a protective effect from falls.
Table 3 Univariate logistic regression analyses for falls by the year of survey
Covariate (reference)
|
2005
|
2009
|
2013
|
OR 95%CI
|
OR 95%CI
|
OR 95%CI
|
Age (65–69)
|
|
|
|
70–74
|
1.30 (0.99–1.71)
|
1.40 (1.06–1.84)
|
1.40 (1.04–1.89)
|
75–79
|
1.48 (1.12–1.96)
|
1.20 (0.90–1.62)
|
1.58 (1.15–2.17)
|
80–84
|
1.92 (1.39–2.65)
|
1.83 (1.34–2.51)
|
1.67 (1.20–2.34)
|
85+
|
1.74 (1.14–2.65)
|
1.66 (1.13–2.42)
|
2.33 (1.62–3.35)
|
Sex (male)
|
|
|
|
Female
|
1.80 (1.47–2.21)
|
1.57 (1.28–1.93)
|
1.18 (0.95–1.45)
|
ADL difficulty (none)
|
|
|
|
1 task
|
3.84 (2.34–6.30)
|
2.29 (1.46–3.60)
|
5.00 (3.22–7.75)
|
≧2 tasks
|
2.93 (2.23–3.85)
|
2.22 (1.71–2.87)
|
2.33 (1.77–3.07)
|
IADL difficulty (none)
|
|
|
|
1 task
|
1.32 (0.96–1.82)
|
1.92 (1.18–3.11)
|
1.42 (1.00–2.01)
|
≧2 tasks
|
3.14 (2.52–3.90)
|
2.36 (1.85–3.00)
|
2.82 (2.24–3.54)
|
Use of sleeping pills (no)
|
|
|
|
Yes
|
1.56 (1.17–2.08)
|
1.48 (1.11–1.96)
|
1.58 (1.22–2.04)
|
Vision (clear)
|
|
|
|
Average
|
1.02 (0.78–1.33)
|
1.39 (1.07–1.82)
|
1.33 (1.01–1.75)
|
Unclear
|
1.86 (1.41–2.45)
|
1.94 (1.44–2.60)
|
3.07 (2.28–4.13)
|
Comorbidities (0)
|
|
|
|
1
|
1.71 (1.27–2.30)
|
1.30 (1.00–1.68)
|
1.39 (1.03–1.86)
|
≧2
|
2.86 (2.15–3.79)
|
1.47 (1.14–1.91)
|
1.60 (1.21–2.11)
|
Urinary incontinence (no)
|
|
|
|
Yes
|
1.82 (1.46–2.26)
|
1.78 (1.33–2.38)
|
2.10 (1.67–2.65)
|
Depressive symptoms (no)
|
|
|
|
Yes
|
2.20 (1.76–2.75)
|
2.44 (1.94–3.07)
|
2.32 (1.80–3.00)
|
Frequency of exercise (none)
|
|
|
|
Irregular
|
0.75 (0.48–1.17)
|
0.56 (0.34–0.91)
|
0.60 (0.33–1.10)
|
Regular
|
0.74 (0.60–0.91)
|
0.60 (0.48–0.74)
|
0.57 (0.45–0.71)
|
Table 4 Multivariate logistic regression analyses for falls by the year of survey
Covariate (reference)
|
2005
|
2009
|
2013
|
Age (65–69)
|
|
|
|
|
|
|
70–74
|
1.16
|
(0.83–1.62)
|
1.26
|
(0.93–1.69)
|
1.13
|
(0.81–1.58)
|
75–79
|
1.24
|
(0.87–1.76)
|
0.87
|
(0.62–1.22)
|
1.17
|
(0.81–1.70)
|
80+
|
1.34
|
(0.88–2.03)
|
1.35
|
(0.97–1.89)
|
1.19
|
(0.82–1.73)
|
Sex (male)
|
|
|
|
|
|
|
Female
|
1.64
|
(1.26–2.15)
|
1.38
|
(1.09–1.76)
|
0.93
|
(0.72–1.20)
|
ADL difficulty (none)
|
|
|
|
|
|
|
1 task
|
2.39
|
(1.25–4.58)
|
0.44
|
(0.10–1.87)
|
2.74
|
(1.55–4.86)
|
≥2 tasks
|
1.41
|
(0.80–2.47)
|
0.42
|
(0.09–2.04)
|
1.14
|
(0.66–1.95)
|
IADL difficulty (none)
|
|
|
|
|
|
|
1 task
|
0.76
|
(0.51–1.14)
|
1.41
|
(0.74–2.72)
|
1.13
|
(0.77–1.66)
|
≥2 tasks
|
1.45
|
(1.00–2.11)
|
4.56
|
(0.98–21.23)
|
1.27
|
(0.85–1.90)
|
Use of sleeping pills
(no)
|
|
|
|
|
|
|
Yes
|
1.09
|
(0.75–1.60)
|
1.06
|
(0.75–1.49)
|
1.21
|
(0.88–1.67)
|
Vision (clear)
|
|
|
|
|
|
|
Average
|
0.93
|
(0.69–1.27)
|
1.25
|
(0.94–1.65)
|
1.10
|
(0.82–1.48)
|
Unclear
|
1.09
|
(0.77–1.55)
|
1.23
|
(0.88–1.71)
|
1.92
|
(1.36–2.72)
|
Comorbidities (0)
|
|
|
|
|
|
|
1
|
1.61
|
(1.16–2.24)
|
1.16
|
(0.87–1.54)
|
1.18
|
(0.85–1.64)
|
≥2
|
2.41
|
(1.74–3.35)
|
1.19
|
(0.89–1.61)
|
1.12
|
(0.81–1.54)
|
Urinary incontinence (no)
|
|
|
|
|
|
|
Yes
|
1.09
|
(0.80–1.49)
|
1.29
|
(0.90–1.84)
|
1.42
|
(1.04–1.94)
|
Depressive symptoms (no)
|
|
|
|
|
|
|
Yes
|
1.51
|
(1.12–2.03)
|
1.77
|
(1.35–2.31)
|
1.45
|
(1.06–1.98)
|
Frequency of exercise (none)
|
|
|
|
|
|
|
Irregular
|
1.20
|
(0.70–2.04)
|
0.77
|
(0.46–1.29)
|
0.87
|
(0.45–1.69)
|
Regular
|
1.12
|
(0.85–1.49)
|
0.81
|
(0.63–1.04)
|
0.80
|
(0.62–1.03)
|
Note: Adjusted odds ratios and 95% confidence interval (OR and 95%CI) are presented for each dummy variable. Variables controlled across three waves of survey in the MLR model included age, sex, developing difficulty in performing ADLs or IADLs, use of sleeping pills, vision, comorbidities, urinary incontinence, depressive symptoms, and frequency of exercise.
Figure 2 demonstrates that the effect size varied by age and sex of study population and outcome indicators selected. During 2005 and 2009, the effect size of prevalence of falls presented as 14.5% for old men and 21.4% for old women, and 17.2%, 11.5%, 29.3%, 18.1%, and 18.4% respectively for those aged 65-69, 70-74, 75-79, 80-84, and ≥85 years. In contrast to the universal positive effect on the prevalence of falls among older adults, the effect size of fall-related hospitalization rates revealed a 2% relative risk reduction only for those aged 65-74 years, but deteriorated for those aged 75-84 (-10.9%), for old men (-2.0%) and old women (-10.7%).