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Proper shoe sizes for Thai elderly
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The Foot 18 (2008) 186–191
Proper shoe sizes for Thai elderly Dootchai Chaiwanichsiri a,∗ , Natthiya Tantisiriwat b , Siriporn Janchai a a b
Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Thai Red Cross Rehabilitation Center, Thai Red Cross Society, Samutprakarn, Thailand
Received 7 February 2008; received in revised form 2 May 2008; accepted 9 May 2008
Abstract Background: Problems from improper shoe fitting are common, but there are limited foot data for the older Thai population. Objectives: To study foot dimensions and determine proper shoe sizes for Thai elderly. Methods: Healthy older people: 108 men, 105 women, aged 60–80 years, who were independent in walking, were recruited. Thirteen foot dimensions and current shoes used were measured. Side-to-side, gender difference, and correlations of main foot measurements were analyzed. Results: About 50% women and 34% men wore too narrow shoes, and this was found to be associated with foot pain. At the same foot length (FL), men had larger foot width (FW) and toe depth. Foot width = 2.39 + (0.29 × FL), r = 0.50, p = 0.001 for women and = 2.48 + (0.31 × FL), r = 0.56, p = 0.002 for men. Arch length = 1.0 + (0.7 × FL), r = 0.93, p = 0.001 for both genders. Toe depth had constant values in all shoe sizes of each gender. Correlations of other foot parameters were reported. Conclusions: These anthropometric data is essential for proper shoe fitting in order to provide foot ergonomics and prevent foot problems for older Thai people. © 2008 Elsevier Ltd. All rights reserved. Keywords: Footwear; Shoe; Elderly; Foot pain
1. Introduction When foot and ankle problems are discussed, shoes are common issues. Improper shoe size is a cause of foot injury, pain and deformity. Many studies emphasized the importance of footwear in diabetes. Poorly fitting shoes can lead to foot ulceration and amputation. There are only few studies concerning the importance of footwear in healthy elderly. Menz and Moris [1] reported the association between ill-fitting shoes and foot problems in older people. They found that narrow shoes are significantly associated with corns, callus and hallux valgus, while short shoes are significantly associated with lesser toe deformity. Burns et al. [2] reported 72% of older patients admitted in rehabilitation ward wearing ill-fitting shoes, and had significantly associated foot pain and ulceration. Chantelau and Gede [3] assessed foot length ∗
Corresponding author. Tel.: +66 2 2564433; fax: +66 2 2564433. E-mail address: [email protected] (D. Chaiwanichsiri).
0958-2592/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foot.2008.05.001
and foot width among elderly with and without diabetes, and found that more than two-thirds of their feet were broader than the ordinary footwear used. This finding revealed that many feet of older people do not fit the shoes which are available in the market. There is an increasing geriatric population in Thailand. It was assumed that the geriatric population would reach 11.4% of total population in 2010. Disease prevention should encourage adequate physical activity of which walking is the most effective and safe activity prescribed for older people. Proper shoes could provide foot protection and stability [4], absorb excessive force, and prevent falls [5,6]. But most footwear in the market is not well fit for our older people. Up to now, there was little information about the feet of elderly in Thailand. Because of possible racial differences in foot anatomy [7], it is essential to define our own elderly foot data. The present study aimed to collect the foot anthropometric data of Thai healthy older people, in order to determine proper shoe shape and sizes.
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
187
Fig. 1. Foot measurements in weight bearing position using Chula foot calipers.
A cross-sectional descriptive study was done at the Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, during September 2006–August 2007. The study was a part of the project “Foot disorders and proper shoes for elderly”, and was approved by the Ethics Committee of the Faculty of Medicine, Chulalongkorn University. Informed consents were obtained from all volunteers before they were recruited.
sured 13 foot dimensions in the weight bearing position (Fig. 1) by using the Chula foot caliper [8] and standard tape measure. Foot length, foot width, arch length, toe depth, heel width, upper ball, upper arch, ball girth, waist girth, instep girth, short heel girth, ankle circumference, and ankle height were recorded in centimeters (cm). Current footwear used was also measured for internal dimensions using Chula shoe caliper and tape measure (Fig. 2). The internal shoe length, shoe width, and toe box were compared with the corresponding foot dimensions. Mismatching of foot–shoe size was defined if any of those three main dimensions was different more than 5 mm.
2.2. Participants
2.4. Data analysis
Healthy older persons, who were independent in self-care and walking, were recruited from urban Bangkok. Sample size of 100 cases for each gender was determined. Those who had a past history of neurological disorders, spinal or lower extremity injury, or had been diagnosed as having inflammatory joint disease were excluded.
All data were analyzed with SPSS software for Window version 11.5 (SPSS, Inc., Chicago, IL, USA). Categorical data were presented as number and percentage. The foot measurements were reported in means and standard deviations. Shoe sizes (numbers) were categorized by foot length in centimeter for both genders. Foot dimensions were compared using paired t-test to determine the equality between both sides. Correlation between foot length and foot width were analyzed by linear regression model in order to determine main foot parameters. Correlations between ball girth vs. foot width, arch length vs. foot length, heel width vs. foot length, and ankle height vs. foot length were also analyzed.
2. Methods 2.1. Study design
2.3. Measurement Two physiatrists interviewed all subjects about their personal data, medical status, musculoskeletal problems, foot symptoms, and shoe type used. Two trained orthotists mea-
Fig. 2. Shoe measurements using tape measure and Chula shoe caliper.
188
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
Table 1 Mean, S.D., minimum, and maximum values of foot measurements Parameter (cm)
Foot length Foot (ball) width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumference Ankle height
Women (189 feet)
Men (209 feet)
Minimum
Maximum
Mean (S.D.)
Minimum
Maximum
Mean (S.D.)
20.6 8.2 15.3 1.6 5.65 12 13.4 19.45 18.8 19.8 19.5 20.45 4.2
25.5 10.65 19.1 2.75 8.1 14.6 25.6 26.4 24.85 25.45 33.75 28.5 6.8
23.2 (0.95) 9.34 (0.53) 17.4 (0.77) 2.01 (0.2) 6.74 (0.5) 13.6 (1.32) 16.1 (1.35) 22.7 (1.21) 21.6 (1.16) 22.5 (1.23) 29.9 (2.29) 24.1 (1.59) 5.49 (0.48)
22.3 8.85 16.3 1.8 5.8 13.1 15.6 21.1 21 22.05 23 22 4.8
28.2 11.65 21.3 3.1 8.85 17.75 21.6 28.65 28 29.15 36.6 30.5 7.75
25.01 (1.06) 10.26 (0.59) 18.66 (0.83) 2.32 (0.23) 7.06 (0.47) 14.95 (0.89) 17.94 (1.15) 24.98 (1.44) 24.08 (1.36) 25.01 (1.39) 32.63 (1.88) 26.08 (1.48) 6.14 (0.56)
3. Results 3.1. Participants’ characteristics There were 213 subjects: 108 men and 105 women, mean age 68.7 ± 5.4 years, recruited into the study. The mean body mass index (BMI) = 24.7 ± 3.3 kg/m2 . Fifty-four percent were over-weight (BMI > 24 kg/m2 ), and about 6% were obese (BMI > 30 kg/m2 ). All of the subjects were Thai. Most of them were educated, had average income, and were still active. Approximately 66% of men and 50% women had retired, about 15% ran their own business, and 23% of older women still did house work. The following medical comorbidities: diabetes (male:female (M:F) = 20.3%:17.1%), hypertension (M:F = 33.3%:29.5%), dyslipidemia (M:F = 24.0%:22.8%), coronary artery disease (M:F = 8.3%:3.8%), visual impairment (M:F = 23.1%:26.8%), and hearing loss (M:F = 5.5%:7.6%) were reported with similar proportion in both genders. 3.2. Foot–shoe size matching The main foot dimensions were compared with their current shoe sizes. There were 50% women and 34.3% men who wore narrow shoes. About 22% of the subjects (35.5% of women) who used small footwear reported foot pain compared to 9.5% of subjects who used appropriate sizes. 3.3. Foot anthropometric data According to the study of Wunderlich and Cavanagh [9] which revealed gender differences in adult foot shape, all foot anthropometric data of each gender was separately analyzed. To determine proper shoe sizes, the feet with severe hallux valgus which could affect ball width were excluded. There was severe hallux valgus in 21 women’s feet and 7 men’s feet. After exclusion of this group, the total number of 189 women’s feet (90%), and 209 men’s feet (96.7%) were left for analyses. All foot measurements were reported as mean
and standard deviation shown in Table 1. Foot dimensions of both sides were compared. Most foot measurements were not significantly different in side especially in main measurements. Parameters which showed side difference were upper arch, ball girth, waist girth, and instep girth. The participants’ foot dimensions were categorized into shoe sizes by ranges of foot length in cm (Japanese shoe size system) as shown in Tables 2 and 3. Approximately 84% of older women had foot length between shoes size 22.5 cm and 24.5 cm, and 89% of older men had foot length between shoes size 24 cm and 27 cm. Comparisons of foot dimensions between genders demonstrated that, at the same foot length, men had larger foot width, ball girth, upper ball, upper arch, toe depth, and ankle height than women, while arch length had the same proportion with foot length in both genders. 3.4. Correlations of foot parameters The most essential foot parameters for shoe fitting are foot length, and foot width (ball width or foot breadth) [10]. Linear regression analysis was used to define foot width for both genders. The correlations are shown in Fig. 3. • For women: foot width = 2.396 + (0.299 × foot length), r = 0.50, p = 0.001. • For men: foot width = 2.487 + (0.311 × foot length), r = 0.56, p = 0.002 Despite the low r-values, it was found that the differences between calculated foot widths and mean measured values were small, which could be accepted for clinical used (Table 4). Other foot dimensions were also brought into regression analysis. The ball girth, upper ball, and ankle height were separately analyzed for each gender. Arch length and heel width were analyzed from data of both genders. The results are shown in Table 5. Unlike other foot measurements, toe depth merely changed among all foot lengths (Tables 2 and 3). So
Table 2 Mean (S.D.) of women’s foot dimensions categorized by foot length in centimeters Parameter
21 (n = 7)
21.5 (n = 2)
22 (n = 6)
22.5 (n = 26)
23 (n = 39)
23.5 (n = 44)
24 (n = 30)
24.5 (n = 18)
25 (n = 12)
25.5 (n = 5)
8.44 (0.18) 15.6 (0.19) 1.79 (0.12) 6.35 (0.26) 12.4 (0.46) 15.1 (0.64) 20.4 (0.64) 20.0 (1.0) 20.5 (0.76) 27.6 (0.87) 21.4 (0.9) 5.18 (0.48)
8.85 (0.28) 15.9 (0.21) 2.08 (0.18) 5.95 (0.28) 13.0 (0.07) 15.1 (0.92) 21.5 (0.28) 20.5 (0.92) 20.6 (0.6) 27.9 (0.67) 21.4 (0.53) 5.53 (0.74)
8.94 (0.34) 16.2 (0.25) 1.89 (0.11) 6.32 (0.31) 13.0 (0.33) 15.8 (1.0) 21.7 (0.73) 20.7 (0.82) 21.6 (1.2) 29.3 (1.16) 23.4 (1.37) 5.37 (0.59)
9.17 (0.5) 16.7 (0.41) 2.25 (0.14) 6.6 (0.44) 13.1 (0.56) 15.5 (0.75) 22.1 (1.05) 20.9 (0.96) 22.0 (0.98) 29.1 (0.7) 23.2 (1.02) 5.27 (0.49)
9.28 (0.54) 17.2 (0.37) 2.3 (0.18) 6.61 (0.49) 13.7 (1.95) 15.9 (1.77) 22.4 (1.01) 21.4 (0.95) 22.2 (0.99) 29.6 (1.01) 23.7 (1.25) 5.33 (0.43)
9.28 (0.48) 17.5 (0.35) 2.5 (0.16) 6.67 (0.49) 13.7 (1.65) 16.4 (1.66) 22.6 (0.87) 21.5 (0.93) 22.4 (0.97) 29.9 (2.29) 24 (1.35) 5.6 (0.51)
9.52 (0.39) 17.8 (0.4) 2.75 (0.23) 6.94 (0.37) 13.8 (0.6) 16.4 (0.88) 23.1 (1.08) 22.1 (1.11) 22.9 (1.05) 29.8 (3.81) 25.1 (1.18) 5.58 (0.36)
9.73 (0.5) 18.3 (0.35) 2.65 (0.27) 7.1 (0.51) 14.1 (0.67) 16.2 (0.9) 23.9 (1.26) 22.5 (1.17) 23.3 (1.19) 31.4 (1.3) 25.2 (1.54) 5.53 (0.5)
9.75 (0.33) 18.4 (0.31) 2.11 (0.19) 7.07 (0.42) 14.2 (0.51) 16.8 (0.92) 23.5 (0.85) 22.4 (1.11) 23.8 (0.77) 31.4 (2.73) 25.7 (1.2) 5.75 (0.34)
9.63 (0.15) 18.86 (0.18) 2.02 (0.14) 7.13 (0.31) 14.22 (0.38) 17.17 (0.38) 23.54 (0.42) 22.31 (0.78) 24.47 (0.6) 32.49 (0.48) 26.15 (1.11) 5.95 (0.23)
Table 3 Mean (S.D.) of men’s foot dimensions categorized by foot length in centimeters Parameter
Ball width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumfer. Ankle height
Foot length (cm) 22.5 (n = 3)
23 (n = 4)
23.5 (n = 10)
24 (n = 22)
24.5 (n = 28)
25 (n = 35)
25.5 (n = 38)
26 (n = 34)
27 (n = 30)
28 (n = 4)
29 (n = 1)
9.47 (0.63) 16.6 (0.28) 2.4 (0.18) 6.3 (0.36) 13.9 (0.78) 17.4 (0.78) 21.8 (0.59) 22.3 (1.51) 23.2 (0.95) 30.7 (0.59) 24.3 (0.8) 5.7 (0.74)
9.8 (0.66) 17.1 (0.43) 2.18 (0.1) 6.48 (0.23) 14.2 (0.84) 17.0 (0.39) 23.3 (1.56) 22.8 (1.12) 23.4 (0.57) 30.8 (0.86) 23.9 (0.7) 5.39 (0.45)
10.0 (0.55) 17.6 (0.87) 2.31 (0.18) 6.84 (0.53) 14.6 (0.63) 17.4 (0.63) 24.3 (1.12) 23.2 (1.25) 24.0 (1.06) 30.5 (2.67) 24.3 (1.14) 6.01 (0.36)
9.74 (0.6) 17.8 (0.26) 2.19 (0.24) 6.93 (0.41) 14.1 (0.74) 16.9 (0.73) 23.7 (1.3) 23.1 (1.09) 23.8 (1.07) 31.2 (0.81) 24.8 (1.17) 5.71 (0.43)
9.92 (0.45) 18.2 (0.39) 2.19 (0.2) 6.76 (0.37) 14.4 (0.61) 17.4 (0.93) 24.2 (1.08) 23.2 (0.97) 24.1 (0.9) 32.0 (0.94) 25.7 (1.11) 5.91 (0.44)
10.2 (0.47) 18.5 (0.32) 2.28 (0.23) 6.9 (0.44) 14.9 (1.01) 17.9 (1.14) 24.8 (1.24) 23.8 (1.33) 24.8 (1.25) 32.2 (2.02) 25.8 (1.3) 6.12 (0.46)
10.4 (0.46) 18.8 (0.37) 2.38 (0.21) 7.2 (0.39) 15.2 (0.62) 18.0 (0.86) 25.5 (1.04) 24.5 (1.05) 25.3 (0.99) 32.8 (1.06) 26.4 (1.33) 6.18 (0.48)
10.5 (0.46) 19.2 (0.38) 2.37 (0.22) 7.2 (0.34) 15.4 (0.85) 18.6 (1.1) 25.6 (1.19) 24.7 (1.22) 25.7 (1.27) 33.4 (2.13) 26.7 (1.09) 6.44 (0.64)
10.7 (0.46) 19.6 (0.48) 2.43 (0.22) 7.42 (0.39) 15.5 (0.62) 18.9 (1.19) 26.0 (0.97) 25.1 (0.94) 26.3 (1.11) 34.3 (1.08) 27.4 (1.15) 6.5 (0.53)
10.9 (0.48) 20.3 (0.68) 2.46 (0.17) 7.56 (0.4) 16.0 (0.67) 17.6 (0.03) 26.8 (1.09) 25.2 (0.9) 26.1 (0.5) 34.7 (0.93) 27.5 (0.46) 6.2 (0.28)
11.6 21.3 2.75 7.75 16.4 18.9 27.6 26.0 27.2 35.7 28.3 6.65
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
Ball width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumference Ankle height
Foot length (cm)
189
190
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
Table 4 Foot (ball) width from width–length correlations and from measurements Foot length (cm) Women’s foot width (cm)
21 21.5 22 22.5 23 23.5 24 24.5 25 25.5 26 27 28 29
Men’s foot width (cm)
Calculated Measured
Calculated Measured
8.68 8.83 8.97 9.12 9.27 9.42 9.57 9.72 9.87 10.02 – – – –
– – – 9.48 9.64 9.80 9.95 10.1 10.26 10.41 10.57 10.88 11.19 11.50
8.44 8.85 8.94 9.17 9.28 9.28 9.52 9.73 9.75 9.63 – – – –
– – – 9.47 9.8 10 9.74 9.92 10.2 10.4 10.5 10.7 10.9 11.6
we determined the proper toe depth by using mean and 2 S.D. for each gender. As the results, appropriated toe depth for women = 2.01 + 2(0.20) = 2.45 cm and for men = 2.32 + 2(0.23) = 2.78 cm.
4. Discussion The present study revealed a high prevalence of ill-fitting shoes especially in older women. This could be explained
by the difference of women’s shoe shapes which usually are narrower at the anterior part than men’s design. Increasing prevalence of foot pain in those who wear too small shoes pointed to the association of ill–fitting shoe and foot health [11]. But limitation of the study design could not clearly confirm the cause—effect of this condition. The findings also reflected the problems of inadequate proper footwear available in the market, and also the ignorance of older persons in taking care of their feet. Foot–shoe examination and foot health education should be parts of routine medical care for every older person. Mismated feet are not uncommon in general populations [12], and even more frequently found in diabetes patients [13]. Our study among healthy subjects revealed unequal foot dimensions mostly at the region from ball of foot to mid-arch area, the region of most deformities due to degenerative processes and plantar arch changes (pes planus/pes cavus). This problem can be modulated by making adequate foot width and ball girth, and using adjustable or opening upper parts of the shoes. The main measurements of concern: foot length, foot width, toe depth, and ball girth were not significantly different between both sides. Thus shoe sizes can be appropriately determined from these parameters. The authors categorized shoe number by using the Japanese shoe size system due to two main reasons. The first is that the Japanese shoe size system is based on Asian people. The second is that this system is mostly consistent with
Fig. 3. Correlations of foot length and foot width. Table 5 Correlations of foot measurements in both genders Parameter
Ball girth Upper ball Ankle height
Women
Men
Correlation
r
p-Value
Correlation
r
p-Value
3.55 + (2.04 × BW) 1.13 + (1.34 × BW) 1.79 + (0.16 × FL)
0.89 0.54 0.32
0.001 0.001 0.001
2.55 + (2.19 × BW) 2.38 + (1.23 × BW) 0.25 + (0.24 × FL)
0.89 0.80 0.44
0.001 0.001 0.001
Arch length Heel width BW = ball width, FL = foot length.
1.042 + (0.705 × FL), r = 0.929, p = 0.001 1.80 + (0.21 × FL), r = 0.56, p = 0.001
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
the Mondopoint international shoe system, which measures shoe length in millimeters. Differed from the report of Chantelau and Gede [3] who found only minor differences in foot dimensions between genders among older German, Thai older men had wider feet than women at the same foot length. Our finding was consistent with Wunderlich and Cavanagh’s report [9] which studied adult Americans. Because of the anatomical difference between genders, most other foot anthropometric data besides foot width also had greater dimensions in men. This is except for the arch length and heel width which had small difference in the same foot length of both genders. The correlation of foot length and foot width in our study showed that women had more variation of foot width than men (lower rvalue). While the foot length–foot width correlation of older Germans had higher r-value [3]. This reflected the ethnic differences and confirmed the importance of using their own foot anthropometric data for shoe making for different racial groups. All variables increased with foot length, except toe depth. As toe depth provides for all toes which often become deformed with aging, it is crucial to make sure that there is enough room. This result is important in designing shoes with adequate toe depth rather than making the same proportion for each shoe number.
5. Conclusion The foot anthropometric data among Thai elderly show that most older women had foot length between shoes size 22.5 cm and 24.5 cm, and most older men had foot length between shoes size 24 cm and 27 cm. Older women and men had different foot shape proportions. These foot data are essential for fitting proper shoes for elderly, in order to provide foot ergonomics and prevent foot problems.
191
Acknowledgements This study was supported by the Ratchadaphiseksomphot Endowment Fund, a grant from the Thai government of the fiscal year 2006. The authors are also grateful to all volunteers who participated in this project.
References [1] Menz HB, Morris ME. Footwear characteristics and foot problems in older people. Gerontology 2005;51(5):346–51. [2] Burns SL, Leese GP, McMurdo ME. Older people and ill fitting shoes. Postgrad Med J 2002;78(920):344–6. [3] Chantelau E, Gede A. Foot dimensions of elderly people with and without diabetes mellitus—a data basis for shoe design. Gerontology 2002;48(4):241–4. [4] Robbins S, Waked E, Krouglicof N. Improving balance. J Am Geriatr Soc 1998;46(11):1363–70. [5] Koepsell TD, Wolf ME, Buchner DM, Kukull WA, LaCroix AZ, Tencer AF, et al. Footwear style and risk of falls in older adults. J Am Geriatr Soc 2004;52(9):1495–501. [6] Tencer AF, Koepsell TD, Wolf ME, Frankenfeld CL, Buchner DM, Kukull WA, et al. Biomechanical properties of shoes and risk of falls in older adults. J Am Geriatr Soc 2004;52(11):1840–6. [7] Hawes MR, Sovak D, Miyashita M, Kang SJ, Yoshihuku Y, Tanaka S. Ethnic differences in forefoot shape and the determination of shoe comfort. Ergonomics 1994;37(1):187–96. [8] Janchai S, Tantisiriwat N. Reliability of foot caliper. J Med Assoc Thai 2005;88(Suppl. 4):S85–9. [9] Wunderlich RE, Cavanagh PR. Gender differences in adult foot shape: implications for shoe design. Med Sci Sports Exerc 2001;33(4): 605–11. [10] Janisse DJ. The art and science of fitting shoes. Foot Ankle 1992;13(5):257–62. [11] Frey C. Foot health and shoewear for women. Clin Orthop Relat Res 2000;(372):32–44. [12] Rossi WA. The high incidence of mismated feet in the population. Foot Ankle 1983;4(2):105–12. [13] Tantisiriwat N, Janchai S. Mismated feet in diabetes. Chula Med J 2006;50(8):531–40.
The Foot 18 (2008) 186–191
Proper shoe sizes for Thai elderly Dootchai Chaiwanichsiri a,∗ , Natthiya Tantisiriwat b , Siriporn Janchai a a b
Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Thai Red Cross Rehabilitation Center, Thai Red Cross Society, Samutprakarn, Thailand
Received 7 February 2008; received in revised form 2 May 2008; accepted 9 May 2008
Abstract Background: Problems from improper shoe fitting are common, but there are limited foot data for the older Thai population. Objectives: To study foot dimensions and determine proper shoe sizes for Thai elderly. Methods: Healthy older people: 108 men, 105 women, aged 60–80 years, who were independent in walking, were recruited. Thirteen foot dimensions and current shoes used were measured. Side-to-side, gender difference, and correlations of main foot measurements were analyzed. Results: About 50% women and 34% men wore too narrow shoes, and this was found to be associated with foot pain. At the same foot length (FL), men had larger foot width (FW) and toe depth. Foot width = 2.39 + (0.29 × FL), r = 0.50, p = 0.001 for women and = 2.48 + (0.31 × FL), r = 0.56, p = 0.002 for men. Arch length = 1.0 + (0.7 × FL), r = 0.93, p = 0.001 for both genders. Toe depth had constant values in all shoe sizes of each gender. Correlations of other foot parameters were reported. Conclusions: These anthropometric data is essential for proper shoe fitting in order to provide foot ergonomics and prevent foot problems for older Thai people. © 2008 Elsevier Ltd. All rights reserved. Keywords: Footwear; Shoe; Elderly; Foot pain
1. Introduction When foot and ankle problems are discussed, shoes are common issues. Improper shoe size is a cause of foot injury, pain and deformity. Many studies emphasized the importance of footwear in diabetes. Poorly fitting shoes can lead to foot ulceration and amputation. There are only few studies concerning the importance of footwear in healthy elderly. Menz and Moris [1] reported the association between ill-fitting shoes and foot problems in older people. They found that narrow shoes are significantly associated with corns, callus and hallux valgus, while short shoes are significantly associated with lesser toe deformity. Burns et al. [2] reported 72% of older patients admitted in rehabilitation ward wearing ill-fitting shoes, and had significantly associated foot pain and ulceration. Chantelau and Gede [3] assessed foot length ∗
Corresponding author. Tel.: +66 2 2564433; fax: +66 2 2564433. E-mail address: [email protected] (D. Chaiwanichsiri).
0958-2592/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foot.2008.05.001
and foot width among elderly with and without diabetes, and found that more than two-thirds of their feet were broader than the ordinary footwear used. This finding revealed that many feet of older people do not fit the shoes which are available in the market. There is an increasing geriatric population in Thailand. It was assumed that the geriatric population would reach 11.4% of total population in 2010. Disease prevention should encourage adequate physical activity of which walking is the most effective and safe activity prescribed for older people. Proper shoes could provide foot protection and stability [4], absorb excessive force, and prevent falls [5,6]. But most footwear in the market is not well fit for our older people. Up to now, there was little information about the feet of elderly in Thailand. Because of possible racial differences in foot anatomy [7], it is essential to define our own elderly foot data. The present study aimed to collect the foot anthropometric data of Thai healthy older people, in order to determine proper shoe shape and sizes.
D. Chaiwanichsiri et al. / The Foot 18 (2008) 186–191
187
Fig. 1. Foot measurements in weight bearing position using Chula foot calipers.
A cross-sectional descriptive study was done at the Department of Rehabilitation Medicine, Faculty of Medicine, Chulalongkorn University, during September 2006–August 2007. The study was a part of the project “Foot disorders and proper shoes for elderly”, and was approved by the Ethics Committee of the Faculty of Medicine, Chulalongkorn University. Informed consents were obtained from all volunteers before they were recruited.
sured 13 foot dimensions in the weight bearing position (Fig. 1) by using the Chula foot caliper [8] and standard tape measure. Foot length, foot width, arch length, toe depth, heel width, upper ball, upper arch, ball girth, waist girth, instep girth, short heel girth, ankle circumference, and ankle height were recorded in centimeters (cm). Current footwear used was also measured for internal dimensions using Chula shoe caliper and tape measure (Fig. 2). The internal shoe length, shoe width, and toe box were compared with the corresponding foot dimensions. Mismatching of foot–shoe size was defined if any of those three main dimensions was different more than 5 mm.
2.2. Participants
2.4. Data analysis
Healthy older persons, who were independent in self-care and walking, were recruited from urban Bangkok. Sample size of 100 cases for each gender was determined. Those who had a past history of neurological disorders, spinal or lower extremity injury, or had been diagnosed as having inflammatory joint disease were excluded.
All data were analyzed with SPSS software for Window version 11.5 (SPSS, Inc., Chicago, IL, USA). Categorical data were presented as number and percentage. The foot measurements were reported in means and standard deviations. Shoe sizes (numbers) were categorized by foot length in centimeter for both genders. Foot dimensions were compared using paired t-test to determine the equality between both sides. Correlation between foot length and foot width were analyzed by linear regression model in order to determine main foot parameters. Correlations between ball girth vs. foot width, arch length vs. foot length, heel width vs. foot length, and ankle height vs. foot length were also analyzed.
2. Methods 2.1. Study design
2.3. Measurement Two physiatrists interviewed all subjects about their personal data, medical status, musculoskeletal problems, foot symptoms, and shoe type used. Two trained orthotists mea-
Fig. 2. Shoe measurements using tape measure and Chula shoe caliper.
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Table 1 Mean, S.D., minimum, and maximum values of foot measurements Parameter (cm)
Foot length Foot (ball) width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumference Ankle height
Women (189 feet)
Men (209 feet)
Minimum
Maximum
Mean (S.D.)
Minimum
Maximum
Mean (S.D.)
20.6 8.2 15.3 1.6 5.65 12 13.4 19.45 18.8 19.8 19.5 20.45 4.2
25.5 10.65 19.1 2.75 8.1 14.6 25.6 26.4 24.85 25.45 33.75 28.5 6.8
23.2 (0.95) 9.34 (0.53) 17.4 (0.77) 2.01 (0.2) 6.74 (0.5) 13.6 (1.32) 16.1 (1.35) 22.7 (1.21) 21.6 (1.16) 22.5 (1.23) 29.9 (2.29) 24.1 (1.59) 5.49 (0.48)
22.3 8.85 16.3 1.8 5.8 13.1 15.6 21.1 21 22.05 23 22 4.8
28.2 11.65 21.3 3.1 8.85 17.75 21.6 28.65 28 29.15 36.6 30.5 7.75
25.01 (1.06) 10.26 (0.59) 18.66 (0.83) 2.32 (0.23) 7.06 (0.47) 14.95 (0.89) 17.94 (1.15) 24.98 (1.44) 24.08 (1.36) 25.01 (1.39) 32.63 (1.88) 26.08 (1.48) 6.14 (0.56)
3. Results 3.1. Participants’ characteristics There were 213 subjects: 108 men and 105 women, mean age 68.7 ± 5.4 years, recruited into the study. The mean body mass index (BMI) = 24.7 ± 3.3 kg/m2 . Fifty-four percent were over-weight (BMI > 24 kg/m2 ), and about 6% were obese (BMI > 30 kg/m2 ). All of the subjects were Thai. Most of them were educated, had average income, and were still active. Approximately 66% of men and 50% women had retired, about 15% ran their own business, and 23% of older women still did house work. The following medical comorbidities: diabetes (male:female (M:F) = 20.3%:17.1%), hypertension (M:F = 33.3%:29.5%), dyslipidemia (M:F = 24.0%:22.8%), coronary artery disease (M:F = 8.3%:3.8%), visual impairment (M:F = 23.1%:26.8%), and hearing loss (M:F = 5.5%:7.6%) were reported with similar proportion in both genders. 3.2. Foot–shoe size matching The main foot dimensions were compared with their current shoe sizes. There were 50% women and 34.3% men who wore narrow shoes. About 22% of the subjects (35.5% of women) who used small footwear reported foot pain compared to 9.5% of subjects who used appropriate sizes. 3.3. Foot anthropometric data According to the study of Wunderlich and Cavanagh [9] which revealed gender differences in adult foot shape, all foot anthropometric data of each gender was separately analyzed. To determine proper shoe sizes, the feet with severe hallux valgus which could affect ball width were excluded. There was severe hallux valgus in 21 women’s feet and 7 men’s feet. After exclusion of this group, the total number of 189 women’s feet (90%), and 209 men’s feet (96.7%) were left for analyses. All foot measurements were reported as mean
and standard deviation shown in Table 1. Foot dimensions of both sides were compared. Most foot measurements were not significantly different in side especially in main measurements. Parameters which showed side difference were upper arch, ball girth, waist girth, and instep girth. The participants’ foot dimensions were categorized into shoe sizes by ranges of foot length in cm (Japanese shoe size system) as shown in Tables 2 and 3. Approximately 84% of older women had foot length between shoes size 22.5 cm and 24.5 cm, and 89% of older men had foot length between shoes size 24 cm and 27 cm. Comparisons of foot dimensions between genders demonstrated that, at the same foot length, men had larger foot width, ball girth, upper ball, upper arch, toe depth, and ankle height than women, while arch length had the same proportion with foot length in both genders. 3.4. Correlations of foot parameters The most essential foot parameters for shoe fitting are foot length, and foot width (ball width or foot breadth) [10]. Linear regression analysis was used to define foot width for both genders. The correlations are shown in Fig. 3. • For women: foot width = 2.396 + (0.299 × foot length), r = 0.50, p = 0.001. • For men: foot width = 2.487 + (0.311 × foot length), r = 0.56, p = 0.002 Despite the low r-values, it was found that the differences between calculated foot widths and mean measured values were small, which could be accepted for clinical used (Table 4). Other foot dimensions were also brought into regression analysis. The ball girth, upper ball, and ankle height were separately analyzed for each gender. Arch length and heel width were analyzed from data of both genders. The results are shown in Table 5. Unlike other foot measurements, toe depth merely changed among all foot lengths (Tables 2 and 3). So
Table 2 Mean (S.D.) of women’s foot dimensions categorized by foot length in centimeters Parameter
21 (n = 7)
21.5 (n = 2)
22 (n = 6)
22.5 (n = 26)
23 (n = 39)
23.5 (n = 44)
24 (n = 30)
24.5 (n = 18)
25 (n = 12)
25.5 (n = 5)
8.44 (0.18) 15.6 (0.19) 1.79 (0.12) 6.35 (0.26) 12.4 (0.46) 15.1 (0.64) 20.4 (0.64) 20.0 (1.0) 20.5 (0.76) 27.6 (0.87) 21.4 (0.9) 5.18 (0.48)
8.85 (0.28) 15.9 (0.21) 2.08 (0.18) 5.95 (0.28) 13.0 (0.07) 15.1 (0.92) 21.5 (0.28) 20.5 (0.92) 20.6 (0.6) 27.9 (0.67) 21.4 (0.53) 5.53 (0.74)
8.94 (0.34) 16.2 (0.25) 1.89 (0.11) 6.32 (0.31) 13.0 (0.33) 15.8 (1.0) 21.7 (0.73) 20.7 (0.82) 21.6 (1.2) 29.3 (1.16) 23.4 (1.37) 5.37 (0.59)
9.17 (0.5) 16.7 (0.41) 2.25 (0.14) 6.6 (0.44) 13.1 (0.56) 15.5 (0.75) 22.1 (1.05) 20.9 (0.96) 22.0 (0.98) 29.1 (0.7) 23.2 (1.02) 5.27 (0.49)
9.28 (0.54) 17.2 (0.37) 2.3 (0.18) 6.61 (0.49) 13.7 (1.95) 15.9 (1.77) 22.4 (1.01) 21.4 (0.95) 22.2 (0.99) 29.6 (1.01) 23.7 (1.25) 5.33 (0.43)
9.28 (0.48) 17.5 (0.35) 2.5 (0.16) 6.67 (0.49) 13.7 (1.65) 16.4 (1.66) 22.6 (0.87) 21.5 (0.93) 22.4 (0.97) 29.9 (2.29) 24 (1.35) 5.6 (0.51)
9.52 (0.39) 17.8 (0.4) 2.75 (0.23) 6.94 (0.37) 13.8 (0.6) 16.4 (0.88) 23.1 (1.08) 22.1 (1.11) 22.9 (1.05) 29.8 (3.81) 25.1 (1.18) 5.58 (0.36)
9.73 (0.5) 18.3 (0.35) 2.65 (0.27) 7.1 (0.51) 14.1 (0.67) 16.2 (0.9) 23.9 (1.26) 22.5 (1.17) 23.3 (1.19) 31.4 (1.3) 25.2 (1.54) 5.53 (0.5)
9.75 (0.33) 18.4 (0.31) 2.11 (0.19) 7.07 (0.42) 14.2 (0.51) 16.8 (0.92) 23.5 (0.85) 22.4 (1.11) 23.8 (0.77) 31.4 (2.73) 25.7 (1.2) 5.75 (0.34)
9.63 (0.15) 18.86 (0.18) 2.02 (0.14) 7.13 (0.31) 14.22 (0.38) 17.17 (0.38) 23.54 (0.42) 22.31 (0.78) 24.47 (0.6) 32.49 (0.48) 26.15 (1.11) 5.95 (0.23)
Table 3 Mean (S.D.) of men’s foot dimensions categorized by foot length in centimeters Parameter
Ball width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumfer. Ankle height
Foot length (cm) 22.5 (n = 3)
23 (n = 4)
23.5 (n = 10)
24 (n = 22)
24.5 (n = 28)
25 (n = 35)
25.5 (n = 38)
26 (n = 34)
27 (n = 30)
28 (n = 4)
29 (n = 1)
9.47 (0.63) 16.6 (0.28) 2.4 (0.18) 6.3 (0.36) 13.9 (0.78) 17.4 (0.78) 21.8 (0.59) 22.3 (1.51) 23.2 (0.95) 30.7 (0.59) 24.3 (0.8) 5.7 (0.74)
9.8 (0.66) 17.1 (0.43) 2.18 (0.1) 6.48 (0.23) 14.2 (0.84) 17.0 (0.39) 23.3 (1.56) 22.8 (1.12) 23.4 (0.57) 30.8 (0.86) 23.9 (0.7) 5.39 (0.45)
10.0 (0.55) 17.6 (0.87) 2.31 (0.18) 6.84 (0.53) 14.6 (0.63) 17.4 (0.63) 24.3 (1.12) 23.2 (1.25) 24.0 (1.06) 30.5 (2.67) 24.3 (1.14) 6.01 (0.36)
9.74 (0.6) 17.8 (0.26) 2.19 (0.24) 6.93 (0.41) 14.1 (0.74) 16.9 (0.73) 23.7 (1.3) 23.1 (1.09) 23.8 (1.07) 31.2 (0.81) 24.8 (1.17) 5.71 (0.43)
9.92 (0.45) 18.2 (0.39) 2.19 (0.2) 6.76 (0.37) 14.4 (0.61) 17.4 (0.93) 24.2 (1.08) 23.2 (0.97) 24.1 (0.9) 32.0 (0.94) 25.7 (1.11) 5.91 (0.44)
10.2 (0.47) 18.5 (0.32) 2.28 (0.23) 6.9 (0.44) 14.9 (1.01) 17.9 (1.14) 24.8 (1.24) 23.8 (1.33) 24.8 (1.25) 32.2 (2.02) 25.8 (1.3) 6.12 (0.46)
10.4 (0.46) 18.8 (0.37) 2.38 (0.21) 7.2 (0.39) 15.2 (0.62) 18.0 (0.86) 25.5 (1.04) 24.5 (1.05) 25.3 (0.99) 32.8 (1.06) 26.4 (1.33) 6.18 (0.48)
10.5 (0.46) 19.2 (0.38) 2.37 (0.22) 7.2 (0.34) 15.4 (0.85) 18.6 (1.1) 25.6 (1.19) 24.7 (1.22) 25.7 (1.27) 33.4 (2.13) 26.7 (1.09) 6.44 (0.64)
10.7 (0.46) 19.6 (0.48) 2.43 (0.22) 7.42 (0.39) 15.5 (0.62) 18.9 (1.19) 26.0 (0.97) 25.1 (0.94) 26.3 (1.11) 34.3 (1.08) 27.4 (1.15) 6.5 (0.53)
10.9 (0.48) 20.3 (0.68) 2.46 (0.17) 7.56 (0.4) 16.0 (0.67) 17.6 (0.03) 26.8 (1.09) 25.2 (0.9) 26.1 (0.5) 34.7 (0.93) 27.5 (0.46) 6.2 (0.28)
11.6 21.3 2.75 7.75 16.4 18.9 27.6 26.0 27.2 35.7 28.3 6.65
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Ball width Arch length Toe depth Heel width Upper ball Upper arch Ball girth Waist girth Instep girth Short heel girth Ankle circumference Ankle height
Foot length (cm)
189
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Table 4 Foot (ball) width from width–length correlations and from measurements Foot length (cm) Women’s foot width (cm)
21 21.5 22 22.5 23 23.5 24 24.5 25 25.5 26 27 28 29
Men’s foot width (cm)
Calculated Measured
Calculated Measured
8.68 8.83 8.97 9.12 9.27 9.42 9.57 9.72 9.87 10.02 – – – –
– – – 9.48 9.64 9.80 9.95 10.1 10.26 10.41 10.57 10.88 11.19 11.50
8.44 8.85 8.94 9.17 9.28 9.28 9.52 9.73 9.75 9.63 – – – –
– – – 9.47 9.8 10 9.74 9.92 10.2 10.4 10.5 10.7 10.9 11.6
we determined the proper toe depth by using mean and 2 S.D. for each gender. As the results, appropriated toe depth for women = 2.01 + 2(0.20) = 2.45 cm and for men = 2.32 + 2(0.23) = 2.78 cm.
4. Discussion The present study revealed a high prevalence of ill-fitting shoes especially in older women. This could be explained
by the difference of women’s shoe shapes which usually are narrower at the anterior part than men’s design. Increasing prevalence of foot pain in those who wear too small shoes pointed to the association of ill–fitting shoe and foot health [11]. But limitation of the study design could not clearly confirm the cause—effect of this condition. The findings also reflected the problems of inadequate proper footwear available in the market, and also the ignorance of older persons in taking care of their feet. Foot–shoe examination and foot health education should be parts of routine medical care for every older person. Mismated feet are not uncommon in general populations [12], and even more frequently found in diabetes patients [13]. Our study among healthy subjects revealed unequal foot dimensions mostly at the region from ball of foot to mid-arch area, the region of most deformities due to degenerative processes and plantar arch changes (pes planus/pes cavus). This problem can be modulated by making adequate foot width and ball girth, and using adjustable or opening upper parts of the shoes. The main measurements of concern: foot length, foot width, toe depth, and ball girth were not significantly different between both sides. Thus shoe sizes can be appropriately determined from these parameters. The authors categorized shoe number by using the Japanese shoe size system due to two main reasons. The first is that the Japanese shoe size system is based on Asian people. The second is that this system is mostly consistent with
Fig. 3. Correlations of foot length and foot width. Table 5 Correlations of foot measurements in both genders Parameter
Ball girth Upper ball Ankle height
Women
Men
Correlation
r
p-Value
Correlation
r
p-Value
3.55 + (2.04 × BW) 1.13 + (1.34 × BW) 1.79 + (0.16 × FL)
0.89 0.54 0.32
0.001 0.001 0.001
2.55 + (2.19 × BW) 2.38 + (1.23 × BW) 0.25 + (0.24 × FL)
0.89 0.80 0.44
0.001 0.001 0.001
Arch length Heel width BW = ball width, FL = foot length.
1.042 + (0.705 × FL), r = 0.929, p = 0.001 1.80 + (0.21 × FL), r = 0.56, p = 0.001
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the Mondopoint international shoe system, which measures shoe length in millimeters. Differed from the report of Chantelau and Gede [3] who found only minor differences in foot dimensions between genders among older German, Thai older men had wider feet than women at the same foot length. Our finding was consistent with Wunderlich and Cavanagh’s report [9] which studied adult Americans. Because of the anatomical difference between genders, most other foot anthropometric data besides foot width also had greater dimensions in men. This is except for the arch length and heel width which had small difference in the same foot length of both genders. The correlation of foot length and foot width in our study showed that women had more variation of foot width than men (lower rvalue). While the foot length–foot width correlation of older Germans had higher r-value [3]. This reflected the ethnic differences and confirmed the importance of using their own foot anthropometric data for shoe making for different racial groups. All variables increased with foot length, except toe depth. As toe depth provides for all toes which often become deformed with aging, it is crucial to make sure that there is enough room. This result is important in designing shoes with adequate toe depth rather than making the same proportion for each shoe number.
5. Conclusion The foot anthropometric data among Thai elderly show that most older women had foot length between shoes size 22.5 cm and 24.5 cm, and most older men had foot length between shoes size 24 cm and 27 cm. Older women and men had different foot shape proportions. These foot data are essential for fitting proper shoes for elderly, in order to provide foot ergonomics and prevent foot problems.
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Acknowledgements This study was supported by the Ratchadaphiseksomphot Endowment Fund, a grant from the Thai government of the fiscal year 2006. The authors are also grateful to all volunteers who participated in this project.
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