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Table 4 Correlation analysis, normative values and between-group difference

From: The relationship between thoracic kyphosis and age, and normative values across age groups: a systematic review of healthy adults

  Body reference Correlation (p-value) Sample size Age group Mean (SD) (degrees) Range (degrees) Group comparisons (p-value)
All ethnicity
All genders
T1–T12 0.23 (0.21) 2154 997 x < 40 39.8 (±5.87) 33.93–45.67 x < 40 – x > 60b (0.015)
x < 40 – 40 < x < 60 (0.32)
40 < x < 60 – x > 60b (0.004)
X < 50 – x > 50 (0.17)
683 40 < x < 60 38.54 (±4.68) 33.86–43.22
474 x > 60 43.56 (±10.5) 33.08–54.04
1454 x < 50 38.94 (±5.18) 33.76–44.12
700 x > 50 43.11 (±9.56) 33.55–52.67
T2–T12 0.64 (0.12) 212 132 x < 40 44.53 (±4.16) 40.37–48.7 x < 40 – x > 60 (0.49)
x < 40 – 40 < x < 60 (0.49)
40 < x < 60 – x > 60 (0.49)
X < 50 – x > 50 (0.07)
35 40 < x < 60 47.7 (±4.53) 43.17–52.23
61 x > 60 48.75 (±1.48) 47.27–50.23
151 x < 50 44.53 (±3.4) 41.13–47.92
61 x > 50 49.47 (±1.63) 47.84–51.09
T4–T12 0.45a (0.048) 1617 1199 x < 40 33.88 (±4.88) 29–38.77 x < 40 – x > 60b (0.00052)
x < 40 – 40 < x < 60 (0.055)
40 < x < 60 – x > 60 (0.16)
X < 50 – x > 50a (0.0003)
242 40 < x < 60 40.1 (±2.69) 37.41–42.79
176 x > 60 47.63 (±7.33) 40.29–54.96
1223 x < 50 34.11 (±4.77) 29.34–38.87
394 x > 50 45.63 (±6.47) 39.17–52.1
T5–T12 0.52a (0.0001) 4018 1037 x < 40 26.32 (±4.33) 21.99–30.65 x < 40 – x > 60b (0.00011)
x < 40 – 40 < x < 60 (0.036)
40 < x < 60 – x > 60 (0.086)
X < 50 – x > 50a (0.001)
644 40 < x < 60 30.31 (±4.31) 26–34.61
2337 x > 60 32.59 (±3.63) 28.96–36.22
1165 x < 50 27.45 (±4.6) 22.75–32.15
2853 x > 50 31.94 (±3.91) 28.03–35.85
Ethnicity North America (N.A.) T2–T12 0.87a (0.02) 120 40 x < 40 42.2 (±1.41) 40.79–43.61  
35 40 < x < 60 47.7 (±4.52) 43.17–52.23  
45 x > 60 48.75 (±1.48) 47.27–50.23 T1–T12
59 x < 50 42.97 (±1.66) 41.3–44.63 Asia - Europe
61 x > 50 49.47 (±1.63) 47.84–51.09 x < 50a (0.036)
T4–T12 0.82 (0.18) 190 49 x < 50 37.5 (±0.7) 36.79–38.21 x > 50a (0.043)
141 x > 50 42.75 (±1.77) 40.98–44.52  
T5–T12 0.65a (0.03) 339 40 x < 40 30.05 (±1.63) 28.42–31.68  
208 40 < x < 60 35.02 (±2.62) 32.4–37.64 T4–T12
91 x > 60 35.93 (±2.19) 33.73–38.12 N.A. - Europe
86 x < 50 32.2 (±2.98) 29.22–35.18 x < 50 (0.5)
253 x > 50 35.73 (±2.42) 33.31–38.15 x > 50 (0.5)
Asia T1–T12 − 0.18 (0.46) 1551 737 x < 40 39.2 (±5.07) 34.13–44.27  
554 40 < x < 60 37.12 (±1.73) 35.39–38.85  
260 x > 60 35.77 (±2.39) 33.39–38.16  
1184 x < 50 38.48 (±4.37) 34.11–42.85 T5–T12
367 x > 50 36.31 (±2.38) 33.93–38.69 N.A. - Asia
T5–T12 0.72a (0.0000006) 2919 997 x < 40 25.39 (±4.33) 21.06–29.71 x < 40 (0.19)
436 40 < x < 60 27.69 (±2.26) 25.43–29.95 40 < x < 60a (0.00013)
1486 x > 60 31.76 (±3.49) 28.27–35.24 x > 60a (0.033)
1079 x < 50 25.55 (±3.86) 21.69–29.41 x < 50a (0.0097)
1486 x > 50 30.81 (±3.58) 27.23–34.39 x > 50a (0.0017)
Europe T1–T12 0.8 (0.57) 404 250 x < 50 44.87 (±3.96) 40.9–48.83  
154 x > 50 55.7 (±7.04) 48.66–62.74  
T4–T12 0.88a (0.00076) 863 610 x < 50 36.18 (±2.41) 33.77–38.6  
253 x > 50 47.08 (±7.77) 39.31–54.84  
Gender Female T1–T12 − 0.17 (0.55) 724 278 x < 40 37.45 (±6.39) 31.06–43.83  
301 40 < x < 60 36.16 (±0.39) 35.77–36.55  
145 x > 60 33.57 (±4.92) 28.65–38.49 T1–T12
345 x < 50 37.09 (±5.44) 31.65–42.52 Female-male
379 x > 50 34.48 (±4.07) 30.41–38.55 x < 40 (0.52)
T2–T12 0.6a (0.15) 126 73 x < 40 44.33 (±4.16) 40.17–48.49 40 < x < 60 (0.27)
28 40 < x < 60 45.9 (±7.78) 38.12–53.68 x > 60 (0.19)
25 x > 60 49.45 (±6.76) 42.73–56.17 x < 50 (0.41)
88 x < 50 43.35 (±3.92) 39.43–47.27 x > 50 (0.1)
38 x > 50 50.1 (±4.88) 45.22–54.98  
T5–T12 0.6a (0.0024) 1254 383 x < 40 27.27 (±5.27) 21.99–32.54  
184 40 < x < 60 29.82 (±4.16) 25.65–33.98 T2–T12
687 x > 60 33.45 (±5.18) 28.27–38.63 Female-male
440 x < 50 27.49 (±4.5) 22.98–31.99 x < 40 (0.92)
814 x > 50 32.71 (±5.12) 27.58–37.83 40 < x < 60 (0.41)
Male T1–T12 0.03 (0.94) 571 172 x < 40 40.38 (±7.22) 33.15–47.6 x > 60 (0.97)
274 40 < x < 60 38.7 (±3.74) 34.96–42.43 x < 50 (0.35)
125 x > 60 38.57 (±3.16) 35.41–41.72 x > 50 (0.75)
390 x < 50 39.56 (±5.83) 33.72–45.39  
181 x > 50 38.78 (±2.61) 37.47–41.39  
T2–T12 0.07 (0.88) 86 59 x < 40 44.8 (±6.87) 37.93–51.67 T5–T12
7 40 < x < 60 54.05 (±7.85) 46.2–61.9 Female-male
20 x > 60 49.2 (±4.53) 44.67–53.73 x < 40 (0.69)
63 x < 50 48.5 (±9.29) 39.21–57.79 40 < x < 60 (0.62)
23 x > 50 48.97 (±3.23) 45.74–52.19 x > 60 (0.4)
T5–T12 0.51a (0.0085) 1393 540 x < 40 26.17 (±4.9) 21.28–31.07 x < 50 (0.81)
152 40 < x < 60 31.87 (±8.88) 22.99–40.75 x > 50 (0.57)
701 x > 60 32.28 (±3.66) 28.62–35.99  
584 x < 50 28.27 (±7.7) 20.55–35.99  
809 x > 50 31.71 (±4.46) 27.24–36.17  
  1. x < 40 people younger than 40 years old, 40 < x < 60 people between 40 and 60 years old, x > 60 people older than 60 years old, x < 50 people younger than 50 years old, x > 50 people older than 50 years old, T thoracic vertebra
  2. aStatistical significance for p < 0.05 (t-test)
  3. bStatistical significance for p < 0.0167 (ANOVA with Bonferroni post hoc correction)