Introduction
Subjects and methods
Study setting
Participants
Study protocols
Sample processing and laboratory analysis
Mass spectrometry
Data analysis
The Gambia (n = 18) | UK (n = 18) |
P valuea
| |
---|---|---|---|
Age and anthropometry | |||
Age, years | 29.2 (3.2) | 29.3 (4.4) | 1.0 |
Weight, kg | 64.5 (8.3) | 73.3 (10.9) | 0.01 |
Height, m | 1.74 (0.06) | 1.80 (0.07) | 0.009 |
BMI, kg/m2
| 21.3 (2.0) | 22.6 (2.3) | 0.08 |
Fat mass, kg | 7.5 (2.6) | 10.3 (4.3) | 0.02 |
Fat-free mass, kg | 55.7 (6.7) | 62.6 (8.0) | 0.009 |
Biochemistry | |||
25(OH)D2, nmol/L | 0.6 (0.2) | 2.1 (1.0) | <0.0001 |
25(OH)D3, nmol/L | 68.4 (13.1) | 26.5 (10.8) | <0.0001 |
25(OH)D, nmol/L | 69.0 (13.2) | 28.6 (11.0) | <0.0001 |
1,25(OH)2D, pmol/Lb
| 181 (165, 197) | 120 (109, 132) | <0.0001 |
24,25(OH)2D, nmol/L | 6.5 (1.3) | 1.9 (1.4) | <0.0001 |
DBP, mg/L | 259 (33) | 268 (23) | 0.4 |
Albumin, g/L | 36.4 (2.2) | 41.0 (2.4) | <0.0001 |
Caalb, mmol/L | 2.25 (0.06) | 2.27 (0.06) | 0.2 |
Phosphate, mmol/L | 1.04 (0.14) | 1.05 (0.10) | 0.9 |
PTH, ng/Lb
| 50.1 (41.9, 60.0) | 32.8 (27.4, 39.3) | <0.01 |
FGF23, RU/mLb
| 79.2 (58.6, 106.9) | 57.0 (52.5, 62.0) | 0.03 |
Plasma BAP, μg/Lb
| 17.3 (12.8, 23.3) | 11.8 (10.1, 13.9) | 0.02 |
Plasma OC, μg/Lb
| 15.0 (12.7, 17.6) | 10.8 (9.3, 12.6) | 0.004 |
Plasma β-CTX, μg/Lb
| 1.0 (0.9, 1.2) | 0.6 (0.5, 0.7) | <0.0001 |
uCa/uCr, mmol/mmolb
| 0.06 (0.04, 0.09) | 0.17 (0.13, 0.26) | <0.0001 |
uP/uCr, mmol/mmolb
| 0.73 (0.59, 0.90) | 0.99 (0.83, 1.17) | 0.02 |
Nutrient intakec
| |||
Energy, kJ/day | 8267 (2383) | 9804 (1931) | 0.04 |
Fat, g/day | 42 (17) | 94 (27) | <0.001 |
Protein, g/day | 68 (26) | 90 (19) | 0.005 |
Carbohydrate, g/day | 358 (115) | 281 (60) | 0.02 |
Calcium, mg/day | 358 (177) | 1087 (248) | <0.0001 |
Phosphate, mg/day | 803 (332) | 1603 (300) | <0.0001 |
Magnesium, mg/day | 506 (222) | 361 (94) | 0.02 |
The Gambia | UK | Countries combined and corrected for countrya
| ||||
---|---|---|---|---|---|---|
Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | |
Age and anthropometry | ||||||
Age, years |
0.63 (0.16, 1.10) |
0.01
| 0.07 (−0.23, 0.37) | 0.6 |
0.27 (0.002, 0.54) |
0.05
b
|
Weight, kg | 0.09 (−0.13, 0.31) | 0.4 | −0.02 (−0.14, 0.10) | 0.7 | 0.02 (−0.09, 0.13) | 0.7 |
BMI, kg/m2
| 0.34 (−0.61, 1.28) | 0.5 | −0.19 (−0.75, 0.37) | 0.5 | 0.03 (−0.48, 0.54) | 0.9 |
Fat mass, kg | 0.14 (−0.56, 0.86) | 0.7 | −0.02 (−0.33, 0.28) | 0.9 | 0.02 (−0.28, 0.33) | 0.9 |
Fat-free mass, kg | 0.12 (−0.15, 0.39) | 0.4 | −0.03 (−0.19, 0.14) | 0.7 | 0.04 (−0.11, 0.18) | 0.6 |
Markers of vitamin D, Ca and P metabolism | ||||||
25(OH)D, nmol/L | 0.09 (−0.04, 0.22) | 0.2 | −0.02 (−0.14, 0.10) | 0.7 | 0.04 (−0.04, 0.13) | 0.3 |
1,25(OH)2D, pmol/Lc
| 4.70 (−5.49, 14.88) | 0.3 | −1.67 (−8.48, 5.12) | 0.6 | 1.27 (−4.54, 7.08) | 0.7 |
24,25(OH)2D, nmol/L | 0.64 (−0.72, 2.01) | 0.3 | −0.09 (−1.04, 0.86) | 0.8 | −0.26 (−0.53, 1.05) | 0.5 |
DBP, mg/L |
0.06 (0.14, 0.11) |
0.01
| 0.004 (−0.05, 0.06) | 0.9 |
0.04 (0.007, 0.08) |
0.02
|
Albumin, g/L | −0.18 (−1.03, 0.67) | 0.7 | 0.25 (−0.28, 0.78) | 0.3 | 0.06 (−0.41, 0.53) | 0.8 |
Caalb, mmol/L | −44.6 (−65.5, −23.6) |
<0.0001
| −1.31 (−23.6, 21.0) | 0.9 | −23.0 (−39.3, −6.58) |
0.007
b
|
Phosphate, mmol/L | 8.37 (−4.07, 20.8) | 0.2 | 9.20 (−2.85, 21.26) | 0.1 |
8.66 (0.43, 16.8) |
0.04
|
PTH, ng/Lc
| −4.06 (−8.87, 0.71) |
0.09
| −1.42 (−5.02, 2.18) | 0.4 | −2.73 (−5.59, 0.13) |
0.06
|
FGF23, RU/mLc
| 0.19 (−2.92, 3.31) | 0.9 | −0.71 (−8.66, 7.24) | 0.9 | 0.13 (−2.32, 2.59) | 0.9 |
uCa/uCr, mmol/mmolc
| −0.78 (−2.97, 1.40) | 0.5 | −1.21 (−3.38, 0.96) | 0.3 | −0.92 (−2.38, 0.53) | 0.2 |
uP/uCr, mmol/mmolc
|
3.46 (−0.51, 7.42) |
0.08
| 1.33 (−2.50, 5.16) | 0.5 |
2.64 (−0.006, 5.28) |
0.05
|
Markers of bone metabolism | ||||||
Plasma BAP, μg/Lc
| −0.94 (−4.05, 2.17) | 0.5 | 1.10 (−3.01, 5.22) | 0.6 | −0.49 (−2.75, 1.78) | 0.7 |
Plasma OC, μg/Lc
| −0.26 (−6.07, 5.54) | 0.9 | −0.49 (−4.83, 3.85) | 0.8 | −0.37 (−3.82, 3.09) | 0.8 |
Plasma β-CTX, μg/Lc
| −2.02 (−8.30, 4.27) | 0.5 | 0.47 (−3.57, 4.50) | 0.8 | −0.64 (−4.12, 2.83) | 0.7 |
Nutrient intake | ||||||
Calcium intake, mg/day | 0.003 (−0.007, 0.14) | 0.4 | 0.003 (−0.002, 0.008) | 0.2 | 0.004 (−0.001, 0.008) | 0.1 |
Phosphate intake, mg/day | 0.003 (−0.002, 0.01) | 0.2 | 0.00003 (−0.004, 0.004) | 1.0 | 0.002 (−0.002, 0.005) | 0.3 |
Gambia (n = 18) | UK (n = 18) | Countries combined (n = 36) | ||||
---|---|---|---|---|---|---|
Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | |
25(OH)D | 0.12 (0.04, 0.19) | 0.004 | −0.02 (−0.18, 0.14) | 0.8 | ||
1,25(OH)2Da
| −6.33 (−12.1, −0.54) | 0.04 | −1.3 (−9.6, 7.0) | 0.7 | ||
DBP | 0.04 (0.01, 0.07) | 0.009 | −0.003 (−0.07, 0.07) | 0.9 | ||
Caalb
| −44.5 (−60.7, −28.2) | <0.0001 | −2.56 (−30.5, 25.4) | 0.8 | −24.2 (−38.3, −10.0) | 0.001 |
PTHa
| −3.20 (−5.53, −0.86) | 0.009 | ||||
Plasma phosphate | 8.38 (1.62, 15.14) | 0.02 | ||||
Country | 0.9 |
The Gambia | UK | Countries combined and corrected for countrya
| ||||
---|---|---|---|---|---|---|
Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | |
Age and anthropometry | ||||||
Age, years | −0.17 (−2.33, 1.99) | 0.9 | 0.71 (−0.57, 1.99) | 0.3 | 0.40 (−0.71, 1.51) | 0.5 |
Weight, kg | 0.53 (−0.27, 1.32) | 0.2 | 0.25 (−0.27, 0.76) | 0.3 | 0.35 (−0.76, 0.77) | 0.1 |
BMI, kg/m2
| 1.83 (−1.63, 5.29) | 0.3 | 0.74 (−1.73, 3.22) | 0.5 | 1.19 (−0.77, 3.16) | 0.2 |
Fat mass, kg | 0.31 (−2.35, 2.98) | 0.8 | 0.72 (−0.58, 2.01) | 0.3 | 0.61 (−0.58, 1.79) | 0.3 |
Fat-free mass, kg | 0.72 (−0.25, 1.69) | 0.1 | 0.25 (−0.47, 0.96) | 0.5 | 0.44 (−0.12, 1.00) | 0.1 |
Markers of vitamin D, Ca and P metabolism | ||||||
25(OH)D, nmol/L | – | – | – | – | – | – |
1,25(OH)2D, pmol/Lb
|
29.8 (−5.97, 65.6) | 0.1 | 20.9 (−6.98, 48.8) | 0.1 |
25.0 (3.72, 46.3) |
0.02
|
24,25(OH)2D, nmol/L |
6.26 (2.20, 10.3) |
0.005
|
6.94 (5.02, 8.87) |
<0.0001
|
6.62 (4.52, 8.72) |
<0.0001
|
DBP, mg/L | 0.04 (−0.16, 0.25) | 0.7 | −0.11 (−0.35, 0.13) | 0.4 | −0.006 (−0.16, 0.14) | 0.9 |
Albumin, g/L | −3.30 (−5.96, −0.63) |
0.02
| 0.51 (−1.88, 2.90) | 0.7 | −1.22 (−3.03, 0.59) | 0.2c
|
Caalb, mmol/L | 2.46 (−115, 120) | 1.0 | −45.1 (−139.8, 49.7) | 0.3 | −21.3 (−93.2, 50.7) | 0.6 |
Plasma phosphate, mmol/L | 12.5 (−36.3, 61.4) | 0.6 | −11.5 (−68.1, 45.0) | 0.7 | 4.38 (−30.3, 39.1) | 0.8 |
PTH, ng/Lb
| −8.62 (−27.6, 10.4) | 0.4 | −11.4 (−26.3, 3.44) | 0.1 | −10.0 (−21.4, 1.36) |
0.08
|
FGF23, RU/mLb
| −5.34 (16.6, 5.94) | 0.3 | −6.98 (−41.6, 27.6) | 0.7 | −5.46 (−15.0, 4.08) | 0.3 |
uCa/uCr, mmol/mmolb
| −1.61 (−9.86, 6.64) | 0.7 | −3.81 (−13.5, 5.87) | 0.4 | −2.32 (−8.18, 3.53) | 0.4 |
uP/uCr, mmol/mmolb
| −0.55 (−16.9, 15.8) | 0.9 | −13.6 (−29.0, 1.78) |
0.08
| −5.61 (−16.5, 5.30) | 0.3 |
Markers of bone metabolism | ||||||
Plasma BAP, μg/Lb
| 3.90 (−7.66, 15.5) | 0.5 | 7.38 (−10.4, 25.1) | 0.4 | 4.68 (−4.16, 13.5) | 0.3 |
Plasma OC, μg/Lb
| −10.3 (−31.3, 10.7) | 0.3 | 3.13 (−15.8, 22.1) | 0.7 | −3.98 (−17.6, 9.61) | 0.6 |
Plasma β-CTX, μg/Lb
| 5.20 (18.4, 28.8) | 0.6 | −1.82 (−19.5, 15.8) | 0.8 | 1.31 (−12.5, 15.1) | 0.8 |
Nutrient intake | ||||||
Calcium intake, mg/day | −0.007 (−0.05, 0.03) | 0.7 | 0.0007 (−0.02, 0.02) | 0.9 | −0.002 (−0.02, 0.02) | 0.9 |
Phosphate intake, mg/day | 0.01 (−0.009, 0.03) | 0.2 | 0.002 (−0.02, 0.02) | 0.8 | 0.007 (−0.006, 0.02) | 0.3 |
Gambia (n = 18) | UK (n = 18) | Countries combined (n = 36) | ||||
---|---|---|---|---|---|---|
Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | Slope (95 % CI) |
P value | |
1,25(OH)2Da
| 33.2 (0.13, 66.3) | 0.05 | 21.3 (−3.50, 46.2) | 0.09 | 29.3 (9.89, 48.8) | 0.004 |
Caalb
| −68.3 (−152, 15.8) | 0.1 | ||||
PTHa
| −15.7 (33.8, 2.4) | 0.09 | −14.6 (−28.4, −0.76) | 0.04 | −9.76 (−19.6, 0.12) | 0.05 |
FGF23a
| −10.5 (−21.4, 0.3) | 0.06 | ||||
Weight | 0.45 (0.08, 0.82) | 0.02 | ||||
Country | <0.0001 |