Characteristics of the study participants
There were 5077 participants included in the final analysis across the quartiles of dietary vitamin B6 intake levels,as shown in the table 1.There was a significant difference among the dietary vitamin B6 intake quartiles in terms of age, gender, marital status, energy, total sugars, vitamin B1, vitamin B2, vitamin B12, vitamin C, vitamin K, vitamin D(D2+D3), total spine BMD, calcium, phosphorus, magnesium, Iron and zinc(P<0.05).
Table 1:Characteristic distribution of the participants in NHANES 2007-2020 across dietary vitamin B6 intake
|
Vitamin B6 (mg)
|
|
variables
|
Q1
|
Q2
|
Q3
|
Q4
|
P value
|
Age
|
35.8 ± 19.7
|
42.7 ± 17.1
|
51.2 ± 16.9
|
50.3 ± 15.8
|
<0.0001
|
Energy (kcal)
|
8.5 ± 22.0
|
11.9 ± 31.7
|
19.3 ± 98.2
|
23.6 ± 48.8
|
0.0062
|
Protein (gm)
|
2.7 ± 7.8
|
0.6 ± 0.4
|
3.4 ± 12.0
|
5.5 ± 13.3
|
0.4028
|
Carbohydrate (gm)
|
1.5 ± 1.7
|
2.1 ± 6.6
|
3.1 ± 22.6
|
3.8 ± 9.3
|
0.1216
|
Total sugars (gm)
|
1.2 ± 1.3
|
1.8 ± 7.9
|
1.5 ± 2.1
|
2.3 ± 5.1
|
0.0031
|
Dietary fiber (gm)
|
1.3 ± 1.2
|
0.9 ± 0.7
|
1.9 ± 2.1
|
3.3 ± 6.9
|
0.0921
|
Total fat (gm)
|
1.1 ± 2.3
|
1.3 ± 2.3
|
1.6 ± 2.2
|
1.7 ± 2.2
|
0.0654
|
Vitamin B1 (mg)
|
1.3 ± 5.2
|
1.7 ± 6.5
|
6.0 ± 27.8
|
27.2 ± 43.6
|
<0.0001
|
Vitamin B2 (mg)
|
0.8 ± 1.4
|
1.4 ± 1.3
|
2.6 ± 5.0
|
23.4 ± 40.5
|
<0.0001
|
Vitamin B12 (mcg)
|
37.3 ± 518.9
|
66.4 ± 340.0
|
61.2 ± 272.1
|
207.3 ± 797.3
|
<0.0001
|
Vitamin C (mg)
|
64.6 ± 245.6
|
107.1 ± 202.1
|
156.4 ± 258.8
|
366.7 ± 589.7
|
<0.0001
|
Vitamin K (mcg)
|
10.3 ± 11.8
|
19.1 ± 11.7
|
27.3 ± 44.4
|
51.0 ± 94.3
|
<0.0001
|
Vitamin D (D2 + D3) (mcg)
|
14.6 ± 143.1
|
15.0 ± 19.2
|
23.0 ± 52.7
|
32.2 ± 91.0
|
0.0001
|
Total spine BMD
|
1.0 ± 0.2
|
1.0 ± 0.2
|
1.0 ± 0.2
|
1.0 ± 0.2
|
<0.0001
|
Calcium (mg)
|
137.1 ± 200.3
|
311.4 ± 340.3
|
412.1 ± 396.4
|
463.5 ± 465.8
|
<0.0001
|
Phosphorus (mg)
|
28.3 ± 31.3
|
50.5 ± 41.4
|
65.1 ± 63.2
|
78.8 ± 106.8
|
<0.0001
|
Magnesium (mg)
|
30.8 ± 77.0
|
55.8 ± 61.6
|
89.9 ± 116.7
|
132.4 ± 182.1
|
<0.0001
|
Iron (mg)
|
7.1 ± 8.0
|
14.8 ± 8.9
|
19.2 ± 14.1
|
15.1 ± 19.3
|
<0.0001
|
Zinc (mg)
|
4.3 ± 4.6
|
9.8 ± 7.2
|
13.9 ± 9.3
|
17.2 ± 19.7
|
<0.0001
|
Gender
|
|
|
|
|
0.0462
|
Male
|
45.1
|
42.2
|
45.2
|
40.3
|
|
Female
|
54.9
|
57.8
|
54.8
|
59.7
|
|
Race
|
|
|
|
|
0.1989
|
Mexican American
|
6.7
|
4.6
|
4.6
|
5.4
|
|
Other Hispanic
|
4.3
|
2.8
|
3.7
|
3.9
|
|
Non-Hispanic White
|
72.5
|
76.4
|
76.9
|
77.6
|
|
Non-Hispanic Black
|
8.4
|
9.5
|
8.2
|
7.1
|
|
Other Race - Including Multi-Racial
|
8.1
|
6.8
|
6.7
|
6
|
|
Education Level
|
|
|
|
|
0.1935
|
Less than 9th grade
|
3.2
|
4.1
|
2.7
|
2.5
|
|
9-11th grade
|
5.9
|
4.1
|
7.6
|
6.2
|
|
High school graduate
|
18
|
16.5
|
21.2
|
17.4
|
|
Some college or AA degree
|
33.9
|
33.8
|
30.7
|
34.1
|
|
College graduate or above
|
39.1
|
41.5
|
37.7
|
39.7
|
|
Missed
|
3.2
|
4.1
|
0
|
0.2
|
|
Marital status
|
|
|
|
|
<0.0001
|
Married
|
62.2
|
61.2
|
66.7
|
61.4
|
|
Widowed
|
6.6
|
5.1
|
8.8
|
10.2
|
|
Divorced
|
9.3
|
8.3
|
10
|
10.6
|
|
Separated
|
2.3
|
2
|
1.6
|
1.3
|
|
Never married
|
14
|
12.6
|
8.9
|
12.6
|
|
Living with partner
|
5.6
|
10.8
|
3.9
|
3.8
|
|
Relationship between dietary vitamin B6 intake level and the total spine BMD
High dietary vitamin B6 intake levels were associated with the total spine BMD in the crude model,and the OR for total spine BMD across the quartiles of dietary vitamin B6 intake levels were 0,0.3(95%CI:0.2-0.5),0.3(95%CI:0.2-0.3) and 0.3(95%CI:0.2-0.4) for Q1,Q2,Q3 and Q4. After adjusted for demographic variables,the association was still significant.In the Model 2,after further adjusted for education level, marital status, total sugars, vitamin B1, vitamin B2, vitamin B12, vitamin C, vitamin K, vitamin D (D2 + D3) and energy,the OR for total spine BMD across the dietary vitamin B6 intake level quartiles were 0,0.4(95%CI:-0.1,0.8),0.4(95%CI:0.0,0.7) and 0.6(95%CI:0.2,0.1) for Q1,Q2,Q3 and Q4,respectively,P for trend was 0.005(Table 2).
Table 2:Association between dietary vitamin B6 intake and total spine BMD among U.S. in NHANES 2007-2020
Exposure
|
Crude model
|
Model 1
|
Model 2
|
continuous
|
0.0 (-0.0, 0.0) 0.339
|
0.0 (-0.0, 0.0) 0.492
|
0.0 (-0.0, 0.0) 0.086
|
Quartile
|
|
|
|
Q1
|
0
|
0
|
0
|
Q2
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.5) <0.001
|
0.4 (-0.1, 0.8) 0.100
|
Q3
|
0.3 (0.2, 0.3) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.4 (0.0, 0.7) 0.027
|
Q4
|
0.3 (0.2, 0.4) <0.001
|
0.4 (0.3, 0.4) <0.001
|
0.6 (0.2, 1.0) 0.004
|
P for trend
|
<0.001
|
<0.001
|
0.005
|
Crude model :adjusted for None
Model 1 model :adjusted for Gender; Age;Race
Model 2 model :adjusted for Gender; Age; Race; Education level; Marital status; Total sugars (gm); Vitamin B1 (mg); Vitamin B2 (mg); Vitamin B12 (mg); Vitamin C (mg); Vitamin K (mcg); Vitamin D (D2 + D3) (mcg); Energy (kcal)
As shown in the Table 3,different dietary vitamin B6 intake levels had a close reverse relationship with the total spine BMD.Stratification analyses by gender showed that the association was significant in female.After further adjusted,the OR for total spine BMD across the dietary vitamin B6 intake level quartiles were 0,0.5(95%CI:-0.0,1.0),0.4(95%CI:-0.1,0.8),0.8(95%CI:0.3,1.3),p for trend=0.007 in the female.Meanwhile stratification analyses by age showed that the association was significant when age over 50 years old.After adjusted for education level, marital status, total sugars, vitamin B1, vitamin B2, vitamin B12, vitamin C, vitamin K, vitamin D (D2 + D3) and energy,the OR for total spine BMD, the OR for total spine BMD across the dietary vitamin B6 intake level quartiles were 0,1.0 (95%CI:0.3, 1.7),0.5 (95%CI:0.0, 1.0),0.8(95%CI:0.3,1.3),p for trend=0.006 among female.In addition, we found that there was a significant difference in BMD between people with different intakes of vitamin B6 in the Non-Hispanic White ( P < 0.05 ), while there was no significant difference between other races.
Table 3:Subgroup analysis of association between dietary vitamin B6 intake and total spine BMD among U.S. in NHANES 2007-2020
|
Crude model
|
Model 1
|
Model 2
|
Exposure
|
Q1
|
Q2
|
Q3
|
Q4
|
P for trend
|
Q1
|
Q2
|
Q3
|
Q4
|
P for trend
|
Q1
|
Q2
|
Q3
|
Q4
|
P for trend
|
Gender
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Male
|
0
|
0.4 (0.2, 0.6) <0.001
|
0.4 (0.3, 0.5) <0.001
|
0.5 (0.3, 0.6) <0.001
|
<0.001
|
0
|
0.4 (0.2, 0.6) <0.001
|
0.3 (0.2, 0.5) <0.001
|
0.4 (0.2, 0.5) <0.001
|
<0.001
|
0
|
-0.3 (-1.2, 0.5) 0.445
|
0.4 (-0.2, 0.9) 0.177
|
0.2 (-0.4, 0.8) 0.564
|
0.355
|
Female
|
0
|
0.3 (0.1, 0.5) 0.006
|
0.1 (0.0, 0.2) 0.017
|
0.2 (0.0, 0.3) 0.006
|
0.011
|
0
|
0.3 (0.1, 0.5) 0.001
|
0.3 (0.2, 0.4) <0.001
|
0.3 (0.2, 0.5) <0.001
|
<0.001
|
0
|
0.5 (-0.0, 1.0) 0.070
|
0.4 (-0.1, 0.8) 0.087
|
0.8 (0.3, 1.3) 0.003
|
0.007
|
Total
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.3) <0.001
|
0.3 (0.2, 0.4) <0.001
|
<0.001
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.4 (0.3, 0.4) <0.001
|
<0.001
|
0
|
0.4 (-0.1, 0.8) 0.086
|
0.4 (0.1, 0.7) 0.020
|
0.6 (0.2, 1.0) 0.004
|
0.004
|
Age
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
>50
|
0
|
0.4 (0.1, 0.6) 0.006
|
0.2 (0.1, 0.4) <0.001
|
0.1 (-0.0, 0.3) 0.129
|
0.311
|
0
|
0.3 (0.1, 0.6) 0.008
|
0.2 (0.0, 0.3) 0.013
|
0.1 (-0.0, 0.3) 0.130
|
0.332
|
0
|
1.0 (0.3, 1.7) 0.008
|
0.5 (0.0, 1.0) 0.041
|
1.0 (0.4, 1.6) 0.001
|
0.006
|
<=50
|
0
|
0.3 (0.1, 0.5) <0.001
|
0.4 (0.2, 0.5) <0.001
|
0.5 (0.4, 0.6) <0.001
|
<0.001
|
0
|
0.3 (0.1, 0.5) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.5 (0.4, 0.6) <0.001
|
0.906
|
0
|
0.1 (-0.5, 0.7) 0.840
|
0.3 (-0.2, 0.8) 0.188
|
0.2 (-0.3, 0.8) 0.402
|
0.232
|
Total
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.3, 0.4) <0.001
|
0.4 (0.3, 0.4) <0.001
|
<0.001
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.4 (0.3, 0.4) <0.001
|
0.397
|
0
|
0.4 (-0.1, 0.8) 0.086
|
0.4 (0.1, 0.7) 0.020
|
0.6 (0.2, 1.0) 0.004
|
0.004
|
Race
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Mexican American
|
0
|
0.2 (-0.2, 0.7) 0.261
|
0.3 (0.1, 0.5) 0.004
|
0.3 (0.0, 0.5) 0.023
|
0.007
|
0
|
0.3 (-0.1, 0.7) 0.206
|
0.4 (0.2, 0.6) <0.001
|
0.3 (0.1, 0.6) 0.007
|
0.067
|
0
|
-1.8 (-8.2, 4.6) 0.636
|
0.5 (-1.4, 2.4) 0.637
|
1.2 (-1.4, 3.7) 0.468
|
0.52
|
Other Hispanic
|
0
|
-0.3 (-0.9, 0.2) 0.253
|
0.1 (-0.1, 0.4) 0.280
|
0.2 (-0.1, 0.5) 0.245
|
0.147
|
0
|
-0.4 (-0.9, 0.2) 0.185
|
0.2 (-0.0, 0.5) 0.115
|
0.3 (0.0, 0.6) 0.039
|
0.077
|
0
|
0
|
65.8 (, ) NaN
|
334.9 (, ) NaN
|
NaN
|
Non-Hispanic White
|
0
|
0.4 (0.2, 0.6) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.3 (0.2, 0.5) <0.001
|
<0.001
|
0
|
0.4 (0.2, 0.6) <0.001
|
0.4 (0.3, 0.5) <0.001
|
0.4 (0.3, 0.5) <0.001
|
<0.001
|
0
|
0.4 (-0.1, 0.9) 0.148
|
0.4 (0.0, 0.8) 0.047
|
0.6 (0.2, 1.1) 0.006
|
0.008
|
Non-Hispanic Black
|
0
|
0.2 (-0.1, 0.5) 0.222
|
0.1 (-0.1, 0.3) 0.324
|
0.1 (-0.2, 0.3) 0.535
|
0.518
|
0
|
0.2 (-0.1, 0.5) 0.255
|
0.1 (-0.1, 0.3) 0.229
|
0.1 (-0.1, 0.3) 0.359
|
0.837
|
0
|
-0.7 (-1.8, 0.5) 0.261
|
-0.3 (-1.1, 0.5) 0.486
|
-0.5 (-1.6, 0.5) 0.344
|
0.34
|
Other Race - Including Multi-Racial
|
0
|
-0.3 (-0.8, 0.2) 0.239
|
-0.1 (-0.3, 0.2) 0.499
|
0.1 (-0.2, 0.4) 0.487
|
0.651
|
0
|
-0.1 (-0.6, 0.4) 0.635
|
0.0 (-0.2, 0.3) 0.763
|
0.2 (-0.1, 0.5) 0.181
|
0.85
|
0
|
-9.7 (, ) NaN
|
-13.8 (, ) NaN
|
-379.8 (, ) NaN
|
NaN
|
Total
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.3) <0.001
|
0.3 (0.2, 0.4) <0.001
|
<0.001
|
0
|
0.3 (0.2, 0.5) <0.001
|
0.3 (0.2, 0.4) <0.001
|
0.4 (0.3, 0.4) <0.001
|
<0.001
|
0
|
0.4 (-0.1, 0.8) 0.086
|
0.4 (0.1, 0.7) 0.020
|
0.6 (0.2, 1.0) 0.004
|
0.005
|