Table 3.
Associations of pyridoxal 5′-phosphate and 4-pyridoxic acid serum levels with all-cause mortality in various subgroups among adults with diabetes in National Health and Nutrition Examination Survey III (2005-2010)
| HR (95% CIs) by quartile | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| PLP, nmol/L | 4-PA, nmol/L | |||||||||
| Characteristic | Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P for interaction | Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P for interaction |
| (< 21.4) | (21.4-35.7) | (35.8-63.6) | (≥ 63.7) | (< 17.6) | (17.6-28.0) | (28.1-55.9) | (≥ 56.0) | |||
| Age, y | ||||||||||
| < 60 | 1 (Reference) | 0.50 (0.21-1.17) | 0.76 (0.35-1.64) | 0.77 (0.32-1.85) | .260 | 1 (Reference) | 2.27 (1.05-4.92) | 2.60 (1.09-6.23) | 2.66 (0.90-7.80) | .776 |
| ≥ 60 | 1 (Reference) | 1.06 (0.79-1.42) | 0.85 (0.62-1.16) | 0.77 (0.56-1.05) | 1 (Reference) | 0.96 (0.65-1.42) | 1.25 (0.86-1.82) | 1.78 (1.20-2.66) | ||
| Sex | ||||||||||
| Female | 1 (Reference) | 1.24 (0.80-1.94) | 1.10 (0.70-1.75) | 1.05 (0.66-1.68) | .011 | 1 (Reference) | 0.66 (0.38-1.12) | 0.99 (0.59-1.66) | 1.65 (0.95-2.86) | .391 |
| Male | 1 (Reference) | 0.75 (0.52-1.08) | 0.69 (0.47-1.00) | 0.56 (0.38-0.83) | 1 (Reference) | 1.29 (0.81-2.05) | 1.40 (0.88-2.23) | 1.62 (0.96-2.71) | ||
| BMI | ||||||||||
| < 25 | 1 (Reference) | 1.02 (0.48-2.17) | 1.56 (0.80-3.05) | 0.71 (0.35-1.44) | .722 | 1 (Reference) | 1.28 (0.47-3.46) | 1.99 (0.78-5.09) | 1.58 (0.58-4.37) | .075 |
| 25-29.9 | 1 (Reference) | 0.91 (0.55-1.50) | 0.84 (0.50-1.42) | 0.85 (0.52-1.41) | 1 (Reference) | 1.17 (0.61-2.26) | 1.75 (0.91-3.35) | 2.31 (1.16-4.59) | ||
| ≥ 30 | 1 (Reference) | 0.87 (0.59-1.28) | 0.65 (0.42-1.00) | 0.62 (0.38-0.99) | 1 (Reference) | 0.80 (0.49-1.31) | 0.95 (0.59-1.52) | 1.34 (0.79-2.27) | ||
| eGFR, mL/min/1.73 m2 | ||||||||||
| < 90 | 1 (Reference) | 0.99 (0.74-1.33) | 0.83 (0.61-1.13) | 0.78 (0.57-1.06) | .262 | 1 (Reference) | 0.98 (0.66-1.47) | 1.20 (0.81-1.77) | 1.68 (1.11-2.55) | .102 |
| ≥ 90 | 1 (Reference) | 0.44 (0.20-0.98) | 0.56 (0.26-1.24) | 0.36 (0.14-0.90) | 1 (Reference) | 1.11 (0.53-2.31) | 1.26 (0.55-2.88) | 0.59 (0.15-2.37) | ||
| Hypertension | ||||||||||
| Yes | 1 (Reference) | 0.96 (0.71-1.30) | 0.82 (0.59-1.12) | 0.69 (0.50-0.95) | .643 | 1 (Reference) | 0.98 (0.67-1.43) | 1.19 (0.82-1.73) | 1.47 (0.97-2.21) | .702 |
| No | 1 (Reference) | 0.89 (0.44-1.79) | 0.78 (0.37-1.64) | 1.01 (0.49-2.10) | 1 (Reference) | 1.35 (0.58-3.13) | 1.66 (0.71-3.88) | 2.90 (1.12-7.51) | ||
| CVD | ||||||||||
| Yes | 1 (Reference) | 1.14 (0.77-1.69) | 0.77 (0.50-1.20) | 0.73 (0.47-1.14) | .867 | 1 (Reference) | 1.70 (0.97-2.99) | 1.73 (0.99-3.02) | 2.35 (1.30-4.23) | .471 |
| No | 1 (Reference) | 0.82 (0.56-1.21) | 0.90 (0.62-1.32) | 0.77 (0.52-1.14) | 1 (Reference) | 0.70 (0.45-1.11) | 1.06 (0.69-1.63) | 1.33 (0.81-2.18) | ||
| HbA1c, % | ||||||||||
| < 7.0 | 1 (Reference) | 0.82 (0.58-1.16) | 0.65 (0.45-0.93) | 0.63 (0.44-0.90) | .448 | 1 (Reference) | 1.06 (0.67-1.67) | 1.17 (0.75-1.82) | 1.66 (1.03-2.69) | .593 |
| ≥ 7.0 | 1 (Reference) | 0.92 (0.58-1.46) | 1.10 (0.68-1.76) | 0.78 (0.47-1.29) | 1 (Reference) | 0.88 (0.51-1.50) | 1.33 (0.78-2.29) | 1.32 (0.72-2.44) | ||
Adjusted for age (continuous), sex (male or female), race (Mexican American, non-Hispanic White, non-Hispanic Black, or other), education (< high school, high school/GED, or > high school), physical activity (never, moderate, or vigorous), serum cotinine (> 10, LOD-10 or < LOD ng/mL), alcohol consumption (yes or no), BMI (< 25, 25-29.9, ≥ 30), and PIR (0-1.0, 1.01-4.99, or 5.0), history of hypertension (yes or no), history of CVD (yes or no), history of cancer (yes or no), history of liver impairment (yes or no), renal impairment (eGFR < 90 or ≥ 90 mL/min/1.73 m2), HbA1c (continuous), duration of diabetes (< 3, 3-10, or > 10 years), medication use (no diabetes medication use, oral medication use only, any insulin use, or others), 4-PA (continuous) or PLP (continuous), mean of vitamin B6 intake (continuous), and use of vitamin B6 supplement (continuous). The strata variable was not included when stratifying by itself.
Abbreviations: 4-PA, 4-pyridoxic acid; BMI, body mass index; CVD, cardiovascular diseases; eGFR, estimated glomerular filtration rate; GED, general education development; HbA1c, glycated hemoglobin A1c; HR, hazard ratio; LOD, limit of detection; PLP, pyridoxal 5′-phosphate.