Table 1.
Population Characteristics in the Newcastle 85+ Study by Quartiles of Total Homocysteine, RBC Folate, and Plasma Vitamin B12
| Total homocysteine (µmol/L) | |||||
|---|---|---|---|---|---|
| Q1 (<13.5) | Q2 (13.5–16.7) | Q3 (16.7–21.4) | Q4 (>21.4) | p* | |
| Men (%, n) | 32 (61) | 32 (62) | 50 (96) | 43 (83) | <.001 |
| Red blood cell folate (nmol/L) | 1,272 (896–1,748) | 940 (675–1,279) | 779 (573–1,084) | 680 (477–898) | <.001 |
| Plasma vitamin B12 (pmol/L) | 297 (225–430) | 230 (185–303) | 225 (161–293) | 186 (134–262) | <.001 |
| Physical activity (high) (%, n) | 38 (72) | 34 (65) | 38 (72) | 31 (58) | .02 |
| Renal impairment (%, n) | 8 (15) | 15 (29) | 22 (41) | 51 (98) | <.001 |
| ALT (U/L) | 18 (15–23) | 17 (14–21) | 16 (13–20) | 15 (12–19) | <.001 |
| Red blood cell folate (nmol/L) | |||||
| Q1 (<612) | Q2 (612–870) | Q3 (870–1,280) | Q4 (>1,280) | p* | |
| Plasma vitamin B12 (pmol/L) | 201 (135–280) | 216 (159–275) | 259 (193–371) | 278 (205–391) | <.001 |
| Total homocysteine (µmol/L) | 19.9 (16.3–24.6) | 18.3 (14.9–22.9) | 15.6 (13.0–19.6) | 13.8 (11.1–17.4) | <.001 |
| Disease count (mean, SD) | 2.0 (1.2) | 2.3 (1.3) | 2.4 (1.2) | 2.4 (1.2) | .01b |
| History of cardiovascular disease (%, n) | 45 (84) | 57 (108) | 66 (123) | 63 (119) | <.001 |
| Plasma vitamin B12 (pmol/L) | |||||
| Q1 (<170) | Q2 (170–232) | Q3 (232–325) | Q4 (>325) | p* | |
| Red blood cell folate (nmol/L) | 683 (479–992) | 838 (605–1,159) | 913 (690–1,393) | 1058 (745–1,608) | <.001 |
| Total homocysteine (µmol/L) | 19.7 (15.9–25.1) | 17.3 (14.5–21.8) | 15.9 (13.3–19.8) | 13.9 (11.1–18.2) | <.001 |
| Disease count (mean, SD) | 2.2 (1.3) | 2.4 (1.2) | 2.2 (1.2) | 2.3 (1.2) | .51b |
| ALT (U/L) | 16 (13–20) | 16 (13–21) | 17 (14–21) | 17 (14–22) | .03 |
Notes: Continuous variables are presented as medians and interquartile range unless otherwise stated. History of cardiovascular disease includes cardiac, cerebrovascular, and peripheral vascular diseases. ALT = alanine aminotransferase; Q = quartile; SD = standard deviation.
*Chi-squared test (χ2) or Kruskal–Wallis test.
bOne-way ANOVA.