\ curves and U curves: Vitamins D3 and K2 again.

Here are some curves relating to Vitamin D. Ref: http://www.ncbi.nlm.nih.gov/pubmed/23601272

Hazard Ratios (HRs) vs serum Vitamin D level

The solid lines are the 95% confidence intervals (CI) & mean for all-cause mortality. 95% CI's are the values within which 95% of the subjects tested fall. 2.5% fall below the lower CI and 2.5% fall above the upper CI. The dashed lines are the 95% CIs & mean for coronary heart disease (CHD) mortality. Most of the curves follow a \ curve, indicating that more Vitamin D is better, up to 66ng/mL (150nmol/L, the level that I'm at). The interesting curve is the upper dashed line, which follows a U curve.

The U curve indicates that a Vitamin D level of greater than 30ng/mL (75nmol/L) increases the Hazard Ratio (HR) for CHD in the top 2.5% of subjects only, relative to 30ng/mL, even though the mean HRs for CHD & all-cause mortality (the more important parameter) are decreasing, up to 66ng/mL. What's occurring?

See Vitamin K. The increase in HR for CHD mortality above 30ng/mL in the top 2.5% of subjects only is probably due to calcification within artery walls, due to under-carboxylation of osteocalcin in bone Matrix Gla Proteins, caused by insufficient Vitamin K2 rather than excessive Vitamin D. This is why I supplement with ~1mg/day of Vitamin K2. See also Vitamin D toxicity redefined: vitamin K and the molecular mechanism.