Prospective Study of Serum 25-Hydroxyvitamin D Level, Cardiovascular Disease Mortality, and All-Cause Mortality in Older U.S. Adults. In noninstitutionalized older adults, a group at high risk for all-cause mortality, serum 25(OH)D levels had an independent, inverse association with CVD and all-cause mortality

During the median 7.3 years of follow-up, there were 1,493 (44%) deaths, including 767 CVD-related deaths. Median 25(OH)D level was 66 nmol/L. Adjusting for demographics, season, and cardiovascular risk factors, baseline 25(OH)D levels were inversely associated with all-cause mortality risk (adjusted hazard ratio (HR)=0.95, 95% confidence interval (CI)=0.92-0.98, per 10 nmol/L 25[OH]D). Compared with subjects with 25(OH)D levels of 100 nmol/L or higher, the adjusted HR for subjects with levels less than 25.0 nmol/L was 1.83 (95% CI=1.14-2.94) and for levels of 25.0 to 49.9 nmol/L was 1.47 (95% CI=1.09-1.97). The association appeared stronger for CVD mortality (adjusted HR=2.36, 95% CI=1.17-4.75, for subjects with 25[OH]D levels<25.0 nmol/L vs those >/=100.0 nmol/L) than for non-CVD mortality (adjusted HR=1.42, 95% CI=0.73-2.79, for subjects with 25[OH]D levels<25.0 nmol/L vs those >/=100.0 nmol/L).

What the report doesn't say is that generally speaking to get from below 50nmol/l 20ng to over 100nmol/l 40ng will take MORE than 2000iu/daily /D3
so 2000iu/d should be the minimum daily intake.
Mostly Dr Davis finds in Wisconsin it takes 5000iu/d for females and 6000iu for males gets them to above 55ng 137.5nmol/l the level associated with least chronic disease incidence.

Cheapest 25(OH)D testing worldwide