| Vitamin D Intake (IU/day) | Duration | Serum Calcium (mg/dL) | Serum 25OHD (nmol/L) | Serum Creatinine (μmol/L) | Urinary Calcium (mmol/L GFR) | Reference |
|---|---|---|---|---|---|---|
| Vitamin D supplementation studies without documented hypercalcemia | ||||||
| 800 | 4–6 mo | NCaa | 60–105b | — | — | Byrne et al., 1995e |
| 1,800 | 3 mo | NCa | 65, 80c | — | — | Byrne et al., 1995e |
| 1,800 | 3 mo | NCa | 57–86 | 82.4–3.8 | — | Honkanen et al., 1990f |
| 2,000 | 6 mo | NCa | — | — | — | Johnson et al., 1980g |
| 10,000 | 4 wk | — | 105d | — | — | Stamp et al., 1977 |
| 10,000 | 10 wk | — | 110d | — | — | Davie et al., 1982 |
| 20,000 | 4 wk | — | 150d | — | — | Stamp et al., 1977 |
| Vitamin D supplementation studies reporting hypercalcemia | ||||||
| 50,000 | 6 wk | 15.0 | 320 | 388 | — | Schwartzman and Franck, 1987 |
| 50,000 | 15 y | 12.5 | 560 | — | — | Davies and Adams, 1978 |
| 100,000 | 10 y | 12.8 | 865 | 215 | 0.508 | Selby et al., 1995 |
| 200,000 | 2 y | 15.1 | 1,202 | 207 | — | Selby et al., 1995 |
| 300,000 | 6 y | 13.2 | 1,692 | 184 | 0.432 | Rizzoli et al., 1994 |
| 300,000 | 3 wk | 11.3 | 800 | 339 | 0.065 | Rizzoli et al., 1994 |
| Accidental vitamin D intoxication | ||||||
| ~ 1,131,840; vitamin D overdose | — | 15.0 | 1,171 | 265 | — | Klontz and Acheson, 2007 |
| ~ 1,700,000; vitamin D poisoning | — | 15.3 | 1,555 | 442 | — | Vieth et al., 2002 |
| ~ 9,000,000; vitamin D overdose | — | 11.3 | > 375 | 159 | — | Chiricone et al., 2003 |
| ~ 18,000,000; vitamin D overdose | — | 15.3 | > 375 | 329 | — | Chiricone et al., 2003 |
| Vitamin D poisoning | — | 13.8–18.4 (n = 11) | 847–1,652 | — | — | Pettifor et al., 1995 |
| Overfortification of milk | — | 13.1 (n = 35) | 560 | — | — | Blank et al., 1995 |
| Reference levels | — | 8.6–10.6 | 20–100 (10) 25–200 (9) | 18–150 | < 0.045 | Blank et al., 1995 Haddad, 1980 |
NOTE: IU = International Units; GFR = glomerular filtration rate; mo = month(s); wk = week(s); y = year(s).
NCa = normocalcemic.
Five studies; n = 188.
Two studies; n = 55.
Indicates extrapolation from graphic data.
Byrne et al. (1995) reported that 3 of 449 subjects had hypercalcemia, but 2 were deemed to be non–vitamin D related.
Honkanen et al. (1990) measured serum 25OHD levels but observed no side effects of the vitamin D or calcium supplements.
Johnson et al. (1980) reported that 2 of 63 subjects developed hypercalcemia but provided no details of the 2 subjects and did not measure serum 25OHD levels in their study protocol.
From: 6, Tolerable Upper Intake Levels: Calcium and Vitamin D
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.