Table 2.
Examples of epidemiological data looking at associations between vitamin D levels and cancer.
| Population | Cancer type | Number of cases/controls | Vitamin D benefit | Comment | Reference | |
|---|---|---|---|---|---|---|
| (a) Cancer risk | ||||||
| Prospective case‐cohort study (nested in osteoporotic fractures in men study) | U.S.A. All ethnicity, 1217 non‐Hispanic whites | Prostate | 297/1351≥65 years | No | No association found between Vit D serum levels and subsequent risk of prostate cancer | (Barnett et al., 2010) |
| Prospective case‐control study (nested within prostate, lung, colorectal and ovarian cancer screening trial) | U.S.A. non‐hispanic white | Prostate | 749/781 | No | No association with Vit D and decreased risk of prostate cancer, higher circulating levels may be associated with increased risk of aggressive disease | (Ahn et al., 2008) |
| Prospective case‐control study (nested European prospective investigation into cancer and nutrition) | Europeans | Prostate | 652/752 | No | The risk of prostate cancer did not vary significantly with Vit D levels | (Travis et al., 2009) |
| Prospective case‐control study (nested α‐tocopherol, β‐carotene prevention study) | Finnish | Prostate | 296/296 | No | No difference in Vit D levels between cases and controls | (Faupel‐Badger et al., 2007) |
| Prospective case‐control study (nested nutritional prevention cancer trial) | U.S.A. Caucasians | Prostate | 83/166 | No | No difference in prostate cancer risk | (Jacobs et al., 2004) |
| Prospective case‐control study (nested European prospective investigation into cancer and nutrition) | Europeans | Colorectal | 1248/1248 | Yes | Strong inverse association between levels of pre‐diagnostic Vit D levels and risk of colorectal cancer | (Jenab et al., 2010) |
| Prospective case‐control study (nested nurses health study) | U.S.A. | Colorectal | 193/386 | Yes | 25(OH)D levels but not 1,25‐dihyrdoxyvit D levels were associated in an inverse linear manner with risk of colorectal cancer (distal colon and rectal) | (Feskanich et al., 2004) |
| Prospective case‐control study (nested α‐tocopherol, β‐carotene prevention study) | Finnish men | Colorectal | 146/292 | Yes | 25(OH)D levels but not 1,25‐dihyrdoxyvit D levels were associated in an inverse linear manner with risk of colorectal cancer (most marked for rectal cancer 55 cases; RR by quartile = 1.00, .93, .77, .37; trend P = 0.06) | (Tangrea et al., 1997) |
| Prospective case‐control study (nested cancer prevention study‐II nutrition cohort) | U.S.A. | Breast | 516/516 | No | No association between 25(OH)D levels and breast cancer risk | (McCullough et al., 2009) |
| Case series | U.K. Caucasians | Breast | 279 | Yes | Serum levels of 25(OH)D are significantly higher in patients with early stage breast cancer than those with locally advanced or metastatic | (Palmieri et al., 2006) |
| Prospective study (third national health and nutrition examination survey) | U.S.A. | Breast | 28 breast cancer deaths | No | No association between Vit D levels and risk of death from breast cancer | (Freedman et al., 2007) |
| Prospective case‐control study (nested nurses health study) | U.S.A. | Breast | 701/724 | Trend to benefit | Higher levels of both 25(OH)D (RR 0.73) and 1,25(OH)2D (RR 0.76) were associated with non significant lower risk of breast cancer. For both metabolites, the association was stronger ≥60 years | (Bertone‐Johnson et al., 2005) |
| Pool nested case‐control study (Cohort consortium vitamin D pooling project of rarer cancers) | Multiple geographical location | Pancreatic | 952/1333 | Negative benefit | High 25(OH)D level (≥100 nmol/L) was associated with a significant 2‐fold increase in pancreatic cancer risk overall (OR = 2.12) | (Stolzenberg‐Solomon et al., 2010) |
| Prospective case‐control study (nested α‐tocopherol, β‐carotene prevention study) | Finnish Male smokers | Pancreatic | 200/400 | Negative benefit | 3‐fold increase risk of pancreatic cancer with high Vit D levels (highest versus lowest quintile, >65.5 versus <32.0 nmol/L: OR, 2.92; 95% CI, 1.56–5.48, Ptrend = 0.001) | (Stolzenberg‐Solomon et al., 2006) |
| (b) Outcome | ||||||
| Prospective study (nested physicians health study) | U.S.A. | Prostate | 492/664 | Yes | Pre‐diagnostic Vit D levels tended to be inversely associated with risk of aggressive prostate cancer at diagnosis, especially men >65 years | (Li et al., 2007) |
| Association study | Norway | Prostate | 160 | Yes | Serum Vit D levels 50–80 nmol/L and >80 compared to <50 had better prognosis (cause specific mortality) (RR0.33; RR0.16) | (Tretli et al., 2009) |
| Prospective cohort study | Japan | Colorectal | 257 | Yes | Higher Vit D levels were associated with better overall survival (HR, 0.91, P = .027) | (Mezawa et al., 2010) |