Table 1.

Study characteristics and main results of epidemiologic studies investigating the association between vitamin D and survival in patients with colorectal cancer

Overall mortalityCRC-specific mortality
First author, year, countryPopulationFollow-upTime point blood draw25(OH)D (nmol/L)HR (95% CI)P for trend25(OH)D (nmol/L)HR (95% CI)P for trendConfounders
Ng, 2008, United States (64)304 CRC casesMedian 6.5 yearsPrediagnosis (median 6 years before diagnosis)Quartile 1a1.00.02Quartile 1a1.00.23Age at diagnosis, sex, season of blood collection, cancer stage, grade of tumor differentiation, location of primary tumor, year of diagnosis, BMI at diagnosis, postdiagnosis physical activity
Mean age: 68Quartile 20.81 (0.49–1.35)Quartile 20.76 (0.41–1.42)
Stage: I–IV 123 deaths, 96 CRC-specific deathsQuartile 30.81 (0.48–1.37)Quartile 31.04 (0.58–1.89)
Quartile 40.52 (0.29–0.94)Quartile 40.61 (0.31–1.19)
Fedirko, 2012, Western Europe (EPIC) (65)1,201 CRC casesMean 6.1 yearsPrediagnosis (on average 3.8 years before diagnosis)Quintile 1 (<36.3)1.0<0.01Quintile 1 (<36.3)1.00.04Age at diagnosis, sex, season of blood collection, cancer stage, grade of tumor differentiation, location of primary tumor, year of diagnosis, BMI, physical activity, smoking status, and stratified by country of residence
Mean age: 62Quintile 2 (36.4–48.6)0.82 (0.63–1.07)Quintile 2 (36.4–48.6)0.76 (0.56–1.02)
Stage: I–IV 541 deaths, 444 CRC-specific deathsQuintile 3 (48.7–60.5)0.91 (0.70–1.18)Quintile 3 (48.7–60.5)0.93 (0.69–1.24)
Quintile 4 (60.6–76.8)0.78 (0.59–1.03)Quintile 4 (60.6–76.8)0.78 (0.58–1.06)
Quintile 5 (>76.8)0.67 (0.50–0.88)Quintile 5 (>76.8)0.69 (0.50–0.93)
Mezawa, 2010, Japan (66)257 CRC casesMedian 2.7 yearsPeri-operativeQuartile 1 (7.5–17.5)0.50 (0.16–1.54)NAContinuous per 2.5 nmol/L0.98 (0.89–1.08)NAAge at diagnosis, sex, calendar month of blood sampling, cancer stage, residual tumor after surgery, time period of surgery, location of tumor, adjuvant chemotherapy, number of lymph nodes with metastasis
Mean age: 65Quartile 2 (20–25)0.55 (0.18–1.65)
Stage: I–IV 39 deaths, 30 CRC-specific deathsQuartile 3 (27.5–37.5)1.0
Quartile 4 (40–90)0.16 (0.04–0.63)
Tretli, 2012, Norway (67)52 colon cancer casesFrom 1973–2005 until December 2008Postdiagnosis (median 30.5 days after diagnosis)Quartile 1 (<46)1.00.23Quartile 1 (<44)1.00.16Sex, age at diagnosis, season of blood sampling
Median age: 59Quartile 2 (46–61)0.48 (0.18–1.29)Quartile 2 (45–56)0.46 (0.15–1.48)
Stage: I–IV 26 deathsQuartile 3 (62–81)0.61 (0.23–1.59)Quartile 3 (57–77)0.73 (0.25–2.15)
Quartile 4 (>81)0.40 (0.10–1.60)Quartile 4 (>77)0.20 (0.04–1.10)
Ng, 2011, United States/Canada (68)515 CRC casesMedian 5.1 yearsPost diagnosis, but before chemotherapyQuartile 1 (5.8–32.8)1.00.55NANANAAge, sex, season of blood collection, treatment arm, metastatic sites, BMI, baseline performance status
Mean age: 61Quartile 2 (33–49.8)0.78 (0.60–1.02)
Stage: IV 475 deathsQuartile 3 (50–67.8)1.13 (0.87–1.47)
Quartile 4 (68–188.5)0.94 (0.72–1.23)
Zgaga, 2014, Scotland (9)1,598 CRC casesMedian 8.9 yearsPostoperatively (median 105 days after treatment)Tertile 1 (<18.1)1.00.003Tertile 1 (<18.1)1.00.009Season of blood collection, tumor site, surgery, time between definitive treatment and sampling, BMI, level of physical activity
Mean age: 62Tertile 2 (18.2–33.1)0.81 (0.65–1.01)Tertile 2 (18.2–33.1)0.86 (0.66–1.13)
Stage: I–III 531 deaths, 363 CRC-specific deathsTertile 3 (>33.2)0.70 (0.55–0.89)Tertile 3 (>33.2)0.68 (0.50–0.90)

NOTE: Vitamin D levels reported in ng/mL were converted into nmol/L using a conversion factor (1 ng/mL = 2.5 nmol/L).

Abbreviations: CRC, colorectal cancer; BMI, body mass index; NA, not available; EPIC, European Prospective Investigation into Cancer and Nutrition.

  • aQuartile ranges differ per laboratory run (3 runs). Quartile 1: 22.8–47.0, 15.0–48.5, 25.8–56.5; Quartile 2: 47.3–59.3, 51.3–64.0, 57.0–67.8; Quartile 3: 60.0–71.3, 64.3–83.5, 68.0–82.8; Quartile 4: 72.5–175.0, 84.3–142.0, 83.5–138.5.