Vitamin D intake, blood vitamin D levels, and the risk of breast cancer: a dose-response meta-analysis of observational studies

Results

Literature selection and study characteristics

The flow chart of the selection of publications from the existing literature is shown in Figure 1. Firstly, 5587 articles were searched through the databases as well as through hand searching. Next, 1705 articles were excluded for duplication; 3795 articles were excluded after reading the titles and abstracts for the lack of relevance; 10 articles did not contain the relevant data; three articles measured blood vitamin D levels in pg/ml or pmol/l; five articles disabled the extraction data; and one article was associated with pregnancy. Additional there are two studies, O’ Brien et al [16] and Fedirko et al [17], provide data on blood vitamin D and vitamin D intake. So we went through the full texts of 68 articles. Finally, a total of 68 articles that contained 70 observational studies (case-control or cohort) were eligible for the analysis. The characteristics of the 68 selected publications are summarized in Table 1 and Supplementary Table 1.

Figure 1. Flowchart of included studies for the meta-analysis.

Table 1. Characteristics of prospective studies included in the meta-analysis of vitamin D intake and breast cancer risk.

Author	Country	Study type	Follow-up period (year)	Age (year)	No. of cases/controls/ persons	Vitamin D Intake (IU/day)a	Adjusted OR(95%CI)b	Adjustment factors
O’Brien et al, 2017	USA	Cohort	5	35-74	1699/49044	Total ≥600 vs <200	0.90 (0.78–1.05)	Age, BMI, race, education, menopausal status, current birth control use, physical activity, hormone therapy type, current alcohol use, osteoporosis, total energy intake, parity, and a BMI× menopausal status interaction term
Abbas et al, 2013	Europe	Cohort	8.8	50.2	7760/319985	Dietary ≥218.4 vs <74	1.04 (0.94–1.14)	No-fat, no-alcohol energy, fat, alcohol consumption, weight, height, smoking status, menopausal status, physical activity, age at menarche, education level and current use of contraceptives or hormones
Rollison et al, 2012	USA	Case- control	1999-2004	24-79	2318/2521	Dietary 7.0-122.5 vs 308.6-1362.7	1.28 (1.09-1.5)	Age
Fedirko et al, 2012	Mexico	Case- control	2004-2007	35-69	570/638	Dietary >111.8 vs ≤65	0.69 (0.47–1.00)	SES, BMI, alcohol consumption, height, parity/number of children born alive, age at first full term pregnancy, family history of breast cancer, breast feeding, use of hormone for menopause, physical activity index, total energy intake, and menopausal status
Edvardsen et al, 2011	Norway	Cohort	1997-2007	40-70	844/41758	Total ≥832 vs ≤108	1.07 (0.87–1.32)	Age at entry, BMI, height, menopausal status, HRT use, use of oral contraceptives, mothers’ history of breast cancer, frequency of mammography, combined parity and age at first birth and daily intake of alcohol.
Kawase et al, 2010	Japan	Case- control	2001-2005	20-79	1803/3606	Dietary 266-1400 vs 80-114	0.76 (0.63–0.9)	Age, BMI, menopausal status, smoking habit, drinking habit, physical activity, family history of breast cancer in a first degree relative, age at menarche, parity, hormone use, total nonalcohol energy, and referral pattern
Anderson et al, 2010	Canada	Case- control	2002-2003	25-74	3101/3471	Total ≥600 vs <100	0.99 (0.78-1.26)	Age, BMI, education, age at menarche, age at first live birth, parity, menopausal status, smoking, relative energy intake, breast cancer in first degree, moderate physical activity, time spent outdoors, total calcium intake, and total vitamin D intake
Lee et al, 2010	China	Case- control	2004-2005	Cases 52.5 Controls 48.9	200/200	Total 428-1148 vs 6.8-125.6	0.52 (0.25–1.07)	Age, BMI, education, parity, use of HRT, total energy intake, sunlight exposure, menopausal status, and homocysteine.
Engel et al, 2010	French	Cohort	10.4	41.8-72	2871/67721	Dietary >113 vs <80	0.94 (0.86–1.03)	BMI, age at menopause, age at menarche, physical activity, parity, use of menopausal, use of HRT, alcohol intake, daily calcium intake, calcium supplement, energy intake without alcohol, university degree, previous family history of breast cancer, previous personal history of benign breast disease, previous history of mammographic exam, sun burn resistance, menopausal status, and skin complexion.
Kuper et al, 2009	Sweden	cohort	1991-2003 (12.9)	30-49	840/41889	Dietary Q4 vs Q1	0.90 (0.80–1.10)	BMI, parity, age at first birth, age at menarche, use of hormonal contraceptives, consumption of alcohol, breast-feeding, education, family history of breast cancer, physical activity, and smoking.
Rossi et al, 2008	Italy	Case- control	1991-1994	23-74	2569/2588	Total >190.4 vs <60.4	0.76 (0.58–1.00)	age, parity, age at menarche, study center, education, total energy intake, menopausal status, vegetable and fruit consumption, calcium, b-carotene, vitamin E, flavones, and flavonol intake
Abbas et al, 2007	German	Case- control	1992-1995	24-50	278/666	Dietary ≥200 vs < 80	0.50 (0.26–0.96)	BMI, age at menarche, energy intake, duration of breast feeding, first-degree family history, number of births, nonalcohol, alcohol consumption, and mineral and vitamin supplements
Robien et al, 2007	USA	Cohort	1986-2004	50-70	2440/34321	Total ≥800 vs <400	0.90 (0.78–1.04)	Age, BMI, smoking status, age at menarche, age at menopause, first degree relative with breast cancer, estrogen use, age at first live birth, number of live births, education category, activity level, live on a farm, mammogram history, and daily energy, fat, and alcohol intake.
Lin et al, 2007	USA	Cohort	10	55.2	Cases Pre276/Post743 Persons Pre10578/Post20909	Total ≥548 vs <162	Pre 0.65 (0.42-1.00) Post 1.30 (0.97-1.73)	Age, BMI, randomized treatment assignment, physical activity, family history of breast cancer in a first-degree relative, history of benign breast disease, age at menarche, parity, age at first birth, multivitamin use, smoking status, alcohol consumption, total energy intake, age at menopause, and baseline postmenopausal hormone therapy.
McCullough et al,2005	USA	Cohort	1992-2001	50-74	2855/68567	Total ≥700 vs ≤100	0.94 (0.80-1.10)	Age, energy, history of breast cyst, family history of breast cancer, height, weight gain since age 18, alcohol use, race, age at menopause, age at first birth and number of live births, education, mammography history, and hormone therapy.
Frazier et al, 2004	USA	Cohort	1989-1998	34-51	361/47517	Total 591 vs 159.6	0.92 (0.66-1.27)	Age, BMI, time period, height, parity and age at first birth, age at menarche, family history of breast cancer, history of benign breast disease, menopausal status, alcohol intake, energy, oral contraceptive use, and weight gain since age 18.
Shin et al, 2002	USA	Cohort	1980-1996	46.7	Pre827/Post2345/ 88691	Total >500 vs ≤150	Pre 0.89 (0.68-1.15) Post 0.93 (0.80-1.08)	Age, BMI, time period, physical activity, history of benign breast disease, family history of breast cancer, height, weight change, age at menarche, parity, age at first birth, alcohol intake, total energy intake, total fat intake, glycemic index, β-carotene intake, and total active vitamin E intake.
Levi et al, 2000	Switzerland	Case- control	1993-1999	23-74	289/442	Total 108000 vs 56000	1.43 (0.90–2.26)	Age, BMI, education, parity, menopausal status, total energy intake, and alcohol drinking
John et al, 1999	USA	Cohort	1971-1992 (17.3)	25-74	179/4747	Dietary ≥200 vs <100	0.85 (0.59–1.24)	Age, BMI, education, age at menarche, age at menopause, frequency of alcohol consumption, physical activity, and calcium intake
Potischman et al,1999	USA	Case- control	1990-1992	20-44 years	568/1451	Total ≥400 vs 0	0.98 (0.8–1.2)	Age at diagnosis, study site, ethnicity, combination age at first birth and parity, of oral contraceptive use, smoking, education and alcohol consumption.
Abbreviations: OR=odds ratio; CI=confidence interval; BMI=body mass index (kg/m^2); HRT=hormone replacement therapy; HT=hormone therapy; POST=postmenopausal; PRE=premenopausal.
a. Vitamin D intake levels in ug/day were converted to IU/day using the conversion factor, 1ug/d=40IU/day.
b. The ORs of all studies used the lowest category of vitamin D intake levels as a reference in the meta-analysis.

For the association of vitamin D intake with breast cancer risk, there are 20 relevant studies, including 11 prospective cohort studies [16, 18–27] consisting 24040 cases, and 9 case-control studies [17, 28–35] consisting 11696 cases and 15583 controls. Among these, nine studies were performed in the US [16, 18–21, 25, 26, 28, 33], seven in Europe [22–24, 27, 29, 34, 35], two in Asia [31, 32], one in Canada [30] and one in Mexico [17]. There were seven studies [17, 18, 21, 22, 24, 31, 32] that provided risk estimates which were stratified by menopausal status in the 20 studies. The risk estimates of most of the studies were adjusted for potential confounders, including age, body mass index (BMI), education level, and physical activity. The adjusted confounding factors are shown in Table 1.

We identified 50 prospective studies on the association of blood vitamin D levels and breast cancer risk; the six cohort studies [36–41] consisting of 2257 incident cases, and 44 case-control studies [16, 17, 42–83] consisting 29095 cases and 53060 controls were included. Among these, 16 studies were conducted in the Europe [36, 38–40, 43, 44, 47, 50–57], fifteen in the US [16, 19, 37, 41, 42, 45, 46, 48, 58–63, 82], twelve in Asia [64–75], two in Canada [76, 77], one each in Austria [78], Mexico [17], and Brazil [79]. In addition, two studies [80, 81] contained mixed population in Europe and in the US. The menopausal status was categorized as premenopausal, postmenopausal, or mixed. Overall, nine studies [16, 17, 48, 50–53, 62, 64] assessed risk estimates based on participants’ menopausal status and twelve studies [43, 50, 57, 59, 65, 68, 71, 72, 77–79, 83] provided unadjusted results. The majority of the studies were adjusted for potential confounders including age, BMI, race, education level and time at blood collection.

Overall analyses

Vitamin D intake and breast cancer risk

The pooled OR of breast cancer risk for the highest versus lowest category of vitamin D intake was 0.94 (95% CI = 0.88–1.00), with an evidence of heterogeneity I² = 57.2%, P = 0.000 (Supplementary Figure 1). No publication bias was found after visual inspection of the funnel the plot (Supplementary Figure 3). The summary of estimations for case-control studies were OR = 0.89, 95% CI = 0.73–1.08, I²=77.0%, P = 0.228, and for cohort studies were OR=0.95, 95% CI = 0.90–1.00, I² = 16.1%, P = 0.055. Eight case-control studies and seven cohort studies were eligible for the dose-response analysis of the association of vitamin D intake and breast cancer risk. As shown in Figure 2, the random-effects model was used and showed that a 400 IU/day increment in vitamin D intake had no significant effect on occurrence of breast cancer, and the pooled OR were 0.97 (95% CI = 0.92–1.02, I² = 25.6%, P = 0.222) and 0.96 (95% CI = 0.86–1.07, I² = 64.3%, P = 0.427) for cohort studies and case-control studies, respectively. Heterogeneity among studies was statistically significant (I² = 48.1%, P = 0.014). There existed significant publication bias according to Begg's test (P = 0.009) and Egger's test (P = 0.007) (Supplementary Figure 5). In sensitivity analyses, a single study had no influence on the results, and the stable OR in the overall analysis ranged from 0.93–0.98 (Supplementary Figure 7). We failed to identify a significant dose-response relationship between vitamin D intake and breast cancer risk. When the subgroup analysis was stratified by menopausal status, study type, geographical location, and follow-up years, the results were stable; except for Asian studies (OR = 0.97, 95% CI = 0.95–0.99, Table 2) with no significant heterogeneity (I² = 0.0%, P = 0.472), and studies related to premenopuase (OR = 0.79, 95% CI = 0.64–0.96, Table 2) with a significant heterogeneity (I² = 56.1%, P = 0.026). This result suggests that higher vitamin D intake could reduce the risk of breast cancer in Asian women and premenopausal women.

Figure 2. Forest plot of meta-analysis of the association between vitamin D intake increment (per 400IU/d) and breast cancer risk. Abbreviations: OR, odds ratio; CI, confidence interval.

Table 2. Subgroup analyses of vitamin D intake and breast cancer.

Analysis specification	No. of studies	OR(95% CI)	P	Heterogeneity
				I2	p
Highest vs lowest
All studies	20	0.94(0.88-1.00)	0.063	57.2%	0
Case-control	9	0.89(0.73-1.08)	0.228	77.0%	0
Cohort	11	0.95(0.90-1.00)	0.055	16.1%	0.281
Increment of 400 IU/d
All studies	15	0.97(0.92-1.02)	0.201	48.1%	0.014
Case-control	8	0.96(0.86-1.07)	0.427	64.3%	0.006
Cohort	7	0.97(0.92-1.02)	0.222	25.6%	0.216
Menopausal status
Premenopause	8	0.79(0.64-0.96)	0.021	56.1%	0.026
Postmenopausal	8	0.98(0.94-1.02)	0.243	0	0.631
Geographic location
Europe	4	0.83(0.60-1.15)	0.257	48.3%	0.122
America	7	0.99(0.93-1.04)	0.599	47.3%	0.056
Asia	2	0.89(0.82-0.97)	0.008	0	0.472
Follow-up duration
<10 years	9	0.96(0.88-1.05)	0.358	60.9%	0.009
≥10 years	5	0.95(0.88-1.03)	0.245	32%	0.183
Source vitamin D
Dietary	5	0.90(0.73-1.10)	0.308	78.9%	0.001
Dietary+Supplement	10	0.98(0.94-1.01)	0.185	5.3%	0.393

Blood vitamin D levels and breast cancer risk

The summary OR of breast cancer for the highest versus lowest category of blood vitamin D levels was 0.61 (95% CI = 0.53–0.70), with an evidence of heterogeneity I² = 89.3%, P = 0.000 (Supplementary Figure 2). A significant publication bias was observed through the funnel plot (Supplementary Figure 4). The pooled OR for case-control studies was 0.57 (95% CI = 0.48–0.66; I² = 89.9%, P = 0.000), and for cohort studies was 1.17 (95% CI = 0.92–1.48; I² = 31.6%, P = 0.192). Overall, 36 case-control studies and four cohort studies were eligible for the dose-response analysis of the association on blood vitamin D levels with breast cancer risk. The pooled OR for breast cancer risk for a 5 nmol/l increase in blood vitamin D levels was 0.94 (95% CI = 0.93–0.96), with a significant heterogeneity among all studies (I² = 91.0%, P = 0.000) (Figure 3). The summary OR for case-control studies was 0.94 (95% CI = 0.92–0.95) and for cohort studies was 1.01 (95% CI = 0.96–1.05). Begg’s test (P = 0.004) and Egger’s test (P = 0.004) showed a significant publication bias and the funnel plot was asymmetrical (Supplementary Figure 6). The sensitivity analyses indicated that the ORs ranged from 0.96–0.97, and our results were statistically stable (Supplementary Figure 8). 36 eligible case-control studies showed an evidence of a linear association between blood vitamin D levels and breast cancer risk (P_nonlinearity = 0.1893) (Figure 4). Subgroup analysis based on menopausal status (Figure 5), showed linear relationship between blood vitamin D levels and breast cancer risk for premenopausal and postmenopausal women (P_nonlinearity = 0.2140 and P_nonlinearity =0.4900, respectively). The results of subgroup are presented in Table 3. A 5 nmol/l increase in blood vitamin D corresponded to a 16% decrease in breast cancer risk in Asian women.

Figure 3. Forest plot of meta-analysis of the association between blood vitamin D increment (per 5nmol/L) and breast cancer risk. Abbreviations: OR, odds ratio; CI, confidence interval.

Figure 4. Dose–response meta-analysis of blood vitamin D and breast cancer risk (linear and nonlinear models).

Figure 5. Dose-response meta-analysis of blood vitamin D and breast cancer risk stratified by menopausal status (linear and nonlinear models). Note: (A) Premenopause; (B) Postmenopause.

Table 3. Subgroup analyses of blood vitamin D and breast cancer.

Analysis specification	No. of studies	OR(95% CI)	P	Heterogeneity
				I^2	p
Highest vs lowest
All studies	50	0.61(0.53-0.70)	0	89.3%	0
Case-control	44	0.57(0.48-0.66)	0	89.9%	0
Cohort	6	1.17(0.92-1.48)	0.192	31.6%	0.198
Increment of 5 nmol/l
All studies	40	0.94(0.93-0.96)	0	91.0%	0
Case-control	36	0.94(0.92-0.95)	0	91.1%	0
Cohort	4	1.01(0.96-1.05)	0.734	82.6%	0.001
Menopausal status
Premenopause	11	0.96(0.93-0.99)	0.011	68.2%	0
Postmenopausal	15	0.96(0.94-0.98)	0.001	86.4%	0
Geographic location
Europe	13	0.95(0.92-0.98)	0	89.1%	0
America	14	0.98(0.96-0.99)	0.034	82.4%	0
Asia	9	0.84(0.77-0.92)	0	95.7%	0
Follow-up duration
<10 years	24	0.94(0.91-0.96)	0	92.4%	0
≥10 years	10	0.99(0.98-1.00)	0.051	26.7%	0.198
Serum or Plasm
Serum	31	0.93(0.91-0.97)	0	92.80%	0
Plasm	9	0.97(0.96-0.98)	0	50.50%	0.04

Abbreviations

OR: odds ratio; RR: relative risk; HR: hazard ratio; CI: confidence interval; NOS: Newcastle-Ottawa Scale; SI: standard international.

Author Contributions

All authors read, critically reviewed and approved the final manuscript. SDL, DYJ and LK conducted the database searches, screened titles, abstracts and full-texts for eligibility, performed study quality assessments. DZJ planed and designed the research; ZLH and LN provided methodological support/advice; ZY tested the feasibility of the study; HQ, SY and YW extract data; ZZ performed the statistical analysis; SDL wrote the manuscript.

Acknowledgments

We thank all members of our study team for their whole-hearted cooperation and the original authors of the included studies for their wonderful work.

Conflicts of Interest

The authors declare that there are no competing interests associated with the manuscript.

Funding

National Natural Science Foundation of China, Grant/Award Number: 81471670.

References

• 1. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018; 68:394–424. https://doi.org/10.3322/caac.21492 [PubMed]
• 2. Clegg LX, Li FP, Hankey BF, Chu K, Edwards BK. Cancer survival among US whites and minorities: a SEER (Surveillance, Epidemiology, and End Results) Program population-based study. Arch Intern Med. 2002; 162:1985–93. https://doi.org/10.1001/archinte.162.17.1985 [PubMed]
• 3. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2019. CA Cancer J Clin. 2019; 69:7–34. https://doi.org/10.3322/caac.21551 [PubMed]
• 4. Okazaki R. [Vitamin D and cancer]. Clin Calcium. 2014; 24:1193–99. [PubMed]
• 5. Dunn JA, Jefferson K, MacDonald D, Iqbal G, Bland R. Low serum 25-hydroxyvitamin D is associated with increased bladder cancer risk: A systematic review and evidence of a potential mechanism. J Steroid Biochem Mol Biol. 2019; 188:134–40. https://doi.org/10.1016/j.jsbmb.2019.01.002 [PubMed]
• 6. Li F, Zhao H, Hou L, Ling F, Zhang Y, Tan W. A higher circulating concentration of 25-hydroxyvitamin-D decreases the risk of renal cell carcinoma: a case-control study. Int Braz J Urol. 2019; 45:523–30. https://doi.org/10.1590/s1677-5538.ibju.2018.0186 [PubMed]
• 7. Giovannucci E. The epidemiology of vitamin D and cancer incidence and mortality: a review (United States). Cancer Causes Control. 2005; 16:83–95. https://doi.org/10.1007/s10552-004-1661-4 [PubMed]
• 8. Feldman D, Krishnan AV, Swami S, Giovannucci E, Feldman BJ. The role of vitamin D in reducing cancer risk and progression. Nat Rev Cancer. 2014; 14:342–57. https://doi.org/10.1038/nrc3691 [PubMed]
• 9. Vanoirbeek E, Krishnan A, Eelen G, Verlinden L, Bouillon R, Feldman D, Verstuyf A. The anti-cancer and anti-inflammatory actions of 1,25(OH)₂D₃. Best Pract Res Clin Endocrinol Metab. 2011; 25:593–604. https://doi.org/10.1016/j.beem.2011.05.001 [PubMed]
• 10. Hiatt RA, Krieger N, Lobaugh B, Drezner MK, Vogelman JH, Orentreich N. Prediagnostic serum vitamin D and breast cancer. J Natl Cancer Inst. 1998; 90:461–63. https://doi.org/10.1093/jnci/90.6.461 [PubMed]
• 11. Yin L, Grandi N, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis: serum vitamin D and breast cancer risk. Eur J Cancer. 2010; 46:2196–205. https://doi.org/10.1016/j.ejca.2010.03.037 [PubMed]
• 12. Hong Z, Tian C, Zhang X. Dietary calcium intake, vitamin D levels, and breast cancer risk: a dose-response analysis of observational studies. Breast Cancer Res Treat. 2012; 136:309–12. https://doi.org/10.1007/s10549-012-2172-8 [PubMed]
• 13. Gissel T, Rejnmark L, Mosekilde L, Vestergaard P. Intake of vitamin D and risk of breast cancer—a meta-analysis. J Steroid Biochem Mol Biol. 2008; 111:195–99. https://doi.org/10.1016/j.jsbmb.2008.06.002 [PubMed]
• 14. Estébanez N, Gómez-Acebo I, Palazuelos C, Llorca J, Dierssen-Sotos T. Vitamin D exposure and Risk of Breast Cancer: a meta-analysis. Sci Rep. 2018; 8:9039. https://doi.org/10.1038/s41598-018-27297-1 [PubMed]
• 15. Bauer SR, Hankinson SE, Bertone-Johnson ER, Ding EL. Plasma vitamin D levels, menopause, and risk of breast cancer: dose-response meta-analysis of prospective studies. Medicine (Baltimore). 2013; 92:123–31. https://doi.org/10.1097/MD.0b013e3182943bc2 [PubMed]
• 16. O’Brien KM, Sandler DP, Taylor JA, Weinberg CR. Serum Vitamin D and Risk of Breast Cancer within Five Years. Environ Health Perspect. 2017; 125:077004. https://doi.org/10.1289/EHP943 [PubMed]
• 17. Fedirko V, Torres-Mejía G, Ortega-Olvera C, Biessy C, Angeles-Llerenas A, Lazcano-Ponce E, Saldaña-Quiroz VA, Romieu I. Serum 25-hydroxyvitamin D and risk of breast cancer: results of a large population-based case-control study in Mexican women. Cancer Causes Control. 2012; 23:1149–62. https://doi.org/10.1007/s10552-012-9984-z [PubMed]
• 18. Shin MH, Holmes MD, Hankinson SE, Wu K, Colditz GA, Willett WC. Intake of dairy products, calcium, and vitamin d and risk of breast cancer. J Natl Cancer Inst. 2002; 94:1301–11. https://doi.org/10.1093/jnci/94.17.1301 [PubMed]
• 19. McCullough ML, Rodriguez C, Diver WR, Feigelson HS, Stevens VL, Thun MJ, Calle EE. Dairy, calcium, and vitamin D intake and postmenopausal breast cancer risk in the Cancer Prevention Study II Nutrition Cohort. Cancer Epidemiol Biomarkers Prev. 2005; 14:2898–904. https://doi.org/10.1158/1055-9965.EPI-05-0611 [PubMed]
• 20. Robien K, Cutler GJ, Lazovich D. Vitamin D intake and breast cancer risk in postmenopausal women: the Iowa Women’s Health Study. Cancer Causes Control. 2007; 18:775–82. https://doi.org/10.1007/s10552-007-9020-x [PubMed]
• 21. Lin J, Manson JE, Lee IM, Cook NR, Buring JE, Zhang SM. Intakes of calcium and vitamin D and breast cancer risk in women. Arch Intern Med. 2007; 167:1050–59. https://doi.org/10.1001/archinte.167.10.1050 [PubMed]
• 22. Engel P, Fagherazzi G, Mesrine S, Boutron-Ruault MC, Clavel-Chapelon F. Joint effects of dietary vitamin D and sun exposure on breast cancer risk: results from the French E3N cohort. Cancer Epidemiol Biomarkers Prev. 2011; 20:187–98. https://doi.org/10.1158/1055-9965.EPI-10-1039 [PubMed]
• 23. Edvardsen K, Veierød MB, Brustad M, Braaten T, Engelsen O, Lund E. Vitamin D-effective solar UV radiation, dietary vitamin D and breast cancer risk. Int J Cancer. 2011; 128:1425–33. https://doi.org/10.1002/ijc.25463 [PubMed]
• 24. Abbas S, Linseisen J, Rohrmann S, Chang-Claude J, Peeters PH, Engel P, Brustad M, Lund E, Skeie G, Olsen A, Tjønneland A, Overvad K, Boutron-Ruault MC, et al. Dietary intake of vitamin D and calcium and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition. Nutr Cancer. 2013; 65:178–87. https://doi.org/10.1080/01635581.2013.752018 [PubMed]
• 25. John EM, Schwartz GG, Dreon DM, Koo J. Vitamin D and breast cancer risk: the NHANES I Epidemiologic follow-up study, 1971-1975 to 1992. National Health and Nutrition Examination Survey. Cancer Epidemiol Biomarkers Prev. 1999; 8:399–406. [PubMed]
• 26. Frazier AL, Li L, Cho E, Willett WC, Colditz GA. Adolescent diet and risk of breast cancer. Cancer Causes Control. 2004; 15:73–82. https://doi.org/10.1023/B:CACO.0000016617.57120.df [PubMed]
• 27. Kuper H, Yang L, Sandin S, Lof M, Adami HO, Weiderpass E. Prospective study of solar exposure, dietary vitamin D intake, and risk of breast cancer among middle-aged women. Cancer Epidemiol Biomarkers Prev. 2009; 18:2558–61. https://doi.org/10.1158/1055-9965.EPI-09-0449 [PubMed]
• 28. Potischman N, Swanson CA, Coates RJ, Gammon MD, Brogan DR, Curtin J, Brinton LA. Intake of food groups and associated micronutrients in relation to risk of early-stage breast cancer. Int J Cancer. 1999; 82:315–21. https://doi.org/10.1002/(SICI)1097-0215(19990730)82:3<315::AID-IJC1>3.0.CO;2-N [PubMed]
• 29. Rossi M, McLaughlin JK, Lagiou P, Bosetti C, Talamini R, Lipworth L, Giacosa A, Montella M, Franceschi S, Negri E, La Vecchia C. Vitamin D intake and breast cancer risk: a case-control study in Italy. Ann Oncol. 2009; 20:374–78. https://doi.org/10.1093/annonc/mdn550 [PubMed]
• 30. Anderson LN, Cotterchio M, Vieth R, Knight JA. Vitamin D and calcium intakes and breast cancer risk in pre- and postmenopausal women. Am J Clin Nutr. 2010; 91:1699–707. https://doi.org/10.3945/ajcn.2009.28869 [PubMed]
• 31. Kawase T, Matsuo K, Suzuki T, Hirose K, Hosono S, Watanabe M, Inagaki M, Iwata H, Tanaka H, Tajima K. Association between vitamin D and calcium intake and breast cancer risk according to menopausal status and receptor status in Japan. Cancer Sci. 2010; 101:1234–40. https://doi.org/10.1111/j.1349-7006.2010.01496.x [PubMed]
• 32. Lee MS, Huang YC, Wahlqvist ML, Wu TY, Chou YC, Wu MH, Yu JC, Sun CA. Vitamin D decreases risk of breast cancer in premenopausal women of normal weight in subtropical taiwan. J Epidemiol. 2011; 21:87–94. https://doi.org/10.2188/jea.JE20100088 [PubMed]
• 33. Rollison DE, Cole AL, Tung KH, Slattery ML, Baumgartner KB, Byers T, Wolff RK, Giuliano AR. Vitamin D intake, vitamin D receptor polymorphisms, and breast cancer risk among women living in the southwestern U.S. Breast Cancer Res Treat. 2012; 132:683–91. https://doi.org/10.1007/s10549-011-1885-4 [PubMed]
• 34. Abbas S, Linseisen J, Chang-Claude J. Dietary vitamin D and calcium intake and premenopausal breast cancer risk in a German case-control study. Nutr Cancer. 2007; 59:54–61. https://doi.org/10.1080/01635580701390223 [PubMed]
• 35. Levi F, Pasche C, Lucchini F, La Vecchia C. Dietary intake of selected micronutrients and breast-cancer risk. Int J Cancer. 2001; 91:260–63. https://doi.org/10.1002/1097-0215(200002)9999:9999<::AID-IJC1041>3.0.CO;2-%23 [PubMed]
• 36. Cheney CP, Thorand B, Huth C, Berger K, Peters A, Seifert-Klauss V, Kiechle M, Strauch K, Quante AS. The Association between Serum 25-Hydroxyvitamin D and Cancer Risk: Results from the Prospective KORA F4 Study. Oncol Res Treat. 2018; 41:117–21. https://doi.org/10.1159/000485512 [PubMed]
• 37. Palmer JR, Gerlovin H, Bethea TN, Bertrand KA, Holick MF, Ruiz-Narvaez EN, Wise LA, Haddad SA, Adams-Campbell LL, Kaufman HW, Rosenberg L, Cozier YC. Predicted 25-hydroxyvitamin D in relation to incidence of breast cancer in a large cohort of African American women. Breast Cancer Res. 2016; 18:86. https://doi.org/10.1186/s13058-016-0745-x [PubMed]
• 38. Ordóñez-Mena JM, Schöttker B, Fedirko V, Jenab M, Olsen A, Halkjær J, Kampman E, de Groot L, Jansen E, Bueno-de-Mesquita HB, Peeters PH, Siganos G, Wilsgaard T, et al. Pre-diagnostic vitamin D concentrations and cancer risks in older individuals: an analysis of cohorts participating in the CHANCES consortium. Eur J Epidemiol. 2016; 31:311–23. https://doi.org/10.1007/s10654-015-0040-7 [PubMed]
• 39. Skaaby T, Husemoen LL, Thuesen BH, Pisinger C, Jørgensen T, Roswall N, Larsen SC, Linneberg A. Prospective population-based study of the association between serum 25-hydroxyvitamin-D levels and the incidence of specific types of cancer. Cancer Epidemiol Biomarkers Prev. 2014; 23:1220–29. https://doi.org/10.1158/1055-9965.EPI-14-0007 [PubMed]
• 40. Ordóñez-Mena JM, Schöttker B, Haug U, Müller H, Köhrle J, Schomburg L, Holleczek B, Brenner H. Serum 25-hydroxyvitamin d and cancer risk in older adults: results from a large German prospective cohort study. Cancer Epidemiol Biomarkers Prev. 2013; 22:905–16. https://doi.org/10.1158/1055-9965.EPI-12-1332 [PubMed]
• 41. McDonnell SL, Baggerly CA, French CB, Baggerly LL, Garland CF, Gorham ED, Hollis BW, Trump DL, Lappe JM. Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): pooled analysis of two randomized trials and a prospective cohort. PLoS One. 2018; 13:e0199265. https://doi.org/10.1371/journal.pone.0199265 [PubMed]
• 42. Bertone-Johnson ER, Chen WY, Holick MF, Hollis BW, Colditz GA, Willett WC, Hankinson SE. Plasma 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D and risk of breast cancer. Cancer Epidemiol Biomarkers Prev. 2005; 14:1991–97. https://doi.org/10.1158/1055-9965.EPI-04-0722 [PubMed]
• 43. Lowe LC, Guy M, Mansi JL, Peckitt C, Bliss J, Wilson RG, Colston KW. Plasma 25-hydroxy vitamin D concentrations, vitamin D receptor genotype and breast cancer risk in a UK Caucasian population. Eur J Cancer. 2005; 41:1164–69. https://doi.org/10.1016/j.ejca.2005.01.017 [PubMed]
• 44. Abbas S, Linseisen J, Slanger T, Kropp S, Mutschelknauss EJ, Flesch-Janys D, Chang-Claude J. Serum 25-hydroxyvitamin D and risk of post-menopausal breast cancer—results of a large case-control study. Carcinogenesis. 2008; 29:93–99. https://doi.org/10.1093/carcin/bgm240 [PubMed]
• 45. Chlebowski RT, Johnson KC, Kooperberg C, Pettinger M, Wactawski-Wende J, Rohan T, Rossouw J, Lane D, O’Sullivan MJ, Yasmeen S, Hiatt RA, Shikany JM, Vitolins M, et al, and Women’s Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of breast cancer. J Natl Cancer Inst. 2008; 100:1581–91. https://doi.org/10.1093/jnci/djn360 [PubMed]
• 46. Freedman DM, Chang SC, Falk RT, Purdue MP, Huang WY, McCarty CA, Hollis BW, Graubard BI, Berg CD, Ziegler RG. Serum levels of vitamin D metabolites and breast cancer risk in the prostate, lung, colorectal, and ovarian cancer screening trial. Cancer Epidemiol Biomarkers Prev. 2008; 17:889–94. https://doi.org/10.1158/1055-9965.EPI-07-2594 [PubMed]
• 47. Abbas S, Chang-Claude J, Linseisen J. Plasma 25-hydroxyvitamin D and premenopausal breast cancer risk in a German case-control study. Int J Cancer. 2009; 124:250–55. https://doi.org/10.1002/ijc.23904 [PubMed]
• 48. Crew KD, Gammon MD, Steck SE, Hershman DL, Cremers S, Dworakowski E, Shane E, Terry MB, Desai M, Teitelbaum SL, Neugut AI, Santella RM. Association between plasma 25-hydroxyvitamin D and breast cancer risk. Cancer Prev Res (Phila). 2009; 2:598–604. https://doi.org/10.1158/1940-6207.CAPR-08-0138 [PubMed]
• 49. McCullough ML, Stevens VL, Patel R, Jacobs EJ, Bain EB, Horst RL, Gapstur SM, Thun MJ, Calle EE. Serum 25-hydroxyvitamin D concentrations and postmenopausal breast cancer risk: a nested case control study in the Cancer Prevention Study-II Nutrition Cohort. Breast Cancer Res. 2009; 11:R64. https://doi.org/10.1186/bcr2356 [PubMed]
• 50. Rejnmark L, Tietze A, Vestergaard P, Buhl L, Lehbrink M, Heickendorff L, Mosekilde L. Reduced prediagnostic 25-hydroxyvitamin D levels in women with breast cancer: a nested case-control study. Cancer Epidemiol Biomarkers Prev. 2009; 18:2655–60. https://doi.org/10.1158/1055-9965.EPI-09-0531 [PubMed]
• 51. Almquist M, Bondeson AG, Bondeson L, Malm J, Manjer J. Serum levels of vitamin D, PTH and calcium and breast cancer risk-a prospective nested case-control study. Int J Cancer. 2010; 127:2159–68. https://doi.org/10.1002/ijc.25215 [PubMed]
• 52. Engel P, Fagherazzi G, Boutten A, Dupré T, Mesrine S, Boutron-Ruault MC, Clavel-Chapelon F. Serum 25(OH) vitamin D and risk of breast cancer: a nested case-control study from the French E3N cohort. Cancer Epidemiol Biomarkers Prev. 2010; 19:2341–50. https://doi.org/10.1158/1055-9965.EPI-10-0264 [PubMed]
• 53. Lope V, Castelló A, Mena-Bravo A, Amiano P, Aragonés N, Fernández-Villa T, Guevara M, Dierssen-Sotos T, Fernandez-Tardón G, Castaño-Vinyals G, Marcos-Gragera R, Moreno V, Salas-Trejo D, et al. Serum 25-hydroxyvitamin D and breast cancer risk by pathological subtype (MCC-Spain). J Steroid Biochem Mol Biol. 2018; 182:4–13. https://doi.org/10.1016/j.jsbmb.2018.04.005 [PubMed]
• 54. Shirazi L, Almquist M, Borgquist S, Malm J, Manjer J. Serum vitamin D (25OHD3) levels and the risk of different subtypes of breast cancer: A nested case-control study. Breast. 2016; 28:184–90. https://doi.org/10.1016/j.breast.2016.06.002 [PubMed]
• 55. Deschasaux M, Souberbielle JC, Latino-Martel P, Sutton A, Charnaux N, Druesne-Pecollo N, Galan P, Hercberg S, Le Clerc S, Kesse-Guyot E, Ezzedine K, Touvier M. Weight Status and Alcohol Intake Modify the Association between Vitamin D and Breast Cancer Risk. J Nutr. 2016; 146:576–85. https://doi.org/10.3945/jn.115.221481 [PubMed]
• 56. Kühn T, Kaaks R, Becker S, Eomois PP, Clavel-Chapelon F, Kvaskoff M, Dossus L, Tjønneland A, Olsen A, Overvad K, Chang-Claude J, Lukanova A, Buijsse B, et al. Plasma 25-hydroxyvitamin D and the risk of breast cancer in the European prospective investigation into cancer and nutrition: a nested case-control study. Int J Cancer. 2013; 133:1689–700. https://doi.org/10.1002/ijc.28172 [PubMed]
• 57. Pazdiora P, Svobodova S, Fuchsova R, Kucera R, Prazakova M, Vrzalova J, Narsanska A, Strakova M, Treskova I, Pecen L, Treska V, Holubec L Jr, Pesek M, et al. Vitamin D in colorectal, breast, prostate and lung cancer: a pilot study. Anticancer Res. 2011; 31:3619–21. [PubMed]
• 58. Eliassen AH, Warner ET, Rosner B, Collins LC, Beck AH, Quintana LM, Tamimi RM, Hankinson SE. Plasma 25-Hydroxyvitamin D and Risk of Breast Cancer in Women Followed over 20 Years. Cancer Res. 2016; 76:5423–30. https://doi.org/10.1158/0008-5472.CAN-16-0353 [PubMed]
• 59. Mohr SB, Gorham ED, Alcaraz JE, Kane CI, Macera CA, Parsons JK, Wingard DL, Horst R, Garland CF. Serum 25-hydroxyvitamin D and breast cancer in the military: a case-control study utilizing pre-diagnostic serum. Cancer Causes Control. 2013; 24:495–504. https://doi.org/10.1007/s10552-012-0140-6 [PubMed]
• 60. Neuhouser ML, Manson JE, Millen A, Pettinger M, Margolis K, Jacobs ET, Shikany JM, Vitolins M, Adams-Campbell L, Liu S, LeBlanc E, Johnson KC, Wactawski-Wende J. The influence of health and lifestyle characteristics on the relation of serum 25-hydroxyvitamin D with risk of colorectal and breast cancer in postmenopausal women. Am J Epidemiol. 2012; 175:673–84. https://doi.org/10.1093/aje/kwr350 [PubMed]
• 61. Peppone LJ, Rickles AS, Janelsins MC, Insalaco MR, Skinner KA. The association between breast cancer prognostic indicators and serum 25-OH vitamin D levels. Ann Surg Oncol. 2012; 19:2590–99. https://doi.org/10.1245/s10434-012-2297-3 [PubMed]
• 62. Yao S, Sucheston LE, Millen AE, Johnson CS, Trump DL, Nesline MK, Davis W, Hong CC, McCann SE, Hwang H, Kulkarni S, Edge SB, O’Connor TL, Ambrosone CB. Pretreatment serum concentrations of 25-hydroxyvitamin D and breast cancer prognostic characteristics: a case-control and a case-series study. PLoS One. 2011; 6:e17251. https://doi.org/10.1371/journal.pone.0017251 [PubMed]
• 63. Eliassen AH, Spiegelman D, Hollis BW, Horst RL, Willett WC, Hankinson SE. Plasma 25-hydroxyvitamin D and risk of breast cancer in the Nurses’ Health Study II. Breast Cancer Res. 2011; 13:R50. https://doi.org/10.1186/bcr2880 [PubMed]
• 64. Budhathoki S, Hidaka A, Yamaji T, Sawada N, Tanaka-Mizuno S, Kuchiba A, Charvat H, Goto A, Kojima S, Sudo N, Shimazu T, Sasazuki S, Inoue M, et al, and Japan Public Health Center-based Prospective Study Group. Plasma 25-hydroxyvitamin D concentration and subsequent risk of total and site specific cancers in Japanese population: large case-cohort study within Japan Public Health Center-based Prospective Study cohort. BMJ. 2018; 360:k671. https://doi.org/10.1136/bmj.k671 [PubMed]
• 65. Colagar AH, Firouzjah HM, Halalkhor S, Vitamin D. Vitamin D Receptor Poly(A) Microsatellite Polymorphism and 25-Hydroxyvitamin D Serum Levels: Association with Susceptibility to Breast Cancer. J Breast Cancer. 2015; 18:119–25. https://doi.org/10.4048/jbc.2015.18.2.119 [PubMed]
• 66. Yousef FM, Jacobs ET, Kang PT, Hakim IA, Going S, Yousef JM, Al-Raddadi RM, Kumosani TA, Thomson CA. Vitamin D status and breast cancer in Saudi Arabian women: case-control study. Am J Clin Nutr. 2013; 98:105–10. https://doi.org/10.3945/ajcn.112.054445 [PubMed]
• 67. Chen P, Li M, Gu X, Liu Y, Li X, Li C, Wang Y, Xie D, Wang F, Yu C, Li J, Chen X, Chu R, et al. Higher blood 25(OH)D level may reduce the breast cancer risk: evidence from a Chinese population based case-control study and meta-analysis of the observational studies. PLoS One. 2013; 8:e49312. https://doi.org/10.1371/journal.pone.0049312 [PubMed]
• 68. Atoum MF, Al-Khatib YM. Association between Serum 25-hydroxy Vitamin D Concentration and TaqI Vitamin D Receptor Gene Polymorphism among Jordanian Females with Breast Cancer. Chin Med J (Engl). 2017; 130:1074–78. https://doi.org/10.4103/0366-6999.204933 [PubMed]
• 69. Jamshidinaeini Y, Akbari ME, Abdollahi M, Ajami M, Davoodi SH. Vitamin D Status and Risk of Breast Cancer in Iranian Women: A Case-Control Study. J Am Coll Nutr. 2016; 35:639–46. https://doi.org/10.1080/07315724.2015.1127786 [PubMed]
• 70. Alipour S, Hadji M, Hosseini L, Omranipour R, Saberi A, Seifollahi A, Bayani L, Shirzad N. Levels of serum 25-hydroxy-vitamin d in benign and malignant breast masses. Asian Pac J Cancer Prev. 2014; 15:129–32. https://doi.org/10.7314/APJCP.2014.15.1.129 [PubMed]
• 71. Bidgoli SA, Azarshab H. Role of vitamin D deficiency and lack of sun exposure in the incidence of premenopausal breast cancer: a case control study in Sabzevar, Iran. Asian Pac J Cancer Prev. 2014; 15:3391–96. https://doi.org/10.7314/APJCP.2014.15.8.3391 [PubMed]
• 72. Imtiaz S, Siddiqui N, Raza SA, Loya A, Muhammad A. Vitamin D deficiency in newly diagnosed breast cancer patients. Indian J Endocrinol Metab. 2012; 16:409–13. https://doi.org/10.4103/2230-8210.95684 [PubMed]
• 73. Sofi NY, Jain M, Kapil U, Seenu V, Kamal VK, Pandey RM. Nutritional risk factors and status of serum 25(OH)D levels in patients with breast cancer: A case control study in India. J Steroid Biochem Mol Biol. 2018; 175:55–59. https://doi.org/10.1016/j.jsbmb.2016.09.020 [PubMed]
• 74. Sofi NY, Jain M, Kapil U, Seenu V, R L, Yadav CP, Pandey RM, Sareen N. Reproductive factors, nutritional status and serum 25(OH)D levels in women with breast cancer: A case control study. J Steroid Biochem Mol Biol. 2018; 175:200–04. https://doi.org/10.1016/j.jsbmb.2017.11.003 [PubMed]
• 75. Park S, Lee DH, Jeon JY, Ryu J, Kim S, Kim JY, Park HS, Kim SI, Park BW. Serum 25-hydroxyvitamin D deficiency and increased risk of breast cancer among Korean women: a case-control study. Breast Cancer Res Treat. 2015; 152:147–54. https://doi.org/10.1007/s10549-015-3433-0 [PubMed]
• 76. Anderson LN, Cotterchio M, Kirsh VA, Knight JA. Ultraviolet sunlight exposure during adolescence and adulthood and breast cancer risk: a population-based case-control study among Ontario women. Am J Epidemiol. 2011; 174:293–304. https://doi.org/10.1093/aje/kwr091 [PubMed]
• 77. Amir E, Cecchini RS, Ganz PA, Costantino JP, Beddows S, Hood N, Goodwin PJ. 25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1. Breast Cancer Res Treat. 2012; 133:1077–88. https://doi.org/10.1007/s10549-012-2012-x [PubMed]
• 78. Bilinski K, Boyages J. Association between 25-hydroxyvitamin D concentration and breast cancer risk in an Australian population: an observational case-control study. Breast Cancer Res Treat. 2013; 137:599–607. https://doi.org/10.1007/s10549-012-2381-1 [PubMed]
• 79. Oliveira Sediyama CM, Dias MM, Pessoa MC, Queiroz AR, Suhett LG, Freitas RN, De Paula SO, Peluzio MD. Lifestyle and vitamin D dosage in women with breast cancer. Nutr Hosp. 2016; 33:584. https://doi.org/10.20960/nh.584 [PubMed]
• 80. Scarmo S, Afanasyeva Y, Lenner P, Koenig KL, Horst RL, Clendenen TV, Arslan AA, Chen Y, Hallmans G, Lundin E, Rinaldi S, Toniolo P, Shore RE, Zeleniuch-Jacquotte A. Circulating levels of 25-hydroxyvitamin D and risk of breast cancer: a nested case-control study. Breast Cancer Res. 2013; 15:R15. https://doi.org/10.1186/bcr3390 [PubMed]
• 81. Wu Y, Sarkissyan M, Clayton S, Chlebowski R, Vadgama JV. Association of Vitamin D3 Level with Breast Cancer Risk and Prognosis in African-American and Hispanic Women. Cancers (Basel). 2017; 9:E144. https://doi.org/10.3390/cancers9100144 [PubMed]
• 82. Kim Y, Franke AA, Shvetsov YB, Wilkens LR, Cooney RV, Lurie G, Maskarinec G, Hernandez BY, Le Marchand L, Henderson BE, Kolonel LN, Goodman MT. Plasma 25-hydroxyvitamin D3 is associated with decreased risk of postmenopausal breast cancer in whites: a nested case-control study in the multiethnic cohort study. BMC Cancer. 2014; 14:29. https://doi.org/10.1186/1471-2407-14-29 [PubMed]
• 83. Veldhuis S, Wolbers F, Brouckaert O, Vermes I, Franke HR. Cancer prevalence in osteoporotic women with low serum vitamin D levels. Menopause. 2011; 18:319–22. https://doi.org/10.1097/gme.0b013e3181f81ad5 [PubMed]
• 84. Grant WB. A Review of the Evidence Supporting the Vitamin D-Cancer Prevention Hypothesis in 2017. Anticancer Res. 2018; 38:1121–36. https://doi.org/10.21873/anticanres.12331 [PubMed]
• 85. Gilbert R, Bonilla C, Metcalfe C, Lewis S, Evans DM, Fraser WD, Kemp JP, Donovan JL, Hamdy FC, Neal DE, Lane JA, Smith GD, Lathrop M, Martin RM. Associations of vitamin D pathway genes with circulating 25-hydroxyvitamin-D, 1,25-dihydroxyvitamin-D, and prostate cancer: a nested case-control study. Cancer Causes Control. 2015; 26:205–18. https://doi.org/10.1007/s10552-014-0500-5 [PubMed]
• 86. Chandler PD, Buring JE, Manson JE, Giovannucci EL, Moorthy MV, Zhang S, Lee IM, Lin JH. Circulating Vitamin D Levels and Risk of Colorectal Cancer in Women. Cancer Prev Res (Phila). 2015; 8:675–82. https://doi.org/10.1158/1940-6207.CAPR-14-0470 [PubMed]
• 87. McCullough ML, Zoltick ES, Weinstein SJ, Fedirko V, Wang M, Cook NR, Eliassen AH, Zeleniuch-Jacquotte A, Agnoli C, Albanes D, Barnett MJ, Buring JE, Campbell PT, et al. Circulating Vitamin D and Colorectal Cancer Risk: An International Pooling Project of 17 Cohorts. J Natl Cancer Inst. 2019; 111:158–69. https://doi.org/10.1093/jnci/djy087 [PubMed]
• 88. Gao J, Wei W, Wang G, Zhou H, Fu Y, Liu N. Circulating vitamin D concentration and risk of prostate cancer: a dose-response meta-analysis of prospective studies. Ther Clin Risk Manag. 2018; 14:95–104. https://doi.org/10.2147/TCRM.S149325 [PubMed]
• 89. Cattaruzza MS, Pisani D, Fidanza L, Gandini S, Marmo G, Narcisi A, Bartolazzi A, Carlesimo M. 25-Hydroxyvitamin D serum levels and melanoma risk: a case-control study and evidence synthesis of clinical epidemiological studies. Eur J Cancer Prev. 2019; 28:203–11. https://doi.org/10.1097/CEJ.0000000000000437 [PubMed]
• 90. Colston K, Colston MJ, Feldman D. 1,25-dihydroxyvitamin D3 and malignant melanoma: the presence of receptors and inhibition of cell growth in culture. Endocrinology. 1981; 108:1083–86. https://doi.org/10.1210/endo-108-3-1083 [PubMed]
• 91. Huhtakangas JA, Veijola J, Turunen S, Karjalainen A, Valkealahti M, Nousiainen T, Yli-Luukko S, Vuolteenaho O, Lehenkari P. 1,25(OH)₂D₃ and calcipotriol, its hypocalcemic analog, exert a long-lasting anti-inflammatory and anti-proliferative effect in synoviocytes cultured from patients with rheumatoid arthritis and osteoarthritis. J Steroid Biochem Mol Biol. 2017; 173:13–22. https://doi.org/10.1016/j.jsbmb.2017.01.017 [PubMed]
• 92. Chen L, Yang R, Qiao W, Yuan X, Wang S, Goltzman D, Miao D. 1,25-Dihydroxy vitamin D prevents tumorigenesis by inhibiting oxidative stress and inducing tumor cellular senescence in mice. Int J Cancer. 2018; 143:368–82. https://doi.org/10.1002/ijc.31317 [PubMed]
• 93. Kim Y, Je Y. Vitamin D intake, blood 25(OH)D levels, and breast cancer risk or mortality: a meta-analysis. Br J Cancer. 2014; 110:2772–84. https://doi.org/10.1038/bjc.2014.175 [PubMed]
• 94. Crew KD, Anderson GL, Hershman DL, Terry MB, Tehranifar P, Lew DL, Yee M, Brown EA, Kairouz SS, Kuwajerwala N, Bevers T, Doster JE, Zarwan C, et al. Randomized Double-Blind Placebo-Controlled Biomarker Modulation Study of Vitamin D Supplementation in Premenopausal Women at High Risk for Breast Cancer (SWOG S0812). Cancer Prev Res (Phila). 2019; 12:481–90. https://doi.org/10.1158/1940-6207.CAPR-18-0444 [PubMed]
• 95. Li J, Li B, Jiang Q, Zhang Y, Liu A, Wang H, Zhang J, Qin Q, Hong Z, Li BA. Do genetic polymorphisms of the vitamin D receptor contribute to breast/ovarian cancer? A systematic review and network meta-analysis. Gene. 2018; 677:211–27. https://doi.org/10.1016/j.gene.2018.07.070 [PubMed]
• 96. Shi J, Grundy A, Richardson H, Burstyn I, Schuetz JM, Lohrisch CA, SenGupta SK, Lai AS, Brooks-Wilson A, Spinelli JJ, Aronson KJ. Genetic variation in vitamin D-related genes and risk of breast cancer among women of European and East Asian descent. Tumour Biol. 2016; 37:6379–87. https://doi.org/10.1007/s13277-015-4417-8 [PubMed]
• 97. Shahbazi S, Alavi S, Majidzadeh-A K, Ghaffarpour M, Soleimani A, Mahdian R. BsmI but not FokI polymorphism of VDR gene is contributed in breast cancer. Med Oncol. 2013; 30:393. https://doi.org/10.1007/s12032-012-0393-7 [PubMed]
• 98. Wang J, Eliassen AH, Spiegelman D, Willett WC, Hankinson SE. Plasma free 25-hydroxyvitamin D, vitamin D binding protein, and risk of breast cancer in the Nurses’ Health Study II. Cancer Causes Control. 2014; 25:819–27. https://doi.org/10.1007/s10552-014-0383-5 [PubMed]
• 99. Vojdeman FJ, Madsen CM, Frederiksen K, Durup D, Olsen A, Hansen L, Heegaard AM, Lind B, Tjønneland A, Jørgensen HL, Schwarz P. Vitamin D levels and cancer incidence in 217,244 individuals from primary health care in Denmark. Int J Cancer. 2019; 145:338–46. https://doi.org/10.1002/ijc.32105 [PubMed]
• 100. Stang A. Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol. 2010; 25:603–05. https://doi.org/10.1007/s10654-010-9491-z [PubMed]
• 101. Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med. 2002; 21:1539–58. https://doi.org/10.1002/sim.1186 [PubMed]
• 102. DerSimonian R, Laird N. Meta-analysis in clinical trials revisited. Contemp Clin Trials. 2015; 45:139–45. https://doi.org/10.1016/j.cct.2015.09.002 [PubMed]
• 103. Greenland S, Longnecker MP. Methods for trend estimation from summarized dose-response data, with applications to meta-analysis. Am J Epidemiol. 1992; 135:1301–09. https://doi.org/10.1093/oxfordjournals.aje.a116237 [PubMed]
• 104. Liu Q, Cook NR, Bergström A, Hsieh CC. A two-stage hierarchical regression model for meta-analysis of epidemiologic nonlinear dose–response data. Comput Stat Data Anal. 2009; 53:4157–67. https://doi.org/10.1016/j.csda.2009.05.001
• 105. Orsini N, Li R, Wolk A, Khudyakov P, Spiegelman D. Meta-analysis for linear and nonlinear dose-response relations: examples, an evaluation of approximations, and software. Am J Epidemiol. 2012; 175:66–73. https://doi.org/10.1093/aje/kwr265 [PubMed]