On 2015 Jan 07, William Grant commented:

Differences in 25-hydroxyvitamin D concentrations may explain some of the black-white disparity in endometrial cancer prevalence in the United States

The paper by Cote and colleagues examined risk factors for endometrial cancer in an effort to determine the cause of higher rates for blacks than for whites [1]. Overlooked in this paper was any discussion of the possible role of solar UVB exposure and vitamin D in reducing risk. This comment presents the evidence for solar UVB exposure in reducing risk of endometrial cancer, with the most likely mechanism being production of vitamin D.

Geographical ecological studies provide the best evidence that solar UVB exposure reduces risk of endometrial cancer. An ecological study in the U.S. found a significant inverse correlation between July solar UVB doses and endometrial cancer mortality rates for white women in a multifactorial analysis [2]. (Maps of endometrial and other cancer mortality rates can be generated at http://ratecalc.cancer.gov/. A map of solar UVB doses for July 1992 can be found at www.sunarc.org. The maps for endometrial cancer for black women do not show the inverse correlation with respect to solar UVB doses, although there is a hint in that mortality rates are lowest in the southwest and higher in the east; the higher mortality rates in the southeast could be related to diet as well.) Ecological studies have also found inverse correlations between solar UVB and endometrial cancer in Spain [3] and France [4]. A study in Sweden found that women who used sunbeds or sunbathed in summer had significantly reduced risk of developing endometrial cancer [5].

The role of vitamin D in reducing risk of cancer in general is discussed in Ref. 6. In the U.S., the mean 25-hydroxyvitamin D [25(OH)D] concentrations for elderly black women in 2001-4 was 15 ng/mL while that for elderly white women was 25 ng/mL [7]. This difference was proposed as the explanation for black-white disparities in cancer survival rates after consideration of socioeconomic status, stage at diagnosis and treatment for 13 types of cancer including endometrial cancer [8]. Obesity, identified as a risk factor for endometrial cancer in Ref. 1, lowers 25(OH)D concentrations, and has been evaluated as a contributing risk factor for breast cancer in terms of lowering 25(OH)D concentrations [9]. However, it is noted that there is little direct evidence that vitamin D lowers risk of endometrial cancer [10]. On the other hand, there is a recent mouse model study of intestinal tumor growth and progression to malignancy finding that raising 25(OH)D concentrations to about 30 ng/mL by UVB exposure was more effective than doing the same with oral vitamin D [11].

Thus, women wishing to reduce their risk of endometrial cancer could consider spending more time in the sun, especially during midday when the UVB doses are highest, but not so long as to develop erythema, and taking vitamin D3 to raise 25(OH)D concentrations to 30-40 ng/mL.

References 1. Cote ML, Alhajj T, Ruterbusch JJ, Bernstein L, Brinton LA, Blot WJ, Chen C, Gass M, Gaussoin S, Henderson B, Lee E, Horn-Ross PL, Kolonel LN, Kaunitz A, Liang X, Nicholson WK, Park AB, Petruzella S, Rebbeck TR, Setiawan VW, Signorello LB, Simon MS, Weiss NS, Wentzensen N, Yang HP, Zeleniuch-Jacquotte A, Olson SH. Risk factors for endometrial cancer in black and white women: a pooled analysis from the epidemiology of endometrial cancer consortium (E2C2). Cancer Causes Control. 2014 Dec 23. [Epub ahead of print] 2. Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res. 2006;26(4A):2687-99. 3. Grant WB. An ecologic study of cancer mortality rates in Spain with respect to indices of solar UV irradiance and smoking. Int J Cancer. 2007;120(5):1123-7. 4. Grant WB. An ecological study of cancer incidence and mortality rates in France with respect to latitude, an index for vitamin D production. Dermatoendocrinol. 2010;2(2):62-7. 5. Epstein E, Lindqvist PG, Geppert B, Olsson H. A population-based cohort study on sun habits and endometrial cancer. Br J Cancer. 2009;101(3):537-40. 6. Moukayed M, Grant WB. Molecular link between vitamin D and cancer prevention. Nutrients. 2013;5(10):3993-4023. 7. Ginde AA, Liu MC, Camargo CA Jr. Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Arch Intern Med. 2009;169(6):626-32. 8. Grant WB, Peiris AN. Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans. Dermatoendocrinol. 2012;4(2):85-94. 9. Lagunova Z, Porojnicu AC, Grant WB, Bruland Ø, Moan JR. Obesity and increased risk of cancer: Does decrease of serum 25-hydroxyvitamin D level with increasing body mass index explain some of the association? Molec Nutr Food Res. 2010;54(8):1127-33. 10. Liu JJ, Bertrand KA, Karageorgi S, Giovannucci E, Hankinson SE, Rosner B, Maxwell L, Rodriguez G, De Vivo I. Prospective analysis of vitamin D and endometrial cancer risk. Ann Oncol. 2013;24(3):687-92. 11. Rebel H, der Spek CD, Salvatori D, van Leeuwen JP, Robanus-Maandag EC, de Gruijl FR.UV exposure inhibits intestinal tumour growth and progression to malignancy in intestine-specific Apc mutant mice kept on low vitamin D diet. Int J Cancer. 2015;136(2):271-7.

Disclosure I receive funding from Bio-Tech Pharmacal (Fayetteville, AR) and MediSun Technology (Highland Park, IL).

On 2015 Jan 07, William Grant commented:

Differences in 25-hydroxyvitamin D concentrations may explain some of the black-white disparity in endometrial cancer prevalence in the United States

The paper by Cote and colleagues examined risk factors for endometrial cancer in an effort to determine the cause of higher rates for blacks than for whites [1]. Overlooked in this paper was any discussion of the possible role of solar UVB exposure and vitamin D in reducing risk. This comment presents the evidence for solar UVB exposure in reducing risk of endometrial cancer, with the most likely mechanism being production of vitamin D.

Geographical ecological studies provide the best evidence that solar UVB exposure reduces risk of endometrial cancer. An ecological study in the U.S. found a significant inverse correlation between July solar UVB doses and endometrial cancer mortality rates for white women in a multifactorial analysis [2]. (Maps of endometrial and other cancer mortality rates can be generated at http://ratecalc.cancer.gov/. A map of solar UVB doses for July 1992 can be found at www.sunarc.org. The maps for endometrial cancer for black women do not show the inverse correlation with respect to solar UVB doses, although there is a hint in that mortality rates are lowest in the southwest and higher in the east; the higher mortality rates in the southeast could be related to diet as well.) Ecological studies have also found inverse correlations between solar UVB and endometrial cancer in Spain [3] and France [4]. A study in Sweden found that women who used sunbeds or sunbathed in summer had significantly reduced risk of developing endometrial cancer [5].

The role of vitamin D in reducing risk of cancer in general is discussed in Ref. 6. In the U.S., the mean 25-hydroxyvitamin D [25(OH)D] concentrations for elderly black women in 2001-4 was 15 ng/mL while that for elderly white women was 25 ng/mL [7]. This difference was proposed as the explanation for black-white disparities in cancer survival rates after consideration of socioeconomic status, stage at diagnosis and treatment for 13 types of cancer including endometrial cancer [8]. Obesity, identified as a risk factor for endometrial cancer in Ref. 1, lowers 25(OH)D concentrations, and has been evaluated as a contributing risk factor for breast cancer in terms of lowering 25(OH)D concentrations [9]. However, it is noted that there is little direct evidence that vitamin D lowers risk of endometrial cancer [10]. On the other hand, there is a recent mouse model study of intestinal tumor growth and progression to malignancy finding that raising 25(OH)D concentrations to about 30 ng/mL by UVB exposure was more effective than doing the same with oral vitamin D [11].

Thus, women wishing to reduce their risk of endometrial cancer could consider spending more time in the sun, especially during midday when the UVB doses are highest, but not so long as to develop erythema, and taking vitamin D3 to raise 25(OH)D concentrations to 30-40 ng/mL.

References 1. Cote ML, Alhajj T, Ruterbusch JJ, Bernstein L, Brinton LA, Blot WJ, Chen C, Gass M, Gaussoin S, Henderson B, Lee E, Horn-Ross PL, Kolonel LN, Kaunitz A, Liang X, Nicholson WK, Park AB, Petruzella S, Rebbeck TR, Setiawan VW, Signorello LB, Simon MS, Weiss NS, Wentzensen N, Yang HP, Zeleniuch-Jacquotte A, Olson SH. Risk factors for endometrial cancer in black and white women: a pooled analysis from the epidemiology of endometrial cancer consortium (E2C2). Cancer Causes Control. 2014 Dec 23. [Epub ahead of print] 2. Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res. 2006;26(4A):2687-99. 3. Grant WB. An ecologic study of cancer mortality rates in Spain with respect to indices of solar UV irradiance and smoking. Int J Cancer. 2007;120(5):1123-7. 4. Grant WB. An ecological study of cancer incidence and mortality rates in France with respect to latitude, an index for vitamin D production. Dermatoendocrinol. 2010;2(2):62-7. 5. Epstein E, Lindqvist PG, Geppert B, Olsson H. A population-based cohort study on sun habits and endometrial cancer. Br J Cancer. 2009;101(3):537-40. 6. Moukayed M, Grant WB. Molecular link between vitamin D and cancer prevention. Nutrients. 2013;5(10):3993-4023. 7. Ginde AA, Liu MC, Camargo CA Jr. Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Arch Intern Med. 2009;169(6):626-32. 8. Grant WB, Peiris AN. Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans. Dermatoendocrinol. 2012;4(2):85-94. 9. Lagunova Z, Porojnicu AC, Grant WB, Bruland Ø, Moan JR. Obesity and increased risk of cancer: Does decrease of serum 25-hydroxyvitamin D level with increasing body mass index explain some of the association? Molec Nutr Food Res. 2010;54(8):1127-33. 10. Liu JJ, Bertrand KA, Karageorgi S, Giovannucci E, Hankinson SE, Rosner B, Maxwell L, Rodriguez G, De Vivo I. Prospective analysis of vitamin D and endometrial cancer risk. Ann Oncol. 2013;24(3):687-92. 11. Rebel H, der Spek CD, Salvatori D, van Leeuwen JP, Robanus-Maandag EC, de Gruijl FR.UV exposure inhibits intestinal tumour growth and progression to malignancy in intestine-specific Apc mutant mice kept on low vitamin D diet. Int J Cancer. 2015;136(2):271-7.

Disclosure I receive funding from Bio-Tech Pharmacal (Fayetteville, AR) and MediSun Technology (Highland Park, IL).